Meetings between Chinese and American leaders are not exactly routine, but few are historically groundbreaking.
The exceptions include the very first visit by a sitting U.S. president to China, when Richard Nixon met with Chairman Mao Zedong in Beijing in February 1972 – at a time when America did not even formally recognize the People’s Republic of China. Deng Xiaoping’s visit to the U.S. in 1979 generated a similarly iconic moment when the reformist Chinese leader donned a Stetson at a Texas rodeo, a sign that he would be willing to engage with America in a way that Mao contemplated only near the end of his life.
Donald Trump may harbor hopes that his upcoming visit, slated for May 14-15, 2026, could have similar historical significance to those moments half a century ago. It will, after all, be the first face-to-face meeting of U.S. and Chinese leaders in Beijing since Trump’s own visit nearly a decade ago in 2017.
Chinese Communist Party Chairman Mao Zedong welcomes U.S. President Richard Nixon to his house in Beijing in 1972.AFP via Getty Images
Yet the outcomes of this Trump summit with Xi Jinping are likely to be vague because the goals for both leaders are also only partially evident. The visit is being driven by trade imperatives, but there are other issues that threaten U.S.-China relations in the longer term.
It will be extremely hard for the two sides to address these more deep-rooted divides. Indeed, as an analyst of U.S.-China relations, I believe the world’s two largest economies will have an essentially competitive relationship for years to come, and areas of plausible cooperation – whether on climate change or AI regulation – are increasingly hard to find.
Taiwan: A change in US position?
One area that has been a source of contention for quite some time is Taiwan. Xi has made it clear that the unification of the island with the mainland cannot be left to “another generation” but has left it vague – up to now – as to how that goal will be achieved.
The summit has been preceded by lots of chatter about U.S. preparedness to honor its somewhat ambiguous promise to defend Taiwan in the event of an invasion – with Chinese analysts concluding that the war in Iran has severely weakened Washington’s capabilities on this front.
However, there are plenty of signs that Xi would rather find peaceful means to unite with Taiwan that avoid all-out war, particularly as the examples of Russia in Ukraine and the U.S. in Iran show that the outcomes of wars are not predictable.
Instead, China has seemingly concentrated its efforts on influencing the upcoming January 2028 Taiwan presidential election. The leader of the island’s major opposition Kuomintang party, Cheng Li-wun, recently visited the mainland and had a photo op with Xi – a sign that she thinks dealmaking with China might just be acceptable to the Taiwan electorate despite its deep distrust of Beijing.
To further fuel the narrative of a seemingly inevitable path toward unification, it would be helpful for Xi to have signals that the U.S. is no longer committed to defending Taiwan.
China will push for a change from the official position that the U.S. “does not support Taiwan independence” to “the U.S. opposes Taiwan independence.” The latter change sounds minor but would have great significance, as it would essentially be an acknowledgment that the U.S. recognizes unification, by some means, as a legitimate goal in its own right.
Taiwan’s ruling Democratic Progressive Party does not specifically endorse independence, as it knows that’s a red line for Beijing, but it would regard this change in American language as a serious blow to its position. It’s unlikely that the U.S. would make such a major concession during Trump’s visit – but that won’t stop Beijing from asking for it.
AI: The battle for global leadership
A more tentative but increasingly important area for discussion during the Xi-Trump summit is technology in general and AI in particular.
Just three years ago, the attitude of the U.S. government was summed up in the phrase of then national security adviser Jake Sullivan: “small yard, high fence.”
In other words, there would be only a few restricted areas of technology, but they would be fiercely guarded.
In 2026, things have changed. In some areas, tech restrictions have just become looser; the U.S. government now permits the sale to China of some high-specification, American-manufactured chips that were previously restricted. That policy was probably driven by the sense that China was developing its own domestic alternatives anyway and that the U.S. was losing market share.
Yet there is growing concern both in the U.S. and China that AI developments are moving too fast for governments – or companies – to know fully what the technology is capable of doing, let alone being able to regulate it.
China and the U.S. both desire to dominate AI and set the global norms and standards surrounding it. But they are also aware that AI has the potential to cause immense damage.
There has been loose discussion of whether any joint form of supervision or regulation of AI between the U.S. and China might be possible. And that could well form part of the discussions during the leaders’ summit.
But realistically, both sides see themselves in fierce competition, and the likelihood that either American or Chinese companies would restrain themselves may be fanciful.
The trade elephant in the room
The most substantial achievements of the summit, however, are likely to be in the least glamorous area: remedying the trade deficit.
U.S. first lady Melania Trump, Donald Trump, Chinese President Xi Jinping and his wife, Peng Liyuan, in West Palm Beach, Fla., on April 6, 2017.Jim Watson /AFP via Getty Images
While there are many American products that China would like to buy, most of them are not products that the U.S. government is willing to let them have, including high-tech equipment that could be used for military purposes.
Instead, the key products are likely to be agricultural, including U.S. soybeans and beef. Look out for concessions from China that would benefit farmers in key Republican states, such as Iowa.
The current tariff dispute between the U.S. and China has frozen into a standoff: The U.S. has agreed to allow China’s goods into its immense market at manageable tariff rates, and China has – mostly – agreed to allow critical minerals and rare earths to flow to U.S. manufacturers.
That truce lasts until October, but the summit may see it extended.
Neither side is keen to restart the trade war that marked the summer of 2025, when Trump announced tariffs of over 100% on China and the U.S. was in danger of having key mineral supplies cut off as a result.
Summit to talk about? Perhaps not
So how consequential will the Trump-Xi summit be? Well, don’t expect another “Nixon meets Mao” moment.
The circumstances more than a half-century on are also remarkably different. Today’s China, unlike in 1972, has an economy and military second only to the U.S. and a central position in global organizations, from the United Nations to the World Trade Organization, particularly as the U.S. retreats from such institutions.
Both the U.S. and Chinese sides know that they can expect limited cooperation at best from their opponent.
But after a period, particularly during the COVID-19 pandemic, when communication between the countries atrophied, it’s still important that they are talking at all.
Rana Mitter does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
Four percent of Americans – roughly 12 million people – believe that “lizard people” secretly control the Earth. At least, that was the finding of an infamous 2013 public opinion survey.
Do so many people really believe such outlandish claims? Or do results like these partly reflect people giving silly answers or deliberately skewing surveys for fun?
US psychiatrist Alexander Scott believes the latter plays a significant role.
Using the survey as an example, he coined the term “the Lizardman constant” to describe the idea that a certain amount of noise and trolling will always exist in surveys about unusual beliefs.
As Scott warned: “Any possible source of noise – jokesters, cognitive biases, or deliberate misbehaviour – can easily overwhelm the signal.”
As researchers who study uncommon beliefs such as conspiracy theories, we wanted to investigate how this kind of cheeky trolling can muddy the waters.
We did this in two ways. First, we directly asked people a yes/no question at the end of the survey:
“Did you respond insincerely at any earlier point in this survey? In other words, did you give any responses that were actually just joking, trolling, or otherwise not indicating what you really think?”
Second, we included in the survey a “conspiracy theory” so ridiculous we could assume most, if not all, people who said they believed it were taking the mickey.
We asked them if they believed:
The Canadian Armed Forces have been secretly developing an elite army of genetically engineered, super intelligent, giant raccoons to invade nearby countries.
In our representative online sample of 810 New Zealanders, 8.3% of respondents confessed to being insincere in the survey.
Another 7.2% said they thought the Canadian raccoon army theory was probably or definitely true. That proportion – similar to findings from Australia – would equate to more than 300,000 adult New Zealanders.
To complicate things slightly, there was some overlap between those admitting to insincere answers and those claiming to believe the raccoon conspiracy. Combined, 13.3% of respondents fell into one or both groups – roughly one in eight people not appearing to take the survey seriously.
Importantly, these respondents were also much more likely to endorse other conspiracy theories, inflating estimates of how widespread those beliefs really are.
For instance, 6.5% of the full sample endorsed the claim that governments around the world are covering up the fact that 5G mobile networks spread coronavirus.
But once we removed the insincere responders, that figure dropped by more than half to 2.7%.
Across 13 different conspiracy theories, the estimated proportion of believers fell substantially once those respondents were excluded.
Another interesting insight from our study was that people endorsing contradictory conspiracy theories were much more likely to show signs of responding insincerely.
Previous studies have found some people appear to believe conspiracy theories that directly contradict each other. In our survey, for example, some participants agreed both that COVID-19 is a myth and that governments are covering up the fact that 5G networks spread the virus.
But nearly three-quarters of those respondents also showed signs of joking or dishonest answers.
This suggests genuinely believing contradictory conspiracy theories may be less common than previously thought.
Not every conspiracy believer is joking
Our findings add further weight to the idea that surveys may overestimate how many people truly believe some conspiracy theories – thanks, in part, to trolls.
But does that mean all conspiracy theory research is bunk?
Fortunately not. Most research in this area is not focused on counting conspiracy believers, but on understanding why people hold these beliefs and what effects they can have.
We tested several well-established findings from earlier conspiracy theory research to see whether they still held up once insincere respondents were removed from the data.
For example, previous studies have found that people who endorse conspiracy theories are more likely to see the world as a dangerous and threatening place.
We found the same pattern. In fact, removing insincere respondents made little difference to the broader relationships identified in earlier research.
Nevertheless, we recommend that future surveys include ways to gauge whether respondents are answering sincerely and account for this in the analysis. At the very least, researchers should acknowledge that trolls and joking responses can distort their results.
While our research suggests some people are taking the mickey in surveys, it also shows a significant minority genuinely appear to believe some of these claims.
In some cases – such as believing authorities are covering up the fact that the Earth is flat – this may be relatively harmless. But other conspiracy beliefs can lead to real-world harm.
Good-quality research is essential for understanding how sincere believers end up down these rabbit holes, and how those beliefs influence real-world behaviour.
Research into why people embrace conspiracy theories – and the real-world consequences of those beliefs – remains important.
But when surveys suggest millions may believe in lizard overlords or genetically engineered raccoon armies, it is also worth remembering the “Lizardman constant”: some respondents may simply be having us on.
The authors acknowledge the contributions of Rob Ross, Mathew Ling and Stephen Hill to this article.
John Kerr is supported by a Royal Society Te Apārangi Mana Tūānuku Research Leader Fellowship.
This research was supported by the Marsden Fund Council from Government funding, managed by Royal Society Te Apārangi.
Mathew Marques does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
The outrage was swift and severe when the U.S. Supreme Court, by an ideologically divided 6-3 vote, recently struck down Louisiana’s majority Black congressional district as an unconstitutional racial gerrymander. Critics lambasted the court for gutting the Voting Rights Act, the federal law that had until recently garnered strong bipartisan support and had ensured Black political representation in the South for more than half a century.
Whether Louisiana v. Callais will wreak this kind of havoc remains to be seen, although some Southern states have already begun to redraw their legislative districts, aiming to ensure Republican control. Several Black legislators – all Democrats – are expected to lose their seats in the upcoming midterm elections. Democrats are threatening to retaliate with their own redistricting plans.
Because of a 2019 decision by the court, such political gerrymanders, where a legislative district is crafted to ensure partisan control, cannot be challenged under federal law. Both parties had taken full advantage of that ruling.
Prior to the Callais ruling, however, legislators had to be sure that when they sought partisan control of a district, they did not excessively dilute the voting power of minority residents. Multiple lawsuits had challenged political gerrymanders on exactly these grounds.
After Callais, that guardrail is gone. Indeed, lest they provoke the same type of litigation faced by Louisiana, state legislators must now ignore the race of voters altogether. From here on out, gerrymandering is fine, but only if it’s race-neutral.
This does not mean, however, that the race-blind mapmaking process envisioned by the Supreme Court majority will manifest. Based on our recently published research, it may, in fact, be just the opposite.
Race, we found, is – at least in the South – a more reliable predictor of how someone will vote than their party identification. And that makes race, we believe, a potentially irresistible lure for those designing congressional districts.
In 1972, Andrew Young, left, was the first Black person to be elected to Congress from the deep South since Reconstruction.AP Photo
Race a more reliable predictor
We are both political scientists – one of us an expert on Congress and national elections and the other a constitutional law and Supreme Court scholar. In Southern states, race and political party overlap significantly, with the vast majority of Black voters favoring Democrats and most white voters favoring Republicans. And in our study, we document that in this region, mapmakers actually have an incentive to take race into account when conducting a political gerrymander.
Political gerrymandering is the process of drawing electoral districts to favor one party over another. In most states, the responsibility for drawing districts rests with the state legislature. Thus, the party that controls state legislatures very often controls elections – at both the state and congressional level.
The goal of partisan redistricting is to maximize the chance that candidates from that political party will win elections. Our study shows that using both the race and party of voters to redraw districts, rather than just party alone, better ensures partisan advantage.
The research we conducted was motivated by a claim made by Justice Samuel Alito in another recent racial gerrymandering case decided by the Supreme Court, Alexander vs. South Carolina NAACP. He argued in the court’s majority opinion that when drawing districts to favor one party, mapmakers would need to look only at voters’ party affiliation – their race would be irrelevant to ensuring partisan control.
It is a straightforward, seemingly sensible claim. It is also wrong.
Our study uses an original dataset of precinct-level election results in South Carolina from 2010 to 2020 to explore how well a precinct’s racial and partisan composition before redistricting predicts how it votes over the following decade.
What we found reveals a more complicated picture than Alito – and the subsequent Callais decision – presumes.
A precinct’s Democratic and Republican vote share prior to redistricting was the strongest predictor of future election results. But there are two problems with relying on only such partisan data when gerrymandering a district.
First, our analysis showed that roughly a quarter of a precinct’s voters in the next election did not follow what the partisan data predicted – a sizable amount, given the supposed ease of gerrymandering by party.
Second, precinct election results are surprisingly volatile. Our analysis shows that the effect of preredistricting partisanship varies with election cycles, national conditions, gradual changes in party coalitions and other factors. A precinct that leaned Republican in the election before redistricting may vote very differently in a midterm wave year when the president is unpopular, precisely the type of election coming in November.
By comparison, the analysis shows that voters’ race is a more reliable predictor than their party of how they will vote in the next election. Consequently, it seems that, at least in Southern states, legislators have a genuine, data-driven incentive to use racial data when drawing partisan districts.
Republicans in South Carolina want to draw a new congressional map, and it could eliminate the district that has for decades elected Democrat Jim Clyburn.Kevin Wolf/AP Photo
Will race still affect political gerrymanders?
Consider this redistricting scenario: South Carolina’s Republican-led legislature wants to flip the state’s lone Democratic congressional seat – long held by prominent African American U.S. Rep. Jim Clyburn – for the 2026 midterms. A simple approach is to identify those who voted for Donald Trump in 2024 and then just redraw the district to add enough of those voters to ensure Republican control.
The plan backfires, however. Not only does Clyburn hold his seat, but a neighboring district also elects a Democrat. What went wrong?
Simply put, the legislature failed to realize that past partisan returns are an imperfect predictor of future voting behavior.
A heavily Democratic area that is predominantly Black will vote Democratic far more consistently than a heavily Democratic area that is predominantly white. Two precincts that look identical on a partisan map can behave very differently at the ballot box. And a legislature that fails to take this into account has taken an unreliable route to partisan advantage.
If Republican legislators want to oust Democratic officials, the most reliable route is to oust from a district the minority Democratic voters who would have elected them.
This is not to suggest that legislators should use race in this way. It certainly smacks of racism and echoes the type of electoral machinations used during Jim Crow. But that analogy is not exactly on point. The approach we identified targets the power of Black voters not because they are Black, but because they are such reliable Democrats.
To many, that may be a difference that makes no difference. More litigation over gerrymanders is inevitable. If litigants can demonstrate that race was a “predominant” factor that “drove” redistricting, or that mapmakers purposefully attempted to diminish the power of Black voters because of their race, legal liability can still follow.
Voting rights advocates should be aware of the temptation legislators may have to let race affect their political gerrymanders.
Perhaps minority voters are as free from invidious discrimination as Alito’s majority opinion in the Callais case suggests. This does not mean, however, that those charged with ensuring all voters are fairly represented in American democracy will be colorblind. Our findings show that race could easily remain embedded in the political gerrymandering landscape, despite vehement claims to the contrary.
Jordan Ragusa has served as an expert witness in racial gerrymandering litigation, most notably in Alexander v. South Carolina State Conference of the NAACP. He also serves on the advisory board of Charleston Civil Rights and Civics (C3), an educational non-profit that fosters civic engagement and civil rights awareness among high school students
Claire B. Wofford does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
Focusing on the word “rights” hides something more serious underneath: how people live and survive in this situation. What’s unfolding in Afghanistan is not just a women’s rights crisis, but a humanitarian disaster.
It affects how people access health care, education, food systems and basic supports and whether these system can function at all when half the population has been systematically removed from them. It forces families to deal with women’s limited access to work and services, often pushing households into deeper economic and social vulnerability.
The Taliban has steadily removed women from public spaces including work, health care and education. Recently, for example, female health-care workers were stopped at the gates of a United Nations office and banned from entering the facility by Taliban authorities.
These ongoing removals are incrementally creating a system that determines who has the right to exist, to provide assistance and to receive assistance.
What’s happening in Afghanistan is not simply gender discrimination; rather, it’s pushing an entire gender out of public systems altogether. The predicament of Afghan women is less a social problem and more a structural crisis that shapes institutions and everyday life.
Gender apartheid
This is why the situation in Afghanistan is increasingly referred to as a form of gender apartheid rather than a women’s rights crisis. The exclusion of women reveals how institutions are built and will be maintained in the future.
Gender apartheid refers to a situation in which people are banned from certain spaces or activities based on their gender identity.
Its effects are also accumulative, with each restriction reinforcing others and deepening the overall crisis. These systemic rights violations would be increasingly difficult to reverse even if political bodies and the ruling government changed tomorrow.
That’s because removing women from professional spaces leads to schools losing teachers, hospitals losing trained staff and aid networks losing access to half the population. And this loss isn’t temporary; it limits how systems can respond to the growing needs around them.
When women get barred from institutions, the problem isn’t just that these organizations suffer in their service delivery and performance. It also results in the loss of institutional memory — the skills, professional knowledge and experience that is no longer transferred to future generations.
Over time, institutions also scale down or suspend certain services due to a shortage of female workers. As services shrink, significant gaps appear in the networks of care and support leaving entire groups of people without consistent access to support.
Blocking aid and support
The Taliban refusal to allow female workers into UN and UNICEF offices is one of many examples happening today in Afghanistan that ban qualified women from entering places where they can deliver urgent care and assistance.
Taliban rule consequently delays or prevents life-saving interventions for women and children, a violation of the human right to survive.
It’s not just UN and UNICEF offices where women workers are banned from entry: they’re being turned away at other aid organizations, hospitals, schools and various public institutions in a widespread erosion of human rights. The Taliban has put in place a network of human rights violations across the entire humanitarian system.
Humanitarian aid also depends on access to information and correct data: who is hungry, who is unsafe and who needs protection. In Afghanistan, where women are limited in who they can interact with and where female staff are largely absent from outreach, surveys and home visits, this information becomes incomplete.
Poor data leads to incomplete distribution of assistance and mismatched allocation of aid. As a result, the most vulnerable populations can remain invisible in official assessments.
This invisibility especially affects households headed by women and those living in remote or rural areas with already limited access.
Normalizing crises
The impact of Aghanistan’s gender apartheid might not be visible to many outside the country, but in the near future, humanitarian systems will break down.
UNICEF estimates the ban could cost Afghanistan 25,000 teachers and health-care workers. In a country where women are prohibited from receiving care from male providers, banning women from both education and health-care work creates a profound medical emergency.
Over time, systems will be redesigned without women as providers even as they remain central as recipients. As gender restrictions disrupt the flow of resources, knowledge and care, the capacity to deliver services is declining every day despite high demand. Many women are also pushed into informal or hidden work that is insecure and vulnerable to exploitation and abuse.
Gender apartheid in Afghanistan will not end through recognition alone. Naming systemic terror does not stop it and, without action, repeated exposure to crisis can instead normalize it through compassion fatigue. Humanitarian organizations now face a stark choice: operate under restrictive conditions and risk legitimizing them, or withdraw and leave people without support.
The longer the situation persists, the more the exclusion of women in Afghanistan risks becoming a normalized structure rather than an emergency. The question is no longer only how to restore what’s been lost, but whether systems once dependent on women’s participation can be rebuilt at all.
Sepita Hatami does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
Health disparities across racial and ethnic groups persist in Canada. But how the country can effectively address them hinges upon how it can better study these differences.
In a recent paper I co-authored, we examine how researchers study racial and ethnic inequalities in health. We identify four persistent problems: unclear categories of race and ethnicity, a white-centred lens, heavy reliance on majority-defined health outcomes and limited explanation of why these disparities arise.
We discuss these issues drawing heavily on evidence from the United States. This reflects the state of the field: Much of the research and many of the frameworks used to study racial and ethnic health inequality come from the U.S. and have been widely applied in Canadian research.
Canada and the U.S. share a history of colonialism, structural racism and white dominance that continues to shape persistent health inequalities across racial and ethnic groups.
But Canada is also different in several important ways. It has a larger immigrant population shaped by selective immigration policies, wider variation in social and economic conditions across regions and communities and a higher proportion of Indigenous Peoples. Data are often more limited, and policies such as universal health care shape how inequality is experienced and addressed.
To better understand and address health inequalities in Canada, Canadians must rethink how race and ethnicity are studied and ground approaches in the Canadian context.
Canada is not the U.S.
Canada’s social policies are distinct from American policies. To begin with, the racial and ethnic makeup of the populations differ. Canada, for example, has a smaller Black population and a larger Asian population than the U.S.. These differences reflect broader historical and institutional contexts that shape how racial and ethnic inequalities are structured in each country.
But this coverage is partial. Services such as prescription drugs, dental care and mental-health support are not fully covered and often depend on employment benefits or where people live. Since health care is organized at the provincial level, access and quality also vary across regions. These gaps shape who gets timely care and who falls through the cracks.
The problem with ‘visible minority’
The term “visible minority” is prevalent in research on racial and ethnic health disparities in Canada. But it often does more harm than good.
At its core, it lumps all non-white, non-Indigenous people into one group. That means populations with vastly different histories, migration paths and socioeconomic status are treated homogeneously. The ability to see meaningful differences in health across groups like Chinese, South Asian and Black communities is diminished.
It also mixes up race and immigration. Many studies don’t separate immigrants from Canadian-born racialized populations. This matters because of the healthy immigrant effect. If newer immigrants are healthier on average, combining them with long-settled groups can make inequalities look smaller than they really are.
The term itself is also ambiguous. People do not always understand or interpret it in the same way, and it’s often taken literally to include anyone visibly different, such as those with disabilities or who are transgender, which complicates its use in health research.
In many ways, the problem stems from data. Canada has limited, inconsistent race-based data. Racial categories are not standardized, and detailed race-based data are often hard to access. Due to limited data availability, researchers could only rely on broad racial terms. This aggravates the problem: instead of revealing inequality, it hides it.
We measure health too narrowly
Another issue is how health is defined in the first place. Most studies rely on standard measures such as life expectancy, chronic illness or mortality. These measures are important, but they only tell part of the story. They reflect a narrow, biomedical view, often omitting how diverse racial and ethnic groups actually experience health and well-being.
Considering Indigenous communities as an example, health is not solely about the absence of disease. It includes connections to land, culture, community and spirituality, alongside physical and mental well-being. Defining health narrowly can marginalize groups by neglecting how different groups understand and experience health.
A narrow focus also makes inequality harder to see. Different groups face distinct health risks and barriers. When we rely on only a few measures, important health problems and inequalities can be overlooked.
A Canadian approach
Studying racial and ethnic health inequality in Canada requires a distinctly Canadian approach. The population, data and policy context differ from those in the U.S., and these differences shape both how inequalities emerge and how they should be studied.
This means moving beyond broad categories, improving race-based data, and using more meaningful and diverse measures of health. It also requires closer attention to context, including Indigenous and rural settings, as well as Canada’s social, immigration and health policy landscape.
To effectively address health disparities, research needs to be grounded in Canada’s realities, not simply adapted from models developed elsewhere.
Chloe Sher previously received funding from the Social Sciences and Humanities Research Council (SSHRC).
Prime Minister Mark Carney recently announced Canada’s first national sovereign wealth fund, the Canada Strong Fund. It’s aimed at investing $25 billion in domestic projects while offering Canadians a chance to invest alongside the government.
But these goals can conflict, and the fund’s current design raises questions the government has not yet fully answered.
What is a sovereign wealth fund?
A sovereign wealth fund is a pot of money owned and invested by a government to generate returns and build national wealth over time.
More than 100 exist globally, collectively managing more than US$10 trillion in assets. Most are funded from commodity surpluses or foreign-exchange reserves.
They differ from other public funds in important ways. Public pension funds manage money on behalf of retirees. Public banks and development funds lend or invest at below-market rates to achieve policy goals. Central bank reserves are held as a financial buffer, not invested for return.
Sovereign wealth funds are explicitly in the business of growing state capital. Governments can also use them to achieve geopolitical and economic goals.
Norway’s Government Pension Fund Global, valued at approximately US$2.2 trillion, is the best-known example. It invests oil revenue in a globally diversified portfolio to preserve the country’s resource wealth for future generations.
The Santiago Principles — a set of voluntary governance standards adopted by the international sovereign wealth fund community in 2008 — outline what responsible management looks like.
How does Canada Strong compare?
Canada’s new sovereign wealth fund fits the criteria of being government-owned and seeking market-rate returns. However, it diverges from standard practice in three notable ways.
First, it will be funded from a budget that is already in deficit. Canada’s projected deficit for 2025-26 is $66.9 billion. The $25 billion for the fund will be drawn from the federal budget over three years, meaning the fund is being prioritized over debt reduction and other spending commitments.
Second, the fund will focus on domestic investment. Most sovereign wealth funds invest globally, following best practices from the Santiago Principles to diversify risk.
A fund concentrated in one country’s economy heightens financial risk and is more exposed to political pressure. This concern is serious enough that some sovereign wealth funds have banned domestic investments completly.
Third, it will include an option for retail investors to directly invest in the fund. No existing sovereign wealth fund offers this.
Asset recycling and its risks
To grow the fund over time, the government is also considering raising funds through what it calls “asset recycling” or “asset optimization.”
Early reporting suggests the federal government is considering selling or leasing airports and reinvesting those funds into the Canada Strong Fund.
When asset managers take over public infrastructure, it introduces an additional dimension of risk. The Thames Water company’s record of sewage dumping, crumbling infrastructure and high levels of debt in the United Kingdom offers one cautionary case study.
Research on the privatization of both the Heathrow and Brussels airports highlights increased costs for airlines and passengers, with poorer levels of service.
A dual mandate and its trade-offs
In addition to higher risk, the Canada Strong Fund’s dual mandate may also lead to lower returns. If the fund invests on fully commercial terms alongside private investors, it risks crowding out private capital in projects that would have been funded anyway.
If, instead, it accepts lower returns when supporting strategic projects, it quietly abandons the market-rate mandate and the promise of creating wealth for Canadians.
Where the government identifies infrastructure priorities without a clear business case, it could consider direct public ownership rather than routing investment through the Canada Strong Fund.
When mixing priorities, the trade-off against financial performance is unavoidable. To have a genuine impact, the Canada Strong Fund will need to behave less like a sovereign wealth fund and more like the Canada Infrastructure Bank or the Canada Growth Fund.
Unlike the Canada Strong Fund, however, those two vehicles are upfront about accepting below-market returns to advance their priorities.
What about retail investors?
The most novel feature of the Canada Strong Fund is the retail investment product. The government has said the product will be broadly accessible to Canadians, simple to purchase and structured so investors share in any upside while their initial capital is protected.
According to a 2024 survey conducted for the Financial Consumer Agency of Canada, there has been a significant drop in the retirement readiness of Canadians since 2019. A retail product tied to Canadian nation-building could, in principle, help address that gap.
Yet challenges remain. The promise of shared upside with limited downside risk introduces complexity to the product. The performance of complex instruments is lower than the performance of simpler instruments. Retail investors may also struggle to gauge the risk-reward trade-offs associated with the Canada Strong Fund’s dual mandate.
There is also the question of what happens if the fund loses money. The government has stated they will protect the initially invested capital of retail investors, but it is not clear where this money will come from.
If retail investors effectively pay an embedded insurance premium, that premium reduces their return. If the government subsidizes the cost of that protection, it amounts to a cross-subsidy from Canadians who do not participate in the fund to those who do — an outcome that could be regressive, depending on who invests.
What would make it work?
A well-designed Canadian sovereign wealth fund has genuine potential to grow our nation’s generational wealth and financial resilience.
Other sovereign wealth funds have achieved these ends through a focused mandate to invest for financial objectives, as outlined in the Santiago Principles. The odds of Canada Strong Fund succeeding would be improved by pivoting towards these principles.
Canada could follow Norway’s model of running two separate funds. It could leave the existing Canada Growth Fund to pursue domestic strategic investments, and have the Canada Strong Fund invest abroad with the sole goal of building national wealth.
That separation would reduce internal conflict, clarify accountability and give the retail product a cleaner return profile.
Paul Calluzzo receives funding from Social Sciences and Humanities Research Council.
Dan Cohen receives grants from the Social Sciences and Humanities Research Council of Canada: one on monetary policy (grant number 435-2022-0069) and one on social finance (grant number 4030-2020-00085). He is also a member of the New Democratic Party.
Evan Jo does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
As a professor of finance, I see these phenomena as different expressions of the same underlying bias: we apply too high a discount rate to the future.
The idea of a discount rate is straightforward. A dollar today is worth more than a dollar tomorrow. The discount rate tells us by how much. Set that rate too high, and you systematically undervalue what lies ahead. Set it too low, and you over-invest in distant outcomes.
Psychologist Hal Hershfield’s research on the future self helps explain why. People often perceive their future selves more as another person than as a continuation of who they are now. This makes it easier for the self that benefits today to shift costs onto the self that must bear them tomorrow.
Looking at this through a finance lens, it resembles a “principal-agent problem,” where managers may prioritize short-term incentives over the long-term interests of shareholders.
In both cases, the person making the decision does not fully bear the long-term cost. But the future does not disappear. It simply becomes easier to ignore.
Investment in relationships
This logic becomes easier to see if we look at how we build relationships. Strong relationships require time and a willingness to tolerate discomfort.
Trust and intimacy involve immediate effort but the benefits accumulate gradually. By contrast, autonomy and flexibility offer immediate rewards. They preserve options and reduce constraints, making it easy to defer relational investment.
But relationships, like other forms of capital, depend on sustained investment, and delayed investment is often hard to recover later.
The same logic can also be seen in family structures and broader social connections. Strong ties in families, friendships and communities depend on time and repeated interaction. Without it, those ties weaken.
How loneliness is killing us, according to Harvard professor Robert Waldinger.
These patterns are not only individual. They also reflect the way modern life is increasingly organized around immediacy and convenience. Technology makes interaction faster, easier and more responsive, but many of the things that matter most in the long run still require time, patience and discomfort. The result is a social environment that increasingly rewards responsiveness over endurance.
Immediate benefits
Seen in this light, AI companions are not an anomaly. They are emerging in an era of widespread loneliness, where many people are seeking connection that feels reliable and low in emotional cost.
The concern is not that AI companionship fails. It’s that it succeeds too well in the present. By reducing effort, uncertainty and emotional risk, AI companions make connection easier to access but may also shift expectations in ways that are harder to sustain over time in human relationships. In that sense, they reflect the same trade-off: immediate comfort at the expense of longer-term relational depth.
The same logic extends beyond individual life and helps explain how societies respond to long-term problems.
Climate change is perhaps the clearest example. The impacts of our warming planet are already very evident and yet we’re slow to act. This is, in part, because the economic benefits of extraction and consumption are immediate, while many of the costs are delayed and dispersed across time.
A voiceless future
Across many human domains, from AI and personal relationships to climate change, the structure is the same: The present is immediate and rewarded; the future is abstract, distant and silent. So, decisions skew toward today.
This is not simply a matter of awareness or intention. It is structural. The future has no meaningful representation in present decision-making. It has no voice, no urgency and no direct claim. And so it’s discounted.
This is what Canadian Prime Minister Mark Carney called the “tragedy of the horizon.” Whether in the climate crisis or the loneliness epidemic, the catastrophic impacts will be felt beyond the traditional horizons of investment cycles and political terms.
Until we find ways to give the future a real stake in present decisions, we will continue to choose what is easier now and pay for it later.
The tendency to discount the future is deeply human. But in a world increasingly shaped by AI systems, weakening social ties and accelerating climate risk, the costs of doing so are becoming harder to ignore.
Rahul Ravi does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
We know that university students are at risk of mental-health struggles, particularly depression and anxiety. If writing can help instead of stress them out, it could be a refreshing change for English studies — and a new way for teachers to introduce essay writing.
Students first need to find out that writing can actually support well-being.
In the course, they took up a journalling habit, but it wasn’t just about venting their feelings or writing whatever came to mind. We looked at studies on how writing can reshape your thinking and boost positivity.
Three methods stood out:
Write down “three good things” about each day and, importantly, your own role in bringing them about. This technique was pioneered in a study led by psychologist Martin Seligman. Participants who adopted the approach reported feeling happier and less depressed at the one-month, three-month and six-month points. It’s now been widely shared, and it’s a great way to start a new journalling habit because it’s straightforward and effective.
Look to the future and write about your best possible self. When you imagine a fulfilled version of yourself, it will motivate you to do the hard work to get there. According to psychologist Laura A. King, when you imagine a fulfilled version of yourself, you can experience the health benefits of writing without revisiting negatives from the past.
Add creativity to your journalling. Turn a moment from your day into a comic; narrate your day as if it were happening in Middle Earth; write a haiku about your toothpaste. A diary-based study of more than 600 young adults led by psychologist Tamlin Conner showed a straightforward effect where being creative one day boosted well-being the next.
Case study on the self
Where journalling provides a space to play around with techniques, essays give students a place to reflect on their efforts, report on the results and hypothesize about positive effects of the experience.
One of the fascinating things about writing for well-being is that no one knows for certain why it works. Across studies it shows reliable, modest benefits, but the underlying mechanism for its effects hasn’t been pinned down — so students’ own theories could contribute to solving a real mystery.
Writers feed off inspiration. Showing students that authors have been using writing for well-being — and making great art in the process — gives them that extra push to keep writing and go deeper.
Inspiration from literature
Among Canadian authors, L. M. Montgomery’s story is especially compelling. Her famous books like Anne of Green Gables and Emily of New Moon have made a utopia of Prince Edward Island; but inwardly, Montgomery experienced deep mental anguish, leading to addiction in her later life.
Her journals detail this other side to her life and show how she used writing to ease her mental suffering. As she memorably notes in an entry from 1904:
“I feel better for writing it out. It is almost as efficacious as swearing would be and much more respectable.”
Looking to Montgomery as a mentor helped students realize how creative and immersive personal writing can be, in turn motivating them to push forward with their own journalling.
Discussing Montgomery’s life writing in their essays made sense because they could see how her efforts to find solace through writing were relatable to their own.
Easing back on literary jargon
Poetry can beautifully map a state of mind. But traditional approaches to teaching it have a tendency to suck the life out of literature that should be a joy and a delight.
Instead of taking what some teachers call a “technique spotting” approach where you count up the metaphors, teaching English from a well-being perspective taps into poetry’s healing qualities.
His curated poetry collections pair thoughtfully selected poems with one-page prescriptions, highlighting each work’s curative potential for conditions like insecurity, regret, loneliness and more. Both the poem itself and the interpretation serve to advance self-knowledge and alleviate mental suffering.
‘The Healing Power of Poetry’ TEDxOxford talk with William Sieghart.
Students easily ran with this idea. They found joy in poems that spoke to their lived experience, used empathy to recommend poems to others in need and wrote movingly in essays about the mental-health issues they face most often — like academic pressure, fear of failure, homesickness, social anxiety, perfectionism, procrastination and more.
The poetry-remedy concept also lent itself to experiential approaches where students could tape a chosen poem on their mirror, make it the lock screen on their phone, share it with a loved one, create a painting or visual, text it to a distant friend — and ultimately share the story of what happened in essay form or classroom discussion.
Essays are a notoriously difficult part of academic life, which is why generative AI presents such an irresistible pull to the stressed-out student. If essay writing is no more than a tedious recital, it’s no wonder they would gladly pass along what AI spews out on such topics.
Writing instead about your own interior world, finding evidence in your own experience and using literature to light a personalized path to growth are tasks that cannot be easily farmed out to a text-generator — because they speak directly to your own humanity.
The idea that writing can offer fresh avenues for growth and betterment is a welcome reminder of what genuine human writing is truly for.
In teaching a course on it, I found writing for well-being to be an exciting expansion of English studies broadly and essay writing in particular. It can support students’ writing and communication skills while genuinely enriching their lives, and it can help us inspire students with what’s most important in the study of literature: a lifetime love of reading and a willingness to take up the pen.
Lindsey McMaster does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
Chronic obstructive pulmonary disease, or COPD, is one of the world’s leading causes of death, responsible for 3.5 million deaths in 2021 alone. It is often thought of as a disease of older smokers. But that picture is too simple. COPD usually develops slowly over many years, often long before symptoms become obvious.
COPD is a long-term lung condition that makes it harder to move air in and out of the lungs. It includes damage to the airways, often described as chronic bronchitis, and destruction of the tiny air sacs in the lungs, known as emphysema. Because this damage builds up gradually, many people do not realise anything is wrong until symptoms become difficult to ignore. There are treatments that can help, but there is no cure, and by the time COPD is diagnosed the damage is often permanent.
Common symptoms include a long-term cough, bringing up mucus and shortness of breath. These symptoms often appear later in life, which helps explain why COPD is so often seen as an older person’s disease. But in many cases, the damage started decades earlier.
Many environmental irritants can harm the lungs, but cigarette smoke remains the main cause of COPD. Cigarette smoke contains thousands of chemicals, including toxic gases and cancer-causing substances, that injure lung tissue and trigger oxidative stress, a form of cellular damage that drives inflammation.
Inflammation is part of the body’s normal defence and repair system. Usually, it settles once the source of harm has gone. But in COPD, the lungs may be exposed to cigarette smoke day after day, so the inflammatory response never properly switches off.
Over time, immune cells sent to repair the damage can end up injuring the lungs further. The airways become narrower, the lungs produce more mucus, and the tiny air sacs known as alveoli can break down. Together, these changes make breathing increasingly difficult.
As the disease progresses, the lungs are physically altered in ways that cannot be fully reversed, even if someone stops smoking. COPD inflammation also does not always respond well to standard anti-inflammatory medicines such as steroids, which is one reason prevention matters so much.
Although cigarette smoking remains the main driver of COPD, e-cigarettes are also raising concerns. Vaping aerosols can contain nicotine, ultrafine particles and flavouring chemicals that may irritate the lungs and contribute to inflammation. The long-term effects are still unclear because these products are relatively new.
That matters particularly for younger people. In Great Britain, recent survey data suggest that 7% of 11- to 17-year-olds currently vape. While that does not mean they will go on to develop COPD, it does mean more young lungs are being exposed to substances whose long-term effects are not yet fully understood.
COPD is often diagnosed only after major lung damage has already occurred. Because it develops so gradually, people may dismiss early breathlessness, coughing or mucus production as a consequence of getting older, being unfit or smoking. Respiratory organisations warn that symptoms such as cough, phlegm and shortness of breath should not be treated as a normal part of ageing, while studies show that COPD remains widely underdiagnosed, including among people with respiratory symptoms.
The burden on health systems is huge. A 2023 study estimated that COPD could cost the global economy around INT$4.3 trillion between 2020 and 2050. International dollars adjust for differences in prices between countries; in broad terms, this is roughly equivalent to US$4.3 trillion in US purchasing power, or about £3.2 trillion if treated as US dollars at current exchange rates. Hospital admissions often rise in winter, when people with COPD are more vulnerable to bacterial and viral infections that can worsen symptoms and speed up decline.
That is why the most important window for action may come much earlier in life. By the time many people are diagnosed, the disease has been developing for years. Better education about lung health at school age could help people understand that choices made in their teens and twenties may shape their breathing decades later.
COPD care has traditionally focused on treating symptoms once they appear. But by then the lungs may already be permanently damaged. Seeing COPD as a disease that develops slowly over decades could shift attention towards earlier prevention and, ultimately, reduce its human and economic cost.
Jennifer Loudon Moxen does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
EMS training could be particularly beneficial for people with osteoarthritis who have limited mobility or pain.roibu/ Shutterstock
An estimated 595 million people globally are living with osteoarthritis. This makes it one of the leading causes of pain and disability.
Osteoarthritis is a degenerative joint disease, in which tissues in the joint break down over time. The condition can affect any joint, but most commonly the knees, hips, hands and spine.
However, the impact of osteoarthritis often goes beyond the affected joint. The condition can have profound effects on daily life.
Research shows that people with osteoarthritis are less likely to remain in work and more likely to develop additional health problems, such as diabetes, obesity and poor mental health, than those without the disease.
One of the key approaches recommended for managing osteoarthritis is exercise, including aerobic exercise and muscle strengthening. It’s shown to be extremely beneficial for managing the condition and its associated symptoms.
But not everyone who has osteoarthritis is able to exercise due to pain and limited mobility. This is why electrical muscle stimulation, a novel technology that uses small electrical impulses to help muscles contract, is being investigated for managing osteoarthritis.
Exercise for osteoarthritis
Aerobic and muscle strengthening exercises are both proven to address key drivers of osteoarthritis symptoms.
Muscle strengthening exercise improves joint stability by supporting the surrounding musculature. This reduces stress on the joint and improves movement.
Together, these approaches can help to break the cycle of pain, inactivity, weight gain and physical decline that can happen in osteoarthritis.
In fact, data suggests that people with musculoskeletal conditions (such as osteoarthritis) are around twice as likely to be physically inactive as their healthy counterparts.
Reported barriers to physical activity include pain, limited mobility, negative experiences of physical activity and a lack of motivation. But the less we move, the more muscle mass and strength we gradually lose.
A difficult cycle can then emerge, whereby pain, stiffness and fear of making symptoms worse all discourage movement. Then, without movement, stiffness and pain worsen.
An alternative approach
When exercise feels too painful or isn’t possible, electrical muscle stimulation (EMS) may offer an alternative method for maintaining and improving strength.
This works by placing electrodes on the skin to deliver small electrical impulses, causing muscles to contract without the joint needing to move. The electrical impulse is similar to the signal we normally send from our nervous system when we want to perform a movement.
The therapy can be used in isolation, or it can be applied during exercise to activate even more muscle fibres in what is called a superimposed muscle contraction.
Electrical muscle stimulation also shows promise for those with severe, end-stage osteoarthritis who are preparing for surgery.
For example, one study compared the effects of performing EMS or exercise before surgery for knee osteoarthritis on postoperative outcomes. The study found that participants who used EMS for 20 minutes a day, five days a week in the six weeks before surgery saw greater improvements in postoperative muscle mass, strength and function, compared with patients who performed physical exercise.
Muscle weakness is common both before and after surgery, partly due to pain and reduced movement. While exercise programmes before and after surgery are widely recommended, research suggests they often only have modest effects on functional recovery from joint replacement surgery.
That said, electrical muscle stimulation is not a magic solution and has its limitations. In many cases, it works best as a complement to, not a substitute for, active rehabilitation.
The body of evidence for its effectiveness in osteoarthritis is also still evolving. Some studies showed inconsistent results or were only conducted using a small sample.
Some people find the sensation of electrical stimulation uncomfortable. Some aren’t suitable for its use (for example, those with pacemakers) and devices can be expensive to buy.
Nonetheless, for those who cannot exercise due to pain, swelling or limited mobility, EMS offers a practical tool to maintain muscle strength. This can help them stay active and independent for longer, recover quicker from surgery, and maintain a better quality of life.
Louise Burgess does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
Feelings of despair at the state of the world can be overwhelming. Social and environmental problems persist, but political discourse is polarised, divisive and often ineffective.
A couple of decades ago, some behavioural scientists – ourselves included – began to think there might be a better way of addressing these challenges.
Instead of relying on governments to change things, we figured, perhaps we should switch the focus to people’s own actions. And maybe improving their choices would provide an alternative route to social and environmental transformation.
The idea developed from the fact that people sometimes make bad decisions which may be harmful – to themselves, to others or to the environment.
So what if we tried to discourage things like smoking or frequent flying, not with the heavy hand of government, but by appealing directly to the psychology of the individual?
Two pioneers of this approach, Richard Thaler and Cass Sunstein, argued that governments and institutions could “nudge” people by subtly redesigning the decision-making process. A typical nudge might involve making certain arrangements the default option, such as automatic enrolment into pension schemes. Or it might mean placing healthier meals first on menus.
In these situations, nothing needs to be banned. The undesirable options remain available – they’re just tucked away or more difficult to access.
Behaviour gets nudged along in personally and socially beneficial directions, without removing freedom of choice, and without getting into politically contentious territory. Like many enthusiasts, we were optimistic that focusing on individual behaviour might prove to be an effective route to a better world.
Sadly, things turned out rather differently.
Recent results from large meta-analyses (studies that bring together findings from many previous experiments) suggest that the effects of nudges and other individualistic interventions are disappointingly small.
Some authors have even concluded that there may be no reliable evidence that nudges work at all. Other evidence suggests that even when nudges do have an effect, those effects are small, short lived and difficult to scale up.
And there is another problem, as we argue in our new book It’s On You. By focusing attention on individual responsibility for the world’s problems, behavioural scientists may have inadvertently assisted a broader process known as “responsibilisation”“.
Responsibilisation means placing the burden of blame onto individual consumers – deflecting attention from the need to regulate or constrain big businesses which benefit and profit from maintaining the status quo.
Oil companies for example, might want the world to focus on the responsibility of individual car drivers and frequent flyers. Plastics and packaging companies stress the scourge of individual littering. Manufacturers of ultra-processed foods and sugary drinks want us to blame ourselves for poor diets.
In each case, individual behaviour is placed centre stage, while the need for regulations to shift corporate practices recedes from view.
And persuading us to place responsibility on the individual goes very much with the grain of human psychology. Our social lives are built around interacting with small numbers of other people, even while we are governed by complex systems of norms, conventions and rules that change slowly. Systems that we largely take for granted, do not control and rarely even notice.
Taking responsibility
It is hardly surprising then, that when we look for explanations for social problems such as climate change or gun violence, we naturally attribute them to the actions of bad people. It’s the drivers of big cars or violent types with mental health problems.
This means that people are wired to be all too ready to buy into the responsibilisation narrative that individuals, including ourselves, are at the heart of the problems that bedevil society.
But when social problems arise and intensify, it is unlikely that human nature has suddenly deteriorated en masse.
It is far more plausible that large-scale systemic forces – changes in regulation, market structure, technology and incentives – are at work. And when problems are systemic and self-reinforcing, systemic solutions are what is required.
In a world that feels increasingly contentious and imperilled, it is tempting to hope that individual consumers can really make a difference – to imagine that we can improve the world one recycled yoghurt pot at a time. And each of us should, of course, do our bit by making good consumer choices where we can.
But we must not allow a focus on the individual to distract us from the need for deeper systemic change. Gentle nudges will never be enough. To address our persistent social and environmental challenges, we need the collective political will to reshape the rules that govern all of our lives.
Nick Chater receives funding from UKRI and NSF. I am also a co-founder of Decision Technology, a behavioural science consulting company founded in 2002 (and I continue to be a share-holder and director). The company doesn't stand to benefit from this article (if anything, the reverse!).
George Loewenstein does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
A great Tyrannosaurus rex strides through the conifer trees of her territory, sniffing the air. She picks up the scent from the carcass of a dead horned dinosaur, Triceratops, that she was feeding on yesterday. She walks over and strips off some more shreds of meat, but the smell is foul even for her.
She goes down to the lake to drink and small crocodiles and turtles scuttle into the water. But she hardly sees them. Of more interest is an armoured dinosaur, Ankylosaurus, lurking nearby. However, she knows this dinosaur won’t be an easy kill and she isn’t desperate enough for food to risk a fight. Little does she know there are bigger dangers ahead. She looks up and sees a bright light racing downwards accompanied by faint crackling and sizzling noises.
Our T. rex has excellent hearing for low frequency sounds and she is disturbed by the vibrations she can feel. But her upset only lasts for a moment. In a flash, she has been burnt to a crisp and her world changed forever.
This all happened 66 million years ago, when a huge asteroid famously hit the Earth in the area of what is now the Caribbean. At the end of the Cretaceous period, sea levels were 100–200 metres higher than today, so the shores of the Caribbean lay far inland over eastern Mexico and the southern United States. The impact happened entirely within these waters.
The event triggered instant changes to our planet and its atmosphere and led to the extinction of the dinosaurs and about half Earth’s other species. But what would it have been like to experience such a gargantuan impact? What would you have seen, heard or smelled? And how would you have died – or survived?
The Insights section is committed to high-quality longform journalism. Our editors work with academics from many different backgrounds who are tackling a wide range of societal and scientific challenges.
As experts on meteoritics and palaeontology, respectively, we’ve created a detailed timeline, based on decades of research, to take you right there. So let’s start by travelling back in time to the very last day of the Cretaceous.
T-minus one day
All is calm and the Cretaceous day proceeds as usual. In what will soon be ground zero, it is pleasantly warm, about 26°C, and wet. It often is. For about a week, the asteroid has been visible only at night. Because the giant rock is heading straight towards Earth, it looks like a motionless star. There is no dramatic tail; this is a rocky asteroid rather than a comet.
The dinosaurs were enjoying nice weather before the big impact.Orla/Shutterstock
In the last 24 hours, the light becomes visible during the daytime. But it still looks like a star or planet, getting brighter in the final few hours before impact.
T equals 0: the impact
If you were close by, you would first have experienced a brief light and sound show. Minutes to seconds before the impact, you’d have seen the bright fireball, and its accompanying crackling or fizzing noises. This sizzling sound is a result of the photo-acoustic effect: the intense light of the fireball warms the ground, which then heats the air above it, causing pressure waves, or sound.
Next, a deafening sonic boom, which occurs because the asteroid is travelling faster than the speed of sound. But the asteroid is so huge, perhaps 10km in diameter, that it almost certainly hits the ground before any living creature near the impact zone has time to run for cover.
The asteroid’s enormous energy forms a crater through a series of processes that together take only a few seconds. As the asteroid collides with the surface, its kinetic (movement) energy is instantly transferred to the surface as a combination of kinetic, thermal (heat) and seismic energy (released during earthquakes). This results in a series of shock waves that heat and compress both the asteroid and its target.
As the shock waves propagate, rocks fracture, break up and are ejected, producing a bowl-shaped depression, or transient cavity, about ten seconds after impact. The heat and compression also melt and vaporise large volumes of material, including the asteroid itself, releasing a fountain of incandescent vapour (its temperature is more than 10,000 K, or 9726.85°C).
Over the next few seconds, the cavity increases in size to many times the diameter of the original asteroid. Simulations suggest that around 20 seconds after impact, the transient cavity is at least 30km deep – deeper than the deepest depth currently known on Earth, the 11km Challenger Deep valley, part of the Pacific Ocean’s Marianas Trench. The rim of the crater is over 20km high – more than twice the height of 8,900m Mount Everest.
But this enormous feature lasts for less than a minute before it starts to collapse. Within three minutes of the impact, the centre of the crater has rebounded to form a peak several kilometres high. The peak only lasts about two minutes before collapsing back into the crater.
Whether a dinosaur or a dung beetle, if you were near the transient cavity you would have been incinerated instantly by the blast. But even if you were up to 2,000km from the epicentre, you’d likely have been killed quickly by the thermal radiation and supersonic winds now spreading out from the impact site.
T-plus 5 minutes
Five minutes after the impact, the winds have “eased” to those of a category 5 hurricane, flattening everything within about 1,500km of the impact. Destroying everything, that is, which has not already been burnt. Atmospheric temperatures in the region rise to over 500K (226.85°C). This would feel like being inside an oven – causing burns, heatstroke and death. Wood and plant matter ignite, creating fires everywhere.
Because the asteroid struck the sea, the atmosphere is also filled with super-heated steam, making the hurricane-force winds even deadlier.
Next come the tidal waves, triggered by the vast quantities of displaced rock and water. These 100-metre megatsunamis first strike the shores of what is now the Gulf of Mexico, engulfing the land before depositing huge amounts of debris as they retreat.
By now, the crater has almost reached its final dimensions – 180km across and 20km deep. But making an enormous hole in the ground isn’t the only outcome of the impact. All the rock and vapour displaced during the collision has to go somewhere. Several locations in Northern America show that metre-sized blocks of debris from the impact were thrown distances of hundreds of kilometres.
So if you were 2,000km to 3,000km from the epicentre and survived the first few seconds, you’d most likely die from overheating, earthquakes, hurricanes, fires, tsunami-driven floods or being hit by impact melt.
But what is happening much further away? In the first five minutes after impact, dinosaurs roaming the Cretaceous forests of what are now China or New Zealand are so far undisturbed.
But it won’t be long before that changes.
T-plus one hour
Shockwaves on land and sea are only minor inconveniences compared with the fire that is still radiating down from the sky. Some of the impact energy has been transferred into the atmosphere, heating the air and dust to incandescence.
An hour after impact, a belt of dust has circled the globe. Deposits of solidified molten droplets (impact spherules) and mineral grains have been found in numerous locations from New Zealand in the south to Denmark in the north. In these locations, you would not have been aware of the tsunamis around the Americas or the wildfires, but the skies would certainly have begun to darken.
T-plus one day
By now, huge tsunamis are moving east across the Atlantic and west across the Pacific, entering the Indian Ocean from both sides.
They are still around 50m high – causing death and destruction across many coasts around the world. By comparison, the 2004 Boxing Day tsunami reached heights of up to 30 metres. Tsunamis kill fishes and marine life that are washed high on the shore and then dumped, just as they kill coastal trees and drown land animals. But the tsunamis gradually fade away and probably don’t wipe out any entire species – at least on their own.
The hurricane force winds have also died down, but tropical storm strength winds are whipping up debris and causing further chaos and destruction across the tsunami-affected areas. The burning sky is also triggering wildfires across the globe – which, in turn, carry ever more soot into the atmosphere. The sooty signature of these wildfires has been found deposited as carbon particles in sediments from the K-Pg boundary – a 66-million-year-old thin clay layer.
Further away, in what is modern Europe and Asia, the skies continue to fill up with dust and soot, as they do everywhere. Temperatures start to drop as sunlight is blocked. Trees and plants in general, including phytoplankton, close down as if for winter, unable to photosynthesise. Any animals that rely on warm conditions ultimately hunker down and die.
T-plus one week
It’s getting darker and darker. Simulations of solar radiation reaching the Earth’s surface following the impact indicate that, after about a week, the solar flux (the amount of heat and light per a certain area) is just one thousandth of that prior to the impact. This is caused by particles of dust and soot in the atmosphere.
The continued decrease in light levels is accompanied by a global drop in surface temperatures of at least 5°C. This means that most of the dinosaurs and other large flying and swimming reptiles probably die from freezing within the course of this first week (smaller reptiles with slower metabolisms or more flexible diets could survive longer). Cooling temperatures and cloud cover also lead to rain. But not just any rain. Storms of acid rain fall across the Earth.
Two separate mechanisms generate acid rain. The first is down to the geology of the impact region. The asteroid happened to hit an area of sediments rich in sulphur, which vaporised and caused sulphur oxides (acidic and pungent gas compounds composed of sulphur and oxygen) to be part of the plume of plasma blasted into the atmosphere. Second, the energy of the collision was sufficient to turn nitrogen and oxygen into nitrogen oxides – highly reactive gases that can form smog.
The dropping temperature ultimately allows water vapour to condense into drops, and the sulphur and nitrogen oxides dissolve to form sulphuric and nitric acids. This is sufficient to generate a rapid drop in pH. Early models suggest that the pH of the rain might be as low as 1 – the same acidity as battery acid.
At this point, Earth is not a great place to be. Rotting vegetation, choking smoke and sulphur aerosols combine to make the planet stink. Plants and animals on land and in shallow seas that have survived the darkness and cold succumb to the corrosive acid rain and ocean acidification. Acid rain also kills trees by leaching nutrients such as calcium, magnesium and potassium from the soil. Shallow marine shellfish, crustaceans and corals also die as acid seawater destroys their skeletons.
T-plus one year
Winds die down, wildfires are extinguished and the oceans are once again calm. It might appear that the asteroid collision is just a scar on the ocean floor. But its effects are still destructive. The atmosphere is still filled with dust and the Sun hasn’t shone for a year. Temperatures have continued to drop, with the average surface temperature now 15°C lower than before the impact. Winter has come.
Any dinosaurs or marine reptiles that survived the first week of freezing conditions would have died very soon after. A year after the impact, only rotted skeletons of these behemoths remain. Here and there, smaller animals like mammals the size of rats and insects would be nestling in crevices, barely surviving on their reserves and decaying plants.
While most plant groups and many of the modern groups of insects, fishes, reptiles, birds and mammals recover reasonably rapidly, things don’t look great for other species. Dinosaurs and pterosaurs living on land are extinct, as are many marine reptiles, ammonites, belemnites and rudist bivalves in the oceans. Ammonites and belemnites are high in their food chains, and so suffer not only from the cold and acidification but also from the loss of abundant food resources, such as smaller marine organisms.
T-plus ten years
The Earth is still in the grip of a fierce winter. Although most of the sulphur has rained out of the atmosphere, dust and soot particles remain. The average surface temperature is still about 5°C lower than before the impact. The main oceans have not frozen, but inland lakes and rivers around the world are iced over.
Clearly, there were no humans about at this time – there weren’t even any larger mammals. But given the only species that survived were those that could burrow or live below water, it is unlikely that you could have survived this long.
Surviving plant and animal groups such as turtles, smaller crocodiles, lizards, snakes, some ground-dwelling birds and small mammals repopulate the Earth at this point. But they are forced back to limited areas of relative safety a long way from the impact site. These areas are now receiving sufficient sunlight for plants and phytoplankton to photosynthesise again. As leaves and seeds provide the basis for the food chains on land and in the sea, life begins to rebuild.
Eventually, life returns to the devastated landscapes, but ecosystems are very different and the dinosaurs are no more.
T-plus 66 million years
Today, 66 million years after the impact, the scars of the collision are hidden within geological strata – and scientists have started deciphering them. It was in 1980 that researchers first reported evidence of the impact. In their classic paper, Luis Alvarez, a Nobel-prize-winning physicist, and co-authors, described a sudden enrichment in the element iridium in a specific clay layer in Denmark and in Italy.
Iridium is rare in surface rocks because most of it was sequestered in Earth’s core when the planet first formed. However, iridium is found in meteorites, and Alvarez and colleagues inferred that the rate of accumulation of the metal in the sediments was so high that it could only have been produced by impact of a gigantic meteorite.
Because the scientists had only observed the iridium spike in two locations, the impact hypothesis was rejected by many scientists at the time. However, through the 1980s, iridium spikes were identified in clay layers at more and more locations – in muds laid down on land, in lakes, in the sea.
Support for an impact hypothesis strengthened when a crater of the correct age was found in 1991. The crater is buried beneath younger rocks, but clearly visible in geophysical surveys, lying half on land in the Yucatán Peninsula of Mexico, and half offshore. Since 1990, evidence for the impact has increased, not least when scientists discovered that there was indeed a sharp cooling event at the end of the Cretaceous.
Possible T rex footprint from New Mexico.Wikipedia, CC BY-SA
In total, it is estimated that half the species of plants and animals alive at the end of the Cretaceous disappeared. It was once thought that surviving groups such as many plants, insects, molluscs, lizards, birds and mammals somehow escaped unscathed. But detailed study shows that this is not the case – they were all hit hard.
But, by chance or luck, enough individuals and species were able to survive the cold and absence of food, or were in parts of the world where the effects were less extreme. As the world returned to normal, they had the opportunity to expand rapidly into their old niches, but also to occupy the space vacated by extinct groups. In fact, one important consequence of the extinction of the dinosaurs, apex predators in their heyday, was the successful spread and evolution of mammals.
When Alvarez and colleagues first described the drop in temperature following the impact, they called it a “nuclear winter”, reflecting the political climate of the early 1980s. Now we might be more inclined to describe the effects as a global climate change – similar events are currently resulting from increased carbon dioxide in the atmosphere (flooding, temperature fluctuations).
It is salutary to think that without the asteroid collision, primates might never have reached the level we are at today. But it is equally salutary to consider that modern humans are causing some of the same changes to the atmosphere that ultimately killed our reptilian forbears and may one day also lead to our own demise.
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Monica Grady receives funding from the Leverhulme Trust for an Emeritus Fellowship and from the STFC. She is affiliated with The Open University, Liverpool Hope University and the Natural History Museum, London.
Michael J. Benton does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
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