An investigation over whether temperature sensors at the Paris airport were tampered with to manipulate winning bets online is putting a new focus on the growing popularity of climate-related wagers.
A few accounts on Polymarket, an online betting platform, made hundreds of thousands in winnings after temperature readings spiked 5 C in just one day earlier this month.
The incident is fuelling debate over how platforms, such as Polymarket and Kalshi, allow users to bet on climate disasters, be it how strong a hurricane will be or whether 2026 will be the hottest year on record.
But experts tell CBC News that weather betting could improve climate science — and is already converting some climate change skeptics.
Prediction markets like Kalshi and Polymarket have exploded in popularity, processing billions in daily trades. For The National, CBC’s Nora Young breaks down how they work and why experts say it’s just another form of gambling that comes with risks of insider trading and manipulation.
Moran Cerf, professor of neuroscience and business at Columbia University in New York, has worked on research about the impact of participating in prediction markets on people’s climate perceptions.
Participants in his study bet on the outcomes of various climate events that were happening at the time, such as the California wildfires, and the participants were surveyed before and after to gauge how the betting changed their views. It found that people who bet on these markets became more aware and concerned about climate change, and even those who were climate skeptics were possibly converted.
Cerf’s research goes to the heart of one of the most intractable problems with climate change, which is convincing people with varying levels of skepticism that humans are causing global warming.
Even in the face of growing climate disasters, climate skepticism persists. According to a January 2025 poll from the Angus Reid Institute, almost a quarter of Canadians don’t believe that climate change is primarily caused by humans and another nine per cent don’t believe climate change has been proven at all.
The poll was conducted as an online survey among a representative randomized sample of 2,012 Canadian adults.
Climate change presents a problem that targets “everything that the brain is bad at,” Cerf said.
That’s because some of the impacts of climate change — sea levels rising and inundating major cities or the collapse of major food systems — are sometimes years or decades in the future, and climate impacts are felt more acutely by people in developing countries that are far from the U.S. or Canada.
But prediction markets shorten that time and distance. They give people an immediate feedback from betting on an event, because they can see the probabilities change in real-time, and the payouts provide a more short-term impact.
“It forces them to play a game where they actually see the outcomes they could easily ignore if they didn’t have money on it,” Cerf said.
“By putting money and by actually earning money from being right, they start to change their mind.”
The science of speculative betting
Last year, $239 million US was traded on climate-related markets on Kalshi. Daily weather prediction markets for cities like London and New York regularly see tens of thousands of dollars in trades.
Prediction markets work a little differently from, say, a casino. Instead of betting against the house, users directly trade “shares” in either “Yes” or “No” options on a particular question. The shares are priced from $0 to $1, depending on supply and demand.
So if a “Yes” share is trading at, say, $0.45, then the market has decided that there’s a 45 per cent of a “Yes” outcome to that question. Once the outcome of the question is known, the shares will be paid at either $1 or $0 each.
Mark Roulston, a climate scientist at the University of Lancaster in the U.K., is running an academic project that invites university climate research teams to participate in prediction markets. These markets are designed to operate like Polymarket or Kalshi, but without actually needing the research teams to gamble their own money.
Rather, the research teams submit their predictions, or “bets,” on important climate events, such as hurricane season or the El Nino weather pattern. The goal is to aggregate the expert bets from several research teams to come up with a more accurate prediction, Raulston said, and also reward the teams that were most accurate, therefore encouraging them to develop their models further.
Insurance companies can then use Raulston’s prediction market platform as a better way to calculate actuarial risk, and scientists can use it as a way to get research funding.
Raulston says he wants to expand the research. As an example, he said a government could turn to a prediction market to estimate how much the sea level could rise in a particular region. They could invite a range of research teams to participate in the market and make infrastructure decisions based on the outcomes of that market — rather than paying for one expert.
Prediction markets could also be “a new type of scientific institution for aggregating expertise,” Raulston said.
“If the primary output of the research is a forecast, we’d argue this is a better way to aggregate that information and summarize that information in a more timely fashion,” he said.
“Because you don’t have to wait for the possible years it takes to review a paper.”
Prediction markets in Canada
Short-term binary options, which are yes-or-no bets with timeframes less than 30 days, are technically prohibited in Canada, and the Ontario Securities Commission explicitly banned Polymarket after a settlement and fine in 2025.
But the fintech company Wealthsimple recently got approval to operate certain types of prediction markets in Canada. The company will be allowed to offer contracts on economic indicators, financial markets and climate trends, but not sports and elections, according to reports in the Globe and Mail and Bloomberg.
But the rise of climate-related bets worries some researchers. Cerf said that the short-term bets which are popular now, like the day-to-day temperature, don’t really help people to connect the dots on climate change.
“Their incentives are more to get you to play rather than to actually to get you to learn,” he said.
The added issue of data tampering, like what may have happened in Paris, further compromises the usefulness of these platforms in raising climate awareness, Cerf said.
