As firefighters and other first responders battle an unprecedented summer of fires, floods, tornadoes and heat waves around the country, a group of Canadian scientists are asking why they害羞草研究所檙e happening in the first place.

害羞草研究所淢ay and June were record hot months in Canada and we害羞草研究所檝e got the record wildfire season as well,害羞草研究所� said Nathan Gillett of Environment and Climate Change Canada. 害羞草研究所淵es, it has been busy.害羞草研究所�

Gillett heads the Rapid Extreme Event Attribution Project, a new federal program that uses the growing field of attribution science to promptly establish to what extent 害羞草研究所� if any 害羞草研究所� a specific flood in British Columbia or wildfire in Quebec is due to climate change.

害羞草研究所淭he idea is to be able to make rapid extreme event attribution days or weeks after the extreme events occur,害羞草研究所� he said.

Twenty years ago, if you害羞草研究所檇 asked a scientist if climate change was linked to days of torrential rain or months of desiccating drought, you害羞草研究所檇 probably get an answer along the lines of 害羞草研究所淲e can害羞草研究所檛 say for sure but this event is consistent with the modelling.害羞草研究所�

But in 2003, a paper was published suggesting science could do better. Myles Allen of Oxford University borrowed a concept from epidemiology.

害羞草研究所淵ou can say that smoking increases your risk of lung cancer by a certain amount,害羞草研究所� Gillett said. 害羞草研究所淚n the same way, you can say human-induced climate change increased the risk of a certain event by a certain amount.害羞草研究所�

Since then, hundreds of attribution papers have been peer-reviewed and published. As well as Canada, governments including the United Kingdom, Australia, the Netherlands, South Korea, Japan and the United States are using attribution science.

Attribution science works by comparing climate models. One set of models will use data drawn from actual records while another, otherwise identical, set will be constructed with the influence of greenhouse gases removed.

Simulations will be run using those two sets and the difference in the results reveals the impact of climate change. It allows scientists to say to what extent the presence of greenhouse gases increased the likelihood of the event in question.

害羞草研究所淚t害羞草研究所檚 probabilistic,害羞草研究所� Gillett said.

The process is now established enough, with peer-reviewed protocols and standards, that the calculations can be done quickly.

害羞草研究所淥nce you害羞草研究所檝e got the method in place and it害羞草研究所檚 validated, you really just have to get the observations from that event and you can provide a result,害羞草研究所� said Gillett.

Some events are easier to study than others. Gillett said his group hopes to be able to come to conclusions on heat waves in about a week, but wildfires, which involve more variables, will take longer.

Speed matters, said Clair Barnes, a researcher with the World Weather Attribution group in the U.K., which has studied the role of climate change since 2015 in more than 50 events around the world 害羞草研究所� including the finding that the heat wave preceding the fire that levelled Lytton, B.C., was made 150 times more likely by climate change.

害羞草研究所淥ur aim is to look at high-impact events that are in the news,害羞草研究所� she said. 害羞草研究所淭here was an appetite in the public and the media for more information about what害羞草研究所檚 really happening now.害羞草研究所�

Promptly assessing the role of climate change after extreme events brings actual insight and information to the discussion, Barnes said.

害羞草研究所淚f you spend three years thinking about it, the media has already decided it was climate change or it wasn害羞草研究所檛 climate change and has moved on. If you want to be involved in that discussion and bring some science to that discussion, you害羞草研究所檝e got to move quickly.害羞草研究所�

But attribution science has more uses than just shaping public debate. Governments are using it inform their adaptation strategies. Financial institutions are using it to assess risk. It害羞草研究所檚 come up in hundreds of court cases around the world attempting to attribute climate liability.

It does have its limitations.

Attribution science can only work where there害羞草研究所檚 enough historical weather data to build an accurate climate model. That leaves out much of the global south, where some of the worst human impacts are occurring. As well, extremely local events are often beyond its resolving power.

害羞草研究所淵ou do have to be careful to communicate the uncertainties,害羞草研究所� said Gillett. 害羞草研究所淲e shouldn害羞草研究所檛 be overconfident.害羞草研究所�

There害羞草研究所檚 certainly no shortage of work. Barnes said her group has had to establish a strict protocol that weighs the magnitude of the event, the amount of damage it inflicts and its effect on human lives to weed out which events merit study.

害羞草研究所淭here are so many events that we just don害羞草研究所檛 have the time to look at them all.害羞草研究所�

But World Weather Attribution has found the time to consider Canada害羞草研究所檚 wildfires. It害羞草研究所檚 a complex one, so results aren害羞草研究所檛 expected for another month or so.

By then, chances are there will be a new extreme event to consider. When Barnes joined World Weather Awareness, she assumed winter and summer 害羞草研究所� the times of peak temperature highs and lows 害羞草研究所� would be the busiest. Not so.

害羞草研究所淲e害羞草研究所檝e had temperature records set for the last few months and it害羞草研究所檚 not even the peak of boreal summer,害羞草研究所� she said. 害羞草研究所淚t害羞草研究所檚 just been non-stop.害羞草研究所�

This report by The Canadian Press was first published July 22, 2023.

Bob weber, The Canadian Press