Extreme Weather Attribution - 265

Have you looked at a map of the Canadian Wildfires? It is sobering. Spread across the second largest country on the planet on June 8^th, there were 429 active fires out of 2,360 fires this year. Over 10 million acres had burned. It is the worst fire season in Canada’s history, and we are hardly into summer.

When I started my climate studies, scientists warned us of the danger of wildfires growing with rising temperatures. The chance of wildfires increases four times with each one degree Celsius (1.8 F) rise in temperature.

Today, the NASA Earth Observatory informs us that the earth has, on average, warmed 1.1 C (1.9F) since 1880.

Can the fires today in Canada be linked to Global Warming?  If you asked me this only four years ago, my answer would have been, “Even though it seems obvious there are more extreme weather events, especially heat waves, scientists do not have the data or the means of analyzing it to achieve scientific confidence.”

In 2019, The Intergovernmental Panel on Climate Change (IPCC), in their 5^th assessment, said the scientific evaluation   of the relationship between specific extreme weather events and global warming was “Not fit for purpose.”

By the end of the 6^th assessment in 2021, the IPCC reported the scientific means of determining if global warming was to blame for specific disastrous weather events as “robust” science.  What changed?

Attribution science is the term used to describe blame for specific weather events. By the way, we used to blame God, and the term was, “That was an act of God.” The development of attribution science is credited primarily to two scientists, Friederike Otto, and Geert Jan van Oldenborgh. They not only brought the science to its current respected and “robust” state, but they brought together a worldwide team of scientists who analyzed weather events, comparing the actual weather to the weather expected if we had not warmed the earth with greenhouse gasses.

Climate scientists use “attribution science” to determine how much of a weather event can be explained by human-induced climate change and how much by natural variability. Attribution studies compare the observed weather with simulations of what the weather would have been like in a world without human influence. They also use statistical techniques to estimate the likelihood and intensity of such events in different scenarios. Attribution helps us understand the impacts and risks of climate change and the benefits of reducing greenhouse gas emissions.

The team has also streamlined the peer review process to speed up their findings to the public without compromising the integrity of the process. In today’s world of immediate eye-catching news, if the analysis is over two weeks old, people will not remember the event or make the association. Research must be accurate and fast while the weather event is fresh in people’s minds. Accuracy must be foremost, but if the analysis takes too long, it will not be instrumental in driving public opinion.

The group formed by Otto and Oldenborgh is called the World Weather Attribution initiative. (WWA). Their goal is to be accurate, fast, and properly peer-reviewed. In any year, there are chances of extreme weather with or without human-induced climate change. What the WWA has done is accurately attribute the increased likelihood that the weather disasters we are experiencing are the result of our carbon pollution.

As an example of the WWA’s many findings, the South African wildfires of 2021 were found to be 1.9 times more likely to have occurred due to climate change. The Iranian drought of 2020/21 as 2.2 times more likely. The unprecedented heat wave which hit South Korea in 2021 as 4 times more likely. The record-warm temperatures that hit East Asia in 2023 as 11 times more likely. And the marine heat waves, the killer “blob” which forms in the north Pacific, as 43 times more likely. 

The WWA is getting fast at doing its analysis. In July 2021, just 11 days after temperatures in Pacific northwest areas of the U.S. and Canada reached high above 40ºC, shattering records by as much as 5ºC, a WWA study found that climate change made the heatwave at least 150 times more likely and 2ºC more intense. 

We will have to wait and see how the WWA rates the unprecedented wildfires in Canada this summer to know what/whom to blame.  Even though firefighters from nations worldwide, including the USA, are coming to help Canada’s firefighters, many of the fires probably will not be out until winter.

And then, the WWA will inform us about the Canadian forest fires and climate change, just as they have about the Swedish fires, the European Floods and multiple heat waves, the Australian bushfires, and the Siberian meltdown. We can wait.

Or we can heed Eugene Robinson, who, taking measure of the darkening red skies thick with smoke in Washington, D.C., noted what needs no more scientific evidence:

“Once again, nature is sending us an unambiguous message: We had better get serious about mitigating the consequences of human-induced climate change. And we are, as a species, a bunch of idiots unless we make switching from fossil fuels to clean-energy sources our top global priority.”

References:

Scientific American June 2023, “The Blame Game”

Bloomberg: “How Climate Scientists Do Extreme Weather Attribution”

Columbia University Education: “Attribution Science: Linking Climate Change to Extreme Weather”

NOAA Climate.gov: “Extreme event attribution: the climate versus weather blame game

 BBC News: “Is climate change causing droughts, heatwaves, wildfires and floods?

Canadian Wildfire Maps: Canadian Interagency Forest Fire Centre Inc