Attribution Method Pinpoints Major Emitters’ Roles in Climate Disasters

A new statistical approach is being put forward to isolate the part that individual major emitters’ greenhouse gas production plays in specific climate-related disasters—opening a new front in identifying those liable for trillions in dollars of damage from droughts and storms.

The method strides into one of the most sensitive minefields in climate diplomacy: the attribution of responsibility for climate change, and its increasingly damaging and costly consequences, to the emissions of individual nations. Attribution leads to a focus on liability that could invite victims of climate change, especially in small countries with minute carbon footprints, to seek compensation for lost assets, expensive adaptations, and in some cases the disappearance of entire countries and ways of life.

To that end, InsideClimate News reports, “a team of scientists has published a method for estimating how individual countries’ shares of global greenhouse gas emissions over time contributed to the risk of specific extreme climate events, like heat waves, occurring in other countries.”

The researchers, from World Weather Attribution and the Center for International Climate and Environmental Research, described their method in a peer-reviewed paper in the journal Nature Climate Change. They claim their techniques “make it possible to assign extreme events to human-induced climate change and historical emissions,” and “allow losses and damage associated with such events to be assigned country-level responsibility.”

Building on previous research which demonstrated that human-caused climate change had made a 2013-14 heat wave in Argentina 400% more likely, the researchers “calculated the change in the frequency of this event attributable to individual countries’ or regions’ greenhouse gas emissions.”

Against the background of global greenhouse gas emissions, there was about a 1:12 chance of Argentina’s heat wave happening. But take away the European Union’s emissions, and that risk drops to 1:15. “The difference,” ICN writes, “suggests the EU’s emissions alone increased the risk of the heat wave by 37%.” By the same calculation, U.S. emissions added 34% to the likelihood of the event, while China and India increased its risk by 21% and 18%, respectively.

The Paris climate agreement specifies that such national attributions “will not be the basis for discussions on loss and damage,” ICN observes.

But that hasn’t stopped a number of efforts to pursue so-called non-national entities—the largest global oil companies—for their part in specific costs incurred by climate changes. Jurisdictions in the United States have sued 37 oil and coal companies, seeking compensation for the damage climate change is doing to their local infrastructure. Others in Canada have delivered what they describe as “demand letters” to some of the same companies.

With as much as a 33% of greenhouse-gas emissions to date traceable to a relative handful of fossil giants—a share larger than China’s—the new technique may quickly find other applications.