Assigning historical responsibility for extreme events
Historical responsibility of individual countries and regions can now be quantified for specific extreme events
A new paper by Dr Friederike Otto, Professor Myles Allen et al describes how scientific advances make it possible to assign extreme events to human-induced climate change and historical emissions from individual countries.
These developments could allow losses and damage associated with such events to be assigned country-level responsibility. Assigning historical responsibility is of relevance not only for financial interests, but also for climate justice.
Methodological developments in the science have increased robustness and confidence in event attribution, and it is now possible to say with high confidence that the likelihood of occurrence of individual classes of extreme weather events has increased due to anthropogenic climate change for some classes of extreme events (e.g. heatwaves, extreme rainfall). The paper, published recently in Nature Climate Change, goes a step further to highlight the potential of assigning individual countries’ greenhouse gas and aerosol emissions to specific extreme weather events.
The study looks at the summer 2013–2014 heatwave in Argentina as an example, during which large parts of the country witnessed the highest temperatures on record. This particular heatwave was chosen on the basis that previous studies (involving CPDN simulations) reveal anthropogenic influences made the event five times (400%) more likely.
Dr Otto’s study builds on previous work on assigning historic emissions to individual countries and explores two different statistical methods to combine this research with event attribution to estimate the change in the frequency of this event attributable to individual regions’ greenhouse gas emissions.
The researchers found that EU28 emissions made the Argentinian heatwave 19–60% more likely, out of the 400% increase in likelihood caused by total anthropogenic emissions.
The paper concludes that the fact that it is possible to provide such quantifications will greatly advance the possibility of an informed discussion on whether such information is useful, necessary, and should be included in multi-national agreements.
Furthermore, the possibility of assigning contributions of individual regions to damage could have the potential to reshape environmental litigation, raising questions regarding damage and responsibility in national jurisdictions, and thus climate justice.
 Friederike E. L. Otto, Ragnhild B. Skeie, Jan S. Fuglestvedt, Terje Berntsen & Myles R. Allen« Back to News