TROMSØ, Norway: The climate change-attributed costs of extreme weather between 2000 and 2019 are estimated to be US$2.86 trillion, or an average societal cost of US$143 billion per year.

The conclusion, produced by Rebecca Newman from the Reserve Bank of New Zealand and Ilan Noy, Victoria University of Wellington, was published in Nature Communications in September 2023.

Extreme Event Attribution (EEA) is a methodology the authors used to examine how anthropogenic (human-related) greenhouse gas emissions (GHG) have altered the frequency of specific extreme weather events.

Newman and Noy collected data from available EEA studies and combined it with the socio-economic costs of these events to determine how much can be attributed to climate change in the past two decades.

From the 185 events studied over the period, 60,951 deaths were attributable to climate change at a statistical value of life cost of US$431.8 billion.

More than 62 percent of the climate change-attributed damages were connected to storms; 16 percent from heatwaves; floods and droughts 10 percent each; and two percent from wildfires.

The authors note the economic value of life lost to climate change-attributed extreme weather is dependent on the assumed value of statistical life. Using the US-UK mean Value of Statistical Life calculation, the mortality cost rises to US$1.79 trillion based on a U.S. Department of Transportation 2022 figure of US$12.5 million per person.

A related study* published in October this year in Nature has determined a melting Greenland ice sheet (GrlS) will result in sea level rises of “several metres” if global mean temperatures (GMT) pass a global threshold between 1.7 °C and 2.3 °C above pre-industrial levels.

“With further global warming, a partial to complete loss of the ice sheet is expected, implying an increase of the global sea level by up to seven metres,” according to the authors, who add: “We find a threshold for an abrupt, complete loss of the GrIS around 2.3 °C GMT above pre-industrial levels.”

They note, however, an ice-free GrIS state can still be avoided if the temperature “overshoot is reduced within a few centuries” to less than the Paris Agreement ceiling of 1.5 °C.

In 2022 the National Oceanic and Atmospheric Administration (NOAA) reported the GrIS experienced its 25th consecutive year of ice loss. In September of that year unprecedented late-season warming created surface melt conditions over 36 percent of the ice sheet, including the 10,500ft. ice sheet summit.

*The GrlS study authors Nils Bochow, Anna Poltronieri, Alexander Robinson, Marisa Montoya, Martin Rypdal and Niklas Boers variously work at the Department of Mathematics and Statistics, UiT – The Arctic University of Norway, Tromsø, Norway; Physics of Ice, Climate and Earth, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark; Potsdam Institute for Climate Impact Research, Potsdam, Germany; Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung, Potsdam, Germany; Department of Earth Science and Astrophysics, Complutense University of Madrid, Madrid, Spain; Instituto de Geociencias, CSIC-UCM, Madrid, Spain; Earth System Modelling, School of Engineering & Design, Technical University of Munich, Munich, Germany; and the Department of Mathematics and Global Systems Institute, University of Exeter, Exeter, UK.