La veille

Des chercheurs ont mis au point un cadre qui permet de relier les émissions des entreprises à des dommages climatiques spécifiques.

Human-caused climate change increased the likelihood and intensity of the hot, dry and windy conditions that fanned the flames of the recent devastating Southern California wildfires, a scientific study found. But the myriad of causes that go into the still smoldering fires are complex, so the level of global warming's fingerprints on weeks of burning appears relatively small compared to previous studies of killer heat waves, floods and droughts by the international team at World Weather Attribution. Tuesday's report, too rapid for peer-review yet, found global warming boosted the likelihood of high fire weather conditions in this month's fires by 35% and its intensity by 6%.

People around the world suffered an average of 41 extra days of dangerous heat this year because of human-caused climate change. The figure comes from analysis done by researchers at World Weather Attribution and Climate Central. In 2024 climate records were shattered as heat across the globe made it likely to be the hottest year ever measured, with few countries spared fatal weather events.

Every December, people ask us how severe the year’s extreme weather events were. To answer this question, we’ve partnered with Climate Central to produce a report that reviews some of the most significant events and highlights findings from our attribution studies. It also includes new analysis looking at the number of dangerous heat days added by climate change in 2024 and global resolutions for 2025 to work toward a safer, more sustainable world.

Nouveau "TALK" sur LIMIT avec Davide Faranda Directeur de recherche CNRS (permanent) en sciences du climat au laboratoire LSCE de l’Université Paris-Saclay. Son expertise principale est l’attribution des événements météorologiques extrêmes au changement climatique. Il aborde la Science de l'attribution qui permet de définir si des événements extrêmes sont liés ou non au changement climatique d'origine anthropique, comprendre les ouragans et ce à quoi il faut se préparer.

Greece, Italy, Spain, Portugal, France and Morocco experienced extreme heat in July 2024, causing at least 23 fatalities, widespread wildfires and bringing public life to a hold.

The floods displaced more than 80,000 people, led to over 150,000 being injured and, on the 29th of May, to 169 fatalities with 44 people still missing (Governo do Estado de Rio Grande do Sul, 2024). Essential services were also disrupted, leaving 418,200 households without electricity and over a million consumer units without water. Dozens of municipalities lost telephone and internet services.

Le changement climatique d’origine humaine modifie la probabilité de survenue de nombreux phénomènes météorologiques. Et il est possible de relier l’effet d’un réchauffement sur le temps long à des événements isolés.

De extreme hittegolven deze maand in grote delen van de VS, Zuid-Europa en China zouden ‘vrijwel onmogelijk’ geweest zijn zonder de door de mens veroorzaakte klimaatverandering. Dat is de conclusie van het World Weather Attribution-initiatief (WWA).

The method used to conduct an attribution study consists of eight steps, described here. The first step is the selection of an extreme event to study. After selecting an extreme weather event to study, the first step is to define the event, which provides a framework for the study. Researchers determine the geographical boundaries of the most impacted area, the best index to quantify the meteorological extreme (eg. maximum temperature, average rainfall, etc), and the duration of the event.

Following a record hot June, large areas of the US and Mexico, Southern Europe and China experienced extreme heat in July 2023, breaking many local high temperature records.

Sans le savoir, vous avez peut-être déjà entendu parler de la science de l’attribution par les unes des journaux : “En 2022, le changement climatique a rendu les canicules meurtrières en Inde et Pakistan 30 fois plus probables“. Ou encore “Une étude confirme que la vague de chaleur qui frappe l’Inde et le Pakistan depuis début mars a été rendue trente fois plus probable par le changement climatique“.

Un guide sur l’attribution pour les journalistes - traduction

Some two dozen climate liability suits have been making their way through the courts since 2015, bolstered by media investigations and attribution studies that are able to accurately pinpoint the precise contribution climate change has made to the damages inflicted by extreme weather events. A 2021 study in the journal Nature, for example, found that just over $8bn (£7bn) of the $62.7bn (£55.3bn) in damages caused by Superstorm Sandy across New York, New Jersey and Connecticut, is attributable to sea-level rise caused by climate change.

Le Pakistan a subi pendant de longs mois des inondations meurtrières. Il est désormais courant d'attribuer ces événements extrêmes au changement climatique. Mais s'il est certain que ce dernier augmente leur intensité et leur fréquence, il est plus difficile d'attribuer directement tel événement au changement climatique, notamment quand il s'agit de précipitations, qui résultent généralement de plusieurs facteurs. C'est ce à quoi s’attelle la science de l'attribution, née en 2004, et qui est de plus en plus sollicitée.