Mexico, Pakistan and India suffer deadly heatwaves ; Californian forests are devastated by fires ; northern Europe has just experienced multiple floods… These snapshots remind us, if necessary, that climate change offers no respite. In fact, it is growing at an unprecedented rate.
This is what the second report on global climate change indicators reveals (IGCC), published on June 5 in the newspaper Earth System Science Data (ESSD). “ The Paris Agreement’s most ambitious threshold, limiting global temperature warming to 1.5°C, is getting dangerously close »warns Aurélien Ribes, researcher at the National Center for Meteorological Research (CNRM), in a press release.
Temperatures are getting warmer faster than ever »
Led by the University of Leeds, with the support of more than fifty renowned scientists, this report updates the main results of the IPCC (Intergovernmental Panel on Climate Change) Working Group 1 report published in 2021, dedicated to the physical bases of climate change.
The results it contains are scathing: global warming of temperatures, caused by human activities, increased by 0.26°C over the decade 2014-2023. This is the highest rate observed since records began. Since pre-industrial times, average temperatures have increased by 1.19°C. A figure revised upwards compared to the 1.14°C observed between 2013 and 2022 – which therefore did not include the exceptionally hot year 2023.
“ Global temperatures continue to move in the wrong direction, faster than ever », summarizes Piers Forster, coordinator of the report and director of the Priestley Center for Climate Futures at the University of Leeds. According to’IGCCin 2023, i.e. in a single year, the rise in temperatures reached 1.43°C on average [1], compared to the pre-industrial period. It was the hottest year on record, marked by the return of the super-warming weather phenomenon El Niño. Even excluding natural variability linked to El Niño, researchers estimate that warming linked to human activities was 1.3°C that year.
This acceleration is linked to ever-high greenhouse gas emissions, driven by human activities, notably deforestation and the exploitation of fossil fuels such as coal, oil and gas. They are equivalent to 53 billion tonnes of CO2 per year.
Accelerated warming is linked to greenhouse gas emissions from human activities, including the exploitation of fossil fuels such as coal, oil and gas.
Pxhere
The concentrations of the main greenhouse gases in the atmosphere, which cause the climate system to spiral out of control, are therefore reaching peaks. 419.3 parts per million (ppm) for carbon dioxide (CO2) – compared to 410.1 ppm in the 2021 IPCC report (i.e. the number of molecules of CO2 present for a million molecules of all the constituents present in the air). A value unseen for more than 2 million years. 1,922.5 parts per billion (ppb) for methane and 336.9 ppb for nitrous oxide. The climate system is racing under the effect of this excess energy.
Other data, a priori paradoxical. Aerosols, created by polluting activities, nevertheless allow part of the sun’s rays to be reflected back into space. And therefore to cool the planet. However, thanks to global efforts to improve air quality, there is less of it. The drop in these particles suspended in the atmosphere, such as sulfur emitted by maritime transport, could therefore have played a role in climate warming, the researchers indicate.
How much room for maneuver remains ?
The question that now arises is: what room for maneuver remains to contain the increase in global temperatures below 1.5°C, the threshold set by the Paris Agreement to avoid immeasurable consequences? ? L’IGCC estimates that our residual carbon budget, that is to say the emissions not to be exceeded to maintain a 1 in 2 chance of remaining below 1.5°C, is around 200 billion tonnes of CO2, the equivalent of approximately five years of emissions at the current rate. It was around 500 billion in the IPCC’s assessment in 2021.
As the latest IPCC report indicated, warming will continue whatever happens in the short term, until 2040, and the limit of 1.5°C could be crossed at the start of the 2030s. These are our current actions that will determine the extent of climate change in the longer term. However, today, the account is not there. According to the report of theUN on the gap between needs and prospects for reducing emissions, countries’ commitments are leading the planet towards warming of 2.5 to 2.9°C by the end of the century.
“ Dashboard lights flash red »
“ This second update of the IPCC report highlights the rapid intensification of the influence of human activities on the climate, observes Valérie Masson-Delmotte, research fellow at the Atomic Energy and Alternative Energies Commission (CEA). The severity of the consequences observed in recent months, the intense heat on land and at sea, extreme precipitation, drought, fires, and their effects on ecosystems, infrastructure and the economy, remind us why the slightest increase in warming is disastrous. »
“ The dashboard lights flash red. Without meaningful action, things will continue to get worse, faster and faster », reacts Peter Thorne, director of the Icarus climate research center. This warning comes as representatives of nearly 200 countries are currently meeting in Bonn (Germany), until June 13, to prepare for the next global climate conference (COP29), which will be held in November in Baku, Azerbaijan.
This new report is also accompanied by an open data and science platform: the Climate Change Tracker, which provides easy access to up-to-date information on the main climate indicators.
