On Monday 8 October, experts from the Intergovernmental Panel on Climate Change ( IPCC) published their findings, in a Special report, on the possible consequences of a global warming of 1.5°C and the measures required to limit the impact of climate change.

After 5 days of discussions, a consensus finally emerged among the representatives of the 195 UN member countries and IPCC experts. This 400-page special report, prepared by nearly one hundred authors from forty countries on the basis of more than 6,000 scientific studies, features a twenty-page “summary for policy-makers”, approved line by line and intended to inform governments.

Arona Diedhiou, IRD research director, climatologist and atmospheric physicist with the IGE UMR, contributed to this report. Expert in the African climate system and climate change in tropical regions, Arona Diedhiou specifically contributed to chapter 3 on the impact of 1.5°C global warming on natural and human systems, and to summaries on sub-Saharan Africa.

The salient point of this report is that climate change is already affecting populations, ecosystems and livelihoods worldwide. While limiting global warming to 1.5°C is not impossible, it would require unprecedented transitions in all aspects of society”, says the researcher. “Every degree matters; holding global warming to 1.5°C has obvious advantages compared with 2°C or more, and in sub-Saharan Africa, for example, the decline in crop yields would be less severe at 1.5°C than 2°C”.

A 1.5°C temperature rise beyond pre-industrial levels would have irreversible consequences on ecosystems and human beings. If nothing is done, experts believe that this point could be reached between 2030 and 2050.

In the run-up to COP24, this report once again reminds us of the extent of global warming, its impact and urgency with which the States should take steps to substantially reduce CO2 emissions by 2030.