IPCC warns once again about climate change, 33 years after its creation

Alert, Alarm, Emergency

In August 2021, 33 years after its creation, the scientists of the IPCC (Intergovernmental Panel on Climate Change) warn once again in their 6th report (AR6) on the physical basis of climate change (IPCC Group I) about climate change, already underway, and about the changes to come.

Since their last report in 2013, the science has consolidated and the scientists state this unequivocally in the very first statement in the Summary for Policymakers: "It is unequivocal that human influence has warmed the atmosphere, ocean and land. Widespread and rapid changes in the atmosphere, ocean, cryosphere and biosphere have occurred."

The Summary for Policymakers is divided into 4 parts:

The current state of climate change where one of the novelties of this report is the regional approach to climate change which gives important insights into the observed climate differences since the 1950s across the world.

Possible future climates where the climate consequences of 5 different scenarios of GHG emissions to the atmosphere are analyzed. According to the simulations of the 5 scenarios, the higher the cumulative CO₂ emissions to the atmosphere, the lower the proportion of CO₂ emissions captured by land and ocean.

Regional risk assessment and adaptation, where scientists assess how the climate responds to both human influence and natural factors and their internal variability. But scientists warn that while natural factors and internal variability will modulate human-induced changes, particularly on a regional scale and in the short term, this will have little effect on the temperature increase by 2100. However, the impacts of climate change will be greater at 2°C than at 1.5°C, and even greater if the temperature exceeds 2°C, in all regions of the world.

In the final section of the report entitled "limiting future climate change", the scientists insist, "every tonne of CO₂ emissions adds to global warming" and state, "From a physical science perspective, limiting human-induced global warming to a specific level requires limiting cumulative CO2 emissions, reaching at least net zero CO2 emissions, along with strong reductions inother greenhouse gas emissions."

In the media, the scientists who participated in the writing of this report continue to warn about the current and future state of climate change.

"This report is a reality check that should normally provide all the objective bases for action."

"There is no going back, climate change is a journey of no return"

"To limit global warming, we must achieve carbon neutrality, we must not allow a single molecule of CO₂ to accumulate in the atmosphere, and this is a geophysical constraint"

(Christophe Cassou, Mediapart, A l'Air Libre, 9 September 2021)