After a first part published in August 2021 on the current state of the climate, how it is changing and the role of human influence, the Intergovernmental Panel on Climate Change published the second part of its sixth assessment report (AR6) on 28 February. This new publication, written by Working Group II (WG2) comprising 270 scientists from around the world, was built on the basis of 34,000 studies and focuses on impacts, vulnerabilities and adaptation to the climate crisis. A third part, on solutions to reduce greenhouse gas emissions, was published at the beginning of April and a synthesis is planned for September 2022.
A new report, new findings
Climate impacts worse than initially estimated
The IPCC is hardening its diagnosis compared to 2014 as the latest report shows that risk levels are increasing from "high" to "very high" in all RFCs and at lower global warming levels. This is in addition to recent estimates that, by 2100, global climate risk will increase by a factor of two or four for global warming of 2°C and 4°C respectively, and that each additional 0.5°C of warming will increase global climate risk by one third.
Thus, the climate impacts are and will be worse than previously thought. Climate change, caused by anthropogenic greenhouse gas emissions, has already resulted in "widespread adverse effects" and caused irreversible damage to all societies and ecosystems, at all latitudes. This is one of the main novelties of the AR6: the IPCC report no longer focuses solely on projections, but also on the observable impacts of climate change.
Today, about 3.3 to 3.6 billion people live in contexts that are highly vulnerable to climate change.
It is crucial to understand that human and ecosystem vulnerability are interdependent, and current unsustainable development patterns increase the exposure of ecosystems and people to climate hazards. In addition, it is important to note that climate change impacts and risks are becoming increasingly complex and difficult to manage due to their potential simultaneity and possible interactions. Multiple climate and non-climate risks will interact, exacerbating the overall risk and cascading risks across sectors and regions.
Finally, while short-term actions to limit global warming to around 1.5°C would significantly reduce projected climate change-related losses and damages in human systems and ecosystems compared to higher levels of warming, this would not be sufficient to eliminate them all. Beyond 2040, the extent and rate of climate change and associated risks will depend heavily on mitigation and adaptation measures taken in the short term. Although closely linked to the mitigation component (i.e. the reduction of greenhouse gas emissions), there is therefore also a real challenge to act now on the adaptation component.