The cover art of the AR6 WGI report: “Changing” by Alisa Singer (IPCC 2021)
As Europe and China suffered from disastrous floods and fires and heatwaves raged in Greece, Siberia, Algeria and the US, the Intergovernmental Panel on Climate Change (IPCC) concluded its historic first all-virtual approval session in early August 2021. During this two-week-long process, all 195 member governments signed off on every single line of the Summary for Policymakers , including the following:
“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.”
IPCC (2021), the first key finding in the Working Group I Summary for Policymakers.
At over 3000 pages long, the report is the result of the hard work of hundreds of scientists from all over the world who have volunteered their time to bring together information from over 14,000 peer-reviewed studies. It is the first of three assessment reports that are part of the IPCC’s sixth assessment cycle1, each prepared by a dedicated Working Group. (The sixth assessment cycle also includes a methodology report and three special reports published in recent years: “Global Warming of 1.5°C”, “Climate Change and Land”, and “The Ocean and Cryosphere in a Changing Climate”).
The new Working Group 1 contribution, titled “The Physical Science Basis”, draws from multiple lines of evidence to provide an updated understanding of the physical science of the climate system and how it changes. It provides a rock-solid foundation for the two follow-up reports, which will discuss potential solutions, among other aspects. The Working Group 2 contribution, planned for early 2022, will assess climate change impacts, vulnerability, and adaptation options. This will be followed shortly after by the Working Group 3 contribution which will focus on methods to mitigate climate change. Finally, the Synthesis Report will wrap up the Sixth Assessment cycle in September 2022.
“The key messages are still the same as in the first IPCC report which was published already in 1988. […] The report published today echoes the same messages with much higher urgency.”
Petteri Taalas, Secretary General of the World Meteorological Organisation AR6 WG1 press conference 8/8/21
While some of its main messages echo what scientists have been repeating with growing confidence and an increasing sense of urgency for decades, the AR6 WG1 report itself is nothing if not innovative. This innovation extends beyond simply reporting the advances in scientific understanding over the last decade. The (stunningly beautiful) static graphs and maps in the report’s pages are for the first time being supplemented by an Interactive Atlas, which you can find here: http://interactive-atlas.ipcc.ch/. Exemplar in adopting FAIR (Findable, Accessible, Interoperable and Reusable) practices, its source code is fully available on GitHub, along with notebooks that explain how the analyses and figures provided by the platform are generated.
Video of the IPCC Interactive Atlas demonstrating both its global and regional analysis
The Atlas is split into two parts. While we have to wait until 27 September for the Regional Synthesis component, the Regional Information component is ready to explore. Its graphical interface gives access to a range of highly customizable yet user-friendly regional and global analyses of different modelled and observed datasets, climate indices and scenarios. The video gives a taster of what you can do in just a few clicks. To me, it looks like an immensely valuable resource for decision makers, students, scientists, and any other internet-using Earth inhabitant who wants to explore global and regional changes in our climate for themselves.
“Based on the science, it behooves every political figure and every decision maker – be it in the company, be it in local government, in city government, or indeed in national government, to look at their climate actions, to look at their emissions reductions, to assess how they can be a contributor , and to report that into the conversation that is going to be happening at COP26. For governments obviously through the NDC’s, but for others – including companies – to set up science-based targets against which they can measure their own performance, and to ensure business as usual does not become the continuation.”
Inger Andersen, Executive Director of the United Nations Environment Programme AR6 WG1 press conference 8/8/21
IPCC Co-Chair Valérie Masson-Delmotte: “unless there are immediate, rapid and large-scale reductions in greenhouse gas emissions, limiting warming to 1.5°C will be beyond reach.”
One of the key messages of the report, presented during the press conference by Working Group 1 co-chair Valérie Masson-Delmotte, is that “unless there are immediate, rapid and large-scale reductions in greenhouse gas emissions, limiting warming to 1.5°C will be beyond reach.” Based on this, there is no excuse not to act to reduce emissions as fast as possible. If global net-zero is reached by 2050, followed by net negative emissions, it is extremely likely that warming stays below 2°C, and more likely than not that it declines to below 1.5°C.
IPCC AR6 WGI Ch1 Figure 25 (accepted version subject to final edits)
Keeping below 1.5°C and 2°C of warming is not just a pass/fail situation: every tonne of carbon dioxide brings additional warming and the increasing extreme events associated with it, alongside other effects. The link between extreme events and climate change in this sixth assessment report is markedly stronger than in its predecessors. And these extreme events – heatwaves, droughts, floods, fires – can result in enormous ecological and socio-economic damage, death, and trauma to those living through them.
Between writing a paper on future droughts in the UK and reading news on recent flooding in my home country Belgium, I fully empathise with the sense of emergency radiating from the sixth Working Group 1 report. Our futures depend on how much CO2 and other greenhouse gases we still choose to emit – starting now.
