Mitigation of Climate Change: The IPCC AR6 WGIII report

Jamie Males, Executive Editor, PLOS Climate

In the latest instalment of the Intergovernmental Panel on Climate Change (IPCC) AR6 assessment process, today saw the publication of Working Group III’s report on Mitigation of Climate Change. As with all the Working Groups reports, this was the result of an enormous international effort involving months and years of work on the part of its contributors, including sleepless nights as the approval process reached its culmination over the last couple of weeks.

The report draws together a wealth of scientific evidence in support of a set of very clear messages. First, past and present greenhouse gas emissions are extremely unevenly distributed between global regions and countries. The cumulative emissions of the Least Developed Countries (LDCs) and Small Island Developing States (SIDS) between 1850 and 2019 account for less than 0.4% and 0.5% respectively of total global emissions across this period. The sources of regional emissions also vary. For both Africa and Latin America and the Caribbean, per capita emissions associated with land use and land use change were of approximately the same magnitude as emissions from fossil fuels and industry in 2019. By contrast, in both Europe and North America, where per capita emissions from fossil fuels and industry are much higher, land use and land use change represent a relatively small but important net sink.

Secondly, existing commitments to emissions reductions are not sufficient to put us on track for a global mean temperature rise of 1.5 degrees Celsius or less. In fact, the median projection based on current policies is for 3.2 degrees of warming. The past decade has seen the highest average emissions in history (driven largely by fossil fuel use), and only deep and rapid cuts across all sectors of industry and society, in all parts of the world, will bring us below the 1.5 threshold. Indeed, under the scenarios considered by the report authors, a 43% reduction in emissions will be required by 2030 to ‘keep 1.5 alive’, followed by global net zero emissions by the early 2050s. Choices made and actions taken over the next few years will therefore be of huge significance to the trajectory we find ourselves on for the remainder of the century.

The good news, as the report points out, is that we now have access to a range of technological, political and economic measures that can put us on this path to decarbonisation, and that could even halve emissions by 2030. Renewable energy and energy storage technologies have become dramatically cheaper since 2010, unlocking the potential for rapid and widespread adoption of cleaner energy production, distribution and use. Furthermore, real and meaningful action towards emissions reductions is already happening in many countries, and can be accelerated further if all the tools at our disposal are brought to bear.

The report places particular emphasis on the potential for the world’s cities to play a leading role in emissions reductions (through innovations and interventions in urban planning, infrastructure, building design, transportation etc.), a theme that will be picked up in a planned IPCC Special Report on climate change and cities. Watch this space for further announcements on this subject from PLOS Climate too! Other issues called out in the report include the importance of major changes in industrial production, as well as the advancement of circular resource use. The urgent need for increased financial flows in support of climate change mitigation is also raised; the report suggests that part of the solution will be a clearer alignment between public sector finance and policy.

With expert-led journal sections dedicated to- among others- Mitigation, Nature-based Solutions, Energy, Politics and Justice, Technology and Engineering, Urban Climate, Economics, and Behaviour and Psychology, PLOS Climate offers a multidisciplinary venue for research covering all aspects of the transition to the net-zero emissions scenario that the report shows we must achieve. We look forward to publishing research that carries forwards the many strands running through this and the other Working Group reports.

The reports of the other Working Groups (on the Physical Basis of Climate Change and on Adaptation) have been discussed elsewhere on this blog:

WGI: Climate change: the message is clear

WGII: Reflections on the IPCC WGII report- A.R. Siders