This blog is written by Stephen Wilkinson. Stephen is the Head of the Smart and Sustainable Cities Research Cluster at the University of Wollongong in Dubai. One of his first jobs was working in a Coal Mine at Orgreave in the UK. He is now focused on researching more sustainable materials, energy sources and processes for the future.
Have you ever wondered what the IPCC report is and how it is compiled?
I reviewed the most recent IPCC report back in April 2020 (it’s a long process so it has only just been published). Here I will explain what the IPCC reports are, how they are structured and the concerning implications of the most recent publication.
In August 2021 the United Nations released the first part of its sixth assessment report titled “AR6 Climate Change 2021: The Physical Science Basis”. It is the work of 234 scientists who have referenced over 14,000 research articles. So, you can see why the process of generating these reports is so lengthy.
“By 2030, Global Surface Air Temperature (GSAT) in any individual year could exceed 1.5°C relative to 1850–1900 with a likelihood between 40% and 60%, across the scenarios”
IPCC AR6
What is the IPCC report?
These reports are released by the United Nations Intergovernmental Panel on Climate Change (IPCC). The first one (AR1) was release in 1990, and reports have been released periodically since then. Each report comprises four parts, one from each of the three working groups and an additional synthesis (summary) report. So “AR6 Climate Change 2021: The Physical Science Basis” is the first of four parts that will make up the complete sixth assessment report. The other three parts are due to be published in 2022. This first installment of the report is huge, at 3949 pages. But it is a substantially complete collection of human knowledge and understanding of the physical science basis for climate change.
“it is likely that the Arctic Ocean in September, the month of annual minimum sea ice area, will become practically ice-free (sea ice area less than 1 million km2) averaged over 2081–2100 and all available simulations.”
IPCC AR6
Why is it important?
The aim of the IPCC report is gathering together and communicating science to policy makers and the public. The report is not used for publishing new research, it is an exposition of the research that has been published in scientific journal and conference publications. However, one key thing that the reports do is to place a weighting on each of the key statements. After statements there are things like “(high confidence)” or “very low confidence” for example:
“Cities intensify human-induced warming locally, and further urbanization together with more
frequent hot extremes will increase the severity of heatwaves (very high confidence).”
These statements are really important as they indicate the preponderance of evidence behind everything that is stated in the report. These provide added value to the reports.
“Overshooting specific global warming levels such as 2 °C has effects on the climate system that persist beyond 2100 (medium confidence).”
IPCC AR6
What does the IPCC report say?
So what does the report say… Well, quite a lot. But some of the key things are:
The report first states our current understanding of climate change, and then Chapter 3 is dedicated to explaining how humans are responsible for climatic and ecosystem changes. This goes into high levels of detail. For example, it states that it is “very likely” that humans have reduced the amount of snow in the Northern Hemisphere. As another example, it says that the shallow ocean has become fresher (less salty) and the deep ocean has become saltier driven by human activity (with a “very likely” confidence level).
The report looks at interactions between climate and other systems, such as the water cycle, the ocean, the cryosphere, weather and biogeochemical cycles. It outlines the basis, and extent for the impact on these systems both now and in the future.
Finally the report looks at connecting global and regional climate change and makes a risk assessment of the impact on different regions. This is summarised in a visual interactive atlas, which makes clear what is expected in each country around the world due to climate change.
“Across each of the continents, higher warming is likely to occur in northern Africa, the central interior of southern and Western Africa; in northern Asia; in Central Australia; in Amazonia; in northern Europe and northern North America (high confidence).”
IPCC AR6
What are the implications of the report and what will happen in the future?
The evidence from the IPCC report is clear. Global surface temperatures between 2001 and 2020 were 0.84-1.10 degrees higher than 1850-1900. Human induced warming factors account for practically all of the observed rise. The impact of current and future predicted rises, even under the best-case scenario, are highly damaging- from sea level rise to biodiversity loss.
Under all scenarios, including the best-case, global temperatures will exceed 1.5°C warming and we will rely on carbon capture technologies to return to 1.5°C at a later date. So in the future, a target of net-zero is not enough. We need net-negative carbon emissions to reverse climatic changes. It is unlikely that we will achieve the best-case scenario and the impacts of climate change increase with each worsening scenario.
What can we do about it?
- Personal responsibility is a start not an end: We cannot rely on all 8 billion people across the earth to choose the climate friendly option, especially where the climate unfriendly option is readily available and cheaper. Governments must act to orchestrate the change. As long as the option to emit excess CO2 is available, some people will choose this option.
- We will need care in the selection of offset schemes: Many companies advertise that they are net zero. At present, this is done via offset schemes, ways that company compensate for present emissions by investing in ways to reduce emissions in the future. Sadly, many of these schemes are questionable. Some are based on avoided emissions, and removal offsets. Avoided emissions could be from a company promising not to cutdown trees on a piece of land until after 2100 and calculating the carbon that would not be emitted if the trees remain, or if you build a solar power plant you could compare it to the carbon emissions from the coal power plant you could have built. Removal offsets are better, but they provide a calculated offset of carbon at the planting phase for a tree planting project, with the idea that the trees will sequester that carbon in the future. Both of these schemes result in an increase in atmospheric carbon dioxide concentrations. Companies need to choose their offsets wisely.
- We need to prepare to mitigate the impacts of climate change: This discussion is no longer about how much climate change is occurring, nor is it about how much climate change is caused by humans. The discussion is about how to mitigate the effects of climate change on our lives. The consequences for us will be economic, cultural, social and legal. The key to the future will be climate adaptation and climate resilience.
As a final observation, because climate change is subject to political forces, the public conversation is subject to extreme views. The IPCC represents a moderate viewpoint. The summary for policy makers is agreed by the 195 UN member governments line-by-line, it therefore represents a broad global agreement. I would therefore encourage the reading of the summary for policy makers to anyone interested in climate science and climate action.
Image credits: feature image reproduced from the IPCC AR6 Summary for Policymakers cover page. Visual atlas screenshot from IPCC Visual Atlas webpage.