Code Red: New Climate Change Report Summary
Overview
On August 9, 2021, the Intergovernmental Panel on Climate Change (IPCC) released the first component of its Sixth Assessment Report and the UN Secretary General has called it a “Code Red for humanity” (Reuters). At a staggering 3949 pages, this report focuses on the physical science only and was assembled by 234 scientists (28% women, 72% men) from 65 countries who reviewed over 14,000 different scientific articles and studies to compile their findings. The full sixth assessment with all working group contributions will be released in 2022. In this post, I will break down everything you need to know about the report and the main findings.
About the IPCC
The IPCC is an intergovernmental body that “provides regular assessments of the scientific basis of climate change, its impacts and future risks, and options for adaptation and mitigation.” (IPCC) A key item to note here is that the IPCC does not produce research, rather it systematically compiles, reviews, and assesses climate research being produced by scientists all over the world.
The IPCC was formed in 1988 by the World Meteorological Organization (WMO) and the UN Environment Programme (UNEP) and currently has 195 countries as members. For those of you keeping track, the IPCC actually pre-dates the UN Framework Convention on Climate Change (UNFCCC) which was established 4 years later at the Rio Earth Summit in 1992. The easiest distinction between the two entities is that one is scientifically-focused and one is policy-focused. The IPCC provides a scientific basis for understanding climate change, its impacts and options for addressing it, while the UNFCCC negotiates multilateral agreements and mechanisms for addressing climate change (like the Kyoto Protocol or Paris Climate Agreement).
The IPCC has three working groups that focus on different dimensions of climate change. Collectively, they receive input from thousands scientists and experts who volunteer their time to advancing scientific knowledge on climate change. Their work then undergoes an open and transparent review by experts and governments around the world to build the assessment reports. The assessment reports of the IPCC are often described as the biggest peer-review exercise in the world (MSN). The working groups are as follows:
Working Group 1 - Physical science
Working Group 2 - Impacts, adaptation and vulnerabilities
Working Group 3 - Mitigation (reduction of greenhouse gases)
The IPCC also established the Task Force on National Greenhouse Gas Inventories (TFI) which standardizes the methodologies for calculating the emissions produced by individual nations.
Previous assessment reports by the IPCC were published in 2014, 2007, 2001, 1995, 1990. (IPCC)
Key Takeaways
#1 - It is unequivocal that human influence has warmed the atmosphere, ocean and land.
For decades, one of the biggest climate denial arguments has been “sure, climate change may be happening but it’s natural for the earth to go through changes, it’s not the fault of humans.” This new report has completely put this argument to bed. Scientists now are confident in saying the evidence is unequivocal that greenhouse gas concentrations and resulting impacts are the result of human activity.
The current CO2 concentration in the atmosphere (410ppm) is the largest in at least 2 million years.
#2 - We are already experiencing widespread and rapid changes in the atmosphere, ocean, cryosphere and biosphere, the scale of which is unprecedented over many centuries to many thousands of years.
Global surface temperature has increased faster since 1970 than in any other 50-year period over at least the last 2000 years. Each of the last four decades has been successively warmer than any decade that preceded it since 1850 (when we started recording temperatures), the past five years have been the hottest on record. The last decade has been warmer than any period in 125,000 years!!! We are experiencing the fastest levels of sea level rise in at least 3000 years, while simultaneously seeing the lowest level of arctic sea ice in at least 1000 years. Or to put it another way, sea level rise has nearly tripled compared with 1901-1971. Ocean acidification is at the highest levels seen in the last 26,000 years.
Some of changes caused by climate, specifically those related to the ocean (loss of arctic sea ice, ocean rise, etc.) are permanent and irreversible. In addition, the IPCC also has warned in this report that continued emissions could threaten carbon sinks (oceans and land), turning them from stores of GHGs to emitters, which could have devastating effects.
And finally, and worryingly, the report finds cannot rule out the chance that we will cross “tipping points”, such as sea level rise due to collapsing ice sheets or ocean circulation changes - they are still unlikely/low probability events but must be considered in planning due to our current trajectory.
Global temperatures have already risen about by approximately 1°C and are on track to pass 1.5°C in the next two decades.
#3 - Weather and climate extremes are now affecting every region across the globe
In this newest assessment, scientists are certain extreme weather events are increasing in frequency and severity and they are more confident in attributing extreme weather to global warming and specifically to human influence. In addition, they have identified that there is a direct relationship between warming and changes in the climate system, meaning that with every increment our planet warms we will see increases in the frequency and intensity of hot extremes, marine heatwaves, and heavy precipitation; agricultural and ecological droughts in some regions; and proportion of intense tropical cyclones; as well as reductions in Arctic sea ice, snow cover and permafrost. They also believe that human influence will likely increase the chance of compound extreme events (for example concurrent heatwaves and droughts).
#4 - It is still possible to meet Paris agreement goals but deep cuts are needed
The good news in this report is that we are not beyond hope, it is still possible to limit global warming. To do this, strong, rapid, and sustained reductions in CO2, methane, and other greenhouse gases are necessary, and specifically the world needs to aim for net-zero emissions by mid-century (2050).
If we continue with a high carbon economy, global warming could rise to 3.3-5.7°C higher by the end of the century (WRI).