The United Nation’s Intergovernmental Panel on Climate Change (IPCC) has published its most dire assessment on climate change ever as part of its Sixth Assessment Report (AR6). The report, Climate Change 2021: The Physical Science Basis, was contributed by Working Group 1, a group of 234 authors, including PCC Executive Board Member Kyle Armour (ATM S/OCEAN) as a Contributing Author, and cites over 14,000 scientific papers. The contents of the report have been approved by 195 governments across the globe.

Some key aspects of the report include:

• The declaration that “it is unequivocal that human influence has warmed the atmosphere, ocean, and land,” which has led to unprecedented “widespread and rapid changes in the atmosphere, ocean, cryosphere and biosphere,” affecting worldwide climate and weather extremes. This is the most definitive statement on the anthropogenic causes and effects of climate change ever given by the IPCC.
• The IPCC’s assessment that “global surface temperature will continue to increase until at least the mid-century under all scenarios considered. Global warming of 1.5° C and 2° C will be exceeded during the 21st century unless deep reductions in CO2 and other greenhouse gas emissions occur in the coming decades,” which would serve to further intensify the variability and extremes of the planet’s climate and weather. It is increasingly likely that we will see warming of 1.5° C in the 2030’s, the earliest timeframe in the potential range of 2030-2050.
• The harrowing statement that “many changes due to past and future greenhouse gas emissions are irreversible for centuries to millennia, especially changes in the ocean, ice sheets and global sea level.”
• The belief that there is still time to act, as although the situation is dire, and more change is inevitable at this point, it is still possible to limit the total global warming to about 1.5° C with decisive global steps towards net-zero carbon emissions in the coming decades. If the goal of net-zero is reached by 2050, the worst effects of climate change may be mitigated.

The remarks in this report may not be entirely surprising, but this report is nonetheless a landmark assessment, as the tragedy, urgency, and hope conveyed within this report may be exactly the push policymakers need to strive for legitimate, over-arching reform.

For Graduate Students: If you are interested in deeper analysis and discussion on the contents of this report, consider signing up for ATM S/ESS/OCEAN 586, Current Research in Climate Change! This 2-credit Autumn 2021 class is being led by Becky Alexander, and will focus on becoming familiar with the content of the IPCC AR6 WG1 report through peer discussion and talks with professionals. The course intends to help individuals better understand how their research connects to other sub-disciplines and the large-scale picture of climate change, and to better prepare students to speak broadly about climate change in professional and community-outreach settings.

Read the IPCC AR6 WG1’s Full Report, Technical Summary, or Summary for Policymakers here!