IPCC report says immediate, major changes needed to curb climate changes
A new report by the Intergovernmental Panel on Climate Change (IPCC) issued a warning that many of the observed climate changes — unprecedented in thousands of years – are already set in motion, but some can still be reversed.
The IPCC report points out that strong and sustained reductions in carbon dioxide (CO2) emissions and other greenhouse gases would limit further climate change. It stated that benefits for air quality would come quickly and that it could only take 20 to 30 years to see global temperatures stabilize if efforts to reduce greenhouse gases continue.
The report — called Climate Change 2021: the Physical Science Basis — is the first installment of the three-part IPCC Sixth Assessment Report, which will be completed in 2022.
“This report reflects extraordinary efforts under exceptional circumstances,” Hoesung Lee, chair of the IPCC, said. “The innovations in this report and advances in climate science that it reflects provide an invaluable input into climate negotiations and decision making.”
The report provides new estimates of the chances of crossing the global warming level of 2.7°F above the pre-industrial (1850-1900) average in the next decades. Also, it finds that unless there are immediate and large-scale reductions in greenhouse gas emissions, limiting warming to close to 2.7°F or even 3.6°F (2°C) will be beyond reach.
Further, the report shows that emissions of greenhouse gases from human activities are responsible for approximately 2.0°F (1.1°C) of warming above pre-industrial levels. In addition, it finds that averaged over the next 20 years, global temperature is expected to reach or exceed 2.7°F of warming.
“This report is a reality check,” IPCC Working Group I Co-Chair Valérie Masson-Delmotte said. “We now have a much clearer picture of the past, present, and future climate, which is essential for understanding where we are headed, what can be done, and how we can prepare.”
In the coming decades, climate changes will increase in all regions, the report states. For 2.7°F of global warming, there will be increasing heat waves, longer warm seasons, and shorter cold seasons. At 3.6°F of global warming, heat extremes would more often reach critical tolerance thresholds for agriculture and health, the report adds.
Lawrence Livermore National Laboratory scientists Paul Durack, Celine Bonfils, Peter Gleckler, Ben Santer, and Mark Zelinka contributed to this report.
“Every heatwave occurring today is made more likely and more intense by human-induced climate change. What we have known for some time, and what the latest report confirms, is that a higher rate of greenhouse gas emissions leads to a higher warming rate, and this leads to increasing intensity and frequency of extremes. In coming years, we expect to see new extremes that are unprecedented in magnitude and frequency, or in regions that have never encountered those types of events,” Durack said.
The report stated that climate change goes beyond rising temperatures, also affecting things like rainfall patterns. In high latitudes, precipitation is likely to increase, while it is projected to decrease over large parts of the subtropics. Coastal areas will see continued sea-level rise throughout the 21st century, contributing to more frequent and severe coastal flooding and erosion. Also, further warming will amplify permafrost thawing and the loss of seasonal snow cover, melting of glaciers and ice sheets, and loss of summer Arctic Sea ice.
The report states that human actions still have the potential to determine the future course of the climate as carbon dioxide (CO2) is the main driver of climate change.
“Stabilizing the climate will require strong, rapid, and sustained reductions in greenhouse gas emissions and reaching net-zero CO2 emissions. Limiting other greenhouse gases and air pollutants, especially methane, could have benefits both for health and the climate,” IPCC Working Group Co-Chair Panmao Zhai said.
Heather Zichal, CEO of the American Clean Power Association (ACP), commented on the report, saying that addressing climate change requires international collaboration. She cited policies and government actions laid out in the report that can be enacted to drastically reduce carbon emissions.
“As Congress debates infrastructure legislation and prepares for the budget reconciliation process, this report shows that our leaders need to realize the immediate national security threat climate change poses to our country and future generations. As wildfires and hurricanes occur more frequently, the human and economic devastation they cause will only intensify if we do not take immediate action now,” Zichal said.
