New IPCC Report: Time for Debate is Over, This is Our Last Chance for Drastic Action

Graphic by Annabel Driussi for ODP

This morning the U.N.’s Intergovernmental Panel on Climate Change (IPCC) released the first part of its 6th major assessment report. This report provides a high-level summary of the understanding of the current state of the climate, including how it is changing and the role of human influence as well as the state of knowledge about possible climate futures.

This morning’s report makes clear that it is unequivocal that human influence has warmed the atmosphere, ocean and land.”

Human influence has warmed the climate at a rate that is unprecedented in at least the last 2000 years” the report states.

Key findings include:

  • Each of the last four decades has been successively warmer than any decade that preceded it since 1850.
  • Global surface temperatures are reaching levels not seen in 100,000 years.
  • In 2019, atmospheric CO2 concentrations were higher than at any time in at least 2 million years.
  • It is “virtually certain” that human-induced climate change is making hot extremes (heatwaves) more frequent and intense, and cold extremes less common and less severe.
  • Human-induced climate change is driving the frequency and intensity of heavy precipitation events across most land area.
  • It’s likely that climate change is increasing the incidence of tropical cyclones and scientists can say with high confidence that a warmer planet is causing these storms to bring more heavy precipitation.

Why This Matters: In 2013 the IPCC authors concluded that humans were the “dominant cause” of the warming seen since the 1950s. That assessment served as the basis for the Paris Climate Agreement signed in 2015, yet 6 years later there is an even more urgent need for the world to strengthen its commitments to rapid decarbonization. This year, IPCC authors stated without question that there is a near-linear relationship between cumulative CO2 emissions and the increase in global surface temperature. It’s a more dire warning that the outcome of the upcoming COP26 climate meeting in Glasgow will very much determine the future human beings will experience for the coming decades and even millennia.

Time has run out for debate and slow walking, anything less than comprehensive action will set us on a course for drastic climate consequences.

More On the Report: This latest report uses 5 new illustrative emissions scenarios that consider a range of greenhouse gas (GHG) emissions, land use, and air pollutant futures the nations of the world may experience.

  • The scenarios begin in 2015, and include scenarios with high and very high GHG emissions (SSP3-7.0 and SSP5-8.5) and CO2 emissions that roughly double from current levels by 2100 and 2050, respectively, scenarios with intermediate GHG emissions (SSP2-4.5) and CO2 emissions remaining around current levels until the middle of the century, and scenarios with very low and low GHG emissions and CO2 emissions declining to net zero around or after 2050, followed by varying levels of net negative CO2 emissions23 (SSP1-1.9 and SSP1-2.6.
  • Global surface temperature will continue to increase until at least the mid-century under all emissions 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.

Graphic: IPCC


Also worth noting is that scientists haven’t previously had a full accounting of just how much human activity has contributed to warming as aerosols (in large part from pollution) have helped mask their effect through a cooling effect. 

Inevitable Loss: The report makes clear that warming caused by humans has already reached irreversible thresholds especially as it pertains to the loss of sea ice. According to the report:

Mountain and polar glaciers are committed to continue melting for decades or centuries (very high confidence). Loss of permafrost carbon following permafrost thaw is irreversible at centennial timescales (high confidence). Continued ice loss over the 21st century is virtually certain for the Greenland Ice Sheet and likely for the Antarctic Ice Sheet.

In addition, it’s virtually certain that global mean sea level will continue to rise over the 21st century. Yet by how much will depend on how rapidly the world can halt global greenhouse gas emissions.

Moving Forward: In the United States, Congress must act swiftly to pass legislation that slashes emissions and sets the nation on a low-carbon path. As Congresswoman Kathy Castor (D-FL), Chair of the House Select Committee on the Climate Crisis, stated:

This report confirms what Americans are experiencing firsthand – the devastating impacts of the climate crisis are here, and they are getting worse….The stakes of this crisis demand nothing less than the most ambitious plan for clean energy and resilient infrastructure in American history. We cannot afford to squander this once-in-a-generation opportunity to invest in affordable clean energy, deliver good-paying union jobs, and finally secure environmental justice for our communities.

Americans understand this, and it’s why they elected President Joe Biden. With his Build Back Better Agenda and our Climate Crisis Action Plan, we know what it will take to solve this crisis.

Congress must act with the urgency this moment demands, and get President Biden’s climate plan across the finish line.”

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