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Exceeding the 1.5C degree limit on warming now seems inevitable

The major failure of COP27, the recent international climate negotiations, was the absence of any new commitments to limit warming to 1.5C above pre-industrial levels. The source of this target, and the significance of failing to achieve it, is the subject of this blog.

What makes the 1.5C target so significant? As the preceding makes clear, the target is a political and not a scientific number. However, the target also has a scientific basis. Speaking of the difference between 1.5 and 2 degrees centigrade, Espen Eide, Norway’s minister of climate and environment, made the point starkly: “Entire countries . . .will simply disappear from the surface of the planet. Most of all the ice on the world will melt. Cities we love and live in will be gone.” Much of nature, including coral reefs and many animal species, are also candidates for extinction approaching 2C. (For a scientific description of the difference in the dangers of 2C versus 1.5C, see the 2018 report of the Intergovernmental Panel on Climate Change.) Consequently, support for the target is forcefully promoted by the poorest and most vulnerable countries, including small island states, who see it as a matter of survival.

Would limiting warming to 1.5C be sufficient? Given the many recent climate disasters after roughly 1.1C of warming, there is a strong argument that the concentration of greenhouse gases in the atmosphere (about 420 ppm) is already too high. Groups like 350.org argue that emissions must be reduced substantially to levels closer to those prior to the industrial revolution. This position is also supported by evidence the world is approaching, or may even have exceeded, positive feedbacks and tipping points such as release of massive amounts of methane from the melting of permafrost and the end of carbon sequestration by the Amazon rainforest with potentially catastrophic consequences.

What happened at COP27? The parties to COP27 “reaffirmed” the 1.5C target but rejected inclusion of a resolution to cause emissions to peak by 2025 and language endorsing phasing out of all fossil fuels. Both were measures advocated by the US, EU, and small island states and according to recent UN analysis are seen as necessary to achieve the goal. Opposition came from oil-producing countries and some developing nations with hopes for riches from their oil and gas resources, supported by a record number of lobbyists from fossil fuel companies.

Where did the target come from? The 1.5C target was included in the Paris Climate Agreement of 2015. The COP26 Glasgow Climate Pact recognized that to limit warming to this level would require “rapid, deep and sustained reductions in global greenhouse gas emissions” including net zero CO2 emissions “around mid-century.”

Some positive developments outside the COP. While COP27 did not produce any agreement in support of the need for more rapid and dramatic reductions in use of fossil fuels, there was some good news outside the negotiations. One was an increase in support for the Global Methane Pledge, a commitment to reduce emissions of methane (a greenhouse gas 84 times as potent as CO2) by at least 30% by 2030 relative to 2020 levels. The Pledge has now been endorsed by over 130 countries representing over half of global methane emissions (although not by China or Russia). Also, outside the formal negotiations, President Biden and President Xi Jinping of China agreed to restart talks on climate change cooperation. Talks had been frozen by China since August, following Speaker Pelosi’s visit to Taiwan. The two countries are the largest emitters of greenhouse gases and together account for over 40% of global CO2 emissions. President Biden also released a list of smaller but still noteworthy domestic climate initiatives following the COP.

Where do things stand now? National climate policies currently in place are estimated to result in warming well beyond the Paris goals, or 2.8C. Most analyses of pathways to staying below 1.5C, including many corporate “net zero” pledges, rely significantly on large scale carbon capture and sequestration technologies still in its early stages. The energy crisis triggered by Russia’s invasion of Ukraine has also resulted in significant additional investments in fossil fuel production and distribution. Many of these investments, such as new powerplants and liquid natural gas processing and transport, will require many years to payoff making prospects for early termination unlikely. Thus, while the 1.5C target is in theory still achievable, it is on “life support. . .in intensive care,” as UN Secretary General Antonio Guterres has stated. Independent experts have concluded it’s already too late, concluding “Let’s face it. We are going to breach the 1.5 degrees limit in the next couple of decades.”

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If as seems likely the world does exceed the 1.5C warming target, the issue becomes by how much and whether efforts are made to bring it back down. Limiting temperature increases to 1.5C could halve the amount of sea level rise that happens by the end of the century and every tenth of a degree can determine the extent of future damage.

Given the consequences of failing to limit warming to 1.5C, the failure to achieve any steps toward the necessary rapid, dramatic reductions in greenhouse gas emissions required may be the dismal, lasting legacy of COP27.

Alan Miller is a former climate change officer in the International Finance Corporation (2003–13) and climate change team leader, Global Environment Facility (1997–2003). Besides other engagements, Alan is an active editor for Climate Conscious submissions on Medium.