Study shows it’s still possible to keep global warming to 2°C

Data: Zeke Hausfather;  Graphic: Jacques Schrag/Axios
Data: Zeke Hausfather; Graphic: Jacques Schrag/Axios

After years of gloomy projections, countries now have a more than equal chance of limiting global warming to or below the Paris Agreement’s 2°C temperature target, a a new study reveals.

Yes, but: This requires all national emission reduction pledges to be fully met, something countries are not currently on track to do.

  • Additionally, the study, led by Malte Meinshausen of the University of Melbourne, finds that there is only a slim chance, between 6% and 10%, of hitting the more aggressive goal of 1, 5°C of agreement.
  • The only way to achieve this would be for countries to commit to much stricter emissions reductions before 2030 and reach net zero by 2050.

Why is this important: Published in the journal NatureThis is the first peer-reviewed study to show such a high chance of keeping the global temperature increase to 2°C based on existing pledges from world leaders.

Threat level: Warming beyond 1.5 degrees risks catastrophic consequences, including the death of warm-water coral reefs and the irreversible melting of large parts of the polar ice caps.

  • Such warming is particularly dangerous for developing countries and low-lying island nations.
  • With only 1.1°C of warming so far compared to pre-industrial levels, we are already seeing unprecedented heat waves, wildfires, an intensification of tropical cyclones and the melting of glaciers and ice caps.

Driving the news: The study examines the evolution of countries’ emissions commitments, technically known as “nationally determined contributions” (NDCs), between the Paris summit in 2015 and the Glasgow summit at the end of the last year, and where they would take on Earth’s climate if filled.

  • According to the research, as of November 2021, 154 countries had submitted new or updated NDCs. Seventy-six of them had long-term goals such as net zero commitments.
  • By studying more than 1,400 emissions scenarios from the pledges made up to and during the Glasgow summit, the researchers found that if all the pledges were met in time, the warming peak could be limited to a just under 2°C.
  • “This is great news because it is the first time that governments have presented specific targets capable of keeping global warming below the symbolic level of two degrees,” the study’s co-author, told reporters. Christophe McGlade, from the International Energy Agency in Paris.

But, but, but… Policies are still needed to implement these promises, and so far they are scarce.

Be smart: Short-term reductions would be well below where they need to go to stay within the 1.5 degree guardrail.

  • Instead of reducing carbon dioxide emissions by 45% below 2010 levels by 2030, as required to be on a 1.5 degree trajectory, existing NDCs would actually increase emissions by 6% to 13 % during this period, according to the study.
  • The results, according to the researchers, “provide a sobering assessment of how far away current pledges are from limiting warming to 1.5°C,” the study said.

The context: In a accompanying commentaryZeke Hausfather, head of climate research at Stripe, and UC Davis climatologist Frances Moore find that short-term commitments are particularly important for the 1.5 degree goal.

  • “Long-term goals should be treated with skepticism if not backed by short-term commitments to put countries on track to achieve these goals over the next decade,” they wrote.

What they say : Meinshausen told reporters on a conference call that the study offered a warning about the 1.5 degree goal.

  • “Our study clearly shows that increased action over this decade is needed if we are to have a chance of not exceeding 1.5 degrees by a wide margin,” he said.

Teresa H. Sadler