Climate change: Country climate pledges need ratcheting up to meet the 1.5 °C target

More ambitious national climate action pledges before 2030 are crucial to limit temperature change below 1.5 °C this century, according to a study published in Nature Climate Change.

By the end of the 26th Conference of the Parties (COP26) in November 2021, 151 countries had set more ambitious targets compared with the 2015 Paris Agreement pledges, aiming to further cut emissions by 2030. Countries are required to regularly revisit and update their national climate strategies under the Paris Agreement’s mechanism. Although the international community recognizes the necessity to further increase emissions reduction targets, we still do not understand the outcome of ratcheting ambition in 2030 and beyond, as well as its impact on specific regions or sectors.

Using a series of simulated emissions pathways that include ambitious climate action, Haewon McJeon, Gokul Iyer, Yang Ou, and colleagues demonstrate that ratcheting ambition in the near term, or before 2030, is essential to limit peak temperature change. Delaying ratcheting of ambition beyond 2030 could increase the risk of higher temperature overshoots and reduce long-term climate benefits. Ratcheting near-term ambition may also lead to more reductions in non-CO2 emissions, such as methane, and is expected to accelerate transitions to net-zero-emission energy systems.

The authors highlight the need to explore emissions pathways that not only focus on end-of-century temperature targets, but that also limit temperature overshoots throughout the century, as higher temperature overshoots before the end of the century could expose humans and ecosystems to significant risks.