Abstract: The new and updated emission reduction pledges submitted by countries ahead of the Twenty-Sixth Conference of Parties represent a meaningful strengthening of global ambition compared to the 2015 Paris pledges. Yet, limiting global warming below 1.5 °C this century will require countries to ratchet ambition for 2030 and beyond. Here, we explore a suite of emissions pathways to show that ratcheting near-term ambition through 2030 will be crucial to limiting peak temperature changes. Delaying ratcheting ambition to beyond 2030 could still deliver end-of-century temperature change of less than 1.5 °C but would result in higher temperature overshoot over many decades with the potential for adverse consequences. Ratcheting near-term ambition would also deliver benefits from enhanced non-CO2 mitigation and facilitate faster transitions to net-zero emissions systems in major economies.
School Authors: Nathan Hultman, Yiyun 'Ryna' Cui, Jenna Behrendt, Maria Borrero, Christoph Bertram, Xavier Nelson-Rowntree, Jiehong Lou, Alicia Zhao, Andy Miller, Claire Squire, Audrey Rader, Kiara Ordonez Olazabal , Kowan O’Keefe, Mel George, Molly Schreier, Tiruwork Berhanu Tibebu, Xinyue Li
Other Authors: Alexandra Kreis, Dmitry Churlyaev, Mohammed Syed