Can updated climate pledges limit warming well below 2°C?; Increased ambition and implementation are essential

Abstract

As part of the 2015 Paris Agreement, countries agreed to regularly revisit and enhance their national climate strategies and, every 5 years, to offer new emissions targets in the form of nationally determined contributions (NDCs) (1). This year’s 26th Conference of Parties provides a waypoint in this updating process as countries have been offering enhanced or completely new NDCs (2, 3) (henceforth, updated pledges) (4). We find that compared with the 2015 pledges, the updated pledges suggest a strengthening of ambition through 2030. By calculating probabilistic temperature outcomes over the 21st century for five emissions scenarios (see the figure and table S1), we find that the updated pledges provide a stronger near-term foundation to deliver on the long-term goals of the Paris Agreement of reducing the probability of the worst levels of temperature change this century and increasing the likelihood of limiting temperature change to well below 2°C.