PLEA Network

Carbon Brief, 13 June 2024: Analysis: What record global heat means for breaching the 1.5C warming limit. Global temperatures in 2023 blew past expectations to set the warmest year on record, even topping 1.5C in one of the main datasets. This warmth has continued into 2024, meaning that this year is also on track to potentially pass 1.5C in one or more datasets. Crossing 1.5C in one or even two years is not the same as exceeding the 1.5C limit under the Paris Agreement. The goal is generally considered to refer to long-term warming, rather than annual temperatures that include the short-term influence of natural fluctuations in the climate, such as El Niño. Nonetheless, recent warming has led to renewed debate around whether the world might imminently pass the 1.5C Paris Agreement limit – sooner than climate scientists and Intergovernmental Panel on Climate Change (IPCC) have previously estimated. Here, Carbon Brief provides an updated analysis of when the world will likely exceed the Paris 1.5C limit (in a scenario where emissions are not rapidly cut), using both the latest global surface temperature data and climate model simulations. The findings show that, while the best estimate for crossing 1.5C has moved up by approximately two years compared to Carbon Brief’s earlier 2020 analysis, it remains most likely to happen in the late 2020s or early 2030s – rather than in the next few years. Understanding global temperature targets Human emissions of CO2 and other greenhouse gasses have substantially warmed the planet over the past 150 years. On top of this human-driven warming, there is year-to-year natural variability largely associated with El Niño and La Niña events. A big El Niño or La Niña event can result in global temperatures up to 0.2C warmer or cooler, respectively, than they would otherwise be. As the world has been warming by around 0.2C per decade, a large El Niño event can represent an early look at what typical global temperatures will be a decade in the future. Or, to put it another way, human emissions are adding a permanent super-El Niño’s worth of heat to the climate system each decade. Read more here