Fossil CO2 to Hit Record in 2025 as 1.5°C Budget Nears Exhaustion

Overview

• The peer‑reviewed assessment projects fossil‑fuel CO2 up about 1.1% in 2025 to roughly 38.1 billion tonnes, with renewable gains failing to offset rising energy demand.
• Authors estimate the remaining carbon budget for limiting warming to 1.5°C at about 170 billion tonnes of CO2, which would be used up within a few years at current emission rates.
• The study finds land and ocean sinks are weakening, notes some tropical forests have shifted from sinks to sources, and attributes about 8% of the post‑1960 CO2 concentration rise to sink decline.
• Country trends for 2025 show increases in the United States (+1.9%), India (+1.4%), China (+0.4%) and the European Union (+0.4%), with U.S. coal use rising after higher gas prices; 35 countries have cut emissions while growing their economies.
• A separate Climate Action Tracker update presented at COP30 reports policies and 2035 pledges leave the world on roughly a 2.6°C path and links a worsening outlook to the United States' exit from the Paris Agreement and the absence of an official U.S. delegation.