Greenhouse gas levels hit record highs in 2025, locking in centuries of climate change: UN

The UN weather agency said greenhouse gas concentrations reached new record highs in 2025, with carbon dioxide, methane and nitrous oxide all rising to unprecedented levels. The World Meteorological Organization said the increase will lock in long-term warming and climate impacts that will last for centuries, and it issued the warning ahead of the COP31 climate summit in Antalya, Turkey.