Environment

Study warns compound climate extremes are accelerating beyond forecasts

Yesterday 13:47

By: Dakir Madiha

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Rare compound weather disasters such as simultaneous heatwaves and droughts or overlapping floods and extreme rainfall are increasing faster than climate models previously projected, according to a new study published in Nature. Researchers found that the frequency of these combined climate extremes rises almost directly with cumulative carbon dioxide emissions, while the most severe events intensify at an even faster and non linear pace.

The study introduces a new climate risk metric called the Transient Compound Response to cumulative CO2 Emissions, or TCoRE. Developed by researchers including Jian Li, Yongshuo Zhang and Philippe Ciais, the framework measures how the probability of compound extreme weather events changes with each additional unit of carbon dioxide emitted into the atmosphere. Unlike traditional climate indicators focused mainly on average temperature increases, TCoRE directly connects emissions growth with the likelihood of overlapping climate disasters.

Researchers found that moderate compound events such as combined heat and humidity increase steadily as emissions accumulate. However, the rarest and most destructive events intensify much more rapidly. By integrating observational constraints into Earth system simulations, the team concluded that real world TCoRE values exceed averages generated by existing climate models by between 37 and 75 percent. The method also reduced model uncertainty by as much as 56 percent.

The findings could have major consequences for international climate policy and carbon reduction targets linked to the Paris Agreement. Scientists warned that existing carbon budgets designed to limit global warming to 1.5 or 2 degrees Celsius may underestimate the risks posed by combined climate extremes. According to the 2025 Global Carbon Budget assessment, the remaining carbon budget from the start of 2026 for a 50 percent chance of keeping warming below 1.5 degrees Celsius stands at roughly 170 gigatonnes of carbon dioxide, equivalent to about four years of emissions at current rates.

The study also aligns with broader research showing rapid growth in climate related risks across vulnerable regions. A separate analysis published in April projected that 28 percent of the global population could face compound hot and dry extremes five times more frequently by the end of the century, with low income tropical countries expected to suffer the heaviest impacts.

Researchers argued that compound climate events create cascading failures across agriculture, infrastructure, water systems and public health networks. They warned that mitigation and adaptation strategies based on existing climate projections may systematically underestimate future risks. The findings suggest governments may need to reassess decarbonization timelines and emergency preparedness policies as compound climate disasters become more frequent and more severe.