Extreme global climate outcomes are possible even at 2C of warming

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https://www.ufz.de/index.php?en=36336&webc_pm=14/2026

Press Release, 25. March 2026

Study led by UFZ highlights the need for ambitious climate mitigation measures

Extreme climate impacts on people and the environment are often associated with very high levels of global warming (3 or 4°C). A new study led by the Helmholtz Centre for Environmental Research (UFZ) shows that this assumption is too simplistic. Even moderate warming of 2°C could pose considerable climate risks for sectors that are particularly important for society and ecosystems. These include densely populated regions facing heavy rainfall, key agricultural areas affected by droughts, and forests exposed to extreme fire weather conditions. This underlines the urgency of rapid climate mitigation measures to limit these risks. The study has been published in Nature.

Because climate models still involve considerable uncertainties, it cannot be ruled out that the global climate could develop far more dramatically than expected. “In the interest of responsible risk assessment, we should therefore look beyond the most likely ranges projected by climate models and consider extreme outcomes that could have severe societal or environmental consequences”, says lead author and UFZ climate researcher Dr Emanuele Bevacqua. Until now, these worst-case “extreme global climate outcomes” have typically been described using the average results of many climate models at high levels of global warming (3 or 4°C). However, this approach does not take into account the fact that even at moderate levels of global warming, individual climate projections for certain regions can be very severe. “Furthermore, weather patterns in neighbouring regions tend to be strongly correlated, whereas those in distant regions are largely uncorrelated. This makes it difficult to infer global risks from local uncertainty estimates”, says co-author Prof Dr Jakob Zscheischler, climate researcher at the UFZ and Professor for Data Analytics in Hydro Sciences at TUD Dresden University of Technology.

The researchers therefore adopted a new approach for their study: they identified sector-specific drivers of climate impact such as precipitation extremes and droughts as well as regions where vulnerable sectors (e.g. forests, agriculture, and densely populated areas) are located. Combining these factors makes it possible to examine climate changes in locations where they are particularly relevant for specific global risks. For example, they analysed heavy rainfall in densely populated regions, droughts in major global agricultural regions, and fire-conducive weather in forests. To do this, they evaluated global simulations from many different climate models, which also form the basis of the reports of the Intergovernmental Panel on Climate Change (IPCC). In this way, they were able to identify the model projections that show the strongest (worst-case) and the weakest (best-case) outcomes respectively for each sector examined.

The key finding: for each of the three global domains examined (heavy rainfall in densely populated regions, droughts in global agricultural regions, and fire-conducive weather in forests), some individual climate model projections show considerably greater changes at 2°C of warming than the average across all models at 3°C or even 4°C. This is particularly evident in relation to food security, by focussing on growing regions that account for a large share of global production of maize, wheat, soy, and rice. In this area, the climate models show very large differences. Depending on the model, the frequency of droughts at 2°C of warming may remain unchanged or increase by more than 50%. “At 2°C, 10 of the 42 models examined produce a drought increase that is considerably above the model average at 4°C of warming”, says Bevacqua. The risk of droughts in globally important growing regions is therefore much higher than would be expected from an analysis of model averages. Given their importance for food security, global supply chains, and international markets, the consequences of such extreme climate developments need to be examined more closely. In the domains ‘heavy rainfall in densely populated regions’ and ‘extreme fire weather in forested areas’, the worst-case models at 2°C also show climate trends that exceed the average changes at 3°C of warming.

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Bevacqua, E., Fischer, E., Sillmann, J. et al. Moderate global warming does not rule out extreme global climate outcomes. Nature 651, 946–953 (2026). https://doi.org/10.1038/s41586-026-10237-9