New research reveals that the world's leading climate models capture extreme heat only after crucial atmospheric warning signals have already begun

As record-breaking heatwaves increasingly grip the Middle East and Mediterranean, scientists are asking a critical question: Can the models used to forecast our climate accurately capture how these dangerous events actually develop?

A new study led by Andre Klif, Prof. Chaim I. Garfinkel, Prof. Dorita Rostkier-Edelstein, and Dr. Assaf Hochman of the Hebrew University of Jerusalem suggests the answer is only partly yes.

While the world's most advanced climate models successfully reproduce heatwaves once they are underway, they consistently miss key atmospheric processes that trigger these events, potentially limiting the ability to anticipate extreme heat several days in advance.

Published in Weather and Climate Extremes, the study analyzed 11 state-of-the-art climate models used in assessments by the Intergovernmental Panel on Climate Change (IPCC). The researchers compared model simulations with atmospheric observations across the Eastern Mediterranean and Middle East, one of the fastest-warming regions on Earth.

The findings reveal an important distinction: climate models generally reproduce heatwave conditions themselves, but often struggle to capture the gradual atmospheric buildup that occurs in the days leading up to extreme heat events.

The study shows that the warning signs of major heatwaves can begin thousands of kilometers away. Heatwaves in the Eastern Mediterranean are not isolated weather events but rather the result of a complex chain of atmospheric processes involving circulation patterns over Europe, Turkey, India, and parts of Africa. Subtle shifts in wind patterns and high-pressure systems can emerge up to a week before temperatures peak, creating an atmospheric pathway that transports warm air
into the region and gradually sets the stage for extreme heat.

However, the climate models examined in the study frequently delayed, weakened, or failed to reproduce these precursor signals. This suggests that important early-warning processes may not be fully represented in current climate simulations.

The findings have implications beyond climate science. Heatwaves are among the deadliest natural hazards worldwide and are already placing growing pressure on power grids, water resources, agriculture, and public health across the Middle East and Mediterranean.

One of the most important drivers of heatwave development identified in the study is a strengthening high-pressure ridge over Turkey. Models that represented this feature more accurately also tended to better reproduce the intensity of observed heatwaves.

The researchers also identified a notable connection between the South Asian monsoon and Mediterranean heatwaves. Observational data indicate that atmospheric changes over India help create conditions favorable for extreme heat in the Eastern Mediterranean. Yet none of the climate models successfully captured this relationship, pointing to a potentially significant gap in how interactions between tropical and mid-latitude weather systems are represented.

The study does not suggest that climate projections are fundamentally incorrect. Rather, it highlights the importance of evaluating whether climate models accurately reproduce the physical mechanisms that generate extreme events, not just their overall frequency or intensity.

A key conclusion is that models can produce realistic heatwave statistics while still misrepresenting the atmospheric processes that lead to those events. Improving the representation of these mechanisms could increase confidence in future climate projections and enhance prediction capabilities.

To address this challenge, the researchers propose a process-based framework for evaluating climate models. Instead of focusing solely on temperature outcomes, the approach examines the atmospheric dynamics responsible for generating extreme weather events.

This framework could help improve both long-term climate projections and shorter-term heatwave forecasting systems. As climate change continues to increase the frequency and intensity of extreme heat worldwide, identifying the earliest warning signs of heatwaves may become increasingly important for preparedness and adaptation efforts.