Climate change is a global phenomenon, but its effects are not distributed evenly. Research led by the Universidad Carlos III de Madrid (UC3M) and the Universidad de Zaragoza (UNIZAR), based on data from the United States, shows that while some regions face increasingly extreme summers, others lose winter cold; global warming is uneven.
This inequality forces a rethink of how adaptation and mitigation policies are designed.
The study in detail
The team analyzed data from 48 contiguous U.S. states between 1950 and 2021, using the PRISM temperature database, which combines more than 26,000 daily observations per state.
To compare warming, they developed the concept of “warming dominance”, a metric that examines the full distribution of temperatures and not just the average.
The results show that:
- 27 states (55%) show an increase in average temperatures.
- 41 states (84%) show an increase in some part of their temperature range.
- On the west coast (California, Oregon, Nevada), highs rise faster than lows.
- In the north (Dakotas, Minnesota), lows increase faster, softening the difference between winter and summer.
Regional implications
Professor Lola Gadea (UNIZAR) emphasizes that “climate change is global, but it also has a very clear regional component.” Observing only the average temperature is insufficient: “It’s like trying to understand a country’s economic inequality by looking only at GDP per capita,” explains Jesús Gonzalo (UC3M).
Regional differences have direct consequences on:
- Agriculture: crops sensitive to extreme heat or the loss of winter cold.
- Public health: more intense heatwaves or milder winters that alter disease patterns.
- Social and political perception: regions suffering more heat tend to support stricter climate policies, while less affected areas show less commitment.
Political dimension
The study reveals a correlation between the type of warming and political orientation:
- States with strong warming dominance (northeast and west coasts) mostly align with Democratic voting.
- Areas where warming is less evident (south and interior) tend to be Republican.
This suggests that local climate experience can influence attitudes towards climate action, reinforcing the need for policies tailored to each territory.
Uneven warming is a warning: it is not enough to design global strategies based on averages. It is necessary to recognize local dynamics for climate policies to be effective. Detecting whether a region is warming due to more extreme summers or milder winters is crucial to defining adaptation measures that protect both communities and ecosystems.
