Report•April 22, 2025
Analysis: Climate change is increasing the risk of performance-slowing heat in UEFA Champions League matches
Key Facts
Human-caused climate change is increasing the risk of sub-optimal temperatures that impair soccer performance during UEFA Champions League (UCL) matches in April and May 2025.
Elite players are more at risk of facing sub-optimal playing conditions now than in the 1970s across all eight stadiums hosting quarterfinal, semifinal, and final matches in 2025.
In Barcelona, the risk has skyrocketed. At Lluís Companys Olympic Stadium (Barcelona), the likelihood of sub-optimal temperatures during UCL matches in April and May has increased by 800% due to human-caused climate change.
Paris, London, and Birmingham have all seen heat risk double. Climate change has made it twice as likely that players will face sub-optimal temperatures this spring at Parc des Princes, Emirates Stadium, and Villa Park.
Introduction
Research has shown that the running performance of soccer players during matches of the UEFA Champions League (UCL) declines when temperatures are too warm (Pavlinovic et al., 2024). The research found that players covered less total distance in warm conditions (21°C or higher) compared to cooler temperatures. They also ran less at high speeds, sprinted less, and performed fewer high-intensity efforts when it was warm.
Climate Central analyzed how human-caused climate change is affecting the likelihood of these elevated temperatures occurring during the UCL competition in April and May 2025.
The analysis looked at the probability of temperatures exceeding 21°C at 23 stadiums where matches have taken or will take place — this is the threshold above which running performance for elite soccer players was found to decline.
Our analysis compares current conditions to those from the 1970s to highlight the increased risk players now face because of human-caused climate change — sub-optimal temperatures that could impact their performance.
Results
The likelihood of experiencing temperatures of 21°C or greater is much higher now than it was in 1970 for all stadiums analyzed. Below is the data for the eight stadiums where the quarterfinals and semifinals will be played in April and May 2025.
Stadium | Location | Past likelihood of exceeding 21°C (1970) | Modern likelihood of exceeding 21°C (2025) | Percent increase |
|---|---|---|---|---|
Santiago Bernabéu | Madrid | 44.2% | 73.9% | 67% |
San Siro | Milan | 48.3% | 70.4% | 46% |
Lluís Companys Olympic Stadium | Barcelona | 0.44% | 4.18% | 800% (9.5-fold) |
Allianz Arena | Munich | 23.6% | 35.5% | 51% (1.5-fold) |
Parc des Princes | Paris | 16.4% | 33.0% | 101% (2-fold) |
Signal Iduna Park | Dortmund | 14.8% | 27.3% | 85% |
Emirates Stadium | London | 6.3% | 14.9% | 135% |
Villa Park | Birmingham | 5.1% | 10.7% | 111% (2-fold) |
Methods
Previous research on match running performance during UEFA Champions League matches found that in warm conditions (21°C or higher), players covered less total distance compared to moderate and cold conditions. Additionally, players ran less at high speed, sprinted less, and engaged in less high intensity running in warm conditions as compared to cooler conditions.
We applied a probabilistic model to gridded ERA5 climate data to compare the likelihood of exceeding the 21°C threshold in past versus modern climate conditions. Our approach adjusted local temperature distributions using delta values derived from global mean temperature (GMT) trends. We analyzed the probability of surpassing 21°C in April and May across 23 stadiums hosting teams from this year's UCL knockout stages, even if those teams were eliminated before April or May.
Note that in coastal cities, such as Barcelona and Monaco, the ERA5 data may underestimate warming trends and probabilities may be somewhat muted compared to what might be observed at the stadium itself.