Climate Matters•July 16, 2024
Paris: 100 Years of Olympic Warming
KEY CONCEPTS
As the Summer Olympics kick off in Paris, climate change has become an integral part of the Games.
Athletes, fans, and outdoor workers face rising heat risks in Paris, which has been experiencing more frequent and intense summer heat waves due to climate change.
Paris last hosted the Olympics in 1924. In the 100 years since, the city has warmed 5.5°F during the Olympics period, putting athletes and others at risk.
Scorching days (with highs of 86°F or above) are now nearly three times more frequent in Paris (188 days from 2014-2023) than when the city last hosted the Games (69 days from 1924-1933).
Sweltering nights (when temperatures don’t fall below 68°F) are now over 20x more frequent in Paris (84 sweltering nights from 2014-2023) than during 1924-1933 (4 sweltering nights).
Warming climate, higher Olympics heat risk
The Tokyo Olympics in 2021 were the hottest Games ever, when extreme humid heat led to 146 reported cases of heat-related illness among Olympic and Paralympic athletes.
Ahead of the 2024 Olympics, athletes, workers, fans, and volunteers again face potentially dangerous heat in Paris.
Rings of Fire II: Extreme Heat at the Paris Olympics, a joint report from The British Association for Sustainable Sport, Front Runners, and Climate Central, covers these risks in detail.
Heat-trapping pollution and global temperatures have both only continued to rise since the Tokyo Games, and the planet is in the midst of a record heat streak.
June 2024 marked the 13th consecutive month of record-breaking global temperatures — and ranks as Europe’s second-warmest June on record.
Dangerous summer heat is not uncommon in Paris. The Paris area has experienced 50 heat waves since 1947. The deadliest of these, in August 2003, resulted in 14,800 excess deaths across France and was made at least twice as likely due to human-caused climate change.
These levels of extreme heat in Europe are now 10 times more likely to occur because of climate change.
Although it’s too early to know whether the Paris Olympics will coincide with a heat wave, the timing of the Games during what is historically the hottest time of year makes the potential risks to athletes a serious concern.
Here’s how temperatures have changed in Paris since the city last hosted the Games in 1924:
Paris: 100 years of warming
Since 1924, when Paris last hosted the Olympics, annual temperatures in the French capital have warmed by 3.2°F.
The warming stripes visualize this warming trend. Each stripe represents the temperature anomaly relative to the 1971-2022 baseline: blue years were cooler than normal and red years were warmer than normal.
The dramatic shift to deep red reflects rapid warming in Paris over the last 100 years.
Warming during the Olympics and Paralympics
Athletes in this year’s Games will be competing in a far warmer climate than they did a century ago.
Average temperatures in Paris during the period of the 2024 Olympics (July 26 - August 11) have warmed 5.5°F since the city hosted the 1924 Games.
Paris temperatures have warmed 1.7°F during the period of the 2024 Paralympics (August 28 - September 8) since 1924.
More scorching days and sweltering nights
As average temperatures have warmed, extreme heat is also on the rise.
The frequency of scorching days and sweltering nights has increased dramatically in Paris over the 100 years since the city last hosted the Games.
There were 188 scorching days (with maximum temperatures of 86°F or higher) in Paris over the last 10 years (2014-2023).
That’s nearly a three-fold increase compared to the first decade analyzed (69 scorching days from 1924 to 1933).
Extreme heat is also an increasing risk after the sun goes down. Sweltering nights (when temperatures don’t fall below 68°F) are now over 20 times more frequent in Paris (84 sweltering nights from 2014-2023) than during 1924-1933 (4 sweltering nights).
Heat risks to athletes
The health, safety, and performance of athletes and on-field officials suffers in extreme heat and humid heat — conditions that are likely to occur more frequently as global temperatures continue to rise.
In extremely hot weather, our bodies’ main cooling mechanism (sweating) may not cool us enough to prevent overheating. And when the relative humidity is above 60%, sweat evaporates more slowly, preventing quick cooling.
These conditions can overwhelm the body’s temperature control system and lead to heat-related illness including heat cramps, heat exhaustion, and even fatal medical emergencies such as heat stroke.
Extreme heat and humid heat can affect everyone, but athletes face higher risks of heat-related illness and mortality because the body produces 15 to 20 times more heat while exercising.
When nights don’t cool off enough relative to peak daytime temperatures, people have a harder time cooling off and recovering from the heat of the day.
Sweltering nights can reduce sleep and prolong heat stress and related health risks during the hottest time of year.
Olympic athletes, including on Team USA, have cited sleep disruption due to heat as a major concern in the lead-up to the 2024 Games, especially given the lack of air conditioning in the Olympic Village.
Humidity multiplies heat-related risks
The warming trends described above only consider temperature and therefore don’t reflect the additional risks from high humidity, which limits the body’s ability to cool itself through sweating.
The dangers of humid heat were seen in high rates of heat-related illness among athletes during the Tokyo Olympics in 2021 when temperatures averaged 90°F and were coupled with up to 70% relative humidity.
The American College of Sports Medicine recommends canceling practice or competition when a humid heat metric called the wet bulb globe temperature exceeds 90°F for acclimatized, fit, low-risk individuals (or 86°F to 90°F for non-acclimatized or high-risk individuals).
LOCAL STORY ANGLES
How is climate change impacting temperatures at the Paris Games today?
Check Climate Central’s Climate Shift Index map tool to see how much climate change is influencing the temperatures that athletes, fans, and outdoor workers are experiencing at the Paris Games each day.
FIND EXPERTS
Submit a request to SciLine from the American Association for the Advancement of Science or to the Climate Data Concierge from Columbia University. These free services rapidly connect journalists to relevant scientific experts.
Browse maps of climate experts and services at regional NOAA, USDA, and Department of the Interior offices.
Explore databases such as 500 Women Scientists, BIPOC Climate and Energy Justice PhDs, and Diverse Sources to find and amplify diverse expert voices.
Reach out to your State Climate Office or the nearest Land-Grant University to connect with scientists, educators, and extension staff in your local area.
METHODOLOGY
Daily and annual temperature data recorded at the Paris-Montsouris station (1924-2023) were obtained from Météo-France. Access full data on Paris heat trends.