Climate Change Being Blamed for Deadly Record Hot June

Researchers have confirmed that June of 2025 was one of the hottest on record, not just in the U.S. but across many other areas of the Northern Hemisphere. Here is a look back at the fast start to the sizzling summer and what this means for the rest of the year.

How Climate Change Triggered a Deadly Heat Wave

A recent heat wave across Europe is putting the microscope on how deadly extreme heat can be. According to a new study, the impacts of global warming tripled the number of fatalities when a heat wave spread across Europe.

Temperatures soared to well over the century mark for over a week, forcing the closure of several popular tourist attractions and bringing life to a standstill for many. The heat also paired with dry conditions to trigger a rash of wildfires across the continent.

Now that the numbers are coming in, it is being confirmed that thousands of people died due to the heat. The researchers from Imperial College London and the London School of Hygiene and Tropical Medicine examined a stretch of 10 days of extreme temperatures between June 23 and July 2. The data dove into the heat that settled across 12 major European cities, including London, Paris, Madrid, Athens, and Rome.

Scientists involved in the study leaned on historical weather data to determine how intense the temperatures would have been had the world been able to control the burning of fossil fuels. The data determined that climate change created a spike of 1.8 to 7.2 degrees Fahrenheit during this particular heat wave.

The researchers then used the data connecting the relationship between the heat and the daily fatality rate to determine how many Europeans lost their lives. The numbers determined that about 2,300 people died over the period of 10 days throughout the 12 studied cities. This estimate was about 1,500 more than the number of expected deaths that would have occurred in the absence of climate change. Thus, global warming was blamed for about 65% of the total death toll.

Climatologists are using this data to demonstrate how a small increase in daily temperatures can be responsible for significant surges in fatality counts. Extreme heat is even more deadly for people with underlying health conditions, including the elderly and individuals with heart disease, respiratory conditions, and diabetes.

While people over the age of 65 were the most adversely impacted by the recent European heat wave, almost 200 of the estimated fatalities in the 12 urban areas were in people between the ages of 20 and 65.

Researchers also caution that the study results only accounted for deaths across the 12 studied cities. The true death toll across all of Europe could have approached tens of thousands of people.

Climatologists continue to warn that the world must be more committed to stopping the burning of fossil fuels. The continued use of these fuels will amplify the threat of heat waves and their catastrophic impacts. Experts recommend putting a greater emphasis on renewable energy sources, building urban areas engineered to resist extreme heat, and being more intentional about protecting vulnerable populations.

2025 on Pace to Become Second-Warmest Year on Record

Halfway through the year and 2025 is on pace to become the second-warmest year on record across the world. New data out of the National Oceanic and Atmospheric Administration (NOAA) found that the first six months of the year are coming in just behind the record-breaking year of 2024.

June's global average temperature clocked in at 1.76 degrees Fahrenheit over the 20th-century average. This reading was 0.42 degrees cooler than the top warmest June in 2024. The temperature was also 0.18 degrees cooler than the second-warmest June ever recorded, which happened in 2023.

Another set of data released in a joint effort between the European Copernicus Climate Change Service (C3S) and NASA's Goddard Institute for Space Studies also showed that Earth had its third warmest June, coming in just behind the two previous Junes.

NOAA noted that it had "95% confidence" that the year 2025 will end up as the second to fourth warmest year in recorded history. NOAA's global temperature records go all the way back to 1850.

It has already been a record-setting year. According to NOAA, every month in 2025 has been among the top three warmest of each respective month. January was particularly toasty, ending up as the warmest first month of the year on Earth in 176 years.

June 2025 was also distinguished as the third month in the last two years in which global readings did not finish over 2.7 degrees above the pre-industrial levels. However, the recent 12-month time frame through June of 2025 was more than 2.7 degrees above the average late 19th-century readings.

When looking at specific regions, June was the warmest on record in Japan. It was also especially warm when compared to the average for the month in South Korea, France, and the United Kingdom.

Spain shattered its national June heat record on the 28th. An eye-popping high of 114.8 degrees was recorded in the town of El Granado.

Coming back to the U.S., the city of Raleigh, North Carolina, sizzled with its hottest June on record. The state of Hawaii notched its hottest six-month period from January to June, according to the data from NOAA.

Warmer Ocean Waters

The air temperatures were not the only measurement breaking records. The C3S report also found that ocean water readings were measuring warmer than average. Going back to March of 2023, global daily sea surface temperatures were hotter than in other years.

The areas of the world's ocean that saw the greatest departures from normal included the Philippine Sea, the Pacific Ocean off the coast of Hawaii, the northeastern corner of the Atlantic Ocean near Ireland and the U.K, the western portion of the Mediterranean Sea, the southern tier of the Indian Ocean, and the southwest of the Arctic from Greenland to Canada.

The silver lining is that the 2025 ocean water readings have been less extreme than the sizzling temperatures measured in the seas in 2023 and 2024.

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