Satellite image of the summer 2022 heat wave. Source: NASA.


A new report by our Foundation shows temperatures of 65 heat islands in U.S. cities already reaching global warming not expected for decades

There are many forecasts for future warming in the US and globally. Most emphasize the dangers of a future where average temperatures increase by 2º. But what about warming that has already happened? The extended heat waves of the summer of 2022 have given us a clearer idea of a future that is already here, especially in the heat islands of US cities.

Data source: ECMWF ERA5. Summer temperature data for heat islands in 65 cities was selected, analyzed  and displayed with a 10-pt binomial smoothing. Analysis: Daniels Family Sustainable Energy Foundation

New data released this week by the Daniels Family Sustainable Energy Foundation focuses on heat islands—urban areas with much higher temperatures—in 65 U.S. cities. The results of the Foundation's national-wide analysis are staggering. Summer temperatures for all 65 cities have been steadily rising since 1950. Hovering your mouse on the data will show each city name and its average summer temperature each year.

How is this different from other climate reports? Most the data produced by other agencies and foundations focuses on averaging temperatures across the entire legal boundaries of cities, which often include lakes, parks and natural areas where not many people live. That approach is important, but it masks the effects of warming caused by climate change in areas where most people live. 

Today, 308 million people in the United States live in urban areas, out of a total population of 329 million. That means that 93% of Americans are much more likely to be exposed to higher temperatures than most models and reports predict, because urban areas are more likely to be hotter than the surrounding regions, due to the lack of forest cover, and the high concentration of concrete and pavement. Last June, more than 53 million Americans were under excessive heat warnings in their states.


Phoenix, AZ and other Southwestern cities top the chart of highest temperature (above), as is often the case, but there are also some unexpected places getting hot much faster than expected. Seattle, WA, among the lower average temperatures in the last 70 years, experienced record highs and extended heat waves throughout this summer, along with the Pacific Northwest,

resulting in several deaths in non-air-conditioned homes. Heat is the number one cause of death from weather-related events in the U.S., surpassing hurricanes. 


For most Americans, in fact, summer temperatures have increased between 1 and 5 degrees Fahrenheit in the last half century. This increase, above normal average temperatures, is called a "temperature anomaly" and it's usually measured by comparing current average temperatures to a period when we expect temperatures to have been lower (say 1950-60), largely because we had not polluted the air with so many greenhouse gases back then (1960's CO2 was 315ppm), compared to our current extreme carbon pollution (today's CO2 os 414ppm). You can see how much hotter 65 US cities are today, compared to 70 years ago, by looking at the figure below, and hovering your mouse or finger over each line, corresponding to a city.

Data source: ECMWF ERA5. Summer temperature data for heat islands in 65 cities was selected and analyzed with a reference average summer temperature from 1950-60, and then displayed with a 10-pt binomial smoothing. Analysis: Daniels Family Sustainable Energy Foundation

Did anything surprise you? How about Anchorage, AK warming as fas as Phoenix, AZ? Does that mean that Alaska is getting as hot as Arizona? No. But it means that the average summer temperature in Anchorage (+3.54ºF in 2021) is rising as fast as in Phoenix (+3.98ºF), largely due to the much more severe greenhouse effects the Arctic is experiencing. New York (+2.40ºF) is warming as fast as Honolulu, HI (+2.34ºF) even though it's much farther north. Before you buy ocean-front property on Rockaway Beach, NYC note that this doesn't mean that the two cities will enjoy the same climate, but it does show how much NYC's heat island—with its concentrated concrete structures—is causing an increase in summer temperature comparable to that of some tropical areas.

Contrary to models that predict the future (often too conservatively), our Foundation's data shows temperatures that have already happened, in places where people live. If you don't believe the data (used by more than 50 countries worldwide), then perhaps you will consider hearing out the people who have been feeling the effects of the heat this summer and over the past several years. As the National Oceanic and Atmospheric Administration has shown, disadvantaged people are the ones who are bearing the worst effects of manmade warmingThis year alone has set records for the hottest nights in the US since records began, as reported by the Washington Post. That's a feature of heat islands, where urban areas don't cool over night, as forested areas do, but capture the day's heat, only to capture more the next day. The animation below shows the areas of the North America (and Afro-Eurasia) that experienced the worst temperatures during the latest, extended heatwaves in 2022.

One year, however, doesn't count as climate, it's weather. That is why our report focused on 70 years in 65 cities to show that this is not an isolated, odd year, but one in a series of decades of warming.

With the increasing cost of fuel taxing Americans at the gas pump as well as on their power bills, the solution can't be to buy and use more air conditioners and consume more electricity, producing even more greenhouse gases that will only worsen the problem. The more rational solution is to reduce the heat absorbed by our buildings, deflecting it, and keeping our indoor spaces cooler. This can be achieved with green-building technologies, such as composite nano-materials that are specifically engineered to maximize heat reflectance, while also ensuring our homes are properly ventilated. 

We can't wait idly, in ever hotter homes, for our economy to be converted to green energy, which still requires us to solve the problem of efficient batteries that don't require us to destroy the environment to seek rare minerals. The solution is here, it's easily applied and will reduce the strain on our power grids, our wallets and our health much faster than a revolution in power generation.