Nearly 120 Million People in US Under Extreme Weather Alerts as Heat Dome Descends, Summer Danger Season Off to Brutal Start

For the first time this year, nearly 120 million people in the United States and its territories, are threatened by what the Union of Concerned Scientists (UCS) has deemed “Danger Season”—the time roughly from May through October in the Northern Hemisphere when climate change impacts in the United States are at their peak and increasingly likely to collide with one another.

Aided by El Niño, large swaths of the U.S. South, West and Southwest regions are already experiencing extreme heat, with temperatures slated to rise even further in that part of the country and extend further east as a heat dome expands this weekend and into next week. Some places may see the heat index, or “feels like” temperature, set records by exceeding 120 degrees Fahrenheit, threatening people’s health and lives while also placing tremendous pressure on the electric grid as people increase their air conditioning use.

While this heat will affect roughly one-third of people living in the United States, those experiencing poverty or homelessness, people (often people of color) living in urban heat islands, elderly adults, small children, people with cardiovascular and other health conditions, outdoor workers, and people facing electricity shut-offs are at particularly grave risk. Additionally, parts of the Northeast remain flooded from abnormally heavy rains earlier this week and some southern states are still under flood alerts.

Meanwhile, the U.S. National Oceanic and Atmospheric Administration (NOAA) has confirmed that this June was the hottest on record globally and, according to the United Nations, the hottest global average temperature ever was experienced in the first week of July. Ocean temperatures, including in the Atlantic, are also off-the-charts high with the danger to coral reefs proving particularly acute, and sea ice is at record lows, especially in the Antarctic. Furthermore, climate change-driven extreme heat, flooding and wildfires are being experienced by billions of people around the world.

To be extremely clear: this is not normal. Decades of dependence on fossil fuels, decades of deception and obstruction on the part of the fossil fuel industry, and decades of inaction by policymakers who have been in their thrall have landed us where we are today. This has to stop.

For more information, check out UCS’ Danger Season map, which tracks heat, wildfire weather, storm and flooding alerts. Since May 1, 43% of the extreme heat alerts were made more likely by climate change. The map also shows that nearly 34% of the people who are today under extreme weather alerts live in areas designated as disadvantaged. Climate extremes are intersecting with long-standing socioeconomic challenges and racial inequities to further heighten mounting risks.

With extreme heat on the rise because of climate change, it is critical that policymakers and regulators take steps to ensure our communities are protected and our infrastructure is more resilient to extreme weather; that fossil fuels are quickly and sharply phased down while we rapidly transition to clean energy; and fossil fuel companies are held accountable for the damage their products have caused. The United States must also take responsibility for its role in driving the climate crisis as the largest historical emitter by providing adequate climate financing and addressing loss and damage in low-income nations facing crushing climate extremes.

Below are UCS experts available to discuss current and anticipated extreme weather events in the United States; their impact on the grid; and relevant local, states, national, and international policies needed to address the climate crisis:

• Dr. Rachel Cleetus, the policy director and lead economist in the Climate and Energy Program at UCS. She is based in Cambridge, Massachusetts. Click here to view her biography.
• Dr. Kristina Dahl, a principal climate scientist at UCS. She is based in San Francisco, California. Click here to view her biography.
• Dr. Juan Declet-Barreto, a senior social scientist for climate vulnerability at UCS. He is based in Washington, D.C. and is fluent in English and Spanish. Click here to view his biography.
• Dr. Brenda Ekwurzel, the director of climate science and a senior climate scientist at UCS. She is based in Washington, D.C. Click here to view her biography.
• Michael Jacobs, a senior energy analyst. He is based in the Boston area. Click here to view hisbiography.
• Julie McNamara, a deputy policy director in the Climate and Energy Program at UCS. She is based in Cambridge, Massachusetts. Click here to view her biography.
• Erika Spanger-Siegfried, the director of strategic analytics in the Climate and Energy Program at UCS. She is based in Cambridge, Massachusetts. Click here to view her biography.
• Shana Udvardy, a senior climate resilience policy analyst at UCS. She is based in Washington, D.C. Click here to view her biography.

Contact UCS Climate and Energy Media Manager Ashley Siefert Nunes via email at asiefert@ucsusa.org or by phone at +1 952-239-0199 to speak with a UCS scientist or analyst.

Additional UCS Resources and Analyses:

• A 2022 peer-reviewed study “Too Hot to Work,” which found that without global action to reduce heat-trapping emissions, climate change is projected to quadruple U.S. outdoor workers’ exposure to hazardous heat conditions, jeopardizing their health and placing up to $55.4 billion of their earnings at risk between now and 2065. For the interactive mapping tool, click here.
• A 2019 peer-reviewed study “Killer Heat,” which found that without global action to reduce heat-trapping emissions, the number of days per year when the “feels like” temperature exceeds 100 degrees Fahrenheit would more than double from historical levels to an average of 36 across the United States by midcentury and increase four-fold to an average of 54 by late century. To get the results for a specific city or county, use the online widget. For the interactive mapping tool, click here.
• A 2019 report titled “US Military on the Frontlines of Extreme Heat,” which found that over the next three decades military installations in the contiguous United States could average an extra month of days each year when the “feels like” temperature exceeds 100 degrees Fahrenheit.
• A 2019 UCS report titled “Farmworkers at Risk,” which evaluated the risks pesticide exposure and heat stress can pose to U.S. farmworkers’ safety.
• A fact sheet on the science connecting extreme weather events, like extreme heat, and climate change.