This new research points to the need for a more educational approach to extreme heat, especially in the Midwest and Southwest.
Due to global warming, people around the world are experiencing a greater number of temperature extremes. More than 150 million people in the United States there were heat warnings or heat advisories in July 2022, with some areas experiencing record or consecutive days of record temperatures 100°F (38°C). The heat is not only uncomfortable, it is deadly for some, especially the elderly medicinespregnant woman, children, and many others. However, public opinion estimates from the Yale Climate Opinion Maps show that 65% of Americans were “very” or “somewhat” concerned about global warming in the fall of 2021, with considerable variation at the county level. Nationally, only 47% of Americans think they will be was personally injured from global warming.
Exposure to weather-related hazards also varies across the United States, so to better understand the relationship between exposure to extreme heat and concern about global warming, we analyzed historical county-level data from the Federal Emergency Management Agency US need (FEMA) alongside our research data.
FEMA's heat data provides the average number of extreme heat days per year in each county over the past 12 years. Extreme heat days, in this case, are based on locally determined temperature classifications from National Weather Service (NWS) forecast offices. These locally defined classifications of “extreme heat” provide more context than extreme heat indices based on a single threshold (eg, days above 95 degrees) for the entire country. FEMA's data on extreme heat days is incomplete, but covers about 80% of the total US population. Existing data show “hotspots” of extreme heat exposure in the southwestern United States, the south-central Midwest, and the mid-Atlantic region.
Many areas already experiencing severe heat waves will see prolonged heat wave duration and higher temperatures as the effects of global warming deepen.
To what extent previous exposure to excessive heat are associated with worried about global warming?
We compared FEMA's historical extreme heat data with county-level estimates of public concern about global warming. In the figure below, FEMA's past extreme heat exposure is plotted on the horizontal axis (using a log scale), and the estimated percentage of county residents who are “very” or “somewhat” concerned about global warming is plotted on the vertical axis. County data points are sorted by population and colored by region: Midwest (pink), Northeast (yellow), South (green), and West (blue).
When calculating a weighted population correlation coefficient, we observe a positive correlation (r = 0.12) between past exposure to extreme heat and concern about global warming in the 2,293 counties in the FEMA data set. This relationship suggests that living in areas that experience more extreme heat days is associated with higher levels of concern about global warming.
We then divided the scatterplot above into four quartiles, shown below, where the quartiles are defined by the average level of exposure to extreme heat and the average level of concern among the available counties. Counties with (1) lower exposure to extreme heat and greater concern about global warming are in the upper left quadrant. (2) counties of lowest exposure and lowest concern at lower left; (3) higher exposure and higher concern at upper right; and (4) higher exposure but lower concern lower right.
Despite the overall positive association between past exposure to extreme heat and concern about global warming, geography appears to be an important factor influencing this relationship.
Counties in the West (blue bubbles), which have some of the largest populations among counties with existing heat data (but also higher rates of missing data), tend to experience higher exposure to extreme heat and also have higher levels of concern about global warming . Many counties in the Northeast (yellow) show higher levels of concern about global warming despite lower than average (historical) exposure to extreme heat. Southern counties (green) tend to have lower-than-average exposure to extreme heat and vary in their perceptions of global warming.
Of greatest concern are the counties in the lower right quadrant of the scatter plot. These counties are located primarily in the Midwest and have relatively high exposure to extreme heat but lower than average levels of concern about global warming.
A population's exposure to weather and climate-related hazards is only one of many factors shaping the perceived risks of global warming. Age, education, political ideology, social norms, and other factors all influence individual perceptions. Similarly, socioeconomic trends, the political context, the media, and other factors shape the overall climate climate in various states and regions. We thus examined several demographic characteristics of these counties to see how they compare to the overall demographics of the United States.
The 217 counties in the “Highest Exposure, Lowest Concern” quadrant of the scatterplot represent approximately 6.4 million people (2.6% of the US population). Analysis of the socioeconomic characteristics of these counties shows that they have a median household income of about $57,000 per year, which is about 9% lower than the overall median household income in the United States ($62K). Another socioeconomic metric, the percentage of households receiving Supplemental Nutrition Assistance Program (SNAP) benefits (also known as food stamps), is a measure of poverty. In these 217 counties, about 11% of households receive SNAP benefits, which is in line with the US national average (12%) and does not indicate significant economic differences between this group and the US population as a whole.
However, residents of the 217 counties in the “Highest Exposure, Lowest Concern” quadrant are significantly more likely to identify as white, to have voted Republican in the 2020 presidential election, and to live in a rural county compared to the US population as a whole. These counties are located almost exclusively in the Midwest or South and are also generally smaller in population than most other counties included in this analysis. However, it is important to recall that many counties in the western United States are missing heat data and are therefore excluded from this analysis. A table in the appendix, below, provides a list of the 20 largest counties in this group by population along with the demographic characteristics discussed above.
conclusion
Record-breaking heat events are already increasing and heat stress multiplies the risk a number of other health conditions. Policymakers, government officials, educators, and others need to consider the various factors that influence public concern about global warming, especially because public disaster awareness and risk perceptions can support preparedness behaviors. Populations that fail to accurately perceive extreme heat threats will be less prepared for heat waves and thus in higher risk death and serious illness from extreme heat, which is very likely to increase in frequency and severity due to global warming.
Therefore, it is imperative that research continues to explore effective ways to prepare people for more frequent and intense natural disasters, even in the face of global warming skepticism and denial. By identifying US counties that are least concerned about global warming but have experienced greater exposure to extreme heat, we hope to highlight the importance of adapting global warming responses and policies to meet local and regional needs.
The model estimates and the FEMA data on which this analysis is based are available online and are hopefully useful to communicators, health officials, academics, and others working to promote safe behaviors during heat waves, broader community heat resiliency , global warming adaptation efforts and general community health and well-being in these times of climate crisis.
annex
