Extreme heat is among the deadliest weather hazards humanity faces due to the climate crisis, which contributes to thousands of deaths in the US every year.
Heatwaves have been occurring more frequently since the mid-20th century, and there’s mounting consensus among climate scientists that dangerous bouts of high temperatures and humidity will become substantially more common, more severe, and longer-lasting
The Union of Concerned Scientists (UCS), reveals dangerous heatwaves are exacerbating systemic racial inequalities, with soaring temperatures expected to further disadvantage communities of colour if greenhouse gas emissions keep rising
- Killer heat is already affecting communities unequally: between 1971 and 2000, US counties with more than 25% black residents endured an average of 18 days with temperatures above 100F (38C) compared to seven days per year for counties with fewer than 25% African Americans.
- By mid-century if Paris climate accord targets are not met, US counties with larger black populations will face a staggering 72 very hot days a year on average – compared with 36 days in counties with smaller African American populations, according to the UCS.
- Latin communities also suffer disproportionately: historically, counties with more than a 25% Hispanic/Latinx residents experienced 13 days very hot days a year, rising to 49 by mid-century if greenhouse gas emissions are not curtailed.
“The significantly higher exposure to extreme heat is an artefact of where black people tend to live in the US which is a legacy of slavery,” said senior climate scientist Kristina Dahl. He added that “Even if rapid action is taken to limit the future temperature rise to 2C, the US can expect a significant increase in the frequency of extreme heat which will affect people of colour most severely as a result of systemic racism. If we blow past that target, the increase and the disparities will be enormous. Extreme heat is a climate justice issue.”
By mid-century, a third of America’s 481 largest cities will endure temperatures above 105F (40.5C) on at least 30 days a year – a rise from just three cities historically (El Centro and Indio, California, and Yuma, Arizona), according to a UCS report from 2019. By the end of this century, this would rise to 60% of cities, which is the equivalent of 180 million Americans at risk of potentially fatal complications caused by heatstroke and heat exhaustion. In this scenario, children wouldn’t be able to play outside and farmers would struggle to get crops to market. Agriculture, an industry which depends on cheap migrant labour, many workers, especially undocumented migrants, already often lack access to crucial mitigation measures such as regular breaks, shade, medical services, adequate clean water and health insurance. Underlying health and environmental hazards which more commonly affect people of colour such as air pollution, diabetes, obesity and high blood pressure, also increase the risk of heat-related illnesses.
In US cities nationwide, heatwaves disproportionately affect underserved neighbourhoods thanks to the legacy of discriminatory housing policies denying home ownership and basic public services to people of colour, according to research published in Climate earlier this year. This is the result of streets where people of colour lived being graded as “hazardous” starting in the 1930s – otherwise known as redlining – which were then denied a whole range of public and private services including banking, healthcare and parks, while being earmarked for environmentally toxic projects such as landfills and chemical plants. Urban heat islands – characterised by abundant heat-trapping structures such as housing projects and asphalt car parks, and inadequate vegetation – are up to 12.6F hotter than non-redlined neighborhoods in the same city. The heat disparity exists in 94% of the 108 cities analysed. For instance in Birmingham, Alabama, the average temperature in redlined neighbourhoods, which account for 64% of the city, is currently 8F higher than historically white neighbourhoods.
A nationwide study, using data from over 12,000 schools and 10 million middle- and high-school students, researchers found that a 1F hotter-than-average academic year reduces learning by about 1%. But the effects of heat on learning are more pronounced for black and brown students and those living in poorer neighborhoods, because air conditioning – like other essential school infrastructure – is locally funded and unequally distributed.