Fossil fuels are heating America's 250th birthday

The report analyzes a severe heatwave in July 2026 characterized by record-shattering Wet Bulb Globe Temperature (WBGT) values across the eastern US and Canada. Attribution analysis indicates that while the atmospheric circulation pattern (a 'heat dome') is characteristic of the region, the intensity of the event was substantially increased by a background climate that has warmed by 1.4°C due to fossil fuel combustion. The study emphasizes that humid heat extremes are an emerging risk, as WBGT is increasing more rapidly than absolute maximum or minimum temperatures. It also highlights the disproportionate vulnerability of low-income residents, outdoor workers, and those in historically redlined urban districts, while noting the critical role of heat action plans and cooling centers in mitigating mortality.

• The July 2026 heatwave produced record-shattering Wet Bulb Globe Temperature (WBGT) values across the study region, an event that would have been 'virtually impossible' in a climate 1.4°C cooler.
• Humid heat extremes are identified as an emerging risk because WBGT is increasing more rapidly than either maximum (Tx5x) or minimum (Tn5x) temperatures.
• The event's intensity was driven by a strong synoptic-scale ridge (heat dome) superimposed on a warmer modern climate; while large-scale circulation changes were relatively small, the background warming increased both daytime and nighttime heat.
• The likelihood of 'record-shattering' events—those exceeding previous records by unusually large margins—is proportional to the rate of warming, which has been accelerated by the rapid increase in greenhouse gas emissions.
• Urban vulnerability is exacerbated by the urban heat island effect and historical systemic inequalities, with historically redlined districts reaching temperatures up to 7°C higher than non-redlined areas.
• While air conditioning protects much of the population, it creates new risks by stretching electricity grids and leaving those with economic constraints, limited mobility, or outdoor job requirements highly vulnerable.

APA

World Weather Attribution (2026). Fossil fuels are heating America's 250th birthday. https://www.worldweatherattribution.org/fossil-fuels-are-heating-americas-250th-birthday/

Chicago

World Weather Attribution. Fossil fuels are heating America's 250th birthday. 2026. https://www.worldweatherattribution.org/fossil-fuels-are-heating-americas-250th-birthday/.

Wikipedia

{{cite report |author=World Weather Attribution |title=Fossil fuels are heating America's 250th birthday |date=3 July 2026 |url=https://www.worldweatherattribution.org/fossil-fuels-are-heating-americas-250th-birthday/ |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{worldweatherattribution2026fossil, author = {{World Weather Attribution}}, title = {{Fossil fuels are heating America's 250th birthday}}, institution = {World Weather Attribution}, year = {2026}, month = jul, url = {https://www.worldweatherattribution.org/fossil-fuels-are-heating-americas-250th-birthday/}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }