Jun 30, 2023 - Energy & Environment

Blazing temperatures, wildfire smoke compounded by warming climate

Data: NOAA HRRR, GFS; Note: Smoke is as of 2pm Eastern, June 29, 2023; Map: Erin Davis/Axios Visuals

The heat wave scorching much of the U.S., along with dangerously poor air quality from wildfire smoke, is giving Americans a preview of the compound climate disasters that experts fear will become increasingly common as the planet warms.

Why it matters: Extreme heat and hazardous air quality are acute public health threats, and the heat has already proven deadly.

The big picture: The U.S. heat wave and heat and wildfires throughout Canada come as multiple global climate indicators, from ocean temperatures to surface air warmth, are setting all-time records.

  • June is likely to be the world's hottest such month on record by a large margin, leading into July, which tends to be the planet’s hottest month overall.

Zoom in: Since early May, the overall weather pattern across North America has been unusual, with hallmarks of a warming climate.

  • A large and powerful heat dome has dominated Canada's atmosphere during that time.
  • A key driver of Canada's wildfires has been sinking, drying and warming air; heat and dry weather jump-started the wildfire season in early May, even in areas usually covered in snow at that time of year.
  • Greg Carbin, a senior NWS meteorologist, said Canada's weather patterns and the wildfires it has helped stoke, are the most unusual part of North America's recent conditions.
  • And the stuck or "blocked" weather pattern over Canada is connected to another heat dome fanning extreme heat in Texas and Mexico, now spreading out across the South and Southwest.

Of note: Such stagnant weather features have characterized many other extreme heat events, such as the 2021 Pacific Northwest heat wave.

Between the lines: There has been a stubborn area of low pressure aloft across the Northeast, which has pulled wildfire smoke south and eastward via its counterclockwise circulation of air.

  • And over Mexico and Texas, an unusually powerful heat dome is only just now weakening, after shattering all-time heat records.
  • For example, San Angelo, Texas broke or tied its all-time high temperature record on five separate occasions from June 19 to June 26, per NWS meteorologist Victor Murphy. The previous record had stood for 120 years.
  • "Climate change makes U.S. heat waves about 5°F warmer" than they would be in a preindustrial world, Michael Wehner, a researcher at the Lawrence Berkeley National Laboratory told Axios via email.

The intrigue: The scale and scope of Canada's wildfires are staggering, and they in turn are likely to worsen climate change by emitting planet-warming greenhouse gases, in what is known as a positive feedback loop.

  • This year, however, has seen the most acreage burned in any wildfire season since reliable records began in 1959. That has happened prior to July, typically Canada's most active wildfire month.

Threat level: Many of Canada's wildfires are in the boreal forests ringing the Arctic. Peatlands are also are burning, which is worrisome, since they are a major carbon sink that becomes a climate change contributor when burned.

  • Flannigan said some of the blazes in these ecosystems may last through the winter by smoldering in the soils, only to emerge next spring or summer.
  • Such "zombie fires," as they are called, are a hallmark of the new fire regime in the Far North.
  • Wildfires and climate change are intricately connected, Flannigan said, as warmer weather means drier vegetation that is more susceptible to burning, as well as more extreme fire weather days.
  • He said his own research over the past three decades may have underestimated the pace of change, given what he is seeing this season.

The bottom line: "A warmer world means more fire for Canada," Flannigan said. This means more smoke is ahead for the U.S., not just this season, but in the near future too.

  • "Fire is a multi-faceted issue that will need a multipronged approach. There's no silver bullet. There's no techno-fix. Drones or artificial intelligence isn't going to make this problem go away," Flannigan said.
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