Jan 2, 2024 - Energy & Environment

The world's hottest year may soon be an average one

A man sprays water on hot spots during a wildfire in British Columbia during 2023.

A resident sprays water on hot spots near a house during a wildfire in Celista, British Columbia, on Aug. 19, 2023. Photo: Cole Burston/Bloomberg via Getty Images

Humanity's hottest year in at least 125,000 is now over. But with further warming ahead, we may soon look back on it as an average year, rather than an aberration.

Why it matters: Climate change dominated the headlines at several points during 2023, despite armed conflicts around the world, the unprecedented criminal indictments of a former U.S. president, and other major stories.

  • Not since 1988, when Yellowstone National Park was ablaze and heat waves engulfed the country, has the environment been such a high-profile and defining domestic issue.

The big picture: Last year's warming surprised many climate scientists and policymakers alike, and contributed to the sense of urgency diplomats addressed during the COP28 climate summit in Dubai. (Whether the agreement they forged fully reflects that urgency is up for debate.)

Zoom in: Starting early last summer, global average surface temperatures reached record high levels. They briefly flirted with the 1.5°C target set in the Paris Agreement.

Stunning stat: The estimated wildfire-related carbon emissions from Canada during its 2023 blazes was 483 megatonnes. That nearly equals the country's typical annual emissions from all sources and topped multiple countries' emissions.

  • This also totaled a historically high 23% of global wildfire carbon emissions for the year, up to Dec. 10, according to the Copernicus Atmosphere Monitoring Service.

Context: The fires were worsened by relentless heat waves and dry conditions tied in part to climate change.

  • One study found a clear connection between heat waves and the wildfires that burned in Quebec during the summer; voluminous other research has also linked climate change to an increase in wildfire acreage burned, and fire intensity in recent years.

By the numbers: The Earth's climate entered discomforting territory during 2023, with every month from June through December setting heat records.

  • The margin by which the records were set have themselves set milestones, indicating that a sizzling year didn't just eke out its status, but blew away the competition.
  • September's temperature anomaly ranked as the most unusually hot month on record, with a departure from average of 1.7°C (3.06°F) above the pre-industrial average.
  • A historically strong El Niño event in the tropical Pacific Ocean is adding to the trend from human-caused warming. It may place December's temperature anomaly just behind September's.
  • And July went down in history as the globe's hottest calendar month on record, full stop.

Between the lines: Scientists may be studying the climate of 2023 for quite some time. The record-breaking warmth was in part encouraged by the one-two punch of long-term warming from burning fossil fuels and a largely natural El Niño event, which temporarily boosted global average temperatures even higher than they otherwise would have been.

  • But this combination doesn't explain all of the reasons behind the warming trend.
  • At the same time, some climate scientists have noted that while 2023 was unusually hot, it did not depart completely from what projections showed would occur in the future.

Yes, but: A vocal minority think 2023's temperature bounce isn't a fluke at all, but rather a quickening of the planet's thermostat that will become increasingly obvious in the next few years.

What's next: International scientific agencies will tally and release more data during the next two weeks, but the end result of where 2023 ranks is already baked in.

Go deeper:

New study warns climate is warming even faster than some think

2024 may be the hottest year in recorded history

Photo essay: The Earth's warmest year on record

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