Jun 13, 2023 - Energy & Environment

Climate extremes raise questions, concerns about faster warming

Daily global average sea surface temperatures
Data: ClimateReanalyzer.org; Note: Average reflects 1982-2011 mean; Chart: Rahul Mukherjee and Simran Parwani/Axios

An assortment of climate scientists, meteorologists and others are expressing alarm at recent changes in key climate indicators.

The big picture: Global surface air and ocean temperatures have spiked sharply in recent months, along with record low Antarctic sea ice, extreme heat events around the world, as Canada's heat and wildfire crisis grips North America.

  • Along with other developments, the combination of those factors have raised alarms regarding whether climate change is accelerating

Driving the news: In Twitter threads and via other social media platforms, climate experts have been noting the state of affairs with at least some nervousness. Right now, global sea and air temperatures are at record highs for this time of year, and climbing.

  • The unusual warmth in the North Atlantic Ocean is particularly eye-catching, and it raises fears of a more active hurricane season than what is typically expected in a year with an El Niño present.
  • El Niño tends to reduce the number of Atlantic tropical storms and hurricanes.
  • In a viral tweet over the weekend, meteorologist Brian McNoldy of the University of Miami called global air and ocean temperature trends "bonkers," stating: "People who look at this stuff routinely can't believe their eyes. Something very weird is happening."
  • The warmer than usual Atlantic waters are already having dangerous impacts, including contributing to Puerto Rico's worst heat wave on record.

Of note: Global extreme heat events have smashed records during the spring and so far during meteorological summer, which commenced on June 1.

Between the lines: At first glance, it might appear to be a sudden and potentially risky acceleration of climate change. But each of the collective trends observed so far may be explained by a mix of natural and human-made factors that are relatively well-known — with a couple of wild cards thrown in, climate scientists told Axios.

  • Zeke Hausfather, climate research lead at payments company Stripe, attributed some of the warming to the transition out of a cool La Niña phase of the Pacific to El Niño.
  • "In general, I think the level of excitement around recent sea surface temperature records in some quarters is a bit over the top," he told Axios via email.
  • "The world is warming rapidly, broadly in-line with climate model projections. It's going to get bad if we don't rapidly reduce emissions, with more extreme heat events, record-setting global and regional temperatures, severe wildfires, and other extreme events where there are clear climate linkages," he said.

Yes, but: "We don't have any evidence that warming is accelerating beyond the range that scientists have previously predicted it would. What we expect is bad enough!" the researcher added.

  • Hausfather's view was shared by others, including Michael Mann of the University of Pennsylvania, who identified abnormally low levels of dust blowing from the Sahara Desert across the Atlantic as a factor in how warm parts of the tropical Atlantic are right now.
  • Dust transport each year tends to hold down Atlantic Ocean temperatures slightly, and also makes the atmosphere less hospitable to tropical storms and hurricanes.

What they're saying: Daniel Swain, a climate scientist at UCLA, argued during via a Youtube question and answer session Monday that he didn't believe "this current escalation is necessarily an indication that there's any dramatic underestimation of the warming, it's just sort of an exclamation point on the long-term Trend as we stair step up."

  • "It's two steps forward and one step back, that's the natural variability, if you will, on top of the [human-caused, long-term] warming trend."

The intrigue: Two relatively poorly understood factors that may be contributing to the ongoing climate extremes include:

  • A switch made to marine fuels beginning in 2020 that has led to reduced sulfur dioxide emissions in the tropics, which acted to reflect some incoming solar radiation. However, how influential this factor is is not yet clear.
  • There is also the 2022's Hunga Tonga volcanic eruption, which contributed large amounts of water vapor to the stratosphere, warming that atmospheric layer.

The bottom line: Are these trends concerning? Yes. But do they mean climate projections are missing the mark? Not yet, researchers said.

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