There’s a heat wave at both north and south poles, because of course there is.

In general, when I think of heat waves, I think of the damage to crops and infrastructure, the lives lost, and the misery of that suffocating heat. Most of the time, that’s why we care about heat waves. They’re unpleasant for most of us, and deadly for some, and can cause lasting damage to the food supply.

Unfortunately, that’s not the only kind of heat wave that’s worthy of headlines. As many of you are no doubt aware, there’s a heat wave happening at both poles simultaneously:

Startling heatwaves at both of Earth’s poles are causing alarm among climate scientists, who have warned the “unprecedented” events could signal faster and abrupt climate breakdown.

Temperatures in Antarctica reached record levels at the weekend, an astonishing 40 degrees above normal in places.

At the same time, weather stations near the north pole also showed signs of melting, with some temperatures 30 degrees above normal, hitting levels normally attained far later in the year.

At this time of year, the Antarctic should be rapidly cooling after its summer, and the Arctic only slowly emerging from its winter, as days lengthen. For both poles to show such heating at once is unprecedented.

I’ve talked before about why, in the context of a warming planet, a hot year matters more than a cold one. It adds momentum to what’s already happening. These heat waves mean more ice melt, which in turn will mean more ice melt in the future, that would have happened without them. It’s bad news in that regard, but it’s also bad news because of what it says about the speed at which things are happening:

Mark Maslin, professor of earth system science at University College London, said: “I and colleagues were shocked by the number and severity of the extreme weather events in 2021 – which were unexpected at a warming of 1.2C. Now we have record temperatures in the Arctic which, for me, show we have entered a new extreme phase of climate change much earlier than we had expected.”

The Associated Press reported that one weather station in Antarctica beat its all-time record by 15 degrees, while another coastal station used to deep freezes at this time of year was 7 degrees above freezing. In the Arctic, meanwhile, some parts were 50 degrees warmer than average.

“They are opposite seasons. You don’t see the north and the south [poles] both melting at the same time,” said Walt Meier, a scientist at the National Snow and Ice Data Center in Boulder, Colorado. “It’s definitely an unusual occurrence,” he told AP. “It’s pretty stunning.”

The climate denial industry spent decades exploiting minor uncertainties by insisting that climate sensitivity was lower than mainstream climate scientists were estimating. The reality is that sensitivity seems to be higher. Edit: As discussed in the comments below, actual sensitivity calculations have been pretty much on target. The rate at which the heat increase is affecting life on earth is what has been underestimated. Things are happening faster than expected, and honestly that’s been true for quite a while now.



  1. Pierce R. Butler says

    Hasn’t just about every published error in climatological projections been an underestimate?

  2. says

    Most of the ones I’m aware of, but I’m definitely biased. There have definitely been climate doomsday predictions that turned out to be bunk, but I don’t know that any of them were made by scientists.

  3. Dunc says

    I’m not sure it’s true that Equilibrium Climate Sensitivity is turning out to be higher than thought – I admit I’ve not been following recent developments very closely, but my impression is that mainstream ECS estimates are pretty stable and the range is narrowing towards the centre (i.e. around 2.5 – 3°C). I think the real issue here is more that ECS is a pretty crude measure of a global average equilibrium state that’s still a long way off, and we’re seeing far more variability (both spatial and temporal) on the way towards that state than anybody expected.

    It’s not that the ulitmate destination has changed, it’s just that the journey there is turning out to be a lot bumpier than we thought.

  4. says

    Edit: I’m not disagreeing with your definition of climate sensitivity – you’re absolutely correct from what I know. I just tend to think much more in terms of “how quickly will this affect our lives, and how much?” than in terms of “what will the end point of this warming be?”

    When I talk about “climate sensitivity”, I’m talking about how quickly we see the physical and biological results of a given increase in greenhouse gas levels and temperature.

    That’s not about reaching a point of equilibrium, it’s about that “bumpy journey” – how much temperature increase will lead to ecosystem collapse? Turns out not much, at least with ecosystems already on the brink from other human activity.

    How much warming to see salt water intrusion into fresh groundwater? How much before crop failures increase?

    It’s one thing to know the approximate rate at which the planet is trapping heat, but it’s another to be able to actually break down what that means for our own lives.

  5. Dunc says

    I assumed you meant “climate sensitivity” in the specific, technical sense of “what is the equilibrium increase in global average temperature resulting from a doubling of atmospheric CO2 concentrations?” because (a) it’s s very well-understood term that’s immediately familiar to anybody with a passing familiarly with the subject, and (b) you linked the words to a page about that specific, technical usage.

  6. Dunc says

    No problem! I think the correction is much better, as it focusses on what really matters.

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