BFTP | Bless: they’re still confused about weather vs climate

The original version of this post was published almost exactly 4 years ago (2010-01-11) when extreme storms and snow caused havoc in Western Europe. Given that many of the same “so where’s your global warming now?” gotcha tropes are flying around again since the severe cold weather hit Northern America, it seems like it needs repeating (with some minor updates). Scroll down for new links to articles elsewhere explaining recent extreme weather events (including the difference between this year’s polar vortex collapse and 2010’s shift of the jet stream).


Snow covering the UK, satellite photo January 2010

Snow covering the UK, satellite photo January 2010

I knew that people would look at the extreme winter weather currently blanketing the Northern hemisphere and start saying ridiculous things about global warming.

Not one of them seems to realise that the only thing that has ever stopped the UK (and other nations around the North Atlantic) from having the same winters as Moscow (at a similar latitude) is the twin effects of the oceanic Gulf Stream (North Atlantic Conveyor) and the atmospheric Jet Stream over Europe, both bringing warm water and warm air currents from subtropical areas of the North Atlantic.

The 2010 winter whiteout was because the Jet Stream has shifted south. Shifts in air currents are a predicted effect of global warming, and since these currents help distribute equatorial heat to the poles, it is totally consistent with the science of global warming that changes in these air currents will lead to less effective thermal redistribution and thus colder winters at higher latitudes.

The Global Ocean Conveyor of salty water currents

THE GLOBAL OCEAN CONVEYOR—The global ocean circulation system, often called the Ocean Conveyor, transports heat throughout the planet. White sections represent warm surface currents. Purple sections represent deep cold currents. (Illustration by Jayne Doucette, WHOI)

If they think this is counterintuitive, wait until the Gulf Stream shifts and/or shuts down. The atmospheric/air currents are largely dependent upon the oceanic currents (aka the Global Ocean Conveyor) that carry warm water away from the equator to the poles. The effects of global warming on the oceanic thermohaline circulation that drives these currents (and particularly the Gulf Stream) are being studied in increasing detail and abrupt shifts in its force, extent, (and its eventual cessation altogether) have happened in the past and are predicted effects of global warming (more fresh water from icecaps and glaciers entering the Northern oceans leads to less salty oceans leads to shutdown of Oceanic Conveyors).

This winter will seem mild in comparison. And while Eurasia and North America freeze, the tropics will bake in drought. Climate chaos, not just climate change, will be what we have then.


Links for 2013-2014 extreme weather events:

I’m sure you’ll understand why this post has been placed on full comment pre-moderation.



Categories: culture wars, Science

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7 replies

  1. And yet there was an opinion piece in The Australian today using the Tamiflu saga as an opportunity for a sly (and inaccurate) dig at climate science.
    Tigtog, your link about the shut down of thermohaline circulation (I assume it’s to something about the Younger Dryas) gets a 404.

    • Thanks for telling me, angharad – I guess it’s been moved or removed sometime in the last four years. Will see if I can find it again (or another one).

  2. If this isn’t the article I used originally, it at least covers all the bases – Abrupt Climate Change: Should We Be Worried?. Post updated.

  3. Something that isn’t obvious until you actually look at a map:
    Boston, Rome, and Vladivostok are all at the same latitude, but have vastly different climates.
    Vladivostok is further south than Edinburgh and Vancouver, yet is much more frigid. It is robbed of its warming waters by Japan.

  4. Conservatives are snow-trolling again as the US and Canada hunkers down for another heavy snowfall (They’re calling this weather event “Janus”? Drama llamas.).
    Chris Mooney in Mother Jones – Believe It: Global Warming Can Produce More Intense Snows

    To understand the relationship between climate change and intense snowfall, you first need to understand that global warming certainly doesn’t do away with winter or the seasons. So it’ll still be plenty cold enough for snow much of the time. Meanwhile, global warming loads the dice in favor of more intense precipitation through changes in atmospheric moisture content. “Warming things up means the atmosphere can and does hold more moisture,” explains Kevin Trenberth, a climate scientist at the National Center for Atmospheric Research in Boulder, Colo. “So in winter, when there is still plenty of cold air there’s a risk of bigger snows. With east coast storms, where the moisture comes from the ocean which is now warmer, this also applies.”
    Why does the atmosphere hold more moisture? The answer is a key physical principle called the Clausius-Clapeyron equation, stating that as atmospheric temperature rises, there is an exponential increase in the amount of water vapor that the air can hold—leading to more potential precipitation of all types. (A detailed scientific explanation can be found here.)
    Indeed, scientific reports have often noted the snow-climate relationship. An expansive 2006 study of US snowstorms during the entirety of the 20th century, for instance, found that they were more common in wetter and warmer years. “A future with wetter and warmer winters…will bring more snowstorms than in 1901-2000,” the paper predicted.

  5. It tickled my fancy to see Brian Schmidt calling Maurice Newman’s bluff this week.

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