Thursday, February 11, 2010

Weather is not climate: What the bad winter storms in the U.S. northeast have to do with global warming

Jon Stewart had a nice bit last night on the bad winter weather in the northeast, poking fun at those, mostly on the right, who think that all the snow is evidence that global warming is a myth.

The fact is, weather is not the same thing as climate, and a single weather event doesn't really tell us anything meaningful about climate, let alone global climate. This is simple enough to understand, isn't it?

I won't repeat what I've written many times before -- e.g., here, here, and here -- but the gist is this: Climate changes on a global level can lead to all sorts of freakish weather. Indeed, in a world that is warming, winter storms like the one ravaging the northeast will continue to happen -- and may be partly attributable to global warming. Here, via TNR's Brad Plumer, is meteorologist Jeff Masters:

There are two requirements for a record snow storm:

1) A near-record amount of moisture in the air (or a very slow moving storm).
2) Temperatures cold enough for snow.

It's not hard at all to get temperatures cold enough for snow in a world experiencing global warming. According to the 2007 Intergovernmental Panel on Climate Change (IPCC) report, the globe warmed 0.74°C (1.3°F) over the past 100 years. There will still be colder than average winters in a world that is experiencing warming, with plenty of opportunities for snow.

The more difficult ingredient for producing a record snowstorm is the requirement of near-record levels of moisture. Global warming theory predicts that global precipitation will increase, and that heavy precipitation events--the ones most likely to cause flash flooding--will also increase. This occurs because as the climate warms, evaporation of moisture from the oceans increases, resulting in more water vapor in the air.

And here's Brad with some additional points:

Now, that doesn't mean we can definitively blame this snow monstrosity on global warming -- again, it's hard to attribute any single weather event to long-term climate shifts. (For instance, El Niño may be playing a bigger role right now in feeding these storms.) At most, we can say that a warming climate will create the conditions that make fierce winter storms in the Northeast and mid-Atlantic more likely. Or at least it will for awhile: If the planet keeps heating up, then at some point freezing conditions in the Northeast will become very rare, at which point snowstorms will, too But we're not at that point -- the Earth hasn't warmed that much yet.

On the other hand, climate models do predict that snowstorms in the southernmost parts of the United States should become much rarer in the coming decades: There's plenty of moisture down south, but freezing temperatures are likely to decrease and the jet stream is expected to shift northward. So if those regions start seeing a sustained uptick in snowfall, then something's gone awry in climate predictions. But the blizzard in the Northeast, while miserable and incredibly disruptive, doesn't appear whack with long-term forecasts. 

(For more, see Bryan Walsh at Time.)

All this is science, though, and, of course, the global warming skeptics and denialists, like the various talking heads on Fox News, don't want anything to do with science, with truth and the search for truth, with reality. For them, it's about sticking their heads out the window, once they remove them from their asses, and basing everything on a) how they feel, and b) what fits their partisan political ideology and narrative.

"Oh, look, it's snowy, it's cold... Al Gore is wrong!"

Stupid, stupid, stupid.

It's like they're not fully developed human beings, like they're incapable of dealing with the world as it is, but I suppose that's what right-wing politics will do to you.

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  • Prove it! Right now, we're experiencing a similar weather pattern as was seen from 1954 to 1970. Was it global warming then, or are we witnessing tiny amounts of normal cycles over millions of years?

    By Anonymous Anonymous, at 12:47 PM  

  • Prove it? The overwhelming consensus in the scientific community has reached this conclusion based on extensive research and modelling: the earth is warming, and warming rapidly, as a result of greenhouse gas emissions.

    But... let's say you're right and the bad weather is not a result of climate change. Then it doesn't disprove Al Gore and the scientific community either, does it? It's just freakish weather, and global warming is still a reality.

    People who say "prove it" also don't understand science. Science isn't a religion. There isn't a scientific "bible" that tells us everything we need to know, the revealed truth. Darwin understood that evolution was a theory, and the point is to use the scientific method to arrive at conclusions about the physical world. No one denies that there are disagreements and uncertainties in the scientific community, including with respect to climate change. What is striking, though, is the overwhelming agreement on this issue. And it isn't because of some leftist conspiracy, as the denialists suggest, it's because all the research and modelling leads to a pretty clear picture of what's going on.

    By Blogger Michael J.W. Stickings, at 3:34 PM  

  • While I have doubts about the accuracy of computer models, that the average temperatures are increasing has been demonstrated.

    That the increase over the last century or so is independent of the kinds of changes the layman is dimly aware of is adequately demonstrated doesn't seem to matter. What matters is that people perceive that they're being asked to change and in this climate of paranoia, change seems to mean taxes, even when it doesn't.

    The gulf between the exploding body of knowledge gained through science and what the public thinks is true has never been greater and what makes that worse is the growing belief in "common sense" and the wisdom of the ignorant. The irony is that we value faith above objectivity, but demand mathematical proof of the obvious.

    We favor witchcraft, quackery, the magic properties of quartz and pressure washing our colons over science and largely because we don't even know what it is, and it's easier to believe that reality itself is only a conspiracy of scientific liberals to raise our taxes.

    I hate to sound like Rush, but if I have to watch my house float away, it would be adequate consolation to watch them blame the collapse of our prosperity, if not our independence itself on Liberals rather than on themselves.

    And of course they will.

    By Blogger Capt. Fogg, at 10:50 AM  

  • I am from the Netherlands and I've never seen such a winter with so much snow in my entire life. The last summers where the hottest ever. I don't need prove. ;)

    By Anonymous Weather and Climate, at 3:16 AM  

  • Hi "Weather and Climate": If humans could live to, let's say, 500,000 years old, they'd see many such winters and summers like the ones you're describing. I don't know how old you are, but for argueant's sake, I'll assume you're 50. Geologically speaking, that it such a minimal blip in time as to make your observations irrelevant. However, if it's really hot again next summer, be sure to wear lots of sunblock and drink lots of water.

    By Anonymous Anonymous, at 10:58 AM  

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