26 Responses to “Experts: Cold snap doesn’t disprove global warming”
“It’s part of natural variability,” said Gerald Meehl, a senior scientist at the National Center for Atmospheric Research in Boulder, Colo. With global warming, he said, “we’ll still have record cold temperatures. We’ll just have fewer of them.”
Deke Arndt of the National Climatic Data Center in Asheville, N.C., noted that 2009 will rank among the 10 warmest years for Earth since 1880.
Leave it to the Associated Press to state the obvious starting with the blunt headline. They’ve been doing some of the best straight reporting on human-caused climate change (see AP analysis of stolen emails: An “exhaustive review” shows “the exchanges don’t undercut the vast body of evidence showing the world is warming because of man-made greenhouse gas emissions.”)
In fact, 2009 ranks among the 5 warmest on Earth, and the entire planet just keeps warming thanks to human emissions (see Must-read AP story: Statisticians reject global cooling; Caldeira “” “To talk about global cooling at the end of the hottest decade the planet has experienced in many thousands of years is ridiculous”). It’s not just the surface that’s warming, but we’re also seeing it where climate science said more than 90% of the warming would end up “” the oceans (see “Skeptical Science explains how we know global warming is happening: It’s the oceans, stupid!“)
Robert Henson, author of The Rough Guide to Climate Change also has a good piece in the UK’s Guardian, “Snow, ice and the bigger picture“: The cold snap tells us little about climate change, but if you want something to blame it on, try the Arctic oscillation,” which notes:
What’s different now is that climate change is shifting the odds towards record-hot summers and away from record-cold winters. The latter aren’t impossible; they’re just harder to get, like scoring a straight flush on one trip to Vegas and a royal flush the next.
It’s also critical to remember the “global” in global warming. Even if every inch of land in the northern hemisphere were unusually cold, that would only represent 20% of Earth’s surface. There’s plenty of warmth elsewhere around the world. National Oceanic and Atmospheric Administration data through November hints that 2009 may end up ranked as the southern hemisphere’s warmest year on record. For the planet as a whole, last year falls solidly among the 10 warmest years of the past 100. And despite all the talk about Earth having cooled since the late 1990s, this past decade trumps the 1990s as the warmest on record.
I’d also note that the AP story begins:
Beijing had its coldest morning in almost 40 years and its biggest snowfall since 1951. Britain is suffering through its longest cold snap since 1981.
And some in the media have also queried me about stories where people report non-record-breaking cold. It bears repeating, as I said on Fox, that global warming can’t turn January into July. So merely reporting it’s cold in January isn’t news that has any relevancy to global warming.
If we see record-breaking extremes of a very certain kind — once-in-a-century type events — those I think can be evidentiary (see “Hell and High Water hits Georgia” and “Weather Channel expert on Georgia’s record-smashing global-warming-type deluge“). But reading about near-record temps in a city or small country or part of a big country just doesn’t cut it.
It’s one thing to say, for instance, 2009 was one the five warmest years on record — or even Australia had its hottest decade ever, but to say, it was so cold yesterday in one city it didn’t even break the record or we just had a once-in-30-years weather event, well, that’s just not evidence of anything but boredom by the media.
The scientific literature now says “Record high temperatures far outpace record lows across U.S.” (the lead author is NCAR’s Meehl, cited in the AP story). So it’s only the statistical accumulation of record highs versus record lows over an extended period of time that tell us much about the state of the climate.
We’ve only had about 1°F warming in recent decades, which can’t do much more than skew the odds — it certainly hasn’t warmed anywhere near enough to have driven us outside the bounds of the much larger temperature swings that come from regional weather patterns, let alone the seasons. That’s why one needs to do statistical analysis to draw conclusions like the one signed off on by Bush’s Commerce Sec. Carlos Gutierrez, Energy Sec. Samuel Bodman, and Science Advisor John Marburger III (see “why the anti-science disinformers try to shout down any talk of a link between climate change and extreme weather“):
Heavy precipitation events averaged over North America have increased over the past 50 years, consistent with the observed increases in atmospheric water vapor, which have been associated with human-induced increases in greenhouse gases.
And they signed off on the conclusion that those “Extreme precipitation episodes” now “account for a larger percentage of total precipitation. The most significant changes have occurred in most of the United States.”
And for some reason, it always bears repeating that precipitation isn’t temperature — and record snowfall in places where it is normally cold enough in the winter to snow doesn’t provide evidence against the theory of human-caused climate change. Quite the reverse (see Was the “Blizzard of 2009″³ a “global warming type” of record snowfall “” or an opportunity for the media to blow the extreme weather story (again)?).
It doesn’t look like we’ll have to put with these stories much longer:
Jeff Masters, director of meteorology for Weather Underground, a forecasting service, said he expects more typical winter weather across North America early next week.
And, of course, 2010 still remains likely to be the hottest year on record, given the moderate to strong El Ni±o we are still experiencing — more on that shortly.