I just touched down here in Alamo country, and am looking forward to spending a few days at the 2007 American Meteorological Society meeting. The fact that the AMS is holding a special series of talks this year on "Climate Change Manifested by Changes in Weather" is, in my view, extremely important and appropriate.
The distinction between weather and climate--the latter being "the integral over time of weather," as one scientist put it to me--is a source of massive confusion. It frequently leads members of media and public to attribute individual weather events, such as a devastating hurricane or a day of unseasonably hot temperatures in winter, to global warming. Yet as we are constantly reminded by climate scientists, such attribution is fundamentally impossible. Global warming may change the odds of a particular type of event happening, but it doesn't "cause" individual localized occurrences. So if they want to maintain the high ground, environmental advocates must resist the temptation to misuse the weather to argue about the climate. Not only is this a matter of accuracy: It's also good strategy.
In the context of the global warming debate, misstatements about the science, especially from those advocating action on emissions, only provide fodder for the "skeptics" and contrarians, who immediately (and legitimately) slam any and all exaggerations coming from "global warming alarmists." Lending ammo to the "skeptics," especially this type of ammo, is a very dumb idea, because it helps further their longstanding strategy of picking a fight over the substance of the science--which, in turn, distracts us from talking about solutions.
Having recently completed an entire book dealing with an issue at the intersection of weather and climate (the inflence of global warming on hurricanes), I have obviously had to go over this ground in considerable detail over the past year. During that time, I haven't been blogging much about the new project, in part because I was busy but also because I didn't want to get ahead of myself, or take any strong stands before I was really ready to do so. But now, finally, I'm ready.
So, expect one or more in depth blog posts from me daily for the next few days. "The Intersection" is back....
P.S.: Jeff Masters, whose blog has been an invaluable source of information to me over the past year, also says he's here at AMS and will be blogging, so make sure to check it out.
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Chris, your latest warning re attributing single weather events to global warming is necessary and welcome. I am aware of the danger of malign contrarians using this "sloppiness" against us.
But we don't all talk in precise scientific terms all the time and it can be ponderous and somewhat wearing to reach for exactly the right form of words every time the issue comes up.
It is also true that a way to engage the non-expert in discussion re global warming is to make an observation about unseasonal weather. And we, here in London and the UK in general, are experiencing some seriously worrying unseasonal weather at the moment. It can't be Autumn (Fall) because this is January, it's a bit early for Spring really ... but to call this Winter ... !
Well it's not "Winter" and there seems little prospect of there being "Winter" this year and the predictions are for 2007 to be even warmer than 2006.
So how many warm "Winter" days do we have to experience before we can safely assert that global warming is the cause? I think we've had plenty!!
Douglas Coker
Douglas,
If winter ceases to occur as we once knew it, that's a change in climate. All I'm saying is that you have to demonstrate that statistically, not by citing one day of weird weather in one place. Thanks for your comment!
Here in New York City we had a weekend of balmy 70° weather followed by a mid-week snow flurry, and now back up in the 60°s -- it feels more like April or October than January. Until Wednesday, it was the longest the city's gone without snow, breaking a record set in 1878. But that fact in itself says that this has happened before: 129 years ago. One cannot reasonably attribute this year's weather to global warming without suggesting that global warming hasn't changed much in over a century. That's just one glaring logical mudtrap of trying to relate current weather to climate change.
At the same time, the mind grasps for ways to understand this weird weather. Chris, do you know what the explanation for this winter's weird weather may be? Is there any relationship between long-term climatic changes and this unseasonable spell, or is it purely a fluke: every 100 years or so, you get a hot one?
Not being a scientist, let me hedge a bit, emptypockets...global warming certainly makes warmer temperatures during winter more likely. But of course, this year there's also El Nino....it's always complicated. The way you'd know global warming is playing a role would be if you get a spate of these "winters" and then a detection and attribution study is performed to see whether the trend can be explained without greenhouse gas forcings. I don't know whether or not such studies have been performed--this is not my area--so that's why I'm hedging.
Thanks. I hadn't realized El Nino's effects stretched all the way to the Northeast (I always thought of it as a Pacific phenomenon) but I see now that they usually do
(more data here)
Re El Nino
To what extent might global warming affect the El Nino phenomenon?
'The distinction between weather and climate--the latter being "the integral over time of weather," as one scientist put it to me--is a source of massive confusion.'
Even, apparently, to the scientist who said that.
An integral is a sum. If I integrate (ie, add) the temperatures of 3 winter days -- one 10 degF, the second 60 and the last 80 -- I get a temperature which is the sum of all 3 (in this case 150 deg F -- hot as the inside of an oven!), but that's clearly not what I want.
On the other hand, if I average the numbers, I get 50 deg F, which seems to be closer to what I am looking for. One cold day and two hot ones yields a "climate" that is somewhere in the middle but skewed toward the hotter end.
I'd say climate is much closer to an "average of weather (eg, temperature) over time" than it is to an "integral of weather over time" (which is quite an innacurate