Can we attribute specific weather events to climate change?

Yes. Not only that, but we can't separate climate change from any single weather event that ever happens, anywhere, no matter what. So just stop saying that we can't. Here's a thought experiment to explain why this is true.

Imagine that climate science is like it is today with a few significant exceptions. First, humans never messed with fossil fuel, using only solar energy. If you need to, you can add in that there are only a half billion humans on the planet because birth control was discovered and implemented earlier in human history and everybody has Obamacare. Second, the climate scientists have a thousand, no, make that five thousand, years of instrumental records of the planet's weather. Third, there has been virtually unlimited access to super computers and the field is advanced 30 years beyond the present. So, climate science is like it is now plus way smarter and more informed with way more information. Also, there has never been any kind of science denialism on my imaginary Earth, so the negative effects of that particular nefarious activity were never felt, never slowed down progress.

One day astronomers, who are also very advanced in knowledge, understanding, and technology, discover a star that is identical to the Sun, and around it orbits a planet that is identical to the earth. Same atmosphere, similar distribution of continents that move around and stuff, same amount of free water and ratio of land to sea, same orbital geometry, etc. There is only one difference between H'Trae, which is what they named this newly discovered planet, and Earth. The Earth has an equilibrium level of 250ppm of CO2 in its atmosphere and H'Trae has an equilibrium level of 500ppm CO2 in its atmosphere.

The astronomers sent a probe to H'Trae which sent back five years of satellite images from the entire surface in a number of energy bands, so there is a pretty good picture of what is happening there. A thousand dropsondes were dropped across the planet at random intervals which gave more direct atmospheric measurements, and then recorded data from the surface for another couple of years, until the H'Traeans found them, one by one, and ate them. So there's a lot of data.

There emerges a literature, on "The Climate and Weather of H'Trae," and it is peer reviewed and widely distributed and it matures and becomes part of the Planetary Science body of knowledge.

Then one day somebody comes along, probably on the Internet, the first known Science Denialist, and says "The amount of Carbon Dioxide in the Atmosphere has no relationship to the climate or weather on H'Trae. None. Any given study that looks at climate or weather on H'Trae that does not independently test to see if having 200% of the CO2 on H'Trae as compared to earth is invalid. The role of a doubling of this gas must be demonstrated anew each time it is proposed or assumed."

What would the Earthlings do that that person? Ignore him, of course, though they might also be amused to see their first Science Concern Troll. If he got really annoying they might send him off to H'Trae so the H'Traeans eat him.

But they would not take seriously the idea that an increase in one of the most important gasses in the atmosphere, which indubitably alters temperature on average across every cubic meter of the atmosphere and every square meter of the surface, which indubitably increases the amount of water vapor in the atmosphere, which seems to indirectly alter the basic nature of major air currents, has nothing to do with the place where the climate rubber meets the temporal road: The weather. It would be an absurd idea.

So why do people keep repeating that as though it made sense?


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Great metaphor.

You also chose the correct word - attribute. The media, striving towards sensationalism, uses "cause". And denialists of course use cause since they know scientists have higher standards than they do and will likely not use the same word. Humans tend to use cause because we're trying to make sense of our random existence, so the denialists and the captive media automatically gain the upper hand in any debate due to the reticence of scientists to use the word.

Global warming didn't "cause" Sandy, it made the storm worse. Global warming didn't "cause" the Russian heat wave that killed like 50,000 people, it made it worse. Global warming didn't "cause" the polar vortex, but it may have influenced the deviation of that cold air from the Arctic. And so on.


Maybe I'm giving the denialists too much credit, but I think that, at least among some, provability/falsifiability is a concern. Not the idea that global climate - and thus a change in global climate - affects the weather, but rather proving that any one storm or event was caused or worsened by climate change.

Take Lawrence's examples. We can prove how, theoretically, global warming can make hurricanes worse. I'm not sure that we can (yet) prove that it did make Sandy worse. Perhaps I'm wrong there. Similarly, I believe in the science (posted here and elsewhere) that shows how the polar vortex may have been significantly influenced by the current warmth patterns themselves directly influenced by climate change. I'm not sure if it wouldn't or couldn't have happened without such change (on Earth vice H'Trea, for example).

Again, I'm probably giving the denialists too much credit, and their argument is far less nuanced and much more direct.

I'm personally hesitant to automatically make the leap from climate change and warming to specific individual weather patterns and storm severity, because plausibility differs from provability, and I don't think we're there yet. Denialists are correct when they state that big ol' storms happened in the past, too; they're not correct when they imply that this means that a big storm today cannot be linked to global warming. If, however, they say that we simply can't be sure if a specific big storm today is any worse because of global warming, then I'm not sure I disagree. Climate is simply too complex, and I'm not a climate scientist.


Haven't been commenting, but I've been following. Loved the recent(ish) posts on the January we just went through, and putting the regional/sensationalist US news (it's COLD outside!!!!) in perspective against, oh, the entire rest of the world.

I think it is clear that Katrina and Haiyan were made worse by unsually warm seas, and seas warm at depth, that we can attribute to global warming. I would't have picked Sandy as an example of being made worse. Maybe, maybe not, it steered into the coast rather than following the usual course, because of climate change.

You can't separate weather from climate, ever. They are the same thing. If the climate has fundamentally and broadly changed, than the weather has too.

I think the problem you are having is that you are asking the question wrong. (And so is everyone else.) We don't ever ask if a weather event is due to the spin of the earth or the heat of the sun. We don't normally wonder if a very rainy day in the rain forest is because it is in the rain forest and not in an arid land. In other words, we nomrally don't ask weather events where they came from, we just view them in the perspective of regional and temporal aspects of climate. But then, climate change comes along as a factor in climate (obviously) and it has to dance backwards and in high heels. In other words, it is not so much that we need to stop saying "no particular event bla bla bla" and change that. Rather, we have to ask why the heck we were even asking that to begin with.

In the end we simply need to know what the weather is going to do, what sea levels are going to do, etc. as a society for various important reasons, no matter what those things are, and climate change will certainly shape what those expectations are over time. The effects of climate change on patterns of weather is much more apparent in some cases than others, but in general, it is a new phenomenon, probably. Climate science likes 20 years or more time spans to observe and understand. Climate science does not have that luxury, and it may simply be impossible to do anything other than guess in some cases. I share your concern that we may assume too much, but we are forced to assume something. It's a bit like Pascal's Wager. Only with consequences!

We may be saying the same thing, just differently. What I had in mind in bringing up Sandy is that a warmer atmosphere holds more moisture, so the potential for greater rainfall is there. And sea levels have already risen, which exacerbates flooding.

So in a world like you describe, of course Sandy's devastation can be attributed to climate change, because all weather is attributed to the state of the climate.

Right, the flooding in NY was certainly worse than it would have been a century earlier, with a foot lower sea levels.

"We don’t ever ask if a weather event is due to the spin of the earth or the heat of the sun. We don't ... blah blah"
Who's we, kemosahbe?…

Like Will Steffen, you are trying to move the goal posts after the fact. Quote:
"A few years ago, talking about weather and climate change in the same breath was a cardinal sin for scientists."

Only a few years ago?
How convenient.…

As my first link shows, this type of 'thinking' (and I use that term very loosely) has been documented before and is an ugly speed hump on humanity's road to destiny.


That's entirely possible. Again, I don't claim to be a climate scientist; I just try to maintain a healthy level of skepticism. I don't like to think that I can predict things for certain, even though obviously one can do so with a high degree of accuracy in certain circumstances.

Greg & Lawrence,

The additional flooding from Sandy is certainly something I had forgotten to take into effect (probably a perception issue, as in CT, flooding wasn't our major concern, but it was obviously a major issue in NY and NJ). That's definitely an area - higher sea levels - where you could state that a storm was more damaging than it might have been earlier, without ambiguity or contention.

Thanks for the feedback.

@Greg Laden
March 7, 2014
And, that destiny is?

Whadda think I am?

A government funded climate scientist?
Only they can tell the future.
That's if you believe our children's children have a future.
Which obviously, you don't.

P Gosselin: When one compares these hallucinatory depictions to today’s bleak climate scenarios coming from climate scientists, and their shrill demands that we radically change our behavior, the parallels could hardly be more striking.

Ah, but they would be far more striking without our 400 years of scientific progress. Anyone who thinks modern science is a hallucination is free to show us why that is so.

By Christopher Winter (not verified) on 08 Mar 2014 #permalink