I
wrote the following last winter when there were big snowstorms hitting the US.
Let's see if I can make this simple.
What happens in the weather this week or next tells us absolutely nothing about the role of humans in influencing the climate system. It is unjustifiable to claim that a cold snap or heavy snow disproves or even casts doubts predictions of long-term climate change. It is equally unjustifiable to say that a cold snap or heavy snow in any way offers empirical support for predictions of long-term climate change. This goes for all weather events.
Further, it is professionally irresponsible for scientists to claim that some observed weather is "consistent with" long-term predictions of climate change. Any and all weather fits this criteria. Similarly, any and all weather is also "consistent with" failing predictions of long-term climate change. The "consistent with" canard is purposely misleading.
Knowledge of climate requires long-term records -- on the time scale of a decade and longer. Don't look to the weather to learn about climate, unless you have a long time to watch. Using the weather to score cheap political points in the climate debate appears to be a tactical area of agreement among those who otherwise disagree about climate change.
A climate scientist who I have a lot of respect for wrote me an email and asked the following (and expressed a preference not to be involved in a blog discussion of this, so will remain anonymous):
I am interested in how you would deal with a journalist asking for my reaction to the recent string of historically unprecedented heat waves (eg Europe 2003, Australia 2009, Russia 2010 - and there are many more of course).
As context, can I quote the IPCC SAR (1996): "A general warming is expected to lead to an increase in the occurrence of extremely hot days and a decrease in the occurrence of extremely cold days".
We have indeed seen an increase in the occurrence of extremely hot days and a decrease in the occurrence of extremely cold days, since that projection was published. So...if I point this out to a journalist, and also point out that this was projected by the IPCC 15 years ago, does this mean I have completely and utterly lost my senses? If so, why? How would you respond to the journalist?
Here is how I responded:
I wrote something about this when people on the other side were using the cold weather to make different statements, see this here:
http://rogerpielkejr.blogspot.com/2010/02/weather-is-not-climate.html
Were I a scientist talking to the media I would deemphasize the efforts to relate weather events to a specific causality. I would emphasize long term trends since the IPCC defines changes in climate to occur over 30 to 50 years. And I would point out that the IPCC predictions, such as they are, have always been for the longer-term future rather than the present.
I would also emphasize the rather important point that no practical action hinges on debates over causality of specific events -- the case for aggressive mitigation does not rest on such claims (despite what some scientists claim in public) and the need for adaptation has already been well established. It is a practically meaningless debate.
I talked to a reporter yesterday and made this analogy:
Suppose that I predict that the price of copper will be $100,000 per tonne in 2050. Suppose further that I watch the daily spot market. Would it make sense to claim that every day (week etc.) of gains in price is "consistent with" and proves my prediction? Would it make sense to argue that every day of losses in price is "not inconsistent with" my prediction? Or would it make sense to say that such wiggle watching is not a productive use of my time if the goal is to invest productively? You know my preference;-)
The scientific community in my view loses credibility when it tells the public in the winter that "weather is not climate" but then in the summer forgets that admonition.
If scientists want to argue the case for mitigation and adaptation to climate change they should! But in such advocacy the scientific community should avoid making claims about causality of specific events that cannot be judged empirically, have no practical significance and serve only to add political intensity to a field that has seen more than its fair share of waging a political battle through science.
7 comments:
There's a bigger reason, IMHO, why the "consistent with" canard is misguided. It really begs the question of the causality.
To take your copper analogy, you may have predicted that the price would rise due to some particular factor. And then suppose you advocated for policies to reduce that factor, whatever it was. But what if the price went up for other reasons?
As far as we really know, rising temperatures are not the same thing as rising atmospheric CO2.
"So...if I point this out to a journalist, and also point out that this was projected by the IPCC 15 years ago, does this mean I have completely and utterly lost my senses? If so, why? How would you respond to the journalist?"
As the son of a journalist I would say that unless the conditions are outside annual or multi-decade variability then you will discredit yourself.
Journalists generally don't retire at 65, many, including dear old mom are quite active into their 80's.
In the world of journalism, a 'trusted source' gets one strike and they are out.
'The scientific community in my view loses credibility when it tells the public in the winter that "weather is not climate" but then in the summer forgets that admonition.'
Kinda like the WMO's statement [in previous topic] which only mentions heat related events without a word concerning current cold events in the Southern Hemisphere...destructive cold events [not to mention summer cold events here in the US].
If you look at the temperature record since the Little Ice Age the statement, "A general warming is expected to lead to an increase in the occurrence of extremely hot days and a decrease in the occurrence of extremely cold days" would also be correct.
You would also be correct in saying that in the next 100 years 6 billion+ humans will die.
You can be correct on a lot of things, but one thing does stand out is that their is no evidence to suggest that individual and extreme weather events are linked to CAGW.
Tell him these record hot days are only over the short term in some places but never over the longer term anywhere (in the US the 30's are the peak period). The longer the term, the better the analysis. In fact you shouldn't need to tell him that, he should know it. That's the sad part!
As for the decrease in the occurence of extremely cold days. Where did he spend the Winter, and the Winter before, and the one before that? My old mother has just experienced the coldest Winter of her entire life and she's far from alone.
I find it remarkable that no matter how often you tell scientists 'you can't do that,' they will so often respond 'yes, I know, but in THIS case...'
Sample size is the classic example. They know their sample size isn't large enough to give good results, but... 'that's all we've got to work with.
It doesn't matter. If you can't do (or say) that, you just can't. In this case, 'weather is not climate' means 'weather is not climate.' The End.
Pointing to the shift of planting days to earlier in the year by this logic is a good evidence of climate change. Glad to agree.
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