Thursday, October 31, 2002

Hot air on climate change

David Appell is a science writer who maintains a blog called Quark Soup. He takes issue with Kim DuToit, Toren Smith and Robert Prather here about global warming.

The bloggers I mentioned are big boys and can take care of themselves. If they saw this post they probably have, but alas despite their permalinks to the left I haven't seen everything they have written. So I'll take a few whacks at this myself.

What got me were passages like this:
You can lead a skeptic to data, but you can't make them think.
Toren Smith repeats the flat-earther's mantra that "the whole global warming scenario scarcely counts as science and is based primarily on computer models that can't even accurately predict past climate, much less that of an unknown future."
Toren, Toren, Toren. Have you looked at the scientific studies? Have you read them? Have you read anything that doesn't agree with your ideology? As I just pointed out to Kim du Toit, many climate models have predicted past climates.
It is possible to disagree with someone without crap like this.

But let's get more substantial. OK, maybe many climate models have predicted past climates. That might be impressive until you realize that there is an infinite number of models that could do this in principle. So the existence of a number of them is not impressive in itself, and in fact makes me wonder why they can't decide among them.

Here's another item:
Let us continue our corrections of du Toit.
He rants , "I also need to see proof that human activity (eg. releasing more carbon dioxide into the atmosphere) has had a more profound effect on climate change than have volcanic eruptions...."
The global warming effect of volcanoes is not close to that of man:

"Volcanoes contribute about 110 million tons of carbon dioxide per year while man's activities contribute about 10 billion tons per year," according to the Volcano Information Center operated by geologist Ronald Fischer at the University of California at Santa Barbara.

That's 1%, Kim.
However, what volcanoes do do is spew a lot of sulphur aerosols into the atmosphere, but that causes cooling , not warming.
Mr. DuToit said "climate change", not warming. Mr. Appell offered nothing to prove that man's impact is greater than that of volcanoes, and noted that volcanoes had impact on the climate. From this he concluded that "The global warming effect of volcanoes is not close to that of man". If he's right, he hasn't made his case in the post. I propose that he should do so before he resorts to such condescension.

He's not through. Before he gets around to referring to "climate change flat-earthers", he notes the following:
"Several coupled models are able to reproduce the major trend in surface air temperature, when driven by radiative forcing scenarios corresponding to the 20th century. However, in these studies only idealized scenarios of only sulphate radiative forcing have been used.

Many atmospheric models are able to simulate an increase of the African summer monsoon in response to insolation forcing for the Holocene but they all underestimate this increase if vegetation feedbacks are ignored."
Interesting. In both cases he's noting known flaws in the models, yet that's what he uses for his support.

Elsewhere he refers to the period from 1951-1998. I wonder why he chose that period. I will note that aboveground nuclear weapons tests were common in the earlier part of this period. These might have led to abnormal levels of particulates in the atmosphere (a miniature "nuclear winter"). This in turn would have caused the beginning of the period to be cooler than the later part entirely independently of other anthropomorphic influences. I don't know how strong that phenomenon was though, so, unlike Appell, I won't make any claims.

The problems involved with measuring and modeling the relevant parameters would make a long post in itself, but let's assume that these scientists, with their big grants from organizations that want budget increases, are immune from conflicts of interest and are in fact doing everything right. Alright, what would they have to measure or evaluate in the course of developing models?

Atmospheric temperatures. Atmospheric composition. Land temperatures. Ocean temperatures. CO2 concentrations. Ice sheet/glacier coverage/volume. Depth of permafrost. Albedo (a measure of how much solar radiation is reflected back into space). Insolation (the power from the sun, which is not constant). Large fires, such as forest fires or Saddam's stunt of setting oil wells on fire in Kuwait after the Gulf War. Volcanic activity, both atmospheric and beneath the ocean. Non-anthropomorphic biological influences (cattle, termites, wetlands, forestation...). Economic activity (affects power consumption, thus coal/petroleum burning)...

That's just a few things off the top of my head. Some could be trivial, and I could be omitting major influences. The point is that the scientists who produce climate models are biting off a big chunk, and the pressure to produce results that will keep the grants coming is huge.

Now suppose they have data for all of the relevant phenomena above - now what? They have to model more than just the atmospheric temperature - they basically have to model all of the things I mentioned above too. Why? Because nothing happens in isolation. Heat up the atmosphere, heat up the ocean. Then the ocean absorbs more CO2, which allegedly lowers the atmospheric heating effect and at least provides negative feedback. More water will evaporate into the atmosphere, lowering ocean temperatures, changing the transport properties of the atmosphere and increasing greenhouse effects. Plants will grow more, soaking up water and CO2 and changing the transport properties of the land. I'm not convinced we even know all of the interactions and their significance, yet without them how can we model accurately?

Yet the scientists build the models anyway, based on data from a 50 year period which amounts to 0.000001% of the alleged 5 billion year life of the planet. They know full well that we have had a number of major non-anthropomorphic climate changes over that period that to date have not been modeled successfully.

Yet in their vanity and greed they attempt to do their science in the newspapers instead of in the labs, as Eric Lindholm notes here. (Appell doesn't like that post much either).

Enough for now. Let's see if Appell has choice words for me too.

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