Saturday, November 5, 2011

The science is settled

The Greenhouse effect attributed to Carbon Dioxide is generally thought to cause a warming of around 1.2°C for a doubling of CO2.  So why do we hear about catastrophic warming of 5° or more?  Positive forcings.

The theory is that as the planet warms, the increased temperature will cause other reactions that cause further warming.  Essentially, these feedbacks cause an amplification of a modest warming into an out of control disaster.

Well, that's the theory, anyway.  So how does experimental evidence stack up against this theory?  Not so well, actually:

OK, so the world has warmed up a bit since 1950. This is terrible, because it means that the huge amounts of carbon stored in peat bogs will now start to be emitted into the atmosphere, which will cause more warming, which will release more peaty carbon and so on until all the Earth is a baking lifeless hell.

It must be true - it says so in New Scientist ("Peat bogs harbour carbon time bomb ... the process appears to be feeding off itself ... It's a vicious circle ... we have disturbed something critical that controls the stability of the carbon cycle in our planet"). Aaiee!

Steady on. Boffins working in Canada and Germany have looked into this properly, and they say it's a load of cobblers. Studying the decomposition of bog peat in the lab over two years, they have found that increases in temperature have no effect on peat's ability to sequester (that is, keep out of the atmosphere) its huge stores of carbon.
You know, you'd think that if the science were so rock solid, experimental evidence supporting Global Warming would be found everywhere.  Odd that so much of it isn't.


Anonymous said...

Here is a very nice graph of temperature changes over the past few thousand years.

Looking at this graph, intuition would seem to indicate that the earth has very strong negative-feedback mechanisms, that tend to return the temperature to a certain baseline. Indeed, this almost has to be the case, else temperatures would have run away millions or billions of years ago.

Mayberry said...

"Warming since 1950". Yep. That goes right along with the graph in the Farmer's almanac. The one showing cooling since the last peak highs in the 1920s-30s, which we have not quite reached yet...

Tam said...

Anon 12:18,

The guy's graph would have a lot more mainstream credibility if he did not have "Exodus of Hebrews From Egypt" in there.

It was believable before the discovery of the Rosetta Stone; now it is known to be a folk myth like Washington and the cherry tree.

kx59 said...

BP, you sir are much too sciency and kind to these wormists. At this point, they deserve nothing but abject snark. I nominate Tam.

SiGraybeard said...

Lindzen quotes research from Spencer at UAH that shows conclusively that all of the GCMs have the sign wrong. There is no positive feedback, it's negative. As Anon 1218 says, if there was no negative feedback, the system would have runaway millions of years ago when CO2 and temperature levels were much higher than anything predicted now.

Hate to link to myself, but I don't have another handy link for Lindzen's graph that shows the difference in sign for measured vs. all models.