Anthropocentrism

Counting stomata (pores) on ancient oak leaves provided van Hoof's team with a measure of the fluctuations in atmospheric carbon dioxide for the same period.

"Between AD 1200 to 1300, we see a decrease in stomata and a sharp rise in atmospheric carbon dioxide, due to deforestation we think," says Dr van Hoof, whose findings are published in the journal Palaeogeography, Palaeoclimatology, Palaeoecology.

But after AD 1350, the team found the pattern reversed, suggesting that atmospheric carbon dioxide fell, perhaps due to reforestation following the plague.

The researchers think that this drop in carbon dioxide levels could help to explain a cooling in the climate over the following centuries.

The habit of precipitate explanation leads rapidly on to the development of tentative theories. The explanation offered for a given phenomenon is naturally, under the impulse of self-consistency, offered for like phenomena as they present themselves, and there is soon developed a general theory explanatory of a large class of phenomena similar to the original one. This general theory may not be supported by any further considerations than those which were involved in the first hasty inspection. For a time it is likely to be held in a tentative way with a measure of candor. With this tentative spirit and measurable candor, the mind satisfies its moral sense, and deceives itself with the thought that it is proceeding cautiously and impartially toward the goal of ultimate truth. It fails to recognize that no amount of provisional holding of a theory, so long as the view is limited and the investigation partial, justifies an ultimate conviction. It is not the slowness with which conclusions are arrived at that should give satisfaction to the moral sense, but the thoroughness, the completeness, the all-sidedness, the impartiality, of the investigation

The moment one has offered an original explanation for a phenomenon which seems satisfactory, that moment affection for [one's] intellectual child springs into existence, and as the explanation grows into a definite theory [one's] parental affections cluster about [the] offspring and it grows more and more dear ... There springs up also unwittingly a pressing of the theory to make it fit the facts and a pressing of the facts to make them fit the theory ..

"Suppose that the cause of that warming is something else than antrhropogenic greenhouse gas effect?".

Well, that's easy. Then nothing we do will really matter - unless we identify the non-anthropogenic effect and reverse it somehow.

But, since we won't reach certainty that it is not anthropogenic (ie there will always be some concern that human activity contributes), it continues to make sense to try to reduce emissions, reduce population load, look at the long term consequences, and continue to try to research the situation.

We do have a much better understanding of climate than thirty years ago, after all, and that's because science has been trying to understand the factors that contribute to climate.

(I'm still not here. I mean it.)

Why is deforestation bad?

Because plants help take in the carbon dioxide we breath in and turn it into oxygen that we can breath.If hunans > plants that makes the air balance so we have less air to breath.
The Rain forest helps alot with truning carbon dioxide into oxygen and cutting them down would make things very unblanced.

Well I guess that the (huge) albedo changes may or may not have cyclic interaction with ocean surface temperatures and for some reason that cycle is somewhat stronger than the last one in the 1940ies. But that's very tentative.

Then, have a good time elsewhere.

Are they really huge or are you sarcasticizing? I never read that paper somebody posted in the global dimming thread. I even saved it too.

you guys civilly really don't like each other.

which gives Earth blackbody temperature variations of about 3 degrees Kelvin/Celsius, as I said, it dwarfs the greenhouse factor with only a few tenth C at the most.

Let's do another one.

The idea that humans can and have had a big impact on climate is increasingly thriving. Apparently we are the central factor -Anthropocentrism. It started with Ruddiman who had produced a study His point is that the current Holocene shows an unique rise in carbon dioxide (measured in Antarctic ice cores) from some 255 ppm to 280 ppm. The other end of icing stadial spikes that indicate the start of interglacials show a (sometimes very) slow decline after the intial spike as seen here.

How come, well the paleolithic man started to change his environment, cutting down forests to build villages, burn fires and have land for agriculture. This would remove the carbon sink function and would increase the CO2 in the air.

So what do you say about that?

Are you approximating Earth to a black body to get its black body temperature?