Quote:
Originally Posted by kirant
I wonder though how much of the changes are from the natural and how much from the human. We've seen real fast changes historically, and some around the speed of today (to the "fireball" earth, I think we saw much faster increases...if you trust the studies on the billions of years old temperatures).
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Direct observations show CO2 raising significantly, and the increase correlates with the time when we started burning fossil fuels.
The ratio of radioactive isotopes is changing exactly as you would expect if the increase in CO2 was due to burning of fossil fuels (not to mention that the amount of Oxygen is decreasing at the rate indicated by burning of fossil fuels).
CO2 is a greenhouse gas, this has been measured both in the lab and in the real world, and real world measurements of varions greenhouse gasses
over time show the link between changes in these gasses and change in radiative flux
So you have more greenhouse gasses in the atmosphere. All things being equal, that will result in more heat being retained by the earth, and that's exactly what's
measured as well.
Changes happen for a reason, and the only thing that fits the signature of the observed changes currently is warming due to human released CO2.
Quote:
Originally Posted by kirant
On a bit of a tangent is exactly what influences water has. Commonly accepted is that it's a feedback that magnifies the running of CO2. However, it's also noted that vapour and clouds in the atmosphere act as a good reflection source of new incoming radiation (terrestrial albedo was it?).
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Sure, it's a question of which effect is greater. I think at this point the evidence is growing that the net effect of clouds is as a
positive feedback (warming) and that if it is negative it's very small.
But I think this is one area where there's still a lot of research going on and there's no wide consensus yet.