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The IPCC is charged by the UN to focus on manmade contributions to global warming. This would obviously include our emissions of greenhouse gases, but would also (it seems to me) include impacts from deforestation, changes in land use, depletion of ground water–even the effects of jet contrails. Sadly, it seems that the IPCC went after greenhouse gases and has more or less ignored the rest of what man does.
But even had they expanded their investigation to include all of man’s effects on the climate, it would be difficult to chart a useful course for the future without some perspective on other forces that affect the climate. We know that the sun is an obvious driver of change, and that variations in our orbit (some caused by the gravitational pull of large planets like Jupiter and Saturn) change the tilt of this rolling, funny shaped ball that we call home, and move us out of position. The sun also changes its orbit slightly for the same reason, producing cycles of activity that affect our climate. Even the path our solar system takes through the galaxy impacts climate. (Can you tell I’m in the middle of Ian Plimer’s Heaven and Earth? I’m learning a lot…)
There are also natural cycles here on Earth that affect oceanic currents and the air above them that make a difference to weather, storms and climate tendencies. Cosmic rays, right out of science fiction books from the 50s, impact cloud formation. In short, a lot goes on that affects our weather.
This creates a kaleidoscope of cycles that sometimes peak or trough at the same time and produce dramatic climate change in a very short period–sometimes two or three years is enough to see large scale temperature rises and falls, that then last for millenia.
What we need for better understanding is a sense of proportion–how big or dramatic the effect of each of these forces can be, and preferably, has been in the past.
The obvious example is with human emissions of CO2. The greenhouse effect is not at all controversial, but how potent is it in comparison with these other factors? Would the effects of our CO2 emissions (or the cutbacks so many propose) be swamped by the effects of other factors? I personally am not convinced that CO2 is even as important as deforestation or conversion of large tracts of land to agriculture. (My worry is that the effects of CO2, when added into the impacts of other forces, could be quite damaging.)
The sun is pretty big and pretty hot. Changes in our orbit seem pretty potent. Although climate scientists claim they have factored them into their climate models, they are the same people who inflicted the Hockey Stick chart on us–if they can’t get that right, can we trust them on other, far more complicated issues?
The IPCC, by considering our effects in isolation, may not have done climate science any favors.
Related posts:
- Climate warming faster than IPCC report says: Scientist
- CO2 implicated in mass extinction of life
- Eat a low carbon lunch to combat global warming
- Trapping Carbon Dioxide Or Switching To Nuclear Power Not Enough To Solve Global Warming Problem, Experts Say
- Beyond CO2: Study reveals growing importance of HFCs in climate warming
on Dec 27th, 2009
@ 11:09 pm:
I’ve always been a little suspicious of the CO2 greenhouse gas so I did a little analysis. You can read it