Well, first I'd like to say there is a human contribution to the global warming, but people are horribly misguided in certain issues and I'll try to explain about these things as clearly as possible.
| StarcraftManiac said: When global warming goes on like this The northern icecap will be gonne before 2150 (And be 1/5 of the size it is now before 2100). When that happens the Gulfstream is interupted (This can happen as soon as 2075 aprox) The gulfstream makes sure warm waters go to the north just beside Europe. Which makes it possible to live in Europe with a nice climate. When this stream is interupted. An Ice-age occures. |
This is one popular myth. Virtually no scientist thinks this can happen because Europe gains its warmth mostly from winds and both the winds and Gulf-stream are mostly driven by Coriolis force, which results from the rotation of the Earth, not the thermo-haline circulation. So to stop Europe from getting warmth from the lower lattitudes, the rotation of the Earth would have to be stopped.
There's also some other topics where people have been misguided by the sensation-seeking media imo. For example, it's no clear how much the hurricane activity will rise because of global warming. In the year 2005 there was a record amount of them and the media was full of stories linking the record to climate change but the scientists are far more careful. When no hurricanes hit the coast of US in 2006, the media seemed to go silent about the issue. Christopher Landsea, an expert on hurricanes, says the hurricane intensity may rise 1-2% in the next 100 years.
There have also been stories of malaria spreading because of global warming, but that seems far-fetched, because believe it or not, malaria is not purely tropic disease. The malaria mosqitoes were abundant for example here in Finland and east in russia, even Siberia in the 19th century. The malaria started to lose ground after increased level of hygiene. In southern Europe people got finally rid of malaria by drying up bogs and using DDT in the 60s.
The vast ice sheets of West Antarctica and Greenland will NOT melt in 100 years, not even in 1000 years even if the World would warm up according to the worst scenarios. That's simply because the require so much energy to melt. If the melting is slow enough, the ocean floor will adapt to the added weight and so the continents will rise relative to the ocean floor, which results in very little rise in sea-level. The IPCC (Intergovernmental Panel on Climate Change) predicts rise of 20-60 cm from 1990 to 2100.
As far as the main argument of AGW goes, it's clear that greenhouse gases warm up the atmosphere, but again, there is not certainity of how much. IPCC states that the climate sensitivity, that is, the rise of temperature resulting from doubling the amount of CO2, is 1.4-5.5 degrees celsius. Now you may think that it doesn't matter how strong the effect is, because the cumulation keeps on going. (I agree that we should get rid of fossil fuels as soon as possible because that has to be done at some point anyway (they don't last forever), so my points aren't meant to encourage polluting more.)
However, the climate sensitivity works on a logarithmic base. That is, the doubling of the amount of CO2 in atmosphere results in very similar rise in temperature no matter what the starting values are. For example, if the rise from 200 ppm to 400 ppm would raise the temperature by X degrees, so would the rise from 2000 ppm to 4000 ppm. This means that we would most probably die off because of CO2-poisoning before we could make this planet too hot to live due to increased CO2-levels. In addition, there has been as far as 20 times more CO2 in the atmosphere compared to the levels of today and the time is known as the Ordovician glaciation period, one of the coldest epochs ever. That would suggest that the Earth's climatic balance is not easily altered by rise in greenhouse gases.
Some of you might have now thought that why has the climate warmed so little if the percentual increase of greenhouse gases is the one that matters. That surely has been a big problem. The warming should have been fastest from 1950-1970 because of the high forcing, but instead there was no rise in temperature at all in that period. This is explained with global dimming, which results from increased pollution. Now that the technique is cleaner, less pollution is created and the Earth should warm faster. However, the warming hasn't been very fast after year 2000. Here's a graph to show what I mean: http://www.cru.uea.ac.uk/cru/data/temperature/_nhshgl.gif
This might be due to the stabilizing of methane levels or solar activity, for example. We'll see how the climate keeps changing.
