There are clearly vested interests who fight hard to obscure the fact that the fossil fuel emissions increase the onset of climate change (we just have to see how the US, Saudi Arabia and Australia stonewalled at the Montreal UN Climate Change Conference), and I always find it fascinating how their spin finds itself into the mouths of the general public.
Glitch, a regular (possibly my only one) has forwarded the theory that increased solar activity is the driver behind the global warming we observe:
I'm sorry - but I believe that the earth's temp is PRIMARILY driven by variations in the Sun's output.Glitch has a good point, the sun is indeed the greatest influence on the earth's temperature, but that is not the whole story. I will try to illustrate with an example. If I go sunbathing, the sun will initially be the greatest influence on my body temperature, which would rise. So far Glitch's argument is supported in this example. But then my pores would open in response to my body's increased temperature and I would sweat. This sweating will cause evaporation thus cooling down my body and keeping it at an average temperature of around 37 degrees Celsius. The biological name for a mechanism for maintaining equilibrium is called homeostasis. Without a homestatic mechanism for cooling I would just heat up, cook and die.
If EVERY CAR/TRUCK/PLANE/ELECTRIC POWER PLANT was turned off TODAY, I do not believe it would change the 'global climate' - sea levels will go up and go down...and there is NOTHING humanity can do about it.
If we take the view that the earth is an organism of sorts, as in the Gaia theory of James E Lovelock, then we can attribute Gaia with a homeostatic mechanism that keeps her temperature at an equilibrium that sustains life. Gaia's temperature chart for the last 1800 years (Mann, et al, 2003) indicates that this is indeed what happens.
One of the main drivers for this mechanism is called albedo, or the reflectivity of the earths surface. The earth, on average, reflects 31% of the sun's heat back into space, keeping it cool, and can be described as having an albedo of .31 while snow and ice has an albedo of .9 and oceans have an albedo of .1, or 10%.
As an aside, it was Leonardo da Vinci who first explained, almost exactly 500 years ago, that the earth reflects the rays of the sun in his Codex Leistercer.
So now you can see why healthy artic and antartic ice and snow belts are vitally important to regulating the earth's temperature. Where do the greenhouse gases that Glitch referred to fit into the picture? Well, they trap the heat that is reflected. If I may return to my previous example of sunbathing. Many underarm deodourants work by closing the pores of the skin, preventing sweating. Now if I was to cover my body with such a deodourant prior to sunbathing, I would be disabling my cooling mechanism and would thus overheat and suffer sunstroke. By not reversing the rate at which we put CO2 in the atmosphere, humanity is collectively doing pretty much the same thing to Gaia; we are disabling her cooling mechanism.
Yes it is a fact that there has been an increase in solar activity:
Since the middle of the last century, the Sun is in a phase of unusually high activity, as indicated by frequent occurrences of sunspots, gas eruptions, and radiation storms. Researchers at the Max Planck Institute for Solar System Research (MPS) in Katlenburg-Lindau (Germany) and at the University of Oulu (Finland) have come to this conclusion after they have succeeded in reconstructing the solar activity based on the sunspot frequency since 850 AD.But recent studies by German and Finnish research teams conclude that this is just one cause:
The influence of the Sun on the Earth is seen increasingly as one cause of the observed global warming since 1900, along with the emission of the greenhouse gas, carbon dioxide, from the combustion of coal, gas, and oil. "Just how large this role is, must still be investigated, since, according to our latest knowledge on the variations of the solar magnetic field, the significant increase in the Earth?s temperature since 1980 is indeed to be ascribed to the greenhouse effect caused by carbon dioxide," says Prof. Sami K. Solanki, solar physicist and director at the Max Planck Institute for Solar System Research.In summary, Glitch, it all comes down enhancing our collective albedo. ;)
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