The predictability of global warming is ..... uncertain

How much the earth's climate will change as a result of global warming is unpredictable.

Well, tell me something that I didn't know.

This from National Geographic News reports on a new study which looks at the levels of certainty involved in calculating estimated temperature rises as a result of us humans continuing to pump too much CO2 into the atmosphere.

Now, apart from one or two crazy luddites, we all accept that CO2 is a greenhouse gas, and we all know that if we continue to pump ever more into the atmosphere then there is going to be an effect. All the scientists and climatologists tell us that this WILL cause a rise in the temperature of the earth's biosphere. What we don't know is just how much temperature rise equates to what level of CO2 there is, hence, at least to some extent, the endless stream of tis/tisn't arguments, and counter arguments that the earth is not doing anything different than it ever has.

The majority of scientists (the consensus?) tell us that temperature rise is bad on a rising scale, a couple of degrees perhaps maybe OK, but too much and we'll all fry, along with most of the other flora and fauna. (Hence recent headlines warning of mass extinctions.)

What we don't know is just what constitutes too much, the models are so complicated and involve so many interrelated variables that no computer model we can currently produce can provide any answer with any degree of certainty. And that's without starting to factor in natural feedback systems and amplification loops, which make it impossible to predict future temperature rises with any degree of accuracy at all.

All in all the 'science' of temperature rise prediction is a huge can of worms, and those of us not endowed with brains the size of a planet simply have to accept what the scientific consensus tells us, that the numbers are uncertain and that they actually don't know, other than the temperature IS going to increase.

Fossil evidence through geological history over 100's of millions of years shows us that in cool times, flora and fauna have multiplied and genera and species diversity has increased rapidly. It also shoes us that in the much warmer periods, many of the planet's life forms disappear, and that in a few, very short, very hot periods, life forms have almost been wiped out entirely (90%+ of all life forms in one catastrophic event alone). [And that's without mentioning what humanity is already doing to our current flora and fauna.]

Now I'm no scientist (well, in comparison to most of the clever people out there researching away on all of this) but that still worries me significantly. We ARE warming the earth, we simply don't know by how much, or if the temperature rise will accelerate due to natural feedback systems. What we DO know, from fossil evidence that more warmth means less life forms, and that excessive warmth means but very few life forms survive.

Now surely that's a compelling case for looking at reducing our CO2 emissions now, rather than risk hitting some sort of temperature acceleration point in a few decades or so? The science of predicting global warming temperature increases may be uncertain, but I'm pretty sure that if we sit and do nothing, then the consequences appear to be rather dire.