Rebuttal of the Climate Change Skeptic Thing
This post will make no sense if you don't read the original.
A common misconception I'd like to dispell is that melting of polar ice will cause sea levels to rise, flooding great expanses of low-lying land.
Obviously. But there is alot of ice on the south pole, and on Iceland, greenland, etc etc.
This is because the ice is left over from the last ice age, and ocean currents are warming it up and melting it away naturally anyway.
Not all ice is left over from the last ice age. And this doesn't change the fact that antropogenic climate change is accentuating this effect.
and mankind's emissions of CO2 are something in the order of 2% of total CO2 levels I believe, although this last figure may be incorrect.
Grossly incorrect. See this graph. In the past few centuries, carbon dioxide levels rose by 18% – suggesting that 15% of current (2000) CO2 levels are due to human factors.
(Rechecking makes things appear even worse. By 2004, this percentage has risen to almost 30%. Methane - which is a stronger Greenhouse gas than CO2 - shows a 133% increase over the past 200 years. (up to 2000) This suggests that 57% of atmospheric methane is due to human factors ).
And then we need to look at impact, and variability. The IPCC, and other models all take this into account, and are unequivical about the effect. The maths is solid.
This has not been supported by scientific facts gathered during the last 10 years.
This is incorrect. The troposphere riddle has been recently solved. See this article
The earlier problems have been located as a problem with the measurement method failing to adjust for stratospheric cooling. There are also other explanations.
Most of the increase in the air's concentration of greenhouse gases from human activities—over 80 percent—occurred after the 1940s. That means that the strong early 20th century warming must be largely, if not entirely, natural.
This doesn't show that at all. This shows that the warming had either a non-linear relation to atmospheric changes, or that there were non-gas related causes. For example – conversion of land to agrarian farming. Forest clearance. And so on.
The mid-20th century cooling, and some of the latter 20th century warming also seem matched to changes in the sun.
But there are strong, notable exceptions.
Rough limits could be set on the extent of the Sun's influence. Average sunspot activity did not increase during the 1980s and 1990s, and the satellite measurements of the solar constant found it cycling within narrow limits (less than one part in a thousand). Yet the global temperature rise that had resumed in the1970s was accelerating at a record-breaking pace. It seemed impossible to explain that using the Sun alone, without invoking greenhouse gases.(57*) The consensus of most scientists, arduously hammered out in a series of international workshops, flatly rejected the argument that the global warming of the 1990s could be dismissed as a mere effect of changes on the Sun. [For example, in 2004 when a group of scientists published evidence that the solar activity of the 20th century had been unusually high, they nevertheless concluded that "even under the extreme assumption that the Sun was responsible for all the global warming prior to 1970, at most 30% of the strong warming since then can be of solar origin."
The fact that future solar activity would increase still fits in with the evidence for Gobal Warming. The addition of this effect in fact increases the neccessity of acting on the Greenhouse Gas issue – the two effects are supercumulative.
In my mind, the main threat of global climate change is not sea level rises, but local environmental changes. Agriculture today is extremely vulnerable to small changes in temperature. Studies of sealled environments incorporating a combined temperature/atmosphere change all show dieback, and a drop in growth. This is likely catastrophic in today's situation. Diseases too are likely to have an effect.
The last major climate change occured when global population levels are under 10% of current. We've grown very used to the current climate conditions. That's why climate change is a reason to worry.