Everald,just because a lot of bored silly easily led politician's looking to ingratiate themselves with the public jumped on board does not mean society should put up taxes for the hell of it so that industry sectors can barter over the spoils,now that the climate change, global warming, ozone hole,melting icecaps temperature measurement scam is in transition from fact to fictions, players old and young still want part of this non action that will not change the climate or save money or us, just inflate costs and probably produce stagflation as there is no added value, where is the productivity in that? Unaffordable twaddle. Inigo Jones (rip).

Herbert Stencil
You deny the relationaship between rising CO2 and warming. The Swedish scientist Arrhenius showed definitively that carbon dioxide has warming characteristics, similar to that of a greenhouse. Charles Keeling showed us that CO2 has been steadily rising since the 1950s. Deforestation and industrial activity have contributed to the CO2 increase - they are human activities. What don't you understand? Why don't you understand? Have you no science training at all?
And Jon J - we've just had the warmest decade on record. Why do you say there has been no rise in temperatures in ten years? Just because 1997-98 was a very warm year is irrelevant - you have to look at trends over at least a decade, not just individual years.

popnperish.

I, along with nearly all of the sceptics that I have come across, accept (to the extent that it can be known) that the physics seems to say that a doubling of CO2 levels in the atmosphere would lead to around 1 deg C of warming.

Leaving aside for the moment the issue of whether CO2 levels can double, given the response of the biosphere to higher CO2 levels, the real issue relates to the feedbacks. The IPCC generally assumes strongly positive feedbacks which are included in the models that show substantial warming for doubled CO2. However, these assumptions are not strongly supported, and in fact are challenged by many climate scientists who argue that the feedbacks are neutral, or even negative.

If the feedbacks are neutral or negative, then CO2 as a cause of concern falls away. Especially compared with the other impacts that humanity is having on regional and local climate.

Why don't we examine the issue of whether the feedbacks are negative, neutral or strongly positive before we engage in costly and disruptive carbon taxes?

Herbert Stencil
Would that you are right about a mere one degree warming with a doubling of CO2. Given that we have already had 0.7C degree warming by going from 280 to 390 ppm CO2,however, we may anticipate that we will have one degree warming long before we get to 560ppm, say at around 420ppm. And even if there would be no more emissions today, the inertia in the system means we will continue to warm by another 1.5 degrees.
As for feedbacks, the biggest seem to me to be mostly positive (reinforcing)rather than negative (offsetting). Snow and ice reflect more radiation than dark seas. A warming tundra will release methane which is a very potent greenhouse gas. The effect of more clouds in a warmer wetter world is mixed - some reflect light (negative feedback) but others trap heat (positive feedback). Carbon dioxide promotes plant growth but higher temperatures generally reduce yields.
I would like you to be right, then I could sleep more easily. But I fear positive feedbacks will greatly outweigh negative ones.

Herbert Stencil, thanks for the atmospherics lecture.
Just maybe, the chances of your thesis being better than the science community’s observed data are not all that high.
If you want to run with geologist Ian Plimer’s statement that carbon dioxide levels were much higher, yet “life thrived” - then it would be good to admit that such “thriving” was really a re-development following mass extinctions of species accompanied by changes of concentration of carbon dioxide.

"Warming isn't happening" says JonJ. One wonders which planet he inhabits. The evidence for global warming (on Planet Earth) is overwhelming, and very easy to find. Only the most determined denialist could say "warming isn't happening", as each recent decade is measurably warmer than the one which preceded it. Measurements are coming in from satellites, buoys, radiosondes, weather stations, balloons, animal behaviour, plant behaviour, ice sheets, farmers leaning on gates. For "An observationally based energy balance for the Earth since 1950", Murphy et al, Journal of Geophysical Research, see: http://www.agu.org/pubs/crossref/2009/2009JD012105.shtml