Tsk! Tsk! You obviously haven't been here that long. My conversion to more than doubt over Climate Change was brought about by the viciousness and personal level of the attacks that I received when I first broached the subject about 3 years ago. Since I was not anticipating such a series of attacks, over what had been I thought a scientific subject, I became curious about what was causing some much heat, and what clearly appeared to be an attempt to suppress debate.

Since then I have therefore read extensively on both sides of the debate and I used to write about some of the information that I found but which is not brought up when we the largely one-sided pronouncements of coming doom were being advanced. As a result I have come to some clear conclusions. They are my conclusions, but based on information and data that I have derived from many sources. There were warming periods in the past, and the evidence that I have read is that the temperatures during those periods was warmer than today. Thus I find, for example, that Richard Heinberg's concerns over the melting of the permafrost is an over-reaction to a perceived problem given that the permafrost melted during the last warming period (the Medieval one) without the serious consequences that he anticipates. There was a Little Ice Age and naturally the globe warms as we come out of it, that warming has been going on since the 1800's.

If I can give you examples of the sort of things that made me draw the conclusions that I have, these include the migration of the Thule from Alaska to Greenland, the present of trees in the lake beds of California (about a thousand years ago - showing the extent of the droughts of the time), the collapse of the Mayan Empire - it is at that scale that one sees the impact of previous climate change during the Medieval and earlier Warming periods. There is the evidence of the shifting of plant species and ecotones back and forth across France over the Millennia that documents these changes. There is the sudden stop to the penetration of roots into graves as permafrost is re-established in 1350.

It is at a scale much larger than the contentious values that Dr Mann has put forward, based on the occasional bristle cone pine tree, but which NOAA seems to favor.

It's worse than that. Heading Out and others ignoring basic precautionary principles means they are essentially logically and morally bankrupting us. So if we're wrong, we just look silly, but we stopped digging up coal and ensuring the world kept killing the planet's biodiversity off so quickly.

If the denialist camp are wrong, then we are all fucked six ways from Sunday. Clearly the best approach is to not er on the side of caution, as all good scientists and engineers do. I know that's how I work when developing pharmaceuticals, and I've not killed anyone so far (I think).

The evidence is overwhelming, and anyone ignoring these observable changes is so ideological committed, no evidence will convince them.
It is a moot point, the consequences is in, and greenhouse gases are warming the planet to dangerous levels.

I thought Co2 is already causing great harm of acidification of oceans, shells being dissolved etc.

Scenarios, forecasts, semantics. And if the "scenarios" are proved wrong with actual measurements (as Hansen's have been), then the underlying theory is proved wrong.

Greg: My point is that the farther in the future your "Scenario" the more likely it will be inaccurate or sometimes even extremely flawed. This doesn't mean there shouldn't be planning, but one should be reality based when discussing these. A lot is going to happen in the next 25 years that almost no one is able to predict right now or in your words, no one has drawn up a Scenario around. IMO there wasn't anyone that in 1984 (25 years ago) predicted that by 2009 China would rival the USA in economic power. How is it possible that every single thinker could have missed such a huge development? It happens because the farther out your timeline the more unpredictability, or the more flawed your Scenario. Here is an exercise for you: you tell me what is the major development over the next 25 years (rivalling the China story) that not one important voice has mentioned. Almost everything you can mention is exempt-Peak Oil, Climate Change, Collapse of the USA, etc. Something BIG not being mentinoned right now by ANYONE is coming obviously. I realize what I am trying to explain to you isn't conventional thinking or something you were required to memorize to pass a course, but give it a thought.