My point is that scientists put up a variety of models with a variety of assumptions and know full well that some of those assumptions are going to prove wrong, and so will the corresponding models. This is part of the model fitting process.
It is absolutely true that the extreme models from a decade ago are clearly wrong. However you were trying to conclude from that normal and expected result that the entire process a decade ago is clearly wrong and this is somehow a crisis. Far from being a crisis, this is normal science, and entirely expected.
What is far more important is that the best models we can produce today fit in the range that was being predicted a decade ago. And none of that range is good news.
What I don't get is how scientists can advocate multi-trillion dollar public policy initatives and incredibly disruptive changes to our economy based on these uncertain models.
If we could produce better models, we would. But when your best projections about the future show an oncoming train, at what point should you pay attention?
Even if you accept the predictions as certain the costs of the 'remedies' seem to exceed the costs of simply adapting to the higher temperatures.
There have been many, many attempts to quantify this. These attempts are even more controversial than climate studies because they also depend on economics, which is both less settled and more political than climate science. And furthermore they could be changed radically by future scientific improvements that we don't know about yet. However as http://en.wikipedia.org/wiki/Economics_of_global_warming#Res... says, No models suggest that the optimal policy is to do nothing, i.e., allow "business-as-usual" emissions.
As an example of a limitation, there are climate mitigation strategies that have been discussed which might be considerably cheaper. For instance the release of particles into the stratosphere might cool the planet. However wouldn't help with ocean acidification - what value do we put on having shellfish? Adding trace minerals to the ocean in certain places will cause ocean blooms that help with CO2 and acidification, but have unknown impacts on the deep ocean.
This leads to a classic problem. At what point do we decide to act on the basis of what our best available information says? As http://www.amazon.com/Collapse-Societies-Choose-Succeed-Revi... makes abundantly clear, the historical pattern is for cultures who don't want to make hard choices to put them off, despite the best information they had available, until it was too late. With disastrous results for the culture. I don't want that pattern to repeat to my children and grandchildren.
You, obviously, consider the risk worthwhile.