gge, show me a climate scientist who says that global warming will be a net benefit to agriculture? The Brits have not found that 'increased rain' inundating their fields for the last six summers has improved their agricultural output. IIRC, more crops are lost every year due to excess rain than drought. But of course GW can increase both drought and flooding, neither of which are particularly good for crops. Just because we haven't had sustained losses of 2% or more over many decades in the recent past is absolutely no kind of evidence that it will not happen in the near future. We live on a very different planet than we did just a few years ago, and the rate of change is picking up. If you hadn't noticed, the Arctic ice cap is in the the process of vanishing.
You keep harping on what 'science' says, and warn against making absolute statements, then you come out with these utterly idiotic, unscientific statement (that you presumably got from your tours of anti-science denialist sites), and proclaim them as absolute truths. It really makes it hard to take anything you say seriously. Sorry, but you should know what kind of impression you are making with this kind of rant.
The impression I get is someone too emotionally fragile to face the hard cold facts and solidly based projections that the science is now presenting us. I can understand the unwillingness to accept the science since it is pointing to such dire results, but denying that science and then claiming to be the great defender of said science goes rather beyond what I, at least, can stomach.
And why do you assume that your audience have not been 'warriors' on the lines of the environmental and GW lines already for many years? How many people have you introduced to the concept of global warming and resource limits...For me it now runs in the thousands. How much have you challenged yourself, your immediate and larger family, your schools, places of employment, religious groups, neighborhood, city, state, nation, world to change to more sustainable practices, and at what personal expense to you? Most of us don't much like bragging on ourselves, but I have been struggling at all these levels for decades now with some pretty negative consequences to relationships and career.
But I also agree with Hansen, Anderson (Tyndall Centre on CC Research) and many other scientists, scientific organizations, and other major institutions that have carefully researched the situation that we are now in a world of trouble pretty much whatever we do. That doesn't mean give up the fight. But it is important not to lie to ourselves about where we are while trying to improve, however marginally, our and our children's survivability.
Two degrees looks pretty much inevitable, by most assessments now. Recall that this was the international agreed upon guard rail in most talks beyond which everyone agreed we should not go, even though the science for a long time has been clear that very bad things start happening long before you get to two degrees. Many organizations and research programs see us hitting four degrees within this century, a level that has been called incompatible with an organized global community, that is, pretty much with modern civilization. And of course many other groups have concluded that we are pretty much locked into about six degrees by about the end of the century. I recommend to you the book "Six Degrees" by Mark Lynas if you don't know what that would mean for humans and for life on the planet. Here's a short presentation by Anderson (mentioned above) that goes over some of the basic implications for the planet and the economy, if you're actually interested.
Two more things: "prevent the negative effects" Can you explain what you mean here? Do you mean moving hundreds of millions of people away from the coasts? Do you mean moving agricultural production north hundred of miles to poorer soils and shorter growing seasons? Do you mean somehow preventing the Arctic from going ice free, the GIS from collapsing, the permafrost from becoming permathaw...? Just wondering.
And it should also be pointed out that the Green Revolution that squeaked us past the last food bottle neck:
1) Has run its course
2) Is not going to provide further great benefits
3) Does not seem to have a cousin waiting in the wings to save us (and please don't start on GMOs)
4) Helped bring about our current situation where we have even more massive numbers of mouths to feed and the need to 'just in time' provide the massive amounts of grain necessary to feed them. One year of major global crop failure will be utterly catastrophic, and that just means a Russian 2010 heatwave event happening in a couple more of the worlds major breadbaskets.