We have a choice now: either (1) reduce carbon emissions or (2) carry on as we always have. We face a nearly binary risk: either (A) the army of distinguished scientists (many of who have taken enormous pressure for their stands) are right, and continued emissions will have disastrous consequences, or (B) the army of distinguished scientists is wrong, and continued emissions will have little effect on the environment. So we have a two-by-two matrix. Let's examine the payoffs. This can also be represented as a standard decision tree, below.
Scenario 1A will result in a serious cost to the economy, about 2% of GDP. That's bad. However, it will avert disaster.
Scenario 1B will result in a serious cost to the economy, about 2% of GDP, but in about 100 years, our children will find out that their parents wasted some money, with the intention of protecting them. Of course, our children will have the opportunity to go back to gorging on foreign oil again, if they like.
Scenario 2A will result in an environmental and economic disaster on a scale that we cannot imagine. Our children and grandchildren will see the major coastal cities under saltwater. The world's population will have doubled, but the earth's capacity to feed people will have fallen below current levels. How will those people feel? I think they will look back on the years 2000 to 2008 - the Bush years - as a pivotal time when changes could have been made, but were not. Our children, their children, and their children, as far down as we can imagine, will curse our selfishness.
Scenario 2B will result in a life going on pretty much the way it has been - we continue to suck up foreign oil, but the environment will not change too much.
We so want life to continue as is, with certainty and calmness, without change! Are we willing to bet against disaster, when the insurance will cost us only 2% of our incomes?