Couple of interesting quotes:
Indeed, a small amount of warming spread over a long period will, most experts think, bring net improvements to human welfare. Studies such as by the IPCC author and economist Professor Richard Tol of Sussex University in Britain show that global warming has probably done so already. People can adapt to such change—which essentially means capture the benefits but minimize the harm. Satellites have recorded a roughly 14% increase in greenery on the planet over the past 30 years, in all types of ecosystems, partly as a result of man-made CO2 emissions, which enable plants to grow faster and use less water.
Almost every global environmental scare of the past half century proved exaggerated including the population “bomb,” pesticides, acid rain, the ozone hole, falling sperm counts, genetically engineered crops and killer bees. In every case, institutional scientists gained a lot of funding from the scare and then quietly converged on the view that the problem was much more moderate than the extreme voices had argued. Global warming is no different.
And another prominent defector: In the War on Humans, a General Defects: (James) Lovelock Now an Agnostic on Global Warming