Bleak outlook on climate change

Engineer M. Granger Morgan of Carnegie Mellon University, climate scientist Kirsten Zickfeld of the University of Victoria in British Columbia and physicist David Frame of the University of Oxford in England interviewed 14 "leading climate scientists" about three possible climate scenarios to ascertain what might happen depending on how much heat greenhouse gases end up adding.

The aim was to round up the most senior climate experts and gauge their opinions on what is most likely to happen under three scenarios: a high degree of warming, a moderate amount of warming and relatively little warming—as well as to judge when, if ever, the global climate might reach a "tipping point" into a completely altered state.

One main point from the result published in the June 28 Proceedings of the National Academy of Sciences: What was most uncertain to all 14 experts was clouds—specifically, whether clouds would exacerbate climate change by trapping more heat or ameliorate it by reflecting more sunlight. Regardless of the unknown effects of clouds, 13 of the 14 judged the odds better than even that if the extra heat trapped by greenhouse gases peaked and leveled off at seven watts per meter-squared by 2200—we would see an entirely new climate.

In fact, nine of the experts judged the probability of such a "basic state change" in the atmosphere to be at least 90 percent, or more. That corresponds to a warming of as much as 12.5 degrees Celsius—a worst case scenario.

Fortunately, the human-induced extra heat at present hovers at about 1.2 watts per meter squared.

The interviewed experts don't expect to be any more able to understand clouds and the other uncertainties by 2030—even if funding for such research were tripled in the next 20 years.

Pointing to the fact that we dont know 'more than what we knew in 1975 regarding climate sensitivity'. So what is the lesson here, any guesses?