Do I remember specific studies or articles? No, I didn't keep track of them. However, the kind of predictions I'm referring to are specific temperature increase predictions within a certain time period, specific rates of ocean level increase within a certain period of time, and predictions about increases in extreme weather events in particular years.
Exactly, which direction are you going here? Are you claiming that predictions exaggerate or minimize the actual measured results? Because, the general trends of CO2 increase, Arctic sea ice decline, sea level rise, ocean acidification...and many other indicators have far outstripped the earlier IPCC reports such as the one 20 years ago in 1994. Back then they were predicting loss of Arctic sea ice at the end of this century, guess where we are now! A special report prepared for the U.S. Navy last year predicted complete melting by the end of the summer of 2016...hardly more than two years from now...and of course that depends on some other variables...such as the Pacific...which now that there is a growing consensus that we are into a new, strong El Nino Southern Oscillation for later this summer, 2016 would be a near certainty!
So, the predictions have been way behind the real world results of global warming, largely because the reports presented for the IPCC were ignoring the likelihood of positive feedbacks as the global temperatures continue to rise. Now, the question is whether climate change is completely out of our control - because there is enough stored carbon locked up in Arctic permafrost and methane clathrates in shallow Arctic waters to rapidly dump large quantities of methane and CO2 into the atmosphere and trip other climate tipping points - dieoffs of marine life in the oceans, loss of terrestrial carbon sinks such as tropical rainforests through drought, and northern forests from increasing forest fires etc..
As the climate issues have come into clearer focus over the years, there has been less and less willingness by politicians and policymakers do to anything about them! No doubt this is largely because the costs of doing something are significant and growing. In the summary of the latest IPCC report, the dog that doesn't bark, is the fact that the UN was trying to arrange a deal where the richer and heavier polluting nations of the world would pay a significant amount of money for climate mitigation...such as assisting low-lying coastal nations like Bangladesh - which are most at risk of sea level rise. The cost would have been 100 billion per year for the U.S., Europe and other members of the high carbon, high consumption club, to go to the nations like Bangladesh and sub-sahara Africa, with very low per capita carbon footprints/that also face the worst effects of climate change. The cost for the U.S. would have been 30 billion per year...so guess what the answer is so far: a lot of expressed concern and flowery rhetoric by Obama and that's it! Nothing!
So, are we screwed? I have been of the opinion for the past few years already, that there is likely no way to make even liberalized capitalist economies environmentally sustainable, because the basic dynamics of capitalism demand constant growth; and guess what...we live on a finite planet! And we are just beginning to feel the limits of limited ecosystems and resource limits as economies stall out and stagnate in vain attempts to keep on growing.
From some of the literature I've read of late, calculating tipping points towards positive feedbacks is a matter of percentages - not hard limits like 1 degree increase does this, two degrees will do this, four degrees etc.. Instead, it looks more like being at 400 ppm CO2 combined with other GHG's in the atmosphere gives us almost 10% chance of adding an extra 2 degrees to global temperature increase which will be enough to set off other positive feedbacks. We may already be at the stage where we have to seriously consider geoengineering strategies to stop temperatures from rising (sequestering carbon in the atmosphere is much more expensive and difficult). And there have been hardly any serious testing of geoengineering effects on a complex system (the biosphere). We need to know what, if anything, will work, and what would likely make the problem worse and need to be avoided.
But, geoengineering would only provide short term solutions to get through the coming decades...what about after that? The next few generations will face extinction, along with the rest of life on earth if the human animals that use so much of the global biosphere do not reign in their consumption and waste. Up till now, the global warming debate has been about what can we do to fix or make the problem less serious, while working within the constraints of capitalism and human wants and desires. What if we don't have that option any longer? What if saving the future for our children and grandchildren requires a complete upending of our present economic systems and what where we place our values.
