Science Magazine has a paper recently claiming that global warming was "Irreversible". It's an indication of how strongly global warming alarmism is a religious matter that the paper was published with such a title.
Global warming is of course not "irreversible." If CO2 is removed from the atmosphere, temperature will go down. And there is no magic behind removing CO2 from the atmosphere. Plenty of people have studied it. The question is one of cost/affordability.
Below is an analysis of the cost/;affordability removal of CO2 from the atmosphere. What I did was to obtain global GDP and atmospheric CO2 projections for four IPCC scenarios. Then I took the GDP for the years 2080 to 2100, and projected that growth rate out to 2200 for each scenario (since GDP projections to 2200 were not readily available). I did the same thing for projections for CO2 emissions.
Then I calculated what would happen if the world spent 10 percent of its GDP on removing CO2 from ambient air in the year 2100, and continued to do that until the ambient CO2 concentration reached the pre-industrial level of about 300 ppm. My assumption was of a cost for CO2 removal of $1000 per metric ton. That works out to about $7.8 trillion per ppm of CO2 removed.
The results below indicate that for all scenarios but one, the CO2 is reduced to the pre-industrial concentration of about 300 ppm before the year 2200. I'll probably modify this post a bit as I have time. But the bottom line is that global warming, contrary to what you may have read in Science magazine, is clearly not "irreversible."
1) Global GDP values can be found at this site: SRES scenarios.
2) Atmospheric CO2 concentrations can be found here: CO2 concentrations and emissions