RealClimate.org has got a nice write-up on the recently published report from IPCC on the mitigation of climate change. There are some interesting numbers and projections to have a look at:
For the first time, a detailed analysis was performed of how the 2-degree limit can be kept, based on over 1200 future projections (scenarios) by a variety of different energy-economy computer models. The analysis is not just about the 2-degree guardrail in the strict sense but evaluates the entire space between 1.5 degrees Celsius, a limit demanded by small island states, and a 4-degree world. The scenarios show a variety of pathways, characterized by different costs, risks and co-benefits. The result is a table with about 60 entries that translates the requirements for limiting global warming to below 2-degrees into concrete numbers for cumulative emissions and emission reductions required by 2050 and 2100. This is accompanied by a detailed table showing the costs for these future pathways.
You can find the article at: http://www.realclimate.org/index.php/archives/2014/04/mitigation-of-climate-change-part-3-of-the-new-ipcc-report/