The IPCC has released the latest working group contribution to their Fifth Assessment Report, Climate Change 2014: Mitigation of Climate Change.

An interesting piece about it in RealClimate from one of the co-authors can be found here.

The IPCC has also started the review process for the synthesis report, which will be geared toward policymakers and based on the three Working Group Reports and Special Reports of the Fifth Assessment Cycle. 

From IPCC Climate Change 2014: Mitigation of Climate Change Technical Summary.