Ocean acidification is well covered in the Working Group I contribution to the IPCC Fifth Assessment report (Climate Change 2013; the physical science basis), released on 30 September.
Ocean acidification is covered in depth in Section 3.8 of Chapter 3 and Section 6.4. of Chapter 6.
Ocean acidification is also mentioned numerous times in the Introduction, Summary for Policymakers, Technical Summary, and Chapters 7, 9 and 10.
The full report is available here.
Intergovernmental Panel on Climate Change, 30 September 2013. Report.