Ocean acidification

Abstract

In Chapter 16, Tim Stephens directs attention to the ‘ocean acidification’ boundary, which refers to the changing carbon chemistry of the oceans as they absorb carbon dioxide (CO2) from the atmosphere. This boundary is closely linked to the climate change boundary, as both relate to human disturbances to Earth’s carbon cycle. However, the chapter shows that there are important differences, and argues that the safe threshold for climate change may not necessarily be equivalent to that for ocean acidification. The chapter also examines the definition of the ocean acidification planetary boundary and assesses its strengths and limitations. It then sets out the global legal and policy frameworks applicable to ocean acidification and considers the extent to which these are capable of keeping changes to ocean chemistry within the limits of the ocean acidification planetary boundary. It is seen that this planetary boundary has greatest relevance to the climate regime built around 1992 United Nations Framework Convention on Climate Change, and the 2015 Paris Agreement on Climate Change, as this is the primary forum where efforts to limit CO2 emissions are being pursued.