IPCC Working Group II on Climate Change and Ocean Acidification

The Intergovernmental Panel on Climate Change (IPCC) Working Group II wrapped up its work at the end of March in Japan, where the final drafts were accepted for the Fifth Assessment Report of the IPCC.  Both Working Group I and II highlighted ocean acidification as a concern. Below is the final draft of the ocean acidification cross cutting box, which synthesises ocean acidification findings from Working Groups I and II. See the entire report at the IPCC website.

Download a PDF of the final draft of the ocean acidification cross-cutting box from IPCC Working Group II.

Figure from Chapter 6 of the latest IPCC Working Group II, presented in Yokohama, Japan, on 31 March 2014.

Figure on ocean acidification from Chapter 6 of the latest IPCC Working Group II, presented in Yokohama, Japan, on 31 March 2014.


A: Overview of the chemical, biological, socio-economic impacts of ocean acidification and of policy options (adapted from Turley and Gattuso, 2012).
B: Multi-model simulated time series of global mean ocean surface pH (on the total scale) from CMIP5 climate model simulations from 1850 to 2100. Projections are shown for emission scenarios RCP2.6 (blue) and RCP8.5 (red) for the multi-model mean (solid lines) and range across the distribution of individual model simulations (shading). Black (grey shading) is the modelled historical evolution using historical reconstructed forcings. The models that are included are those from CMIP5 that simulate the global carbon cycle while being driven by prescribed atmospheric CO2 concentrations. The number of CMIP5 models to calculate the multi-model mean is indicated for each time period/scenario (WGI AR5 Figure 6.28).
C: Effect of near future acidification (seawater pH reduction of 0.5 unit or less) on major response variables estimated using weighted random effects meta-analyses, with the exception of survival which is not weighted (Kroeker et al., 2013). The log-transformed response ratio (LnRR) is the ratio of the mean effect in the acidification treatment to the mean effect in a control group. It indicates which process is most uniformly affected by ocean acidification but large variability exists between species. Significance is determined when the 95% bootstrapped confidence interval does not cross zero. The number of experiments used in the analyses is shown in parentheses. * denotes a statistically significant effect.