Will capping atmospheric CO2 at 350 or 400 ppm stop OA?
Atmospheric CO2 is already at 390 ppm and is increasing at about 2 ppm per year. Without dramatic reductions in CO2 emissions, atmospheric CO2 will continue to rise, and most emission forecasts for the near future indicate a likely increase (rather than decrease) in atmospheric CO2 growth rate. The first step in addressing ocean acidification, therefore, is to stabilize and eventually reduce CO2 emissions. Atmospheric CO2 almost certainly will peak well above 400 ppm, because we will not stop increasing emissions in the next 5 years. The impacts on marine life at the peak CO2 level may be substantial. In the long run, it may be possible to reduce atmospheric CO2 through natural and artificial uptake mechanisms. The chemistry of seawater is reversible, and returning to 350-400 ppm would return pH and carbonate saturation levels to approximately their current conditions. However, some research has suggested that even current-day conditions may be deleterious for some organisms, and it is
