Polar Ocean Acidification
Fish stocks such as cod are much more negatively affected by changes in the polar oceans at 2°C global warming than at 1.5°C global warming. These changes include ocean acidification, warmer and less salty sea water from increased river runoff, glacier melt and ice sheet melt; as well as greater competition from mid-latitude species moving polewards. In contrast, polar species and ecosystems have nowhere further to migrate.
Today’s rates of ocean acidification are greater than at any time in 3 million years, and pose an immediate and serious threat in cold polar waters, which absorb CO2 more quickly. The oceans will need 50–70,000 years to return to normal pH levels, a key argument for keeping CO2 levels as low as possible and against schemes aiming to decrease solar radiation rather than CO2.