page_title: Human impact on marine life
section_title: Ocean acidification
hierarchical_section_title: Human impact on marine life / Ocean acidification
caption_attribution_description: English: Estimated change in annual mean sea surface pH between the pre-industrial period (1700s) and the present day (1990s). Δ pH here is in standard pH units. Calculated from fields of dissolved inorganic carbon and alkalinity from the Global Ocean Data Analysis Project (GLODAP) climatology and temperature and salinity from the World Ocean Atlas (2005) climatology using Richard Zeebe's csys package. It is plotted here using a Mollweide projection (using MATLAB and the M_Map package). Note that the GLODAP climatology is missing data in certain oceanic provinces including the Arctic Ocean, the Caribbean Sea, the Mediterranean Sea and the Malay Archipelago.
context_page_description: Human activities affect marine life and marine habitats through overfishing, habitat loss, the introduction of invasive species, ocean pollution, ocean acidification and ocean warming. These impact marine ecosystems and food webs and may result in consequences as yet unrecognised for the biodiversity and continuation of marine life forms.
  According to the IPCC, since 1950 "many marine species across various groups have undergone shifts in geographical range and seasonal activities in response to ocean warming, sea ice change and biogeochemical changes, such as oxygen loss, to their habitats."
  It has been estimated only 13% of the ocean area remains as wilderness, mostly in open ocean areas rather than along the coast.
context_section_description: Ocean acidification is the increasing acidification of the oceans, caused mainly by the uptake of carbon dioxide from the atmosphere. The rise in atmospheric carbon dioxide due to the burning of fossil fuels leads to more  carbon dioxide dissolving in the ocean. When carbon dioxide dissolves in water it forms hydrogen and carbonate ions. This in turn increases the acidity of the ocean and makes survival increasingly harder for microorganisms, shellfish and other marine organisms that depend on calcium carbonate to form their shells.
  Increasing acidity also has potential for other harm to marine organisms, such as depressing metabolic rates and immune responses in some organisms, and causing coral bleaching. Ocean acidification has increased 26% since the beginning of the industrial era. It has been compared to anthropogenic climate change and called the "evil twin of global warming" and "the other CO
  2 problem".
caption: Estimated change in sea water pH caused by human created CO
  2 from the start of the industrial revolution to the end of the twentieth century
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