A range of impacts of climate change on ecosystems and biodiversity in Antarctica and the Southern Ocean have already been documented:
- In the past 50 years unprecedented climatic changes in Antarctica include near-surface atmospheric warming on Antarctic peninsula, 2.5 degrees Celcius over past 40 years, is the largest surface warmming on the planet.
- The air above Antarctica has warmed dramatically over the past 30 year - x3 more that the global average. The greatest warming of 0.75 degrees Celcius/decade in winter is about 3 miles (5km) above the surface.
- Nearly 90% of Antarctic glaciers are in retreat.
- A succession of ice shelves have collapsed around the Antarctic peninsula.
- A significant decrease has been recorded in the amount of sea ice observed annually, in particular reduced sea ice in the Antarctic peninsula and Weddell Sea, although increased sea ice is recorded for some areas such as the Ross Sea.
- The upper kilometre of the circumpolar Southern Ocean has warmed, as have the densest components of Antarctic bottom water in the Weddell Sea.
- All over Antarctica and the sub-Antarctic islands, decreases are being seen in a number of penguin populations, including emperor penguins on Antarctica mainland, Adelie penguins on the western Antarctica peninsula, cinstrap and Adelie penguins in the South Orkney Islands and rockhopper penguins on the Campbell Islands (NZ). Scientists are linking these decreases with climatic changes, principally warming.
- Reduced sea ice is identified as a contributory cause in a significant decrease in krill. The decline in krill has been linked to a loss of winter sea ice under which krill over-winters. The sea ice also provides a key spawning and nursery area for krill. Other factors which could be linked to a decline in stocks include comercial harvesting of krill. A significant reduction in krill stocks could have implications for Antarctic marine species for whom krill are a major prey species.
WWF's Global Climate Change Programme is bringing the need for resilience building and adaptation to the forefront of conservation planning and now Antarctic Treaty nations need to commit, as a matter of urgency, to the mitigation of climate change at the global level and to strengthening the Antarctic environment's resilience and ability to adapt to the impacts of climate change.
Activities which put pressure on marine resources must be reduced to allow the system to have a chance at responding to climate change including maintaining and restoring fish stocks (numbers and diversity), so that they can adjust to the new and changing circumstances of the marine environment. Representative neworks of MPAs can also help in building resilience into the system to cope with climate change, for example by ensuring connectivity between areas. Finally, in order to minimise the impacts of climate change on Antarctic ecosystems, greater steps are needed to reduce greenhouse gas emmissions so the global average temperature keeps below 2 degrees Celcius above pre-industrial temperatures.
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