Antarctica, the Southern Ocean & Climate

We now have clear evidence that the atmosphere is getting progressivelywarmer, landmasses are becoming drier in some places and wetter in others,the ocean surface is warming, glaciers are melting, and species distributionsare changing on land and in our oceans.

Changes in climate are not new --- Earth's climate has been changing for millennia. Some of those past changeshave been elucidated by Antarctic research. It is now clear, however, thatrecent climate changes are unusual and probably unprecedented withinthe last million or more years. Antarctic science has been instrumental inestablishing that fact.

Modern human activities, especially during theindustrial age, are contributing to these changes. Copious anthropogenicemissions of gases and particulate matter into the atmosphere were not apart of Earth's history.

In his address for World Meteorological Day 2007, the then ACE CRC CEO Professor Bruce Mapstone spoke about the importance of multidisciplinarity in Antarctic climate research; the relevance of Antarctica and the Southern Ocean to global climate;and the need to understand Antarctica and the Southern Ocean toproperly comprehend climate change.



Sea Level Rise

ACE CRC researchers are investigating how changes in our climate will change sea levels, and what the impact of those changes may be. Most of this work is concentrated in the ACE CRC Sea Level Rise program.

The ACE CRC's package of the latest sea-level rise materials represents a significant body of analysis and interpretation of sea-level rise, from the science of sea-level rise to policy and local planning implications. It provides:

• Position Analysis: climate change, sea-level rise and extreme events - impacts and adaptation issues. The document outlines developments in the science of sea-level rise and its influence on the effects of extreme events like high tides and storm surges.

• Briefing: a post-IPCC AR4 update on sea-level rise developed with leading scientists John Church (ACE CRC/CSIRO), Neil White (ACE CRC/CSIRO), John Hunter (ACE CRC) and Kurt Lambeck (Australian Academy of Science). The document addresses recent progress in understanding sea-level rise and clarifies the interpretations of the IPCC's sea-level projections.

• Website developed jointly with CSRO brings together information on sea level rise and its causes. It also includes estimates of global and regional sea level, links to other web pages and data sets.

• a national program of information sessions and workshops specifically designed for coastal infrastructure owners, planners, engineers and poicy makers in incorporating projections of future sea-level rise into planning codes and schedules.



Ocean Acidification

Ocean acidification is unique among human impacts on the marine environment in its pervasiveness and persistence. Acidification due to ocean uptake of carbon dioxide is likely to have serious consequences for marine ecosystems and biodiversity in our region over this century.

ACE CRC researchers are investigating how changes in the balance of carbon dioxide between the atmosphere and ocean may affect the ocean's ability to act as a carbon sink. Most of this work is concentrated in the ACE CRC Ocean Control of Carbon Dioxide program.

The latest information is available in the ACE CRC Position Analysis: CO2 emissions and climate change: ocean impacts and adaptation issues, available from the ACE CRC website.



Ocean Fertilisation

Proposals have been made to 'fertilise' large areas of the ocean by adding nutrients that are in short supply to increase the growth of microscopic marine plants. These plants consume carbon dioxide (CO2) during photosynthesis, so enhancing their growth would increase the ocean's capacity to draw CO2 out of the atmosphere.

Several commercial organisations are promoting ocean fertilisation as a climate mitigation strategy and a means to gain carbon credits. Much of the emphasis has been on adding iron to the ocean, because this trace micro-nutrient is in short supply in regions which otherwise contain adequate amounts of other major nutrients. In polar and sub-polar seas, only very small amounts of iron are needed to stimulate the growth of marine plants called phytoplankton.

ACE CRC researchers in the Ocean Control of Carbon Dioxide Program are evaluating the importance of iron and other trace micronutrient elements in driving Southern Ocean biogeochemical cycles. The research team will map the distribution of dissolved iron in waters south of Australia, fingerprint supply and removal mechanisms, and quantify trace element limitation of phytoplankton growth and community structure in (sub)-Antarctic ecosystems.

The latest information is available in the ACE CRC Position Analysis: Ocean Fertilisation: science and policy issues, available from the ACE CRC website.



Establishing a Southern Ocean Sentinel

Southern Ocean marine ecosystems, both near to Antarctica and in the subantarctic, are already showing changes due to a warming climate. The manifestations of these climate change impacts now occurring in the Southern Ocean have become obvious long before those reported for other marine ecosystems.

Our ability to make future predictions of ecosystem changes are hampered by a number of large unknowns, including the ability of ecosystem components to adapt to changing sea ice and pelagic environments.

However, sufficient information is now available to identify many aspects of Southern Ocean ecosystems that could be impacted by changes in the physical systems. The tools are now available to integrate a lot of currently disparate data sources, to give us a coherent forecast of imminent and future change in the Southern Ocean ecosystem.

The Southern Ocean Sentinel will be an international multidisciplinary scientific effort to provide early warning of climate change impacts on global marine and other ecosystems based on Southern Ocean ecosystem indicators and assessments of climate change impacts in the region.

Once established, the Southern Ocean Sentinel will help develop a system of Southern Ocean forecasts that could act as early warning signals for triggering planning responses and action. It will give us the ability to see with clarity and consensus, the consequences of future climate for Southern Ocean marine ecosystems.

The workshop including international specialists and was held in Hobart 20-24 April 2009, and was convened by the Australian Antarctic Division, the World Wildlife Fund and the Antarctic Climate & Ecosystems Cooperative Research Centre.