Generally, limited data are available to assess many aspects of the Antarctic environment. This is largely a consequence of the remoteness and sparse habitation of the region. Specific information is available to assess trends and changes in the physical environment. This includes palaeoclimate records from ice cores that extend back hundreds of thousands of years, synoptic weather observations generally starting in the 1950s, and satellite remote-sensing data from the late 1970s onwards. For the various components of the ecosystem, far sparser records are available. For example, data suitable for census studies of species, such as Antarctic krill and fish, are only available for recent decades. For many other species, such as baleen whales, accurate population assessments remain unavailable.
This report presents our best available assessments of the state and trends of the Antarctic environment (the area south of 60°S, the Southern Ocean and Australia’s subantarctic islands), primarily as they relate to Australia’s interests in the region. We have followed the methodology outlined in the Approach report, distilling the opinion of experts in specific fields who have been guided by the latest peer-reviewed literature. In addition, where possible, we have made use of a variety of up-to-date environmental and management data collected in support of the Australian Antarctic Program.
Overall, the material presented here is largely an update on the 2011 state of the environment (SoE) report and is primarily informed by the peer-reviewed literature that has appeared in the intervening 5 years. Consequently, almost all the assessments presented here are directly comparable with those presented in 2011.
For the physical environment, many aspects of change are occurring on multiyear or longer timescales because of the nature of physical processes associated with the Antarctic atmosphere, ice sheet and surrounding oceans. Thus, the assessed changes and trends are generally identical to those presented in SoE 2011. The Fifth Assessment Report of the Intergovernmental Panel on Climate Change in 2014, which provided a comprehensive picture of the state of the Antarctic environment at its release, has been used as a key source of information in preparing the assessment tables in State and trends of the Antarctic environment.
In general, our assessment of the confidence rating for grade and trend is graded using the 3 levels used for SoE 2011 (‘adequate’, ‘limited’ and ‘low’). At present, finer assessment using the 2 additional grades adopted in this report (‘somewhat adequate’ and ‘very limited’) cannot be confidently applied for most of the Antarctic topics considered here.