sign in sign up
<<
Home , East Antarctic Ice Sheet

IP 147 ENG

Agenda Item: ATCM 16, CEP 7a Presented by: ASOC Original: English Submitted: 22/04/2017

Climate Change Report Card

1

IP 147

Climate Change Report Card

Submitted by ASOC1

Summary The and Coalition (ASOC) provides an annual climate change report card, updating the Antarctic Treaty Consultative Meetings on Antarctic climate science research findings and news headlines. The table below summarizes key findings since the 2016 ATCM. Table 1. Climate trends 2017.

WHAT WE KNOW HOW WE KNOW

Antarctic sea ice extent reached a record low in Observations and long-term environmental 2017. monitoring

Antarctic Peninsula surface temperature has Instrumental records risen overall since the 1950s but has cooled approximately 0.5°C per decade since the 1990s due to stronger summer winds. These declines are predicted to be short-lived, however.

Central West is one of the fastest- Instrumental records warming regions on the planet.

Ice sheets, particularly those in , Paleoclimate research, direct and long-term show signs of disintegration, which could lead to observation (both in the field and through significant global . remote sensing), global climate models

Ocean acidification will have negative effects on Studies of species under predicted conditions some key Antarctic species.

Short-term climate change related climate Studies of climate anomalies in subsequent anomalies may have long-term impacts. years, modeling of predicted responses

Adélie and chinstrap penguin populations in the Direct analysis of population trends in colonies; West are likely to decline results of modeling. significantly in the next several decades.

Climate Change Overview There is longstanding and robust scientific evidence that climate change is happening now, is projected to intensify in the short- to long-term, and is caused by emissions from human activities.2 The endeavors of Antarctic researchers to understand anthropogenic climate change have been highly influential in building our knowledge about climate change in Antarctica and globally.

1 Lead authors Claire Christian and Jessica O’Reilly, with contributions from Chris Johnson and edits by Ricardo Roura and Rodolfo Werner. ASOC also thanks scientific reviewers Heather Lynch, Mike Sparrow, Tristy Vick-Majors and Casey Youngflesh. 2 IPCC. Climate Change 2014: Synthesis Report. Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Core Writing Team, R.K. Pachauri and L.A. Meyer (eds.)]. IPCC, Geneva, Switzerland (2014) 151 pp7. 3 IP 147

Below, ASOC presents some of the key research findings in Antarctic climate change since the last ATCM.

Antarctic Sea Ice Climate scientists project that warming of the Southern Ocean and Antarctica will accelerate through this century, with increased heating from the ocean and the atmosphere. Although the is currently seeing increased sea ice extent, the overall area of sea ice in the Antarctic is likely to be reduced.3 2017 saw the lowest extent of Antarctic sea ice since record keeping began in 1979—the previous lowest extent occurred in 1997. The sea ice reached its minimum extent on March 3, 2017 with 2.106 million square kilometers covered.4 This season contradicts recent years of increasing Antarctic sea ice extent, including the October 2014 record maximum sea ice extent.5. The lower cover could produce a feedback effect as more, darker ocean is exposed, absorbing heat, warming the ocean, and causing further decreases.

Temperature While long-term global warming is fact, not everywhere on the planet is warming at the same rate. With a temperature increase of about 2.4°C from 1958 – 2010, Central West Antarctica is one of the fastest- warming regions on the planet.6 A new study by Turner et al. found that, while the Antarctic Peninsula has been rapidly warming since the 1950s, there has been a cooling since the 1990s, at a rate of about 0.5°C per decade.7 This is due to stronger summer winds.8 The cooling does not offset the overall warming trend of the Antarctic Peninsula since the 1950s and, according to the researchers, falls into the range of natural variability. These trends are linked to larger, global-scale patterns of atmospheric circulation.9 The oceans surrounding the Peninsula are also warming. The temperature of the upper ocean west of the Antarctic Peninsula has risen by nearly 1.5°C since the 1950s.10 596 of the 674 glaciers along the west coast of the Antarctic Peninsula have retreated since records began in the 1940s. Ocean warming is the primary cause.11 The Antarctic continental record high of 17.5°C from March 24, 2015 at (), was confirmed by the World Meteorological Organization (WMO) this year.12 Other Antarctic temperature extremes confirmed by WMO include the highest temperature on the at -7.0°C on December 28, 1989 and the highest temperature for the Antarctic Region on northerly , with a temperature of 19.8°C on January 30, 1982.13

Ice Sheets

3 Liu J., Curry J.A. “Accelerated warming of the Southern Ocean and its impacts on the hydrological cycle and sea ice.” Proceedings of the National Academies of Science 107 (2010): 14987–14992. 4 National Snow and Ice Data Center. “Charctic Interactive Sea Ice Graph.” http://nsidc.org/arcticseaicenews/charctic- interactive-sea-ice-graph/ (2017). 5 National Air and Space Administration. “Antarctic sea ice reaches new record maximum.” (2014) Published on 07 October 2014 at https://www.nasa.gov/content/goddard/antarctic-sea-ice-reaches-new-record-maximum/. 6 Bromwich D.H., Nicolas J.P., Monaghan A.J., Lazzara M.A., Keller L.M., Weidner G.A. et al. “Central West Antarctica among the most rapidly warming regions on Earth”. Nature Geoscience (2013): 6: 139–145. 7 Turner, J., Lu, H., White, I., King, J. C., Phillips, T., Hosking, J. S., ... & Deb, P. “Absence of 21st century warming on Antarctic Peninsula consistent with natural variability.” Nature, 535: 7612 (2016) 411-415. 8 Ibid. 9 Steig, E. J. Climate science: Cooling in the Antarctic. Nature, 535: 7612 (2016) 358-359. 10 Turner J., Barrand N.E., Bracegirdle T.J., Convey P., Hodgson D.A., Jarvis M. et al. “Antarctic climate change and the environment: an update.” Polar Record 50 (2014): 237–259. 11 Cook A. J., Holland P.R., Meredith M.P., Murray T., Luckman A., Vaughan D.G. “Ocean forcing of glacier retreat in the western Antarctic Peninsula.” Science 353 (2016): 283–286. 12 Skansi, M. d. L. M., et al. “Evaluating highest-temperature extremes in the Antarctic”. Eos, 98,. Published on 01 March 2017 at https://eos.org/features/evaluating-highest-temperature-extremes-in-the-antarctic. 13 Ibid. 4 IP 147

The Antarctic consists of two major ice sheets, the more stable East and the less-stable, marine-based . Both have been losing mass and have areas of concern,14 but the most significant concern is assessing the likelihood of rapid disintegration of the West Antarctic Ice Sheet and the resulting global sea level rise of about 5 meters. Additionally, research demonstrates that the East Antarctic ice sheet may be more vulnerable to rising temperatures in the than previously thought.15 Major programs of research on the ice sheets’ past, present, and future are underway among several National Antarctic Programs. is one of the most dynamic glacier areas of West Antarctica. Rifts have formed on Pine Island Glacier inland from the margins of the ice sheet. One initiated iceberg calving in 2015; other rifts remain. This rifting behavior could signal below-ice melting through warmer seawater intrusions in basal crevasses.16 This austral summer (2016-2017), a substantial and rapidly growing crack in the Larsen C ice shelf hinted that its calving may be imminent, following the collapse of Larsen A in 1995 and Larson B in 2002.17 Ice shelves float over water but often act as plugs for continental ice sheets, which may flow rapidly into the sea after the ice shelves are removed. Finally, surface drainage systems on ice sheets appear to be much more extensive than previously realized, which researchers believe could “accelerate future ice-mass loss from Antarctic, potentially via positive feedbacks between the extent of exposed rock, melting and thinning of the ice sheet.”18

Ocean Acidification With ocean acidification (OA) expected to affect large areas of the Southern Ocean by 2030,19 understanding resulting changes to species and ecosystems is important so that the can take appropriate actions to protect the environment. A new study indicates that acidification at levels predicted to occur in the Antarctic by the end of the century, in conjunction with changes in light levels due to the retreat of sea ice, could have a negative impact on Antarctic diatoms, including two species which play major roles in the carbon and silicon cycles in the Southern Ocean.20 Thus, essential biogeochemical cycles could be altered, with potentially serious consequences for the ecosystem as a whole. Other diatom species may experience enhanced growth.21 However, it appears that under temperature and pH scenarios predicted for the end of the century, pteropod larvae will experience “synergistic, negative impacts.”22 Local biological and oceanographic characteristics are another important factor in how OA might affect the Southern Ocean. Primary production, mixing of Circumpolar Deep Water with surface water, and sea ice melt all were found to influence pH as well as levels of calcium carbonate in Ryder Bay in the West Antarctic Peninsula.23 This further highlights the complexity of this phenomenon, and the urgency of additional work to predict its near-term effects. New advances in computer modeling may assist in

14 Qiu, J. “Antarctica’s sleeping ice giant could wake soon.” Nature. 544 (2017) 152-154. 15 Golledge, N. R., Levy, R. H., McKay, R. M., & Naish, T. R. “East Antarctic ice sheet most vulnerable to Weddell Sea warming.” Geophysical Research Letters 44 (2017): 2343–2351. 16 Jeong, S., Howat, I. M., & Bassis, J. N. “Accelerated ice shelf rifting and retreat at Pine Island Glacier, West Antarctica.” Geophysical Research Letters, 43.22 (2016): 11720-11725. 17 Luckman, Adrian and the MIDAS Team. “Larsen C Ice Shelf rift continues to grow.” Project Midas. Published on 19 January 2017 at http://www.projectmidas.org/blog/larsen-c-rift-continues-to-grow/. 18 Kingslake, J., Ely, J.C., Das, I. & Bell, R.E.. “Widespread movement of meltwater onto and across Antarctic ice shelves”. Nature 544 (2017): 349-352. 19 Antarctic and Southern Ocean Coalition. Antarctic Climate Change Report Card (2016) ATCM XXXIX, IP 81. 20 Trimborn, S., Thoms, S., Brenneis, T., Heiden, J.P., Beszteri, & Bischof, K. ‘Two Southern Ocean Diatoms Are More Sensitive to Ocean Acidification and Changes in Irradiance than the Prymnesiophyte Phaeocystis Antarctica’, Physiologia Plantarum (2016). 21 Pyper, W. “Mobile Diatoms Flourish in Acid Ocean.” Australian Antarctic Magazine 31 (2016): 20-21. 22 Gardner, J., Bakker, D.C.E, Tarling, G., Peck, V, & Manno, C. ‘The Survival of Pteropod Larvae (Limacina Helicina Antarctica) in a Changing World.’, in 4th International Symposium on the Ocean in a High-CO2 World (Hobart, Tasmania) (2016). 23 Jones, E.M., Fenton, M., Meredith, M.P., Clargo, N.M., Ossebaar, S., Ducklow, H.W., Venables, H. & de Baar, H.J.W. ‘Ocean Acidification and Calcium Carbonate Saturation States in the Coastal Zone of the West Antarctic Peninsula’, Deep Sea Research Part II: Topical Studies in Oceanography (in press) (2017). 5 IP 147 understanding how ocean acidification in combination with other changes might affect microbial communities, as well as guide future research.24

Ecosystems A climate anomaly occurring from September 2001 until February 2002 resulted in significantly warmer temperatures than normal in the McMurdo Dry Valleys, as well as in record high snowfall and a decrease in sea ice extent in the West Antarctic Peninsula.25 Recent research has examined the impacts on the ecosystems at the National Science Foundation’s Long Term Ecological Research Program (LTER) sites in each of these regions and found that even this short anomalous period had ecosystem repercussions during that period. Krill, salp, and pteropod populations increased at the West Antarctic site, but the increased snowfall resulted in “the worst breeding season for Adélie penguins in the 40-year records available for this species.”26 The impact of the anomaly on microbial communities was also examined, and it was found that variations in ice cover due to the anomaly had long and short-term impacts on the sensitive ecosystems in both regions, with potential implications for biodiversity.27 The authors caution that continued climate change may result in “tipping points” being reached for these communities that could change the communities significantly.28 In the case of the West Antarctic Peninsula, this could have implications for higher trophic levels, since the productivity of bacterial communities is linked to that of primary producers (phytoplankton).29 With increasing climate anomalies expected to occur in a warming world, ecosystems may be subjected to periods of intense change.

Species Echoing the findings that climate anomalies can have long-term ecosystem impacts, scientists predict that years that are bad for Adélie penguins in the Antarctic Peninsula in terms of survival or breeding will exacerbate the risk of significant decreases in population size.30 Research into penguins on Signy Island finds trends similar to those seen on the Peninsula, namely that gentoos are increasing (255% over 38 years) while chinstraps and Adélies are on the decline (68% and 42% over 38 years, respectively).31 Furthermore, modeling suggests that 30% of Adélie penguin colonies could be shrinking by as soon as 2060 due to warming in the Western Antarctic Peninsula.32 Somewhat surprisingly, however, changes in the timing of sea ice retreat and phytoplankton blooms, both of which are thought to play a role in the ability of Adélies to successfully forage during the breeding season, do not appear to have a substantial effect on breeding success - these penguins are buffered from phenological variability in the environment. This does not discount the importance of prey availability, but

24 Subramaniam, R.C., Melbourne-Thomas, J, Davidson, A.T., & Corney, S.P. ‘Mechanisms Driving Antarctic Microbial Community Responses to Ocean Acidification: A Network Modelling Approach’, Polar Biology 40 (2017): 727. 25 Fountain, A.G. et al., ‘The Impact of a Large-Scale Climate Event on Antarctic Ecosystem Processes’, BioScience, 66.10 (2016), 848–63. 26 Ibid. 27 Bowman, J.S., Vick-Majors, T. J., Morgan-Kiss, R., Takacs-Vesbach, C., Ducklow, H., & Priscu, J.C. ‘Microbial Community Dynamics in Two Polar Extremes: The Lakes of the McMurdo Dry Valleys and the West Antarctic Peninsula Marine Ecosystem’, BioScience, 66.10 (2016), 829–47. 28 Ibid. 29 Ibid. 30 Hinke, J.T., Trivelpiece, S.G. and Trivelpiece, W.Z. ‘Variable Vital Rates and the Risk of Population Declines in Adélie Penguins from the Antarctic Peninsula Region’, Ecosphere, 8.1 (2017), e01666. 31 Dunn, M.J., Jackson, J.A., Adlard, S., Lynnes, A. S., Briggs, D.R., Fox, D. & Waluda, C.M. ‘Population Size and Decadal Trends of Three Penguin Species Nesting at Signy Island, South Orkney Islands’, PLoS ONE, 11.10 (2016), 1– 15. 32 Cimino, M.A., Lynch, H.J., Saba, V. S. & Oliver, M.J. ‘Projected Asymmetric Response of Adélie Penguins to Antarctic Climate Change’, Scientific Reports, 6 (2016), 28785. 6 IP 147 rather highlights the importance of a number of other factors, such as weather, for breeding success in this species.33 Antarctic krill are also highly vulnerable to climate change. Reiss et al. highlight the importance of studying krill during the austral winter as sea-ice extent declines.34 This situation may allow increased winter fishing in areas such as the , with unknown effects on the krill population and on krill predators.35 Glacial melt may act as another stressor on krill. Mass coastal strandings of krill on King George Island that occurred between 2003-2012 were likely caused by the ingestion of sediments from glacial meltwater.36

Recommendations ASOC recommends individual ATCPs and/or the ATCM and related bodies (including SCAR and WMO) to continue to: • Invest in robust monitoring of the Antarctic region to understand total patterns and anomalies of the Earth’s climate system. • Invest in ecological monitoring, which is imperative for understanding responses to environmental changes among species and ecosystems, including from immediate and diffuse human impacts. • Develop a mechanism for ATCM reporting of Antarctic climate information to the broader public. • Develop precautionary or rapid-response management plans in place to address sudden climate- related events. For example, CCAMLR recently agreed Conservation Measure (CM) 24-04, Establishing time-limited Special Areas for Scientific Study in newly exposed marine areas following ice-shelf retreat or collapse in Statistical Subareas 48.1, 48.5 and 88.3, which automatically designates these areas after a CCAMLR Member notifies the Secretariat and the Secretariat notifies other Members. The designation limits activities that can take place inside the Special Areas and therefore allows scientists time to gather data and understand the environmental changes that have occurred. The ATCM may wish to consider similar measures for terrestrial or coastal areas newly exposed by ice-shelf retreat or collapse. • Establish protected areas that can be used as reference areas to attribute changes to climate change with no or minimal interference from local and regional activities.

33 Youngflesh, C. et al. ‘Circumpolar Analysis of the Adélie Penguin Reveals the Importance of Environmental Variability in Phenological Mismatch’, Ecology, 98.4 (2017), 940–51. 34 Reiss, C.S. et al., ‘Overwinter Habitat Selection by Antarctic Krill under Varying Sea-Ice Conditions : Implications for Top Predators and Fishery Management’, Marine Ecology Progress Series, 568 (2017), 1–16. 35 Ibid. 36 Verónica Fuentes et al. ‘Glacial Melting: An Overlooked Threat to Antarctic Krill’, Scientific Reports, 6.May (2016), 27234. 7