7 April 2016, Carbon Brief, Analysis: the ‘highly unusual’ behaviour of Arctic sea ice in 2016. The decline of Arctic sea ice is already setting records in 2016, with the winter peak in March clocking in as the lowest since satellite records began, scientists say. A new and fuller summary of this year’s Arctic winter by the US National Snow and Ice Data Centre (NSIDC) confirms the preliminary announcement last week that sea icereached its annual maximum extent on 24 March this year. Covering an area of 14.52m square kilometers, this year’s peak winter extent is a shade smaller than the previous record low set in 2015. But the new NSIDC report adds a lot more detail about what it calls a “highly unusual” and “most interesting” Arctic winter. With abnormally warm conditions right across the Arctic, some regions experienced temperatures 4-8C higher than average. While this meant slower ice growth in some places, in others it caused a dramatic thinning by 30cm in one week, according to early model results. Reaching a peak Arctic sea ice ebbs and flows with the seasons, reaching a maximum extent for the year in February or March and a minimum in September, at the end of the summer melt period. This year, scientists were still waiting expectantly at the end of March, explains the NSIDC report: “Very early in the month, extent declined, raising anticipation that an early maximum had been reached. However, after a period of little change, extent slowly rose again, reaching the seasonal maximum on March 24.” As late as a week ago, scientists still hadn’t ruled out the possibility of a late season surge. But sea ice extent has dropped off quite a bit since then, suggesting the peak has been and gone. You can see this year’s sea ice behaviour in the graph below from NSIDC, which shows sea ice extent over the 2015/6 winter (blue line) up to 3 April compared to previous years. Read More here
Category Archives: The Science
5 April 2016, The Conversation, This summer’s sea temperatures were the hottest on record for Australia: here’s why. The summer of 2015-2016 was one of the hottest on record in Australia. But it has also been hot in the waters surrounding the nation: the hottest summer on record, in fact.
Graph above: Difference in summer sea surface temperatures for the Australian region relative to the average period 1961-1990.Australian Bureau of Meteorology While summer on land has been dominated by significant warm spells, bushfires, and dryness, there is a bigger problem looming in the oceans around Australia. This summer has outstripped long-term sea surface temperature records that extend back to the 1950s. We have seen warm surface temperatures all around Australia and across most of the Pacific and Indian oceans, with particularly warm temperatures in the southeast and northern Australian regions. Read More here
4 April 2016, Science Daily, Water cycle instability is here to stay posing major political and economic risks. Adaptation to new risks: A vital necessity for development policies. The current instability and unpredictability of the world water cycle is here to stay, making society’s adaptation to new risks a vital necessity when formulating development policies, a UN water expert warns. Robert Sandford, the EPCOR Chair for Water and Climate Security at the United Nations University’s Canadian-based Institute for Water, Environment and Health (UNU-INWEH), says long-term water cycle stability “won’t return in the lifetime of anyone alive today.” “What we haven’t understood until now is the extent to which the fundamental stability of our political structures and global economy are predicated on relative stability and predictability of the water cycle — that is, how much water becomes available in what part of the year. As a result of these new water-climate patterns, political stability and the stability of economies in most regions of the world are now at risk.” Ontario Lieutenant-Governor Elizabeth Dowdeswell, a former Executive Director of the UN Environment Programme, and UN Under Secretary-General David Malone, Rector of UN University, are among several expert speakers joining Sandford in Ottawa Tuesday April 5 at UNU-INWEH’s day-long 20th anniversary public seminar, “Water: The Nexus of Sustainable Development and Climate Change.” The seminar will focus on national policy changes needed worldwide to achieve global water security — a pre-requisite for reaching the new global Sustainable Development Goals, or SDGs, agreed upon by world leaders in September 2015. Read More here
30 March 2016, Board on Atmospheric Sciences and Climate, Attribution of Extreme Weather Events in the Context of Climate Change (report). The science of extreme event attribution has advanced rapidly in recent years, giving new insight to the ways that human-caused climate change can influence the magnitude or frequency of some extreme weather events. Confidence is strongest in attributing types of extreme events that are influenced by climate change through a well-understood physical mechanism—for example, the more frequent heat waves that are closely connected to human-caused global temperature increases. Confidence is lower for other types of events, such as hurricanes, whose relationship to climate change is more complex and less understood at present. For any extreme event, the results of attribution studies hinge on how questions about the event’s causes are posed, and on the data, modeling approaches, and statistical tools chosen for the analysis. Read More here