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: Ecosystem Stress
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.
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
30 March 2016, Science Daily, No snow, no hares: Climate change pushes emblematic species north. If there is an animal emblematic of the northern winter, it is the snowshoe hare. A forest dweller, the snowshoe hare is named for its big feet, which allow it to skitter over deep snow to escape lynx, coyotes and other predators. It changes color with the seasons, assuming a snow-white fur coat for winter camouflage. But a changing climate and reduced snow cover across the north is squeezing the animal out of its historic range, according to a new study by researchers at the University of Wisconsin-Madison. Writing in the current (March 30, 2016) Proceedings of the Royal Society B, the Wisconsin researchers report that the range of the hare in Wisconsin is creeping north by about five and a half miles per decade, closely tracking the diminishing snow cover the animal requires to be successful. “The snowshoe hare is perfectly modeled for life on snow,” explains Jonathan Pauli, a UW-Madison professor of forest and wildlife ecology and one of the co-authors of the new study. “They’re adapted to glide on top of the snow and to blend in with the historical colors of the landscape.” As climate warms, northern winters have become shorter and milder. And the annual blanket of snow that many organisms have evolved to depend on is in steady retreat, becoming thinner and less dependable in regions that once experienced snow well into the spring months. The Wisconsin study is important because it helps illustrate the effects of climate change on a sentinel species for northern ecosystems, showing how the composition of plants and animals on the landscape is gradually shifting in a warming world. The findings also signal that climate change is beginning to eclipse land use as the dominant driver of ecological change. Read More here
28 March 2016, Climate News Network, Plants’ heat response means fiercer heatwaves. Asia faces more extreme heat by mid-century as some plant species react unexpectedly to rising average temperatures, new research shows. Tomorrow’s heat waves could be even hotter than climate scientists have so far predicted. Maximum temperatures across the Asian continent from Europe to China could be 3°C to 5°C higher than previous estimates – because the forests and grasslands will respond in a different way. Australian scientists report in the journal Scientific Reports that they looked at the forecasts made by the Intergovernmental Panel on Climate Change under the notorious “business-as-usual” scenario, in which the world’s nations go on burning ever more fossil fuels, to release ever more greenhouse gases. The average global temperatures will rise steadily – but this rise will be accompanied by ever greater and more frequent extremes of heat. But then Jatin Kala of Murdoch University in Perth, Western Australia, and colleagues factored in the responses of the plants to rising temperatures.They looked at data from 314 species of plant from 54 research field sites. In particular, they investigated stomatas, tiny pores on the leaves through which plants absorb carbon dioxide and shed water to the atmosphere. Response crucial What matters is how vegetation responds to extremes of heat. Researchers have already established that plants respond, not always helpfully: extremes can alter the atmospheric chemistry unfavourably for plants, and certainly reduce crop yields. But other scientists have confirmed the so-called carbon dioxide fertilisation effect: as more carbon becomes available, plants use water more economically and so even though drylands may get drier the landscape can also get greener, and growth tends to begin ever earlier as winters get warmer, and spring arrives earlier. Read more here