29 August 2015, Climate News Network, Climate models may misjudge soils’ carbon emissions. How soil organisms cope with decaying vegetation is much less certain than climate models suppose, researchers say, and carbon emission estimates may be wrong. Some of the microscopic creatures which live in the soil are able to digest dead plants and trees, turning their contents into gas and minerals. But researchers say their work show that our understanding of how organic material is decomposed is fundamentally wrong, calling into question some current climate models. The researchers, from Lund University, Sweden, and the University of New Hampshire, USA, have published their study in the journal Ecological Monographs. They say it means that climate models which include micro-organisms in their estimates of future climate change must be reconsidered. When plants or trees die, their leaves and branches fall to the ground and the organic matter which is absorbed by the soil is then decomposed, mainly by the activity of fungi and bacteria, which convert the dead materials into the main greenhouse gas, carbon dioxide, and mineral nutrients. Until now, the Lund team says, scientists had thought that high-quality organic materials, such as leaves that are rich in soluble sugars, were mainly decomposed by bacteria, leaving the lower-quality matter, like cellulose and lignin, to be broken down mainly by fungi. Expectations confounded. Previous research has suggested that organic material decomposed by fungi results in less CO2 and nutrient leakage compared with matter decomposed by bacteria. This is important for the climate models in use today, as any change in the loss of CO2 and mineral nitrogen would alter the soil’s contribution to greenhouse gases and eutrophication, the process in which the release of excessive chemical pollution causes algal blooms in watercourses. Read More here
28 August 2015, The Guardian, Extreme Arctic sea ice melt forces thousands of walruses ashore in Alaska. Survival of walruses threatened as they wash ashore on a remote barrier island just before Obama is due to visit region to draw attention to climate change. The extreme loss of Arctic sea ice due to climate change is forcing thousands of walruses to crowd ashore on a remote barrier island off Alaska, and threatening their survival. Barack Obama will be the first US president to visit the Alaskan Arctic on 31 August on a three-day tour to draw attention to the drastic consequences of climate change for the Arctic, such as warming winters and the rapid retreat of sea ice. The first reported sighting of animals forced to come ashore in the Chukchi Sea was by a photographer on 23 August, and confirmed by villagers in the remote hamlet of Point Lay late on Thursday, the US Fish and Wildlife Service said. Such landings, forced by the absence of sea ice on which to rest and feed, put the animals at risk of stampede in the limited space of the barrier island. The animals are easily spooked by aircraft or onlookers, government scientists warned. Trampling deaths are one of the biggest natural risks. Sea ice cover in the winter months fell to a new low this year because of climate change and abnormal weather patterns. Read More here