The North Pole had ice-free summers millions of years ago
April 8, 2016 07:22 AM - Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research via ScienceDaily.
An international team of scientists led by the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI) have managed to open a new window into the climate history of the Arctic Ocean. Using unique sediment samples from the Lomonosov Ridge, the researchers found that six to ten million years ago the central Arctic was completely ice-free during summer and sea-surface temperature reached values of 4 to 9 degrees Celsius. In spring, autumn and winter, however, the ocean was covered by sea ice of variable extent, the scientists explain in the current issue of the journal Nature Communications. These new findings from the Arctic region provide new benchmarks for groundtruthing global climate reconstructions and modelling.
The researchers had recovered these unique sediment samples during an expedition with Germany's research icebreaker RV Polarstern in summer of 2014. "The Arctic sea ice is a very critical and sensitive component in the global climate system. It is therefore important to better understand the processes controlling present and past changes in sea ice. In this context, one of our expedition's aims was to recover long sediment cores from the central Arctic, that can be used to reconstruct the history of the ocean's sea ice cover throughout the past 50 million years. Until recently, only a very few cores representing such old sediments were available, and, thus, our knowledge of the Arctic climate and sea ice cover several millions of year ago is still very limited," Prof. Dr. Ruediger Stein, AWI geologist, expedition leader and lead author of the study, explains.
Using moss as a bioindicator of air pollution
April 8, 2016 07:16 AM - USDA Forest Service via EurekAlert!
Moss growing on urban trees is a useful bio-indicator of cadmium air pollution in Portland, Oregon, a U.S. Forest Service Pacific Northwest Research Station-led study has found. The work--the first to use moss to generate a rigorous and detailed map of air pollution in a U.S. city--is published online in the journal Science of the Total Environment.
Earth's soils could play key role in locking away greenhouse gases
April 7, 2016 06:51 AM - University of Edinburgh via EurekAlert!
The world's soils could store an extra 8 billion tonnes of greenhouse gases, helping to limit the impacts of climate change, research suggests.
Adopting the latest technologies and sustainable land use practices on a global scale could allow more emissions to be stored in farmland and natural wild spaces, the study shows.
Illegal gold mining in Brazil exposing indigenous peoples to high levels of mercury
April 5, 2016 11:52 AM - Sarina Kidd / Survival International, The Ecologist
Illegal gold mining in the Amazon has a devastating effect on indigenous peoples, writes Sarina Kidd. First the miners bring disease, deforestation and even murder. Then long after they have gone, communities are left to suffer deadly mercury poisoning. Now the UN has been called on to intervene.
In Brazil, new statistics reveal alarming rates of mercury poisoning amongst the Yanomami and Yekuana. 90% of Indians in one community are severely affected, with levels far above that recommended by the WHO.
Mercury poisoning is devastating tribal peoples across Amazonia, Survival International has warned.
NASA examines El Nino's impact on ocean's food source
April 4, 2016 07:46 PM - NASA/Goddard Space Flight Center
El Niño years can have a big impact on the littlest plants in the ocean, and NASA scientists are studying the relationship between the two. In El Niño years, huge masses of warm water – equivalent to about half of the volume of the Mediterranean Sea – slosh east across the Pacific Ocean towards South America. While this warm water changes storm systems in the atmosphere, it also has an impact below the ocean’s surface. These impacts, which researchers can visualize with satellite data, can ripple up the food chain to fisheries and the livelihoods of fishermen.
Snowshoe hare range moving northward following retreating snow cover
March 31, 2016 07:52 AM - University of Wisconsin-Madison via ScienceDaily
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.
Severe water stress likely in Asia by 2050
March 30, 2016 05:51 PM - MIT News
Economic and population growth on top of climate change could lead to serious water shortages across a broad swath of Asia by the year 2050, a newly published study by MIT scientists has found.
The study deploys detailed modeling to produce what the researchers believe is a full range of scenarios involving water availability and use in the future. In the paper, the scientists conclude there is a “high risk of severe water stress” in much of an area that is home to roughly half the world’s population.
Ocean temperatures predict U.S. heat waves
March 29, 2016 07:19 AM - National Science Foundation
The formation of a distinct pattern of sea surface temperatures in the middle of the North Pacific Ocean can predict an increased chance of summer heat waves in the eastern half of the U.S. up to 50 days in advance.
The pattern is a contrast of warmer-than-average water coming up against cooler-than-average seas. When it appears, the odds that extreme heat will strike during a particular week -- or even on a particular day -- can more than triple, depending on how well-formed the pattern is.
The past, present and future of African dust
March 28, 2016 07:19 AM - National Center for Scientific Research
So much dust is scattered across the planet by the winds of the Sahara that it alters the climate. However, the emission and transport of this dust, which can reach the poles, fluctuate considerably. Although many hypotheses have been put forward to explain this phenomenon, no unambiguous relationship between this dust and the climate had been established until now. According to research carried out by a French-US team of researchers from LATMOS(CNRS/UVSQ/UPMC), CNRM(CNRS/Météo-France) and SIO3, meteorological events such as El Niño and rainfall in the Sahel have an impact on dust emission, by accelerating a Saharan wind downstream of the main mountain massifs of Northwest Africa. The scientists have also developed a new predictive model showing that emissions of Saharan dust will decline over the next hundred years. Their work is published in the 24 March 2016 issue of the journal Nature.
Human impact on Earth's global energy
March 26, 2016 08:13 AM - University of Leicester via ScienceDaily
The impact humans have made on Earth in terms of how we produce and consume resources has formed a 'striking new pattern' in the planet's global energy flow, according to researchers from the University of Leicester.
The research suggests that Earth is now characterised by a geologically unprecedented pattern of global energy flow that is pervasively influenced by humans -- and which is necessary for maintaining the complexity of modern human societies.
The new study, published in the journal Earth's Future, is led by Professors Mark Williams and Jan Zalasiewicz of the University of Leicester's Department of Geology working with an international team of scholars.