Science Daily

The Arctic is nearing its seasonal sea ice minimum this month, but predicting exactly when the region will see its first ice-free summer may be more difficult than previously believed, according to the results of new research.

The Arctic's ice cover appears to have reached its minimum extent on September 10, 2016, according to scientists. Arctic sea ice extent on that day stood at 4.14 million square kilometers (1.60 million square miles), statistically tied at second lowest in the satellite record with the 2007 minimum.

Clues from prehistoric droughts and arid periods in California show that today's increasing greenhouse gas levels could lock the state into drought for centuries.

For more than 20 million years, the ups and downs of diversity in terrestrial large mammals were determined by primary production, i.e. net production of plant biomass. This pattern changed with the onset of the ice ages. The reason for this is likely the beginning of human impact on nature, according to a new research. Based on 14,000 fossils, the scientists reconstructed the diversity of terrestrial large mammals and compared it with data on the biomass production of plants during the same time period.

A new study finds a trend toward earlier sea ice melt in the spring and later ice growth in the fall across all 19 polar bear populations, which can negatively impact the feeding and breeding capabilities of the bears. The paper is the first to quantify the sea ice changes in each polar bear subpopulation across the entire Arctic region using metrics that are specifically relevant to polar bear biology.

On average, a polar bear loses up to 30 percent of its total body mass while fasting during the open-water season. Although some scientists previously believed land-based foods could supplement the bears' nutritional needs until the sea ice returns, a new study has revealed that access to terrestrial food is not sufficient to reduce the rate of body mass loss for fasting polar bears.

Stalagmites rising from the floor of a cave in southern Indiana may contain traces of past earthquakes in the region, according to a new report.

Operation IceBridge, NASA's airborne survey of polar ice, is flying in Greenland for the second time this year, to observe the impact of the summer melt season on the ice sheet.

European earthworms invading the forests of North America are responsible for a decline in species diversity in the forest understory. Scientists have now been able to demonstrate this general pattern for the first time. In invaded forests, the vegetation on the forest floor has changed dramatically: The species diversity of native plants is declining, yet the amount of non-native (exotic) plants is increasing, and so is the amount of grasses.

By comparing the timing of the evolution of thorns on about 2,000 woody tree species in southern Africa and the time that antelopes arrived in Africa, a group of scientists found that trees like African acacias evolved thorns as a defense mechanism at exactly the same time that antelope arrived in Africa.

Less than one year after President Barack Obama announced a White House Arctic Initiative that included better mapping of the area, a team of researchers has released the first-ever publicly available set of high-resolution, three-dimensional topographic maps of the entire state of Alaska.

New research suggests that Africa has gradually become wetter over the past 1.3 million years -- instead of drier as was thought previously.

Over the past decades, the northward drift of sea ice surrounding Antarctica has strengthened. This not only has increased the extent of the sea ice, but also has freshened the sea water around the sea-ice edge -- with as yet indeterminate consequences for the global climate system and Antarctica's ecosystem.

It takes thousands of years for seabed communities to recover from major glaciation events, new research suggests. The study focused on the seas around South Georgia in the south Atlantic.

The release of methane from the seafloor was much slower than previously thought during a rapid global warming event 56 million years ago, report scientists.

Climate change was less important for technological innovation among Stone Age humans than previously assumed.

Methane is stored under the sea floor, concentrated in form of hydrates, crystalline ice structures that stay stable under high pressure and in low temperatures. Several studies suggest that as the ocean warms, the hydrates might melt and potentially release methane into the ocean waters and atmosphere.

Historic changes to Antarctic sea ice could be unraveled using a new technique, say scientists. The new method builds on an existing technique developed over the last 10 years, which identified a means by which scientists could measure changes to sea ice in the Arctic.

New research shows that a nanometer-thin layer of water between two charged surfaces exhibits ice-like tendencies that allow it to withstand pressures of hundreds of atmospheres. The discovery could lead to better ways to minimize friction in a variety of settings.

The Working Group on the 'Anthropocene' (AWG) will provide its summary of evidence and its provisional recommendations on a potential new geological time interval.