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Ocean circulation implicated in past abrupt climate changes

Science Daily - Thu, 06/30/2016 - 13:50
There was a period during the last ice age when temperatures in the Northern Hemisphere went on a rollercoaster ride, plummeting and then rising again every 1,500 years or so. Those abrupt climate changes wreaked havoc on ecosystems, but their cause has been something of a mystery. New evidence shows for the first time that the ocean's overturning circulation slowed during every one of those temperature plunges -- at times almost stopping.

Understanding ice loss in Earth’s coldest regions

Science Daily - Thu, 06/30/2016 - 09:25
Scientists found that melt on the surface of glaciers in the McMurdo Dry Valley is rare, but internal melting is extensive.

Changes in Antarctic sea ice production due to surrounding ice conditions

Science Daily - Wed, 06/29/2016 - 08:56
Antarctic sea ice production spanning more than 20 years has been understood through the analysis of satellite observations using specially developed techniques. The results of this analysis revealed that changes to the sea ice production in the Southern Ocean were caused mainly because of surrounding ice shelf and fast ice conditions, rather than by wind, temperature, or other factors.

Penguin population could drop 60 percent by end of the century

Science Daily - Wed, 06/29/2016 - 08:48
Approximately 30 percent of current Adélie penguin colonies may be in decline by 2060, researchers predict, and approximately 60 percent may be in decline by 2099. The declines are associated with warming -- many regions of Antarctica have warmed too much and further warming is no longer positive for the species.

Humans artificially drive evolution of new species

Science Daily - Tue, 06/28/2016 - 21:17
Species across the world are rapidly going extinct due to human activities, but humans are also causing rapid evolution and the emergence of new species. A new study summarizes the causes of humanmade speciation, and discusses why newly evolved species cannot simply replace extinct wild species.

Vegetation in Russian Arctic has memory

Science Daily - Mon, 06/27/2016 - 12:30
Adaptation to climate change has a lag of several thousands of years, report researchers. The permafrost regions in the Arctic are among those areas of the world in which the temperature is rising particularly fast due to climate change. However, biologists are currently observing that the tree vegetation is only minimally adapting to these changes. In those areas where pine and spruce trees should be growing according to the air temperature, the Siberian larch is still thriving.

Wind-blown Antarctic sea ice helps drive ocean circulation

Science Daily - Mon, 06/27/2016 - 11:49
Antarctic sea ice is constantly on the move as powerful winds blow it away from the coast and out toward the open ocean. A new study shows how that ice migration may be more important for the global ocean circulation than anyone realized.

Opal discovered in Antarctic meteorite

Science Daily - Mon, 06/27/2016 - 08:59
Planetary scientists have discovered pieces of opal in a meteorite found in Antarctica, a result that demonstrates that meteorites delivered water ice to asteroids early in the history of the solar system.

Super-slow circulation allowed world's oceans to store huge amounts of carbon during last ice age

Science Daily - Mon, 06/27/2016 - 08:48
The way the ocean transported heat, nutrients and carbon dioxide at the peak of the last ice age, about 20,000 years ago, is significantly different than what has previously been suggested, according to two new studies. The findings suggest that the colder ocean circulated at a very slow rate, which enabled it to store much more carbon for much longer than the modern ocean.

What did Earth's ancient magnetic field look like?

Science Daily - Fri, 06/24/2016 - 12:58
Earth's ancient magnetic field was significantly different than the present day field, originating from several poles rather than the familiar two, new research suggests. Then, shortly after our planet's core solidified, this work predicts that Earth's magnetic field transitioned to a 'strong,' two-pole one.

Researchers offer new theory on how climate affects violence

Science Daily - Fri, 06/24/2016 - 10:00
Researchers have long struggled to explain why some violent crime rates are higher near the equator than other parts of the world. Now, a team of researchers has developed a model that could help explain why.

Siberian larch forests are still linked to the ice age

Science Daily - Fri, 06/24/2016 - 09:02
The Siberian permafrost regions include those areas of the Earth, which heat up very quickly in the course of climate change. Nevertheless, biologists are currently observing only a minimal response in forest composition.

New technique settles old debate on highest peaks in US Arctic

Science Daily - Thu, 06/23/2016 - 10:21
Finding out which is the highest mountain in the US Arctic may be the last thing on your mind, unless you are an explorer who skis from the tallest peaks around the globe. A ski mountaineer and a glaciologist aimed to settle a debate of more than 50 years, while testing a new, affordable mapping technique in a steep mountainous region.

Explosive renewables development can deliver on Paris

Science Daily - Thu, 06/23/2016 - 05:50
While some criticize the Paris climate target as impracticable, a team of scholars argues that it is a triumph of realism. First, keeping global warming well below 2 degrees Celsius is necessary in view of the risks that unchecked climate change would pose. The scientists provide for the first time a diagram summarizing the tipping points/temperature issue. Second, implementing the Paris target is feasible through an explosive development of renewables. Third, the target is simple enough to create worldwide political momentum.

Cosmopolitan snow algae accelerate the melting of Arctic glaciers

Science Daily - Wed, 06/22/2016 - 09:19
The role of red pigmented snow algae in melting Arctic glaciers has been strongly underestimated, suggests a study. The new work shows a 13 percent reduction of the albedo over the course of one melting season caused by red-pigmented snow algal blooms.

Mystery of powerful lightning at sea not solved completely

Science Daily - Mon, 06/20/2016 - 11:04
The mystery of why most of the most powerful lightning on Earth happens over the oceans isn't solved, but a few of the usual suspects are no longer in custody. It's possible the increased presence of salt in the atmosphere plays a role.

Ancient DNA shows perfect storm felled Ice Age giants

Science Daily - Fri, 06/17/2016 - 15:03
Giant Ice Age species including elephant-sized sloths and powerful sabre-toothed cats that once roamed the windswept plains of Patagonia, southern South America, were finally felled by a perfect storm of a rapidly warming climate and humans, a new study has shown.

Permafrost thawing below shallow Arctic lakes

Science Daily - Thu, 06/16/2016 - 13:13
Permafrost below shallow Arctic lakes is thawing as a result of changing winter climate, new research shows. These rates of warming are similar to those observed in terrestrial permafrost, yet those soils are still well below freezing and thaw is not expected for at least another 70 years. However, a regime shift in lake ice is leading to sub-lake permafrost thaw now.

700-year-old West African soil technique could help mitigate climate change

Science Daily - Thu, 06/16/2016 - 09:59
A 700-year-old fertile soil technique could mitigate climate change and revolutionize farming across Africa, say researchers. They discovered that the ancient West African method of adding charcoal and kitchen waste to highly weathered, nutrient poor tropical soils can transform the land into enduringly fertile, carbon-rich black soils which the researchers dub 'African Dark Earths'.

Huge ancient river basin explains location of the world's fastest flowing glacier

Science Daily - Tue, 06/14/2016 - 10:44
An ancient basin hidden beneath the Greenland ice sheet may help explain the location, size and velocity of Greenland's fastest flowing outlet glacier. The research also provides an insight into what past river drainage looked like in Greenland, and what it could look like in the future as the ice sheet retreats.

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