Taxonomy term

jessica orwig

Seasonal ice-cover reduction throughout Arctic waters mapped

Nowhere is climatic warming more evident than in the Arctic. Arctic air has warmed almost twice as much compared to the global average in recent decades, and Arctic sea-ice extent has hit historic lows in the last decade.

25 Oct 2014

Subarctic lakes belch more methane on brighter days

Each summer, frozen ground in Arctic and subarctic regions, called permafrost, thaws and releases accumulated methane. For years, scientists have searched for a clear-cut way to estimate the amount of this potent greenhouse gas that these areas contribute to the atmosphere and the changing climate. Now, they have come one step closer to solving part of the problem.

12 Jun 2014

Oceanic records paint a more complex picture of human evolution

It has long been hypothesized that human ancestors evolved the ability to walk upright — a feature that appeared about 6 million years ago — in response to African landscapes changing from forests to grasslands. Now, a group of scientists has assembled the most continuous timeline of landscape evolution and grassland development over the last 12 million years near the African Rift Valley in northeastern Africa — and the timeline contradicts conventional hypotheses.

17 Jun 2013

North star loses mass but still shines bright

The North Star, the Pole Star, the Guiding Star, Polaris: Its many names reflect the many centuries humans have gazed northward to it for guidance. Because Earth’s North Pole is aligned with Polaris’ position in the sky, the star appears motionless, providing a steadfast beacon for early sailors and adventurers alike. But the star itself is far from motionless. In fact, Polaris is a specific type of star known as a Cepheid variable, which pulsates, varying in size and luminosity over a period of days and, according to recent observations, also ejects large amounts of mass into space.

03 May 2012