Earth

Paleontology

Oxygen blew up ancient amoebas

Single-celled creatures' size spiked as oxygen levels rose.

Earth

Trees have a tipping point

Satellite data confirm that the amount of forest cover can shift suddenly in response to relatively small changes in fire frequency and rainfall.

Humans

Columbus’ arrival linked to carbon dioxide drop

The depopulation of the Americas due to introduced European diseases may have spurred Europe's Little Ice Age.

Chemistry

Cloud seeding by trees could alter precipitation, climate

Some tree pollens shed molecules that can affect precipitation.

Earth

Solar changes help create cold northern winters

Fluctuations in ultraviolet light can set up frigid, snowy conditions across parts of the Northern Hemisphere.

Life

When snowpack shrinks, elk can binge on aspen

As winters warm in the Rockies, majestic grazers may be threatening iconic Western tree.

Humans

Really bad year for Arctic sea ice

On October 4, the National Snow and Ice Data Center posted information on its website indicating that the summer melt of sea ice in the Arctic, this year, approached — but did not quite match — the record set four years ago. A team of European scientists now concludes NSIDC underestimated those Arctic losses.

Humans

Study recalibrates trees’ carbon uptake

Photosynthesis appears to be somewhat speedier than conventional wisdom had suggested, a new study finds. If true, this suggests computer projections are at risk of overestimating the potential for trees to sop up carbon dioxide, a major greenhouse gas.

Humans

Arctic ozone: ‘Hole’ or just not whole?

This past spring, the Arctic stratosphere’s ozone layer suffered unprecedented depletion. But whether the record loss constituted a “hole” depends on which experts you consult.

Earth

Arctic ozone loss in 2011 unprecedented

Report describes a ‘hole’ comparable to conditions observed over Antarctica during the mid-1980s.

Earth

Earth/Environment

Diamonds from the depths have shallow elements, New Zealand earthquake helped triggered its successor and more in this week’s news.

Earth

Pole flips tied to plate tectonics

A lopsided arrangement of continents could lead to reversals in Earth's magnetic field.