Taxonomy term

extern

California's big trees dying of thirst

From the days of John Muir’s treks through the valleys and peaks of the Sierra Nevada, California’s majestic forests have attracted nature lovers from around the world. Since Muir’s death in 1914, though, dramatic changes have taken hold. Across the state’s forests, small trees are more common while large trees have declined in number, and oaks seem to be taking over where pines once ruled. A new study cites drought due to warming as a major driving force behind these changes.

29 May 2015

Megafloods mostly shaped Icelandic canyon landscape

A new study suggests that in one environment prone to catastrophic floods, the Jökulsárgljúfur Canyon in northeastern Iceland, the effects of several megafloods in the past 9,000 years have sculpted the canyon landscape far more so than “background” erosion caused by water and sediment flowing through it.

22 May 2015

Shrinking snowpack projected in western U.S. as rain-snow boundary climbs higher

Gauging the impacts of climate change on future precipitation is challenging, especially in the western U.S., a region with highly variable temperatures, precipitation patterns and terrain. But understanding such impacts in the West — and, in particular, how much precipitation will fall as snow versus rain in the future — is important given the region’s dependence on wintertime snowfall as a freshwater resource. Now, a new study forecasts a broad shift from snow to rain for much of the West — a projection that will require attention from land and water resource managers planning for the future.

24 Apr 2015

Wedge approach proposed to lower water stress

Roughly 30 percent of the global population — or about 2.2 billion people — lives in water-stressed parts of the world, where high freshwater withdrawals endanger ecosystems, agriculture and drinking-water supplies. If current population and water usage trends persist, this fraction could rise to about one-half by the century’s end. In a recent study, researchers — taking a page from the climate-change mitigation literature — have proposed a “wedge” approach to address global water stress, laying out how various tactics could ease the growing problem.

22 Apr 2015

Some coral reefs bounce back after bleaching

Ocean temperatures that rise too much or for too long can harm coral reefs, sometimes causing mass die-offs that leave reefs nearly barren of live corals. But scientists don’t know if or under what conditions reefs can recover from such catastrophes. Now, a new study suggests that, given time and the right conditions, even once-decimated reefs can recoup their losses.

09 Apr 2015

Twentieth-century warming linked to Pacific trade winds

Earth’s average atmospheric temperature warmed by about 1.3 degrees Celsius over the course of the 20th century. However, the rate of increase during that time was not constant and scientists have been unable to fully explain the timing and pattern of warming. Now, a recent study has identified a correlation between global temperatures and the strength of Pacific trade winds that may help clear up the some of the confusion.

13 Mar 2015

Old piles of shells reveal ancient El Niño patterns

Understanding of the El Niño-Southern Oscillation (ENSO) is evolving as scientists unearth new data sources. In a study recently published in Science, scientists turned to the discarded remains of shellfish for a 10,000-year record of eastern Pacific ENSO activity, which offered glimpses into unexpected past ENSO behavior and intensity.

03 Jan 2015

High-powered simulation tracks evolution of universe in detail

The universe burst into existence 14.6 billion years ago, and has been expanding ever since. Of course, humans have only been around to glimpse the most recent fraction of stellar history. Now, a new high-powered computer simulation called Illustris, which traces more than 13 billion years of cosmological evolution, is giving scientists and the public alike an armchair view of how things came to look the way they do.

26 Sep 2014

Colorado River Basin sees severe groundwater depletion

Over the past 14 years, the Colorado River Basin has experienced its worst drought since precipitation records have been kept, starting in the 1960s. The basin supplies water used for agriculture and in households in seven states, affecting more than 40 million people. In a study recently published in Geophysical Research Letters, researchers have found that the reservoirs that store water in the basin are at record low levels. What’s more, the research shows that in addition to shrinking reservoirs, groundwater is being depleted much faster than previously thought, which could have major implications for the region’s future water security.

24 Sep 2014

Infrasound reveals lava lake levels

The rises and falls of volcanic lava lakes are not easily tracked, especially when the lakes aren’t visible from crater rims. But recently, researchers found a way to monitor the lava lake at Chile’s Villarrica volcano using complementary methods to keep an eye on a feature they can’t always see.

22 Aug 2014

Pages