Climate
Study traces origin of cirrus clouds
May 9, 2013 2:48 pm | News | CommentsResearchers studying the origin of cirrus clouds have found that these thin, wispy trails of ice crystals are formed primarily on dust particles and some unusual combinations of metal particles—both of which may be influenced by human activities. The findings are important, scientists say, because cirrus clouds cover as much as one-third of the Earth and play an important role in global climate.
Discovered: Unexpected cooling effect on climate
May 7, 2013 8:11 am | News | CommentsUniversity of Manchester scientists, writing in Nature Geoscience, have shown that natural emissions and manmade pollutants can both have an unexpected cooling effect on the world’s climate by making clouds brighter. Clouds are made of water droplets, condensed on to tiny particles suspended in the air. When the air is humid enough, the particles swell into cloud droplets.
Cleaner energy, warmer climate?
May 7, 2013 7:17 am | by Vicki Ekstrom, Joint Program on the Science and Policy of Global Change | News | CommentsThe growing global demand for energy, combined with a need to reduce emissions and lessen the effects of climate change, has increased focus on cleaner energy sources. But what unintended consequences could these cleaner sources have on the changing climate? Researchers at Massachusetts Institute of Technology now have some answers to that question, using biofuels as a test case.
Analysis of 2,000 years of climate records reveals end of global cooling trend
April 24, 2013 8:58 am | News | CommentsThe most comprehensive evaluation of temperature change on Earth’s continents over the past 1,000 to 2,000 years indicates that a long-term cooling trend—caused by factors including fluctuations in the amount and distribution of heat from the sun, and increases in volcanic activity—ended late in the 19th century.
Nitrogen has key role in estimating CO2 emissions from land use change
April 23, 2013 9:42 am | News | CommentsA new global-scale modeling study that takes into account nitrogen—a key nutrient for plants—estimates that carbon emissions from human activities on land were 40% higher in the 1990s than in studies that did not account for nitrogen. Most existing models used to estimate global emissions changes based on land use do not have the ability to model nitrogen limitations on plant regrowth.
Fossil shells, new geochemical technique provide clues to ancient climate cooling
April 23, 2013 9:41 am | News | CommentsUsing a new laboratory geochemical technique to analyze heavy isotopes of carbon and oxygen in fossil snail shells, scientists have gained insights into an abrupt climate shift that transformed the planet nearly 34 million years ago. At that time, the Earth switched from a warm and high-carbon dioxide "greenhouse" state to the lower-carbon dioxide, variable climate of the modern "icehouse" world.
Sunlit snow triggers atmospheric cleaning, ozone depletion in the Arctic
April 15, 2013 4:23 pm | News | CommentsA Purdue University-led team of researchers discovered sunlit snow to be the major source of atmospheric bromine in the Arctic, the key to unique chemical reactions that purge pollutants and destroy ozone. The team's findings suggest the rapidly changing Arctic climate—where surface temperatures are rising three times faster than the global average—could dramatically change its atmospheric chemistry.
Report: Cutting specific atmospheric pollutants would slow sea level rise
April 15, 2013 12:56 pm | News | CommentsNew research indicates that cutting emissions of certain pollutants can greatly slow sea level rise this century. Scientists focussing on emissions of four heat-trapping pollutants—methane, tropospheric ozone, hydrofluorocarbons, and black carbon—found that reductions these pollutants that cycle comparatively quickly through the atmosphere could temporarily forestall the rate of sea level rise by roughly 25 to 50%.
Satellite shelved after 2000 election to now fly
April 11, 2013 2:51 am | by Seth Borenstein, AP Science Writer | News | CommentsObama proposed Wednesday spending nearly $35 million in his 2014 budget to refurbish a satellite, nicknamed GoreSat by critics, that's been sitting in storage after it was shelved in 2001, months after Bush took office. It cost about $100 million by then with NASA's internal auditors faulting its cost increases.
Widely used index may have overestimated drought
April 8, 2013 6:26 pm | News | CommentsFor decades, scientists have used sophisticated instruments and computer models to predict the nature of droughts. The majority of these models have steadily predicted an increasingly frequent and severe global drought cycle. But a recent study from a team of researchers in the United State and Australia suggests that one of these widely used tools—the Palmer Drought Severity Index (PDSI)—may be incorrect.
A ‘green’ Sahara was far less dusty than today
April 6, 2013 3:07 pm | News | CommentsAs recently as 5,000 years ago, the Sahara was a verdant landscape, with sprawling vegetation and numerous lakes. The Sahara’s “green” era likely lasted from 11,000 to 5,000 years ago, and is thought to have ended abruptly. Now researchers have found that this abrupt climate change occurred nearly simultaneously across North Africa.
Thin, low Arctic clouds an important key to Greenland Ice Sheet melt
April 5, 2013 6:06 pm | News | CommentsAccording to a new study by scientists funded by the National Science Foundation (NSF) and at the National Oceanic and Atmospheric Administration (NOAA), clouds over the central Greenland Ice Sheet last July were "just right" for driving surface temperatures there above the melting point. The 2012 melt illustrates the often-overlooked role that clouds play in climate change. Current models don’t do enough, says researchers, to account for their effects.
Extreme algae blooms the new normal?
April 4, 2013 7:36 am | News | CommentsIn 2011, Lake Erie experienced a record-breaking algae bloom that began in the lake's Western region in mid-July and eventually covered an area of 230 square miles. At its peak in October, the bloom had expanded to more than 1,930 square miles, three times greater than any other bloom on record. According to recent research, the bloom was triggered by long-term agricultural practices coupled with extreme precipitation, followed by weak lake circulation and warm temperatures.
New models predict drastically greener Arctic in coming decades
March 31, 2013 6:48 pm | News | CommentsResearchers from several universities, AT&T Labs, and the American Museum of Natural History have built new models that show a widespread redistribution of Arctic vegetation. They say their findings predict a massive “greening” in the Arctic, as much as 50% in over the next few decades. This transition will help accelerate climate warming, they add.
Meeting the computing challenges of next-generation climate models
March 27, 2013 7:47 am | News | CommentsLawrence Berkeley National Laboratory recently hosted an international workshop that brought together top climatologists, computer scientists, and engineers from Japan and the United States to exchange ideas for the next generation of climate models as well as the hyper-performance computing environments that will be needed to process the data from those models. It was the 15th in a series of such workshops that have been taking place around the world since 1999.
Study: Volcanic eruptions triggered the end-Triassic extinction
March 22, 2013 2:28 pm | News | CommentsIt’s not entirely clear what caused the end-Triassic extinction, although most scientists agree on a likely scenario: Over a relatively short period of time, massive volcanic eruptions from a large region known as the Central Atlantic Magmatic Province (CAMP) spewed forth huge amounts of lava and gas, including carbon dioxide, sulfur and methane. Now, a research team has determined that these eruptions occurred precisely when the extinction began, providing strong evidence that volcanic activity did indeed trigger the end-Triassic extinction.
Ocean plankton sponge up nearly twice the carbon currently assumed
March 18, 2013 10:38 am | News | CommentsAccording to new research, models of carbon dioxide in the world’s oceans need to be revised. Trillions of plankton near the surface of warm waters are far more carbon-rich than has long been thought global marine temperature fluctuations could mean that tiny microbes digest double the carbon previously calculated.
Could global warming change tornado season, too?
March 18, 2013 9:12 am | by Seth Borenstein, AP Science Writer | News | CommentsWith the planet heating up, many scientists seem fairly certain some weather elements like hurricanes and droughts will worsen. But tornadoes have them stumped. As the traditional tornado season nears, scientists have been pondering a simple question: Will there be more or fewer twisters as global warming increases?
The science of clouds
March 13, 2013 1:14 pm | News | CommentsClouds can both cool the planet, by acting as a shield against the sun, and warm the planet, by trapping heat. But why do clouds behave the way they do? And how will a warming planet affect the cloud cover? Lawrence Berkeley National Laboratory scientist David Romps has made it his mission to answer these questions.
Amplified greenhouse effect shaping North into South
March 11, 2013 9:00 am | News | CommentsAn international research team has just published a study showing that, as the cover of snow and ice in the northern latitudes has diminished in recent years, the temperature over the northern land mass has increased at different rates during the four seasons. This has caused temperatures and vegetation at northern latitudes to more and more resemble those found several degrees of latitude farther south.
Volcanic aerosols, not pollutants, tamped down recent Earth warming
March 1, 2013 2:38 pm | News | CommentsA research team led by the University of Colorado Boulder had been looking for clues about why Earth did not warm as much as scientists expected between 2000 and 2010. They now think the culprits are hiding in plain sight—dozens of volcanoes spewing sulfur dioxide. The study results essentially exonerate Asia, including India and China, two countries that are estimated to have increased their industrial sulfur dioxide emissions by about 60% from 2000 to 2010 through coal burning.
Mineral diversity offers clue to early Earth chemistry
March 1, 2013 9:50 am | News | CommentsNew research on a mineral called molybdenite by a team led by Robert Hazen at Carnegie's Geophysical Laboratory provides important new insights about the changing chemistry of our planet as a result of geological and biological processes. Analysis of the mineral showed that concentrations of rhenium, a trace element that is sensitive to oxidation reactions, increased significantly—by a factor of eight—over the past three billion years.
Chemistry trick kills climate controversy
February 12, 2013 7:48 am | News | CommentsVolcanoes are well known for cooling the climate. But just how much and when has been a bone of contention among historians, glaciologists, and archeologists. Now a team of atmosphere chemists, from the Tokyo Institute of Technology and the University of Copenhagen, has come up with a way to say for sure which historic episodes of global cooling were caused by volcanic eruptions.
Sunlight stimulates release of climate-warming gas from melting Arctic permafrost
February 11, 2013 3:37 pm | News | CommentsAncient carbon trapped in Arctic permafrost is extremely sensitive to sunlight and, if exposed to the surface when long-frozen soils melt and collapse, can release climate-warming carbon dioxide gas into the atmosphere much faster than previously thought.
Volcano location could be greenhouse-icehouse key
February 7, 2013 8:00 am | News | CommentsA new Rice University-led study finds the real estate mantra “location, location, location” may also explain one of Earth’s enduring climate mysteries. The study suggests that Earth’s repeated flip-flopping between greenhouse and icehouse states over the past 500 million years may have been driven by the episodic flare up of volcanoes at key locations where enormous amounts of carbon dioxide are poised for release into the atmosphere.
