As ice sheets melted during the deglaciation of the last ice age and global oceans warmed, oceanic oxygen levels decreased and "denitrification" accelerated by 30 to 120%, a new international study shows, creating oxygen-poor marine regions and throwing the oceanic nitrogen cycle off balance. By the end of the deglaciation, however, the oceans had adjusted to their new warmer state and the nitrogen cycle had stabilized.
When a solar flare filled with charged particles erupts from the sun, its magnetic fields sometimes break a widely accepted rule of physics. The flux-freezing theorem dictates that the magnetic lines of force should flow away in lock-step with the particles, whole and unbroken. Instead, the lines sometimes break apart and quickly reconnect in a way that has mystified astrophysicists.
On Tuesday, the National Weather Service gave the recent Moore, Okla., tornado the top-of-the-scale rating of EF5 for wind speed and breadth, and severity of damage. Wind speeds were estimated at between 200 and 210 mph. Everything had to come together just perfectly to create this killer tornado: wind speed, moisture in the air, temperature, and timing.
Until recently people believed much of the rain forest’s carbon floated down the Amazon River and ended up deep in the ocean. Research showed a decade ago that rivers exhale huge amounts of carbon dioxide, though it left open the question of how that was possible. A new study resolves the conundrum, proving that woody plant matter is almost completely digested by bacteria living in the Amazon River.
The planets Uranus and Neptune are home to extreme winds blowing at speeds of over 1,000 km/hour, hurricane-like storms as large around as Earth, immense weather systems that last for years, and fast-flowing jet streams. Researchers using a new method for analyzing the gravitational field of these planets have determined an upper limit for the thickness of the atmospheric layer, which limits the depth of stormy weather.
Sulfur dioxide has been pegged as a significant cooling element in atmospheric climate models because of its ability to form sulfate aerosol particles that reflect sunlight. Recent findings from a team suggest that it is likely most models overestimate the cooling effect of these particles. The reason is a largely disregarded reaction pathway catalyzed by mineral dust within clouds.
Detecting greenhouse gases in the atmosphere could soon become far easier with the help of an innovative technique developed by a team at NIST, where scientists have overcome an issue preventing the effective use of lasers to rapidly scan samples. The team says the technique also could work for other jobs that require gas detection, including the search for hidden explosives and monitoring chemical processes in industry and the environment.
The old saying that "what goes up must come down" doesn't apply to carbon dioxide pollution in the air, which just hit an unnerving milestone. The chief greenhouse gas was measured Thursday at 400 parts per million in Hawaii, a monitoring site that sets the world's benchmark. This was last matched about 2 million years ago, or more, and is more than modern humans have ever encountered.
Researchers 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.
University 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.
The 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.
All forms of life that breathe oxygen—even ones that can't be seen with the naked eye, such as bacteria—must fight oxidants to live. These same oxidants also exist in the environment. But neutralizing environmental oxidants such as superoxide was a worry only for organisms that dwell in sunlight—in habitats that cover a mere 5% of the planet. Now researchers have discovered the first light-independent source of superoxide.
In an effort to determine if conditions were ever right on Mars to sustain life, a team of scientists has examined a meteorite that formed on the red planet more than a billion years ago. And although this team’s work is not specifically solving the mystery, it is laying the groundwork for future researchers to answer this age-old question.
Recent work by University of Washington climate scientists have provided new insights into how to keep a drink cold on a hot day. Their work shows that, in sultry weather, condensation on the outside of a canned beverage doesn’t just make it slippery: those drops can provide more heat than the surrounding air, meaning the drink would warm more quickly.
A NASA-funded sounding rocket mission will launch from an atoll in the Pacific in the next few weeks to help scientists better understand and predict the electrical storms in Earth's upper atmosphere These storms can interfere with satellite communication and global positioning signals.
Long-term exposure to air pollution may be linked to heart attacks and strokes by speeding up atherosclerosis, or "hardening of the arteries," according to a University of Michigan public health researcher and colleagues from across the U.S.
The 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.
A 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.
The ability to determine the fate of charcoal is critical to knowledge of the global carbon budget, which in turn can help understand and mitigate climate change. However, until now, researchers only had scientific guesses about what happens to charcoal once it's incorporated into soil. They believed it stayed there. Surprisingly, the findings of a new study shows that most of these researchers were wrong.
Scientists at Lawrence Livermore National Laboratory and the University of California, Berkeley have discovered new materials to capture methane, the second highest concentration greenhouse gas emitted into the atmosphere. The research team performed systematic computer simulation studies on the effectiveness of methane capture using two different materials—liquid solvents and nanoporous zeolites.
A 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.
New 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%.
Researchers have successfully measured reaction rates of a second Criegee intermediate, CH3CHOO, and proven that the reactivity of the atmospheric chemical depends strongly on which way the molecule is twisted. The measurements will provide further insight into hydrocarbon combustion and atmospheric chemistry.
Variations in nutrient availability in the world's oceans could be a vital component of future environmental change, according a research team. Their research reviews what we know about ocean nutrient patterns and interactions, and how they might be influenced by future climate change and other man-made factors. The authors also highlight how nutrient cycles influence climate by fuelling biological production.
For 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.