As climatologists closely monitor the impact of human activity on the world's oceans, researchers at the Georgia Institute of Technology have found yet another worrying trend impacting the health of the Pacific Ocean.

A new modeling study conducted by researchers in Georgia Tech's School of Earth and Atmospheric Sciences shows that for decades, air pollution drifting from East Asia out over the world's largest ocean has kicked off a chain reaction that contributed to oxygen levels falling in tropical waters thousands of miles away.

"There's a growing awareness that oxygen levels in the ocean may be changing over time," said Taka Ito, an associate professor at Georgia Tech. "One reason for that is the warming environment -- warm water holds less gas. But in the tropical Pacific, the oxygen level has been falling at a much faster rate than the temperature change can explain."

The study, which was published May 16 in Nature Geoscience, was sponsored by the National Science Foundation, a Georgia Power Faculty Scholar Chair and a Cullen-Peck Faculty Fellowship.

In the report, the researchers describe how air pollution from industrial activities had raised levels of iron and nitrogen -- key nutrients for marine life -- in the ocean off the coast of East Asia. Ocean currents then carried the nutrients to tropical regions, where they were consumed by photosynthesizing phytoplankton.

SAR11, the most abundant plankton in the world's oceans, are pumping out massive amounts of two sulfur gases that play important roles in the Earth's atmosphere, researchers announced today in the journal Nature Microbiology.

Scientists have calculated that the present day ice sheets keep vast amounts of climate gas methane in check. Ice sheets are heavy and cold, providing pressure and temperatures that contain methane in form of ice-like substance called gas hydrate. If the ice sheets retreat the weight of the ice will be lifted from the ocean floor, the gas hydrates will be destabilised and the methane will be released.

Studies conducted at CAGE have previously shown that ice sheets and methane hydrates are closely connected, and that release of methane from the seafloor has followed the retreat of the Barents Sea ice sheet some 20,000 years ago. But is all such release of the potent climate gas bound to be catastrophic?

Not necessarily, according to a new study published in Nature Communications. It shows that the methane was indeed released as the ice sheets retreated. However the seepage did not occur in one major pulse, but over a period of 7000 to 10000 years following the initial release.

Though a border wall with Mexico is currently a matter of serious discussion in the United States, the aim of which is to prevent the physical movement of people (with few other apparent “benefits”), some walls can actually bring together and preserve communities, rather than divide them.

In only five years, the UN says, around 60 million Africans may be displaced as their land ceases to be arable, a potential humanitarian disaster the scale of which would be unprecedented. This would be devastating to a huge portion of the African continent not only ecologically and economically but socially as well.

That’s where Africa’s ingenious Great Green Wall comes in.

Experts at the United Nations say without action, desertification may claim two-thirds of Africa’s farmlands in under a decade. The Great Green Wall, however, was conceived as a wide-reaching strategy to halt Northern Africa’s rapidly advancing Sahara Desert.

The Great Green Wall, once complete, will stretch an incredible 4,400 miles from Senegal in West Africa to the East African nation of Djibouti. Instead of bricks and mortar, the wall will be made of trees and other vegetation, including plants that can be eaten or used to create medicine.

The idea that the young Earth had a thicker atmosphere turns out to be wrong. New research from the University of Washington uses bubbles trapped in 2.7 billion-year-old rocks to show that air at that time exerted at most half the pressure of today’s atmosphere.

A recent study released by the National Aeronautics and Space Administration (NASA) concludes that the current drought that began in 1998 in the eastern Mediterranean Levant  – which includes Cyprus, Israel, Jordan, Lebanon, Palestine, Syria, and Turkey – is the region’s worst dry spell since 1100 C.E.

NASA scientists reconstructed our regional drought history by studying records of tree rings, from dead and live specimens, across several Mediterranean countries to determine patterns of dry and wet years over a 900-year time span. Tree rings are good indicators of precipitation since dry years cause thin rings while thick rings show when water was plentiful. They concluded that the years between 1998 and 2012 were drier than any other period, and that the drought was likely caused by humans.

Ben Cook, lead author and climate scientist at NASA’s Goddard Institute for Space Studies and the Lamont Doherty Earth Observatory at Columbia University in New York City, said the range of regional weather events has varied widely over the last millennium, but the past twenty years stand out as extreme, falling outside the range of natural variability.

Scientists studying data from the top of the Greenland ice sheet have discovered that during winter in the center of the world's largest island, temperature inversions and other low-level atmospheric phenomena effectively isolate the ice surface from the atmosphere -- recycling water vapor and halting the loss or gain of ice.

A team of climate scientists made the surprising discovery from three years of data collected at Summit Camp, an arid, glaciated landscape 10,500 feet above sea level in the middle of the Greenland ice sheet.

"This is a place, unlike the rest of the ice sheet, where ice is accumulating," says Max Berkelhammer, assistant professor of earth and environmental sciences at the University of Illinois at Chicago. Berkelhammer is first author on the study, reported in Science Advances, an open-access online publication of the journal Science.

Hybrid cars have come a long way since the first frumpy Toyota Prius debuted in Japan almost 20 years ago. The same can be said for electric cars since GM rolled out its EV1 in the late 1990s, only to backtrack, repossess and destroy all of them, infuriating its fans in the process. There are now dozens of hybrid models, and they enjoyed a surge in saleswhen gasoline prices spiked in 2007 and again in 2012. But more recently, their sales overall have been on the decline. Meanwhile electric vehicles are becoming more sophisticated, are improving their range and have seen sales on the uptick while the automakers have become more competitive in their advertising.

As expected, hybrid cars’ sluggish sales numbers have much to do with the fact that oil prices have been in a two-year slump while conventional gasoline engines keep getting cleaner and more fuel efficient. When hybrids started becoming more popular a decade ago, it was often assumed that when it came time for a new upgrade, owners would stay loyal and trade in one hybrid car for another.

The study between the University of Birmingham and University of Hong Kong, published in Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research, adds to growing concern around the health risks of prolonged exposure to ambient fine particulate matter.

From a quarter to half of Earth’s vegetated lands has shown significant greening over the last 35 years largely due to rising levels of atmospheric carbon dioxide, according to a new study published in the journal Nature Climate Change on April 25.