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Scientists have begun to account for the topsy-turvy carbon cycle of the Colorado River delta – once a massive green estuary of grassland, marshes and cottonwood, now desiccated dead land.

“We’ve done a lot in the United States to alter water systems, to dam them. The river irrigates our crops and makes energy. What we really don’t understand is how our poor water management is affecting other natural systems – in this case, carbon cycling,” said Cornell’s Jansen Smith, a doctoral candidate in earth and atmospheric sciences.

New Cornell University research suggests an economically viable model to scrub carbon dioxide from the atmosphere to thwart global warming.

The researchers propose using a “bioenergy-biochar system” that removes carbon dioxide from the atmosphere in an environmental pinch, until other removal methods become economically feasible and in regions where other methods are impractical. Their work appeared in the Oct. 21 edition of Nature Communications.

Arctic sea ice, the vast sheath of frozen seawater floating on the Arctic Ocean and its neighboring seas, has been hit with a double whammy over the past decades: as its extent shrunk, the oldest and thickest ice has either thinned or melted away, leaving the sea ice cap more vulnerable to the warming ocean and atmosphere.

“What we’ve seen over the years is that the older ice is disappearing,” said Walt Meier, a sea ice researcher at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “This older, thicker ice is like the bulwark of sea ice: a warm summer will melt all the young, thin ice away but it can’t completely get rid of the older ice. But this older ice is becoming weaker because there’s less of it and the remaining old ice is more broken up and thinner, so that bulwark is not as good as it used to be.”

Global populations of vertebrates -- mammals, birds, reptiles, amphibians, and fish -- have declined by 58 percent between 1970 and 2012, states a new report from World Wildlife Fund (WWF). Animals living in the world’s lakes, rivers, and freshwater systems have experienced the most dramatic population declines, at 81 percent. Because of human activity, the report states that without immediate intervention global wildlife populations could drop two-thirds by 2020.

The bulk of methane emissions in the United States can be traced to a small number of “super emitting” natural gas wells, according to a new study.

“We’re finding that when it comes to natural gas leaks, a 50/5 rule applies: That is, the largest 5 percent of leaks are typically responsible for more than 50 percent of the total volume of leakage,” said study co-author Adam Brandt, an assistant professor of energy resources engineering at Stanford’s School of Earth, Energy & Environmental Sciences.

The findings, published online in the journal Environmental Science & Technology, could lead to more efficient strategies for sampling emissions and fixing the most significant leaks, said Brandt, who is also a senior fellow at Stanford’s Precourt Institute for Energy. By focusing on finding and fixing the biggest emitters, companies can significantly reduce the amount of methane leaking into the atmosphere.