Photo by NS Newsflash via Flickr.

The top stories included a climate rally over a proposed Keystone XL pipeline, a simple way New York City could reduce its carbon footprint, the rapid loss of grasslands due to federal biofuel mandates, the outlook for wild weather, and what happens when fish take antianxiety drugs.

Thousands Rally in D.C. Against Keystone XL Pipeline
The Feb. 17 climate-change protest drew about 35,000 people who called on President Obama to reject the pipeline plan, which would transport crude oil from tar sands in Alberta to refineries and ports in Texas. Environmentalists say the extraction process creates more greenhouse gases than traditional oil drilling, and that the oil is dirtier. Two days after the rally, TransCanada claimed the pipeline will have no measurable effect on global warming.

Report Claims N.Y. City Can Reduce Its Carbon Footprint 90% by 2050
Research by the non-profit group Urban Green Council details how retrofitting buildings to be more energy efficient, thus reducing heating and cooling loads, would take the city most of the way toward this goal. In a review article, Slate calls the approach “The Triple-Pane Windows Theory.”

Biofuel Rush Wiping Out Grasslands at Fastest Rate Since Dust Bowl
Scientists at South Dakota State University found that U.S. farmers converted more than 1.6 million acres of grasslands to corn and soybean fields between 2006 and 2011. This trend has implications for climate, because grasslands retain more carbon in the soil than crops do. Switching to crops also appears to be reducing populations of ducks and other ground-nesting birds, which breed in the northern prairies.

Scientists Say Wild Weather Is Here to Stay
Researchers at the annual meeting of the American Association for the Advancement of Science (AAAS), held Feb. 14-18 in Boston, said human-driven climate change has made severe weather events more intense and more frequent, according to an AAAS press release.

Traces of Antianxiety Drug in Rivers Alter Way Fish Act
The Wall Street Journal reported that a new study shows that wild perch in a Swedish river have six times the amount of the drug oxazepam in their tissue than is found in the water. Perch raised in the lab in water with trace amounts of the drug separated themselves from each other, acted more adventurously than wild perch, and put themselves in danger more often.