RUNNING ON EMPTY: São Paulo,the world’s 12th-most populous city, is in the middle of a crippling drought, with it's Cantareira reservoir system running on emergency reserves. Brazil's National Water Agency reports that the system currently supplies only 3,563 gallons per second to the city's roughly 11 milllion inhabitants, down from its usual operating capacity of 8,700 gallons per second.

RUBBISH JET FUEL: United Airlines announced it will invest $30 million in Fulcrum BioEnergy, which produces aviation biofuels from farm waste, food scraps, and oil from animal fats. The Pleasanton, California-based company says this new biofuel could reduce airplane greenhouse gas emissions by 80 percent.

MERCURY MADNESS: The Supreme Court blocked the Environmental Protection Agency’s limits on mercury emissions from coal power plants, determining that the EPA is required to conduct a cost-benefit analysis of the regulations under the 1990 Clean Air Act. 

EMISSION DIMINUTION: The United States, China and Brazil each announced new emissions reduction commitments. China pledged to lower its carbon intensity—the carbon pollution generated by each point of economic growth—by 60 to 65 percent by 2030, while President Obama released a statement in conjunction with Brazilian President Dilma Rousseff declaring that the two countries would each use wind, solar, and geothermal sources to produce 20 percent of their electricity by 2030.

ALGAE OVERLOAD: A toxic algal bloom spanning from Central California to Alaska has put birds, sea lions, fish, and other organisms at risk of being poisoned and led to the closing of fisheries in Washington, Oregon, and California. Overly warm water is the suspected culprit.