METHANE ON THE WANE?: The U.S. government proposed requirements to cut methane emissions from oil and gas drilling in the U.S. by 40 to 45 percent by 2025 relative to 2012 levels. The Obama administration had previously announced this target in January.

IT ALL SPILLS OUT: Attorneys general from Colorado, New Mexico, and Utah announced they may take legal action against the EPA after the agency inadvertently triggered a 3-million-gallon pollutant spill in Colorado’s Animas River.

STILL NUMBER ONE: A study published in Nature found that scientists have overestimated China’s carbon dioxide emissions by more than 10 percent due to erroneous calculations of the country’s coal-burning output. Even with the study’s findings, however, China remains the world’s largest CO2 emitter.

MINI JUPITER: Astronomers discovered a planet 100 light-years away that resembles a smaller version of Jupiter, potentially revealing clues about the formation of our solar system. The planet, called 51 Eridani b, was discovered by the high-contrast imaging instrument Gemini Planet Imager. It contains water and the strongest methane signature ever detected on another planet.

GETTING HOTTER: The National Oceanic and Atmospheric Administration reported July had the highest average temperature worldwide of any month since record keeping began. Additionally, 2015 will likely be the hottest year on record, according to the report.