April and May 2016 are the warmest on record. They are also the 12th and 13th straight months to be the hottest in recorded history.

Atmospheric carbon dioxide measured in Antarctica tops 400 parts per million, the highest concentration there in 4 million years. Scientists believe Earth has now crossed the threshold to a 400 ppm future.

The California red-legged frog—the one Mark Twain wrote about in "The Celebrated Jumping Frog of Calaveras County"—returns to Yosemite National Park after being locally extinct for 40 years.

Transportation overtakes power generation as the largest source of carbon pollution in the United States.

Donald Trump, the Republican candidate for president, says that if elected he would "at a minimum" renegotiate the Paris climate accord. 

He also promises to bring back the U.S. coal industry: "We're going to get those miners back to work."

The Bramble Cay melomys, a rodent endemic to a low-lying Australian island, is the first mammal known to have gone extinct because of human-caused climate change.

The American bison (Bison bison) is declared the national mammal of the United States. 

Tourists in Yellowstone National Park, concerned about a newborn bison calf, place it in the back of their SUV. The calf is subsequently rejected by its herd and has to be euthanized.

Fearing a loss of tourism, the Australian government asks the UN to remove a chapter about damage to the Great Barrier Reef from a report on the effects of climate change on World Heritage Sites. 

Norway will ban all fossil-fuel-powered automobiles by 2025.

Norway joins four other Nordic countries and the United States in pledging increased environmental protection for the Arctic. Days later, it awards new licenses to drill for oil in the Arctic to 13 companies. 

Pacific Gas & Electric will close Diablo Canyon, California's only nuclear power plant, by 2025. 

Coral bleaching, caused by unnaturally warm water temperatures, is killing reefs in the equatorial Pacific, including as much as half of the Great Barrier Reef.

Climate change is causing the bodies of red knot shorebirds to shrink: Earlier springtimes are disrupting their feeding schedules. 

The number of charging stations for electric cars in Japan surpasses the number of gas stations.

The world produced more renewable energy in 2015 than ever before, reports REN21. It also consumed a record amount of fossil fuel, reports oil giant BP.

President Barack Obama visits Yosemite on Father's Day and declares climate change to be "the most important challenge we face."

According to a new study, because of light pollution only one in five Americans can see the Milky Way.

This article appeared in the September/October 2016 edition with the headline "Up to Speed."