Two massive asteroids hit Earth around 35.65 million years ago, but did not lead to any lasting changes in the Earth’s climate, according to a new study by UCL (University College London) researchers.

The University of Alaska Fairbanks released a new report this week highlighting environmental changes and extremes that impact Alaskans and their livelihoods. “Alaska’s Changing Environment” provides people with timely, reliable and understandable information on topics ranging from temperature and precipitation changes to salmon and polar bears.

A group of scientists, including researchers from Rutgers University-New Brunswick, Princeton University and Carleton University, has questioned the accuracy and utility of the metaphor “tipping point” in calling attention to the threat of climate change. The phrase, while perhaps initially useful as a clarion call that warns about sudden, drastic changes, may now be confusing the public and impeding action, researchers said.