Earthweek: a Diary of the planet

Extreme El Niño episodes are becoming more frequent under climate change, and researchers say continued global warming is likely to make them even more frequent. A study of Pacific Ocean warming from 1901 to 2017 found that four out of the five El Niños identified as extreme have formed since 1970. The warmer waters are now originating in the west-central Pacific rather than the eastern Pacific as they did before the late 1970s. That has caused more extreme weather shifts, including severe droughts in Australia and floods in California.

Researchers in Virginia say they have trained rats to master the art of driving by teaching them to steer tiny cars to collect tasty bits of sugar-coated cereal. Six female and 11 male rats learned to steer the rodent rover by touching the center, left or right of a metal bar that controlled the wheels, a researcher says, adding that hormone monitors indicated that the rats seemed to relax as they mastered the driving.

Despite humans wielding an overwhelming influence on the planet, scientists say that half of Earth’s land surface not covered in ice still remains relatively wild, albeit broken into small, isolated tracts. The summary of a National Geographic Society global survey conducted in 2017 and 2018 concludes that even with the damage to the environment caused by human activities, there is still an opportunity to protect what wild places are left.