Melting Arctic sea ice—mostly in the summer—is making the polar bear population smaller, weaker and hungrier because they rely on the sea ice to hunt from, scientists said. And winter sea ice is especially important for fisheries and seal pups.
Arctic sea ice had its weakest winter buildup since record-keeping began 47 years ago, a symptom of climate change that will have repercussions globally.
The Arctic reaches its maximum sea ice in March each year and then starts a six-month melt season. The National Snow and Ice Data Center said the peak measurement taken Saturday was 5.53 million square miles (14.33 million square kilometers)—about 30,000 square miles (80,000 square kilometers) smaller than the lowest previous peak in 2017.
Arctic sea ice’s biggest year since record-keeping began was 1979, at 6.42 million square miles (16.64 million square kilometers). That means since satellites began tracking it, Arctic sea ice’s winter peak has shrunk by about the size of Pakistan.
The five lowest amounts for winter peak Arctic sea ice have been since 2015.
Scientists said warming conditions in the Arctic—the region is warming four times faster than the rest of the world—affect weather elsewhere. Pressure and temperature differences between north and south shrink. That weakens the jet stream, that moves weather systems along, making it dip further south with cold outbreaks and storms that often get stuck and rain or snow more.