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Introduction

roams over flat,mostly treeless plains called tundras. Antarctica, mean- while, lacks plants such as shrubs or trees, though it does have two types of flowering plants and algae, moss, and lichen .Temperatures during its summer months rise along the coasts to above freezing. Sometimes they even reach the 50s °F (10s °C)—a heat wave by Antarctic standards. The natural, seasonal warming of thepolar regions,however,doesnot ex- plain some extreme changes scientists have detected in those environments. For several decades, the polar regions have been feeling the effects of cli- mate change,which is also sometimes called global warming.Temperatures across the planet have steadily risen, and in 2014 meteorologists saw the highest average global temperatures ever recorded.The next yearwas even hotter. In 2016, theNationalAeronau- tics andSpaceAdministration (NASA) reported that 15 of the 16 hottest years ever recordedoccurredduring the21st century.Howdoes this extremewarm- ing trend affect the polar regions? In Antarctica, for example, the warming

of the Southern Ocean has led to the melting of glaciers and ice sheets. In the Arctic, higher temperatures have made it harder for polar bears to hunt their traditional prey and the vast ice sheets have started to crack or disappear. Nearly every scientist who has looked at this problem agrees that climate change is in part fueled by human activity. People have shaped the environments of the polar re- gionsbefore,whether throughhunting land or sea animals or,more recently, extracting natural resources such as oil. But the effects of climate change could be more drastic for the polar regions than anything in the past. In a few small cases, it could have a pos- itive impact. Indigenous people of the Arcticmight be able to raisenewcrops or create jobs by digging for minerals. Overall, though, the warming of the polar regions threatens wildlife and the health of other parts of the planet on a local and a global scale. Here’s a closer look at how climate change does andwill continue to affect Earth’s polar regions.