Ava Loomar

Aug 18, 2023 | cnn.com | Ava Loomar

Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more. CNN  —  As the climate warms, scientists have suggested that “time-traveling pathogens” unleashed by thawing Arctic permafrost may pose a risk to modern ecosystems. Permafrost is a hard layer of frozen ground made of soil, sand and rocks in high-latitude areas such as Greenland, Alaska, Siberia, the Tibetan Plateau and northern Canada.