TOPEKA, Kan. (AP) — December is summer in Antarctica, but on the mountaintops where a team of scientists is studying plants from one of the warmest periods in Earth's history, daily high temperatures average about minus-30 degrees.

You read that correctly. Scientists, many from the University of Kansas, are collecting evidence of warm weather plants in a climate so cold it wouldn't register on a household thermometer.

That's because Antarctica holds some of the world's largest deposits of plant fossils from the Permian and Triassic period. Temperatures during the Permian were far colder than d...