Great land plates shifted and came together - 55 million years ago - to create the Tibetan Plateau, the highest and largest plateau in the world today.
Global warming will cause more people to be exposed to the mosquito that carries Zika virus, says a new study. Why this mosquito is such a good virus-spreader.
The recent El Niño has driven a rise in atmospheric CO2. Scientists expect it to surpass 400 parts per million for the year and stay there at least a human lifetime.