The basic argument runs like this: reintroduce still living species (and then megafauna), megafauna turn forests into grasslands (see what modern elephants do to trees), grasslands keep snow on the ground longer and contribute to a cooler climate.
The basic argument runs like this: reintroduce still living species (and then megafauna), megafauna turn forests into grasslands (see what modern elephants do to trees), grasslands keep snow on the ground longer and contribute to a cooler climate.