North America and Europe. With the extinction of large mammals like mastodons and mammoths, species whose numerous and invasive presence contributed to maintaining deforested grasslands are disappearing. This has resulted in a marked increase in forests at high latitudes, since there are no large mammals to knock down or damage young trees. Since grasslands keep the planet cooler than forests (because forests absorb solar heat better), the absence of mammoths and mastodons is not good news for global warming.
