You;re confusing adaption with evolution. There's no evidence that animals have ever adapted to climate change and the rate of extinction supports that. Animals and humans evolve but very slowly. Do you imagine that humans could evolve to withstand climate change? Or animals? There's no way, especially in the century or so we have left on Earth if we don't fix the problem.
Nobody said total destruction in 50 years, they said widespread destruction of habitat. Wars over arable land, water and food.