Climate change is causing some National parks in America to re-think their boundaries. As the earth warms many species try to move to cooler climates but national parks are rooted in one place. The Sequoia National Park in California runs mainly east-west but now plans are being formed to shift it to run north-south, allowing species that need cooler temperatures to thrive. But in an increasingly crowded world, and with climate change continuing to change the earth, can we protect our treasured areas? Monty Don explores how climate change, national parks, wildlife and people are sharing the earth.