31. Fragile - Since Earth has provided a home for all plants and animals for millions of years, it must be indestructible, right? Wrong! Carbon dioxide and other gases trap solar heat within our atmosphere and in the correct amounts make Earth livable. However, recent increases to the amounts of these gases released into our atmosphere threaten the balance our planet needs to provide all species sanctuary. This has resulted in rising arctic temperatures, which are melting the homes of polar bears and penguins, more catastrophic weather events which displace humans and animals, loss of arable land and other critical eco-systems, which threatens our food supply and habitat for countless plant and animal species.