The Global Warmists are concerned about the destruction of wetlands. They say the wetlands contian a huge amount of carbon, that if released would be a "carbon bomb" destroying civilization.
Here is an article describing the situation:

http://www.news24.com/News24/Technology/News/0,,2-13-1443_2360769,00.html

The article says that 60% of the world's wetlands have already been destroyed. So, it appears that the "carbon bomb" has already gone off, without much effect. The "carbon bomb" concept assumes that CO2 will cause significant warming of earth. That has not happened, and there is no data that indicates it will happen.