One of the main sources of conflict between environmental groups and corporations and even political institutions is climate change. There have been politicians who claim that climate change is inexistent, while science provides proof that it is fact. The interests of coal mining and timber corporations are most contrary to the enroironmentalist approach. Also, the palm oil industry has been said to damage the environment, as palm tree plantations are substituting the natural flora in many places. Agricultural bioengineering is equally destructive to the environment, as it reduces the diversity of species through the use of herbicides, and is also wreaking havoc among the bee population.