Marxist groups using environmental concern as a tool to damage western civilization do not get my attention. In fact, as a general rule, I scoff at anyone who mentions the environment. Recycling? Pollution? Those concerns mostly go right past me -- because I find that the people who raise those concerns often don't give a rat's patootie about recycling or pollution.
After seeing Legend with Will Smith, it is conceivable to me that a mad eco-scientist would unleash a deadly virus to depopulate the earth in order to save it. Obviously the best place to spread a plague would be an international airport. It could be around the world in less than a day.
As the eco-zealots get more hysterical, it would be a good idea to keep an eye in them.