Negotiators from around the world held 10 days of talks in Montreal, Canada, on global warming. Environmental issues have triggered passionate protests and movements, and groups and individuals use a number of methods, including illegal means, to get their point across.
Demonstrators marched in the streets of Montreal at the climate conference to protest global warming, and support the Kyoto Protocol that aims to reduce the greenhouse gas emissions that are blamed for global warming.
But not all protesters are as peaceful. So-called eco-terrorists are blamed for causing tens of millions of dollars of damage in the United States by burning construction sites, torching gas-guzzling vehicles and defacing property.
The FBI announced recently the arrests of six people in four states in connection with so-called eco-terrorist attacks in the northwestern United States, in some cases that date back to the late 1990s.
Assistant U.S. Attorney Andrew Friedman says officials are investigating a number of deliberately set fires. "There are charges of committing serious property crimes causing a lot of property damage and endangering life and limb, so these are serious crimes."
Leslie James Pickering, former spokesman for the Earth Liberation Front, a radical group that has taken responsibility for a number of eco-attacks, said in 2002 the activists are trying to protect the environment. "You know, it's destruction of property and it's done in order to further the liberties and freedoms of the people here on Earth."
U.S. officials say eco-terrorists and animal activists have become the most active criminal extremists in the United States in recent years, and they take the threat seriously.
In Europe, environmental and animal activists have blocked roads and hindered traffic, staged mock crucifixions and carried out other graphic demonstrations to make their point.