From a report at NPR:
People who track killings of environmental activists say the numbers have risen dramatically in the last three years. Improved reporting may be one reason, they caution, but they also believe the rising death toll is a consequence of intensifying battles over dwindling supplies of natural resources, particularly in Latin America and Asia.
A report released Tuesday by the London-based Global Witness said more than 700 people -- more than one a week -- died in the decade ending 2011 "defending their human rights or the rights of others related to the environment, specifically land and forests." They were killed, the environmental investigation group says, during protests or investigations into mining, logging, intensive agriculture, hydropower dams, urban development and wildlife poaching.
The Global Witness report indicates that 106 activists were killed last year alone. In 2010, the figure was 96.