The world 's wildlife has declined by 27 percent since 1970 because of humans . `` No one can escape the impact of biodiversity loss because reduced global diversity translates quite clearly into fewer new medicines , greater vulnerability to natural disasters , and greater effects from global warming , '' said James Leape , director-general of WWF International . Comment: Terrestrial , freshwater , marine species all under threat . Pollution and overall climate change are other factors causing loss of wildlife .
The world 's wildlife has declined by 27 percent since 1970 because of humans . Comment: Terrestrial , freshwater , marine species all under threat . Pollution and overall climate change are other factors causing loss of wildlife .