what is the primary cause for loss of biodiversity on earth?
Global warming is also becoming a major cause for loss of biodiversity. For example if the present rate of global warming continues, coral reefs which are biodiversity hotspots will disappear in 20-40 years. 10% of all species might become extinct by 2015, if global warming continues.
The source document for this Digest states: Biodiversity change is caused by a range of drivers. A driver is any natural or human-induced factor that directly or indirectly causes a change in an ecosystem. A direct driver unequivocally influences ecosystem processes. An indirect driver operates more diffusely, by altering one or more direct drivers. Important direct drivers affecting biodiversity are habitat change, climate change, invasive species, overexploitation, and pollution (CF4, C3, C4.3, S7). No single measure or indicator represents the totality of the various drivers.