Question

3. What are the current predictions for the number (or percentage) of species that will go extinct by 2100?

Answer 1

This a very abstract question, but it can be broken down into several components: amount of species that became extinct due to human intervention vs other or natural causes. I believe that we have either directly or indirectly contributed to the extinction of many species (compared to natural extinction, which we also have incomplete data on). Since 2100 is so far into the future, it is anyone's guess and I would like to believe that telling 90 years into the future is not a trivial task at all- pave the way for consciousness.

Also are you considering ALL species? like single-celled species, fungi, plants or just animals?

Here's a scientific blurb that basically says 'we don't know': http://www.unep-wcmc.org/uncertainty-in-predictions-of-extinction-risk-reply_317.html