Which expert forums are focussed on sustainability ?

Hi Abhishek, I don't know of any expert network that is explicitly focused on sustainability topics. However, I can imagine that sustainability topics are increasingly popular for research.

I would recommend you to check out the Expert Network Directory to find firms that allow you to sign up as an expert. This may increase your likelihood of being recruited for a project. You might also like this set of Advice for Experts in Expert Networks here. I hope this helps!