Some points to note here-
1.This article was published with upcoming Paris climate agreement in head.Vast majority of these type of article with a lot of 'haunting' images usually come up just before or during a major climate conference.So you can tell these reports as agenda driven.
2.This article or any others on this matter states clearly, 20 million people are 'at risk' of becoming climate refugee,no one is claiming it will 'definitely' happen.So it means there are some mitigation measures which can be taken,It may come in various forms,like carbon emission reduction,helping poorer affected countries to become climate resilient,forming a global climate fund to built necessary infrastructure etc.
3.These 'haunting' pictures are related to river bank erosion or seasonal monsoon flood and resulting hardship of extreme poor people.This things are happening in this region for thousands of years.Even if any cameraman could go back 1000 years,they still would have found same images. So these images doesn't prove exclusively the climate change phenomenon.Some of them climate refugee 'yes' there were always climate refugee in Bangladesh for the reason of flood,river erosion,cyclone etc.Some move to cities to do other menial jobs and other get rehabilitated in other newly formed land formed by river sleet sedimentation.All these type of article confuse together river bank erosion,seasonal flooding and global warming/sea level rise to present their article in case of BD.
4.This professor himself is an global warming, anthropogenic climate change proponent.He doesn't deny coastal areas can get inundated due to sea level rise.What he says is about, mitigation measures for such eventuality.His seminar in Dhaka, titled 'Protection of Bangladesh coast from adverse effect of climate change: Things to do to save from tidal flow in monsoon'. So obviously he will talk about what Bangladesh can do in such circumstances,he is not a climate change denier or have any tie with BBS.Actually Bangladesh promote itself in international forum as a victim of climate change and BBS have no agenda to go its opposite direction.