+200.000 additional inhabitants in Brussels by 2020. With or withouth Climate Refugees?

By 2020, some +200.000 additional inhabitants are expected in Brussels.  I wonder if the people estimating this number took into account some Global Climate Destabilization factor.  The 1 billion people living in permanent threat of a Climate Distater according to the moderate scenario for an average Global Warming lower than 2°C, are not going to just let themselves "die".  They're going to flee if possible.