Global warming, mass migration, and xenophobia

Kofi Annan writes:

Copenhagen needs to be the most ambitious international agreement ever negotiated. The alternative is mass starvation, mass migration and mass sickness.

Unlike starvation and sickness, migration away from abjectly poor areas where people cannot cope with climate and other hardships is something any rational person should welcome. What makes migration look bad is xenophobia. But Annan seems to take xenophobia for granted. For Annan, xenophobia is not worth discussing; only CO2 is.