In the Stern Report Sir Richard predicted mass migration occasioned by climate change, especially in sub-Saharan Africa. That other apparent causes have triggered this already does not mean that the millions he writes of will no longer arrive; merely that some have started earlier and that we have more to come.
Western Europe is rich, despite the efforts of bankers to cream off the wealth to the Caribbean and elsewhere. It is large and populous but by no means full, as some on the Right would have it. Of course, Western Europe is not the only part of the world to which refugees and others may direct their weary feet. Indeed the failure of some of our so-called allies to open their doors is a disgrace about which our lily-livered governing class fails to act repeatedly.
But others' failure does not exonerate UK from doing the right things: to be generous, reactive and humane, instead of grudging and politically strategic; to collaborate and even take a lead in collaboration in Europe, to make sensible policies for migration instead of looking the other way in a nationalistic and cost-counting funk. Doing things for others is a central tenet of any moral society - which Cameron claims UK to be under his watch. Let him prove it. Migration is here to stay so a permanent, strategic solution had better be developed for the good not only of refugees but of this country. Failure to do so will only mean more unnecessary death, the rise of xenophobic nationalism - and a popular backlash against it which may lead to social breakdown in this country too.