I’ve had the image of this lorry in my head since last week and I can’t get it out. I know I’m not the only one. Over the last few months, there have been many mass murders associated with people smuggling but this one seems to have seems to have seared itself into popular consciousness. It could be the disconnect between the cheery consumer advertising on the outside and the horror within. But I think it has more to do with the fact that this atrocity took place in Austria. Not on our doorstep (writing as a European), but well within our home.

The response to a huge rise in immigration to Europe has been pitiful. A fight between EU states over how many/few to let in. A doomed Hungarian attempt to literally create a Fortress Europe by building a wall to keep them out. And promises to crack down on the heartless criminals paid to provide a product whose end result is often misery, pain and death. A pledge highly reminiscent of the War on Drugs, one which Drugs has been winning for decades.

The largest proportion of the migrants have been identified as Syrians fleeing ISIS. That gets them labelled as refugees. Others are called economic migrants, presumed to be less deserving of our charity. Whatever you want to call them, expect them to keep coming. Because there’s a threat greater and more durable than islamic fundamentalism: the changing climate. So says the US Department of Defense.

Former Secretary Chuck Hagel stated in October 2014 that “Rising global temperatures, changing precipitation patterns, climbing sea levels and more extreme weather events will … likely lead to food and water shortages, pandemic disease, disputes over refugees and resources, and destruction by natural disasters in regions across the globe.”

The UN’s special rapporteur on migration, François Crépeau, has described ongoing global migration caused by climate change as “a certainty”. For the Pentagon it’s a “threat multiplier”. Barriers, policing and hard-right governments aren’t going to stem the tide or slow the swarm (choose your own dehumanising collective noun). So what will? A coherent response involving all European states is needed. Not simply a security arrangement but also an intelligent, holistic policy that takes into account the reasons behind this migratory shift.

Hagel  wrote that “politics or ideology must not get in the way of sound planning.” So far, there’s little evidence that anyone’s heeding his advice.