The current refugee crisis is the most significant since the second world war. This discussion is loud and complex, and thin on facts. Here we present some conclusions drawn from visualizations of the most authoritative data, that of the UN High Commissioner for Refugees (UNHCR). Our purpose is to present a warts-and-all objective overview of refugees, the national security implications of refugees and the failings of the current international system.

Here, are five facts you might not have known.

1. We are legally and morally obliged to respond to refugees who need our assistance

The visualization in the video below shows a timelapse of refugee flows across West Africa over the last 10 years.

Each of these tens of thousands of colourful dots moving between countries represents a single refugee. It is easy to lose sight of the experience of individual refugees in the deluge of large numbers. Refugees by definition are people fleeing conflict and persecution and with no alternative but to leave their country. By definition they lose their homes and their livelihoods. Often they are separated from their families. In many cases they experience violence, discrimination and deprivation during their journey and even after it ends in exile.

2. The refugee ‘burden’, including any potential threat, falls disproportionately on poor countries, yet most of these poor countries have kept open their borders

The visualization below captures the large refugee flows to Europe over the last few years. It shows that Syria has been the epicentre of the world’s and Europe’s refugee crisis, and also highlights the enduring crisis in Afghanistan, and new crises across sub-Saharan Africa.

While record numbers of refugees have indeed entered Europe in recent years, the very significant majority of Syrian refugees remain in the neighbouring countries of Jordan, Lebanon and Turkey. Worldwide, over 80% of refugees are in poor, not rich, countries.

3. Where there is a link between refugees and terrorism, it is that refugees are fleeing terrorism, and not coming to host countries to perpetrate terrorism

This visualization overlays global refugee flows on timelapse maps of deaths around the world resulting from terrorism, based on data from the Global Terrorism Index. The definition of a refugee does not explicitly include terrorism as a reason to flee, and the data on display is not granular enough to allow us to demonstrate correlations. That said, overall the overlay shows refugee flows moving away from terrorism hotspots.

4. The number of people leaving their homes is likely to increase quite soon. What is needed are innovative responses, not closed borders

This visualization looks to the future, showing projected sea-level rises in response to global warming.

Most experts consider a reasonable prediction to be an increase in the average global temperature of 2 degrees Celsius by the end of this century, in which case we can see how much of Bangladesh (and Florida) will become submerged. Once again we hope to steer away from hyperbole, yet conclude that in all likelihood millions of people will leave their homes as a result of the effects of climate change in the coming 50-100 years. At the moment the international system is ill-quipped to cope.

5. The US is a leader on refugee resettlement, and if it falters others will too

There are numerous stories we can't tell from the visualizations. There is a quite large number of dots crossing the Atlantic Ocean from Africa and the Middle East to the US. These were refugees resettled by the American government. The US has consistently resettled more refugees than any other country in the world, and more countries need to follow its lead if we are to begin to resolve the global refugee crisis.