While the United Nations climate change talks in Paris struggled to elicit credible commitments, notably missing from the debate was “environmental displacement” — people fleeing their homes on account of natural disasters. As temperatures and sea levels rise, and land-use patterns change, there will be significant consequences for human mobility within and across borders.

However, public and media debate scarcely discussed the issue, and the only references in the Paris summit’s negotiated outcome document are vague to the point of meaninglessness. This absence is especially striking in a year in which refugees and migration have otherwise been so high on the political agenda.

This political dissonance is of a piece with the compartmentalised way in which we approach many global issues. During a frenzied summer, media coverage and political attention focused almost exclusively on refugees. Now, with saturation point reached, the circus has moved on.

Climate change has, instead, become the de rigueur liberal issue of the day. Remarkably, the global focus on refugees was insufficient to influence the debate in Paris. When we shift our attention so dramatically, we risk missing important analytical connections and, with them, opportunities for meaningful solutions.

To be clear, the so-called European refugee crisis was certainly not caused by climate change. But it is symptomatic of a global protection crisis, with climate change as one key component. That crisis is partly the result of numbers: there are more people displaced around the world than at any time since the Second World War. It is partly the result of political will: asylum is being undermined by governments around the world. However, it is above all a reflection of a growing gap between the contemporary nature of displacement and the institutions that govern forced migration.

In the aftermath of the Second World War, governments created the 1951 Convention relating to the Status of Refugees. It ensures that states have a reciprocal obligation towards people fleeing a well-founded fear of persecution. This framework was well adapted to the refugee movements of the 20th century. It continues to be relevant, but it leaves gaps.

Climate change is one cause that falls outside the existing refugee framework. Sinking islands, desertification and flooding, for instance, can all require people to leave their homes. However, the relationship between environmental change and displacement is complex and multi-causal; shaped by other factors, most notably governance.

As Hurricane Katrina illustrated, in countries with strong governance such as the US, a natural disaster is unlikely to require people to cross borders. It is in countries with weaker governance and limited coping capacity that cross-border movements may take place. This was the case with people leaving Haiti for the Dominican Republic following the earthquake in 2010 and from Somalia to Kenya as a result of famine and drought in the Horn of Africa in 2011, for example.

So far the institutional response remains limited, though there are two embryonic frameworks. First, in December 2010, an earlier round of the UN climate negotiations created the first international legal recognition of the relationship between climate change and migration. However, the framework did not specify how to address the problem of people moving on account of climate change and has not been built upon in subsequent rounds of negotiations.

Second, in October 2015, came a government-led informal process called the Nansen Initiative. This launched a protection agenda, endorsed by 110 countries, though offered no governance framework to support international action.

In Paris, there was little progress. The issue has not been a priority for governments. A draft text proposed “a climate change displacement coordination facility”. But this was watered down in the negotiations, leaving only a vague statement about a “task force” to “develop recommendations for integrated approaches to avert, minimise and address displacement related to the adverse impacts of climate change”.

Standing back from these institutional discussions, it’s debatable whether the climate change negotiations are an adequate venue for addressing the underlying issue. The broader phenomenon is new displacement that falls outside the existing refugee framework but is not reducible to voluntary, economic migration. The huge challenge is how we should respond to the movements of vulnerable people who do not fit the institutional boxes.

With the exception of sinking islands, what drives much supposedly environmental displacement is its interaction with a range of other social, economic and political factors. What’s more, if what we care about is ensuring protection for the most vulnerable people, then what matters is not to privilege a particular cause of displacement but to identify a threshold of fundamental rights. When these are unavailable in the country of origin, border crossing has to be guaranteed as a last resort.

This wider challenge of how we think about new drivers of displacement can be found in the European refugee crisis. Nearly all Syrians would meet the 1951 standard of “persecution”. However, for many other nationalities the picture is more complex. Most are from refugee-producing countries, but not all would qualify for asylum. Yet this does not mean the residual category can be neatly subsumed under a label of “voluntary, economic migrants”.

Rather, a significant proportion of those fleeing countries such as Afghanistan or Iraq are fleeing a chronically fragile state, within which they are unable to secure the minimum conditions of human dignity. It is these types of movement for which the international community lacks an adequate conceptual or institutional response.

Part of the solution is about considering how we update and reform the global refugee regime. However, to respond to the 21st-century realities of people moving around the world also requires us to escape traditional silos. Policy responses cannot be found simply through European justice and home affairs policies. The root causes of displacement are inextricable from broader issues of the environment, development and security.

From the climate negotiations to the sustainable development goals to next year’s World Humanitarian Summit, human displacement should be an integral and ongoing part of the agenda. Responses to the needs of millions of vulnerable people should not depend not upon box-ticking. Instead, across international processes and branches of government, we need to see the connections and opportunities.

— Guardian News & Media Ltd

Alexander Betts is director of the Refugee Studies Centre at the University of Oxford. He is the author of Survival Migration: Failed Governance and the Crisis of Displacement.