While some countries are historically responsible for climate change, should the global community take up responsibility for climate migrants, even if they do not cross international borders? Should there be immigration concessions for climate migrants when they need to or have to cross borders? These are important questions that arise at a time of 
global climate change.

It is important to first carefully ponder the character and probability of "climate migration" before we learn to cope with it. Is climate migration a new phenomenon? How large could it become? And most important, will climate events cause "en masse" local or regional migration?

Climate factors often cause local and global migration independently of the nature and severity of global climate change. In developing countries, drought has rendered large land masses non-arable or essentially unproductive, forcing people to move to cities where jobs are ever scarcer and food increasingly expensive. Emigration out of the country is then seen as the only viable solution. In this way, local climate problems have led to international migration.

Nevertheless, existing moderate climate-bound migration may be exaggerated and the severity and certainty of it, too soon to predict. It is too early to say with certainty that there will be massive consequences of global warming, for example, the oceans wiping out the small-island States and other lowlands. It is also premature to argue that this will result in unprecedented mass migrations.

The factors limiting mass migration have to do with the scope of global warming, as well as with the probability and manner of intercontinental mass emigration in a life-threatening situation.

It is improbable that there would be long-distance mass population movements even in a situation of systemic climate change. As seen today refugee camps and shelter villages are typically set up not far from the site of the calamity.

We can look for an analogy in the number of current wars and levels of human rights violations, compared with the number of refugees and migrants actually fleeing those situations. Comparing the quantity of asylum applicants to the number of people threatened by the twenty or more wars currently being waged in the world, we see that the number of victims is many times that of those who actually flee long distances. While current wars severely disrupt the lives of tens of millions of people, the European Union and the United States, for instance, receive asylum applications only in the hundreds of thousands every year. The number of long-distance migrants is much less than the actual number of victims.

Why do victims tend to stay near the site of the crisis? Why would long-distance mass migration not necessarily ensue in a climate created crisis? First, research has suggested that people whose livelihoods are most sensitive to environmental changes also tend to be those who do not have the means to move very far. They lack the information and the financial capacity to set out on long journeys; and even if they had access to information, they often cannot travel.

Second, victims do not automatically want to migrate. An increasingly accepted view treats emigration as an essentially voluntary decision, even in very compelling, life-threatening situations. Typically, the victim desires to stay as close to her homeland as possible rather than set out on a long-distance journey into the unknown. What attracts the highly skilled as well as the seasonal returning workers to the Western world may not apply among the often poor and weaker victims of crises.

A third reason why climate migrants may not seek shelter, for instance, in the industrialized North is the following: Although sea levels may rise by one metre, and drylands with up to two billion inhabitants may become too dry, it is also true that many uninhabitable areas today, for example in northern, northwestern and western China, or the northern Russian Federation, may become fertile. Many Asians might prefer to remain in the Eastern Hemisphere than migrate to distant destinations in Europe and the United States. Hence, new routes of migration may form between and within developing countries, replacing in part traditional migratory routes.

A fourth reason that would probably impede acute, permanent, long-distance mass migration is that global warming, if it is indeed occurring, will take place at a snail's pace. Even in the worst-case scenarios, sea levels are projected to rise at a maximum of tens of centimetres a year. People have accommodated to much more serious and acute incidents without resorting to non-returning, long-distance migration.

Even if the crisis was a sudden, powerful and all-pervasive one, such as Hurricane Katrina in New Orleans or the tsunami in Asia, people would only have a minimum incentive to migrate permanently to a distant destination. They would rather stay as close to their homes and return as soon as possible. How could slow and long-term climate change, be expected to cause rapid mass global migration when acute full-scale crises have not resulted in that?
Let us look at future scenarios, drawing connections between two questions: Is climate change a local or a spacially szstemic phenomenon? Will the ensuring migration be global and long-term, or short-distance and returning?

Of the four permutations of the above scenarios, the least probable pair is that climate problems are at least de facto systemic and that its consequent migration will be global and long-term. Climate change indications hardly become systemic but remain local, because the populations are able to anticipate them and prepare accordingly. Only relatively small areas of coastal land would most likely be affected, and if the areas were larger, the inhabitants would have a longer time to adjust. The time scale is one of years, or months, in the most extreme scenarios. If more acute cases should occur, people would tend to move to nearby areas, and return when the situation allows. In any case, any permanent movement would occur to the nearest destinations possible, possibly even to areas made recently inhabitable or fertile by the environmental change.

Even in a purely systemic climate change with considerable sea level rises occurring rapidly, e.g. over months or years, and large crop-failures in one very season, migration would still remain local. People of Nauru would most likely move to the Pitcairns. People of the Maldives would seek for land in southern India. In Africa, acute and massive droughts might cause internal displacements, with some migratory streams reaching the Mediterranean. All in all, wiped out lowlands would be replaced by finding new, fertile agriland in higher, formerly harsh altitudes.

However, the most probable scenario would see only localized indications of climate change. Some of these conditions have existed in the past and some might be due to global warming. However, the effects would in any case be slow, with the resultant migration occurring gradually over months and years. Migration would stay within the nearby region, and migrants would return.

Finally, we can return to the question posed at the beginning of the essay: While some countries are historically responsible for climate change, should the global community take up responsibility for climate migrants, even if they do not cross international borders? Based on the above scenarios, it is probable that most migration would remain local or regional. It is imperative that in order for the concerned region and country to cope, the international community should assist in the initial phase of relocation by providing the necessary requirements for a smooth transition.

This means stronger resources for the Office of the United Nations High Commissioner for Refugees, for example, in acute situations, and measures to integrate the migrants with the local population. Due to the quality of the migrations, it is less probable to see acute and full-scale crises but, rather, slower and more orderly movements. In the long run, one could even remain optimistic about the success of the transition. Over time, migrants would make their own way and accommodate themselves elsewhere, and many would want and even be able to return to their countries of origin should conditions allow.

How about immigration concessions for climate migrants? These would be slow and not necessarily related to acute climatic crises. We could talk about "forced migration", similar to that of persecution-related refugees. But the idea of persecution-related forced migration -- a refugee status -- denotes a "no way out" scenario, ie, one cannot resort to the authorities or flee internally. In climate-based migration, particularly if the change has been slow, the population would most probably accommodate voluntarily. If, however, there is a volcanic eruption, an earthquake or a tsunami, and the event essentially causes a climate change, some legal measure is called for to consider such victims as "forced migrants", comparable to Geneva Convention refugees. It is more difficult, however, to think of sea-level rise by ten centimetres per year as acute "force".

In conclusion, one ought not to overstate the scale of the migrations that might occur due to possible global climate changes. The speed and scope of climate change, as well as the human ability to adapt, make forced, acute, climate-induced mass migration improbable. Some surges may be seen, but also managed with good preparation and research into questions such as: Which parts of the globe have the highest population densities and are simultaneously at the greatest risk of a climatic crisis? Which nearby areas could serve as temporary havens for potential climate refugees? Which circumstances, formerly harsh, would turn lucrative? What would be the best measures the global community could take to facilitate the movement of climate migrants? Finally, what legal measures could strengthen the status of a single migrant who has been forced to leave his homeland because of climate change?