01/22/2015 01:10 pm ET Updated Mar 24, 2015

Climate-Induced Migration: A Looming Crisis

Climate change is an immense and multifaceted global challenge, likely to change the planet we call home and our very way of life. In some of the most industrialized settings in the world as well as in the most vulnerable areas, people may find they can no longer live in places they have called home for generations. Climate change causes many serious problems, including extreme weather disasters, the rise of sea levels, species extinction and environmental degradation. Each of these factors is expected to trigger large-scale migration. "We now know," said Mary Robinson, U.N. Special Envoy for Climate Change and former President of Ireland, "that climate change is a driver of migration, and is expected to increase the displacement of populations."

Although there are no exact predictions of migration induced by climate change, future forecasts vary from 25 million to 1 billion "environmental migrants" by 2050. These estimates are wide ranging because the links between climate change and migration are extremely complex and not always direct. It is extremely difficult to isolate climate-specific factors from general environmental challenges that result in migration. For example, climate change can exacerbate natural disasters such as tropical storms, which may also lead to secondary impacts such as landslides. But while sudden natural disasters are likely to result in mass displacement, more people are expected to migrate because of the slow deterioration of their local environment.

Currently, it appears that the most widely accepted estimate of climate change-induced migration is 200 million--far more than the combined populations of France and Germany and almost two-thirds of the entire U.S. population. According to the Nansen Initiative, a program launched by the governments of Switzerland and Norway, natural disasters displaced an estimated 144 million people between 2008 and 2012.

These numbers are staggering. Because climate change is expected to increase the frequency and intensity of weather-related disasters, the total number of climate change migrants will rise in the years ahead.

Just over a month ago, over 190 countries met in Lima and pledged that in a year's time they would reach a more concrete agreement, with specific goals and responsibilities, aimed at mitigating the impact of climate change and adapting to its consequences. A number of countries also pledged that during the period between the two conferences they would examine the links between climate change and human migration and displacement.

The United Nations Intergovernmental Panel on Climate Change has warned that failure to deal with climate change and its side effects will result in a number of circumstances influential to human migration. Yields for crops such as corn and maize will change due to increased temperatures and C02 levels, hurting farmers around the world and increasing food prices. Left unchecked, carbon emissions will put 177 million people at risk of regular flooding. According to The New York Times, about one person in 40 today lives in a place likely to be exposed to flooding by the end of the century.

While we will all feel the impacts of climate change, some regions of the world are more vulnerable and will be forced to deal with more acute migration issues. Sub-Saharan Africa, the Middle East, and South and Southeast Asia will be disproportionately affected. So are all nations at sea level. For example, some people from small island states in the Pacific Ocean, a low-lying area, are already seeking refuge in nearby New Zealand.

Bangladesh is one of the starkest examples of the challenges we face regarding climate induced migration. The country is home to the Ganges Delta, the world's largest delta, which is made up of 230 major rivers and streams. It's also home to 160 million people. The cyclones that already wreak havoc on the nation's inhabitants will increase in number and severity with rising temperatures. Salt water will make its way further inland with rising sea levels and destroy countless crops. By 2050, scientists estimate that rising sea level will displace 18 million people and cover 17 percent of the land.

Climate-induced food insecurity will also play a large role in migration. In addition to changes in crop yields and harvests, global fish populations will change, hurting fishing industries as well as people that depend largely on fish for food. Many species of fish are actually leaving their former tropical habitats because of warming water, and other species of fish are not coming to replace them.

Lack of clean drinking water could cause people to move. In the U.S., the Colorado River serves 30 million people in seven states and is nearly running dry. In the Andes Mountains, glaciers are melting so quickly that millions of people may lose a major source of fresh water by 2020. In Australia, water is so scarce they are building plants to remove salt from seawater. In Nigeria, conflict with the terror group Boko Haram may be caused in part by population movements following a West African drought 10 years ago.

Clearly, climate-induced migration -- within and between countries -- is a global problem that is likely to worsen in the future. It is a problem too vast for any one country to handle on its own. Nations are wrangling over many issues, including whether high-income nations, which have caused most of the emissions driving climate change, should compensate those countries that have not burned as much carbon and yet are victims of this global problem. These ecological justice issues will no doubt take time to sort through.

But certain basics are clear: The world needs to take collective action to mitigate -- and slow down -- climate change. These measures will require a significant change in the way that many people and societies, particularly in industrialized nations, lead their lives. In the context of migration, when solutions are drafted at the next UN Climate Summit in Paris in 2015, nations need to focus on the rights and lives of the migrants rather than on restricting movement. Migration will occur whether it is legal or not. After all, people may very well have no other choice but to leave their homes.

Some proactive policy approaches are available. Since we know what may lie ahead, we need to start enhancing global humanitarian capacities to deal with the mass displacement of populations due to climate-based disasters before they occur. If an area is expected to become uninhabitable, a relocation scheme can be implemented gradually, thus reducing the shock to migrants and host communities. Fiji, for example, a low lying Pacific Island state has already begun finalizing plans for relocation of the 646 communities that will be displaced by climate change. Of course, the question of how to finance such plans for larger populations remains to be discussed. In the case of a country like Bangladesh, what type of planning is necessary to relocate up to 18 million people?

There are clearly no easy answers and solutions when dealing with climate change.

As I look around Manhattan, I know things will change. The water will come closer. New York City may experience more frequent floods like the ones during Hurricane Sandy because of rising sea levels induced by climate change. We need to start planning for this eventuality, and we are lucky that, despite all the debate and wrangling, we are privileged to have the resources to tackle the problem. But what about the millions of people around the world who don't have our resources? Will we abandon them to disasters exacerbated by the emissions our lifestyle causes? I sincerely hope not.

Climate change is yet another reminder of how we live in a connected world -- interdependent and linked by a common ecosystem. As difficult as it may be, it is time to take responsibility for the consequences of our actions and to change our lifestyles. People's lives and homes hang in the balance.