"Human-induced climate and hydrologic change is likely to make many parts of the world uninhabitable, or at least uneconomic," writes Jeffrey Sachs, director of the Earth Institute at Columbia University in New York, in the current online issue of Scientific American. As a result, he says, "Over the course of a few decades, if not sooner, hundreds of millions of people may be compelled to relocate because of environmental pressures."
Rising sea levels, stronger cyclones, the loss of soil moisture, more intense precipitation and flooding, droughts, melting glaciers, and changing snow-melt patterns are among the problems humanity will face, says Dr. Sachs. He warns:
"Combined with the human-induced depletion of groundwater sources by pumping, and the extensive pollution of rivers and lakes, mass migrations may be unavoidable."
The Christian Aid agency predicts that by 2050 global warming could displace as many as 1 billion people.
"All around the world, predictable patterns are going to result in very long-term and very immediate changes in the ability of people to earn their livelihoods," Michele Klein Solomon of the International Organization of Migration told Reuters. "It's pretty overwhelming to see what we might be facing in the next 50 years. And it's starting now."
Forced migration linked to climate change is part of a larger problem: refugees due to floods, famine, and other environmental conditions. In 2002, the United Nations estimated that there were about 24 million environmental refugees.
By 2010, about 50 million people will have migrated for environmental reasons, according to a 2005 study by Norman Myers, a professor of environmental science at Duke University in Durham, N.C., the Associated Press reported recently.
Thomas Downing, director of the Stockholm Environment Institute, told French news service AFP: "There is going to be a lot of population movement linked to climate. ... Not all will be permanent refugees, but when you add climate to other forces that push people beyond the capacity to cope, the numbers will increase."
While concern is rising for low-lying island nations and sub-Saharan countries especially vulnerable to drought, some experts say climate-caused forced migration already has happened on a large scale in North America – in the aftermath of hurricane Katrina along the Gulf Coast.
Lester Brown of the Earth Policy Institute points out that the 2005 hurricane "forced a million people from the [city] of New Orleans and other small towns on the Mississippi and Louisiana coasts in the United States to move inland, either within states or neighboring states, such as Texas and Arkansas," according to an article in Sri Lanka's The Sunday Times.
But the largest numbers of those forced to move by climate change are likely to be in developing countries, especially those threatened by desertification, AFP reported this week after the United Nations' annual World Day to Combat Desertification on June 17."By 2025, Africa could lose as much as two-thirds of its arable land compared with 1990, and there could be declines of one-third in Asia and one-fifth in South America. Migration – from the Sahelian regions to the West African coast, from sub-Saharan Africa to Europe, from Mexico to the United States – will be an inevitable consequence as poor people are driven off their land."
Among the most threatened are people in Bangladesh, reports the Chicago Tribune. Writes Tribune foreign correspondent Laurie Goering:"Bangladesh is hardly the only low-lying nation facing tough times as the world warms. But scientists say it in many ways represents climate change's 'perfect storm' of challenges because it is extremely poor, extremely populated, and extremely susceptible.... The extent of Bangladesh's coming problem is evident in Antarpara, a village stuck between the Jamuna and Bangali rivers five hours northwest of Dhaka, the capital. In it and other low-lying villages nearby, more than half of the 3,300 families have lost their land to worsening river erosion. Some have moved their homes a dozen times and are running out of places to flee."
Meanwhile, according to a report on the People & the Planet website, "climate refugees are already fleeing from the catastrophic rise in sea levels" in the Ganges River delta of India. According to Sugata Hazra, director of Jadavpur University's school of oceanographic studies, over 70,000 people will be rendered homeless in the next 13 years due to the rising seas.
By contrast, officials in Israel worry that climate change will mean less water for them. Warns Gidon Bromberg, director of the Israeli office of Friends of the Earth – Middle East, on the website of The Jewish Chronicle of Pittsburgh:
"There will be less water available for Israel, but there will also be less water available for Israel's neighbors, and that will make [compliance with] existing peace treaty commitments more difficult between Israel and Jordan. ... And it makes difficult future agreements to be struck between Israel and the Palestinian Authority, between Israel and Syria, and between Israel and Lebanon."
Thousands of people have died or been driven from their homes in the Darfur region of Sudan, says UN Secretary-General Ban Ki Moon in a recent column in The Washington Post. Mr. Ban sees a direct link between social and political unrest in Darfur and its roots in an ecological crisis, at least partly attributable to climate change. Ban writes:"Two decades ago, the rains in southern Sudan began to fail. ... Scientists at first considered this to be an unfortunate quirk of nature. But subsequent investigation found that it coincided with a rise in temperatures of the Indian Ocean, disrupting seasonal monsoons. This suggests that the drying of sub-Saharan Africa derives, to some degree, from man-made global warming."
Similarly, political instability resulting from climate-caused forced migration is becoming a major concern among senior military officers, reports the International Herald Tribune . In a recent report, retired senior officers warned that in the next 30 to 40 years, wars could be fought over water resources, hunger instability from worsening disease and rising sea levels, and refugees fleeing other effects of global warming.
"The chaos that results can be an incubator of civil strife, genocide and the growth of terrorism," the 35-page report predicted. "We will pay for this one way or another," wrote retired Marine Corps Gen. Anthony Zinni, former commander of US forces in the Middle East, Central Asia, and the Horn of Africa. "We will pay to reduce greenhouse-gas emissions today, and we'll have to take an economic hit of some kind. Or we will pay the price later in military terms, and that will involve human lives."