Physics of the Future: How Science Will Shape Human Destiny and Our Daily Lives by the Year 2100

situation is that of Bangladesh, a country regularly flooded by storms even without global warming. Most of the country is flat and at sea level. Although it has made significant gains in the last few decades, it is still one of the poorest nations on earth, with one of the highest population densities. (It has a population of 161 million, comparable to that of Russia, but with 1/120 of the land area.) About 50 percent of the land area will be permanently flooded if sea levels rise by three feet. Natural calamities occur there almost every year, but in September 1998, the world witnessed in horror a preview of what may become commonplace. Massive flooding submerged two-thirds of the nation, leaving 30 million people homeless almost overnight; 1,000 were killed, and 6,000 miles of roads were destroyed. This was one of the worst natural disasters in modern history.
    Another country that would be devastated by a rise in sea level is Vietnam, where the Mekong Delta is particularly vulnerable. By midcentury, this country of 87 million people could face a collapse of its main food-growing area. Half the rice in Vietnam is grown in the Mekong Delta, home to 17 million people, and much of it will be flooded permanently by rising sea levels. According to the World Bank, 11 percent of the entire population would be displaced if sea levels rise by three feet by midcentury. The Mekong Delta will also be flooded with salt water, permanently destroying the fertile soil of the area. If millions are flooded out of their homes in Vietnam, many will flock to Ho Chi Minh City seeking refuge. But one-fourth of the city will also be underwater.
    In 2003 the Pentagon commissioned a study, done by the Global Business Network, that showed that, in a worst-case scenario, chaos could spread around the world due to global warming. As millions of refugees cross national borders, governments could lose all authority and collapse, so countries could descend into the nightmare of looting, rioting, and chaos. In this desperate situation, nations, when faced with the prospect of the influx of millions of desperate people, may resort to nuclear weapons.
    “ Envision Pakistan, India, and China —all armed with nuclear weapons—skirmishing at their borders over refugees, access to shared rivers, and arable land,” the report said. Peter Schwartz, founder of the Global Business Network and a principal author of the Pentagon study, confided to me the details of this scenario. He told me that the biggest hot spot would be the border between India and Bangladesh. In a major crisis in Bangladesh, up to 160 million people could be driven out of their homes, sparking one ofthe greatest migrations in human history. Tensions could rapidly rise as borders collapse, local governments are paralyzed, and mass rioting breaks out. Schwartz sees that nations may use nuclear weapons as a last resort.
    In a worst-case scenario, we could have a greenhouse effect that feeds on itself. For example, the melting of the tundra in the Arctic regions may release millions of tons of methane gas from rotting vegetation. Tundra covers nearly 9 million square miles of land in the Northern Hemisphere, containing vegetation frozen since the last Ice Age tens of thousands of years ago. This tundra contains more carbon dioxide and methane than the atmosphere, and this poses an enormous threat to the world’s weather. Methane gas, moreover, is a much deadlier greenhouse gas than carbon dioxide. It does not stay in the atmosphere as long, but it causes much more damage than carbon dioxide. The release of so much methane gas from the melting tundra could cause temperatures to rapidly rise, which will cause even more methane gas to be released, causing a runaway cycle of global warming.
    TECHNICAL FIXES
    The situation is dire, but we have not yet reached the point of no return. The problem of controlling greenhouse gases is actually largely economic and political, not technical. Carbon dioxide production coincides with economic activity, and hence wealth. For example, the United States generates roughly 25 percent of the world’s carbon dioxide. This is because the United States has roughly 25 percent of the world’s economic activity. And in 2009, China overtook the United States in creating greenhouse gases, mainly because of the explosive growth of its economy. This is the fundamental reason that nations are so reluctant to deal with global warming: it interferes with economic