Deforestation is driven mainly by the need of poor people to clear land for farming and by the often uncontrolled harvesting of timber— and this devours around thirteen million hectares (five million square miles) per year from the global area of forest. With the advent of world awareness about the environmental perils of clearing forest and of climate change, however, there has been a marked increase in the rate of tree planting and forest regeneration in recent years. The United Nations Environment Programme estimates that this has almost halved the net rate of forest loss to 7.3 million hectares (2.8 million square miles) per year.
Although this is tremendously heartening from the perspective of restoring forests, it also indicates that less new land will be converted from forest to agriculture than in the past— and that the necessity to protect the world’s remaining forests will conflict sharply with the notions of those who believe that clear- felling the Amazon, the Congo, and Siberia is the answer to the food challenge. In a world in which many people, rich and poor, are struggling to put back trees, razing vast areas of forest for farming is increasingly unacceptable— in terms of the environment and its species, the climate, and the billion people who depend on forests for their livelihoods. In 2008, for example, Norway offered Brazil $1 billion not to cut down more of the Amazon forest.21 This suggests strongly that in the twenty- first century we may have to look to other mea sures to obtain our food than to the ancient resort of plying the ax.
The Intergovernmental Panel on Climate Change (IPCC) expects sea level to rise by between 20 and 60 centimeters (8–24 inches) by the end of this century due to the effects of global warming. The effect of this on low- lying islands has been widely canvassed in the media and policy circles; less so the impact on the delta regions of the world’s great river systems, such as the Ganges, the Nile, the Mekong, the Irrawaddy, the Amazon, the Yellow, and so on. These deltas have some of the Earth’s richest and most productive soil, flushed out of river catchments over eons. They are also extremely low- lying, in many cases a meter or less above the hightide mark. The conservative scenario for climate change thus carries with it considerable added risk of the drowning and salinization of farmers’ fields in a number of food- critical regions due to sea- level rise directly, to the expected increase in storm frequency and ferocity, to increased flooding of rivers held back by the higher sea level, and to the intrusion of saltwater underneath farmland. For example, a sea- level rise of just forty centimeters (fifteen inches) in the Bay of Bengal— the midrange in the IPCC’s scenarios— would put 11 percent of its coastal land underwater, displace thirteen million climate refugees, and wipe out one- sixth of the Bangladeshi rice harvest. A fifty- centimeter (twenty- inch) sea- level rise would displace around fifty million people globally.
Toxic Soil
