By now, almost everybody has heard about the problem of global climate change. Earth’s climate is believed by most scientists to be getting warmer at a faster than usual rate.

That might mean you can go barefoot longer in the summer, and winter won’t be as cold as it sometimes is. But there are other, more serious possibilities, too. Perhaps the most dramatic of these is that warmer climate will cause the level of the oceans to rise, because the polar ice caps will melt and because when water is warmed, it expands in volume. This could have profound effects on communities close to the water, including big cities such as New York, San Francisco, Tokyo, Bombay, Bangkok, Cairo, and Rio de Janeiro.

There could be other important effects, as well:

Insects will love global warming. Corn earworm is one of them. (Texas A&M Entomology Laboratory).

• Insects and diseases that exist now only in the warmer parts of the world (especially in the zones north and south of the Equator known as the tropics) may expand their territory farther north and south of the Equator. Agricultural crops may suffer as the hungry invaders arrive. The corn earworm (see picture at left) is one example. It spends winters in the warmer southern United States, living as a pupa in the soil. With warming temperatures, it emerges and starts eating. The worm is known by many names: As the bollworm it eats cotton plants; as the tomato fruitworm it eats tomatoes, and as a headworm it eats sorghum. A study by the U.S. Department of Agriculture revealed that the worm can migrate great distances in a single night. With a warmer climate, the earworm will reach northern farms earlier in the season and be able to do more damage.

• Similarly, insects that carry diseases that affect human health, such as malaria and dengue, may move into areas where previously temperatures had been too low for them to survive.
  
  
• Some species that cannot readily adapt to a change in environment may become extinct.
  
  
• A change in global temperature could also cause unexpected alterations in world weather patterns, such as hurricanes and cyclones.
  
  
• As temperature rises, carbon trapped in frozen soils in Earth’s northern extremes may be freed to escape into the atmosphere.

What’s going on?
Why is this happening? There’s a lot of scientific research now under way to answer that question, and a simple, all-purpose answer isn’t in yet. But most study points to an alteration in the carbon cycle that was brought on by human activity.

For hundreds of years, the amount of the carbon in the atmosphere and the carbon elsewhere was in reasonable balance. Great quantities of carbon remained below ground, in soil and rock, left there by decaying prehistoric plants and animals. But with the Industrial Revolution of the eighteenth and nineteenth centuries, humans began releasing that carbon. Fossil fuels were burned as never before, releasing carbon dioxide into the atmosphere and into the oceans.

At the same time, millions of hectares of forested land were cut down — to clear space for agricultural crops, shopping centers, or places for humans to live — and that deforestation released carbon, too. It could be said, then, that this massive alteration in the carbon balance (or what some people call the “carbon budget”) was the product of population growth.

Hurricane Michael, as it neared the U.S. Middle Atlantic coast in October 2000. Boundaries of North Carolina, Virginia, and the Chesapeake Bay are added at left. Climate change could make such storms more frequent and less predictable. (Satellite image from SeaWiFS Project, NASA, and ORBIMAGE.)

What’s happening now, most scientists believe, is that our increased burning of fossil fuels and our increased clearing of forested land are releasing more carbon dioxide and other chemicals into the air, where the mixture remains trapped by the gaseous layer. The balance of the carbon cycle is being disturbed. The result is global warming.

Carbon dioxide is not the only “greenhouse gas,” as such substances are called. Others include water vapor, nitrous oxide, ozone, and methane. But carbon is by far the most important one. Carbon dioxide released into the atmosphere by burning fossil fuels can hang around for centuries, and it produces as much climate change as the other sources combined. After several years of debating about whether global climate change is actually happening, the world’s more influential governments are finally accepting the fact that harmful change is happening. They are starting to address the problem.

What does all this have to do with soil?
As we have seen, soil is the storage place for a great part of Earth’s carbon. If carbon can be retained in that soil, rather than released into the atmosphere, the rate of climate change ought to be slowed down. Earth’s temperatures should stay within the manageable range, and the rise in the world’s ocean levels should be less devastating.

As we shall see in these pages, a lot of the research that’s being done by soil scientists has to do with carbon. These scientists are trying to figure out where it is in the soil, how much there is of it, where it comes from, where it goes, and what people and their leaders can do to keep as much of Earth’s carbon in that soil, rather than allowing it to rise into the atmosphere and become part of the global climate change problem.

We might ask why we haven’t had that information at our fingertips all along. The answer is that we have always taken for granted the soil and the organisms and elements that reside within it. Like water and air, soil was “just there.” When we did study soil, it almost always concerned soil’s usefulness for growing crops. But now all that is changing. The soil sleuths are hard at work.