Accelerated warming is not inevitable, but changing our course requires mindfulness.
I recently explained to my son's elementary school class that I do research on soil. What, they wanted to know, was the difference between soil and dirt? After some discussion, we concluded that soil is where most land plants grow, and dirt is the stuff that makes moms mad when it gets on the carpet and under fingernails.
As my son gets older, I'll carry the lesson further and explain that soil is black because it contains carbon, and carbon is also something that we need to keep in the soil, rather than let loose in the atmosphere. Microbes that live in the soil eat the soil carbon, and they tend to eat faster when the soil is warmer. Already, global warming is causing microbes to decompose soil carbon more rapidly, thus releasing it into the atmosphere. Global warming feeds back upon itself by making soil microbes work faster, releasing more carbon dioxide into the atmosphere, and thus further accelerating global warming. The main culprit that has gotten global warming started is our seemingly insatiable burning of coal, oil, and natural gas, which releases carbon into the atmosphere.
Despite a few vocal holdouts, the debate about whether global warming is actually happening is essentially over. Just as the lingering scientific doubts about the health risks of smoking faded away in the 1970s, the global warming skeptics are fading fast now. Overwhelming evidence of melting glaciers and sea ice and early spring blooms and bird migrations has hit home for scientists and nonscientists alike. Topics addressed at scientific conventions now focus on how far and how fast global warming will go, and what the consequences will be for providing food, water, and shelter for humans and habitat for animals. And the release of soil carbon into the atmosphere is gaining even more attention because of its huge potential to accelerate the rate of global warming. More than twice as much carbon exists in soil as in the atmosphere or in living plants.