Without the greenhouse effect, Earth would be a cold, lifeless planet. Carbon dioxide and water vapor in the atmosphere absorb solar heat as it reradiates off Earth’s surface and keep the planet warm. The greenhouse effect, of course, also has a downside. Some researchers predict that in 60 years, global temperatures will rise by nearly 4 degrees Fahrenheit as the carbon dioxide concentration in the atmosphere doubles. Even worse, a new study says that the interaction of higher carbon dioxide levels with Earth’s vegetation could amplify global warming by as much as 50 percent.
How could plants worsen global warming? The culprits, says biologist Jim Collatz of nasa’s Goddard Space Flight Center, are the tiny pores called stomata on leaf surfaces. Stomata allow carbon dioxide to seep into leaves, where it is used in photosynthesis, and they also let water out. Normally, when the sun heats up a plant, water ...
