Listen to part of a lecture in an environmental science class. Professor: Today, we’re going to discuss a surprising factor in climate change: the role of forests. Now, most of you know that trees absorb carbon dioxide and release oxygen. That’s why they’re called the lungs of the Earth. But here’s a twist. Recent research shows that forests, especially those in northern latitudes, can also have a warming effect. How? Well, trees are dark. They absorb sunlight, which warms the surrounding air. In snowy regions, a forest canopy can reduce the reflectivity, or albedo, of the ground. Snow reflects sunlight back into space, but a dark forest absorbs it. So, in some cases, the net effect of planting trees in high latitudes might actually contribute to warming, not cooling. This doesn’t mean forests are bad. In the tropics, where there’s no snow, forests have a strong cooling effect. But it does mean we need to think carefully about where we plant trees for climate mitigation. Any questions?
❓ 题目 What is the main point the professor makes about forests?
A. Forests always cool the climate by absorbing carbon dioxide.
B. Forests can have a warming effect in snowy regions due to reduced albedo.
C. Planting trees in the tropics is ineffective for climate change.
D. Northern forests have no impact on global temperatures.
✅ 正确答案
Forests can have a warming effect in snowy regions due to reduced albedo.