Listen to part of a lecture in an environmental science class.
Today we're going to discuss a surprising factor in climate change: the role of forests. While we often hear that trees absorb carbon dioxide, recent research has shown that forests, especially those in northern latitudes, can actually have a warming effect. How? Well, forests are dark, so they absorb more sunlight than, say, snowy plains or grasslands, which reflect light. This absorption of sunlight warms the local area. In addition, trees release moisture and certain chemicals that can form clouds, but these effects are complex. In tropical forests, the cooling effect from moisture and cloud cover outweighs the warming from darkness. But in boreal forests, where snow is common, the dark trees can make the local climate warmer by reducing the reflection of sunlight. So, when we think about planting trees to combat climate change, we need to consider the location and the net effect on temperature. This is a key lesson for policymakers.
❓ 题目 What is the main point the professor makes about forests and climate?
A. A. All forests help cool the climate by absorbing carbon dioxide.
B. B. The effect of forests on temperature depends on their location and other factors.
C. C. Boreal forests are more effective at cooling than tropical forests.
D. D. Planting trees always reduces global warming.
✅ 正确答案
B. The effect of forests on temperature depends on their location and other factors.