Listen to part of a lecture in an environmental science class. The professor is discussing the concept of 'albedo' and its role in climate change.
Professor: Today we're going to talk about albedo, which is a measure of how much sunlight a surface reflects. Surfaces with high albedo, like snow and ice, reflect most of the incoming solar radiation back into space. In contrast, surfaces with low albedo, such as dark oceans or forests, absorb more of that energy and convert it to heat. Now, here's the critical part: as global temperatures rise, we see a reduction in snow and ice cover. This exposes darker surfaces beneath, like soil or ocean water. These darker surfaces absorb more heat, which further raises temperatures, leading to even more melting. This creates a positive feedback loop, sometimes called the 'ice-albedo feedback.' This loop is a major concern because it can accelerate warming beyond what we might expect from greenhouse gas emissions alone. Understanding albedo is therefore essential for predicting future climate patterns.
❓ Question What is the main point the professor makes about the ice-albedo feedback?
A. A) It causes a cooling effect by reflecting more sunlight.
B. B) It is a process that slows down the rate of global warming.
C. C) It creates a self-reinforcing cycle that accelerates warming.
D. D) It only affects polar regions and has little impact elsewhere.
✅ Correct Answer
C) It creates a self-reinforcing cycle that accelerates warming.
TOEFL Listening Tips
Skim the questions first to predict the content
Watch for signal words in lectures and conversations (however, actually, in fact)
For main idea questions, focus on the beginning; for detail questions, focus on examples and data
For attitude questions, pay attention to the speaker's tone and word choice
Take notes on keywords; don't try to write down every word
