Listen to part of a lecture in an environmental science class. The professor is discussing the concept of 'albedo' and its effects on climate. 'Albedo' is a measure of how much solar radiation is reflected by a surface. Light-colored surfaces, like snow and ice, have high albedo, meaning they reflect most of the sun's energy back into space. Dark surfaces, such as oceans or forests, have low albedo and absorb more heat. This absorption can lead to a warming effect. For example, when polar ice melts due to rising temperatures, it exposes darker ocean water, which absorbs more heat, causing further warming and more ice melt. This is called a positive feedback loop. Scientists study albedo using satellite data to understand how changes in land cover, like deforestation or urban expansion, affect regional and global temperatures. Interestingly, clouds also play a role, as they can both reflect sunlight and trap heat, depending on their type and altitude.
❓ Pregunta What is the main topic of the lecture?
A. The impact of deforestation on local climates
B. The concept of albedo and its role in climate change
C. Methods of measuring ocean temperatures using satellites
D. The importance of clouds in weather prediction
✅ Respuesta correcta
The concept of albedo and its role in climate change
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
