Science · Level 5 · 259 words
The Blanket of Air
Original passage © Team AM, written for Hone Literacy.
Earth stays warm enough for life because of a delicate balance played out in its atmosphere. Energy arrives from the Sun mostly as visible light, which passes easily through the air and warms the planet's surface. The warmed surface then radiates that energy back upward, but it does so as infrared heat, a longer wavelength that behaves differently. Certain gases in the atmosphere, including carbon dioxide, methane, and water vapor, are nearly transparent to incoming sunlight yet absorb outgoing infrared. They re-radiate some of that heat back toward the ground, slowing its escape into space. This natural trapping is the greenhouse effect, and without it the planet would freeze. The concern today is one of degree rather than direction. By burning fossil fuels, humans have raised the concentration of these heat-absorbing gases, thickening the blanket and pushing the balance toward a warmer state. Because the climate system responds slowly and unevenly, the full consequences of a change unfold over decades, long after the gases are released. The oceans, in particular, absorb a vast share of the extra heat and release it only gradually, acting like a sluggish flywheel that keeps turning after the engine is switched off. Understanding this lag is essential, for it means the warming already set in motion will continue even if emissions were to stop tomorrow. It also explains why the effects of choices made today, whether harmful or helpful, may not become fully visible until the people who made them are gone, a feature that makes the problem unusually hard for societies to confront.
Comprehension questions
1. Why does the passage say the warming would continue even if emissions stopped tomorrow?
- A Because the Sun is getting hotter
- B Because the climate system responds slowly, with a lag
- C Because the gases vanish instantly
- D Because sunlight cannot escape at all
Show answer
B. Because the climate system responds slowly, with a lag
The text explains the climate 'responds slowly and unevenly,' so warming already set in motion continues.
2. In this passage, gases described as 'transparent to incoming sunlight' means sunlight
- A is blocked by them
- B passes through them
- C is created by them
- D is reflected by them
Show answer
B. passes through them
Transparent to sunlight means light passes easily through, which the text contrasts with absorbing outgoing infrared.
3. The passage is mainly concerned with
- A how the greenhouse effect works and how humans are intensifying it
- B how the Sun produces light
- C why winters are cold
- D how plants absorb carbon dioxide
Show answer
A. how the greenhouse effect works and how humans are intensifying it
The passage explains the greenhouse effect and how burning fossil fuels thickens the blanket toward a warmer state.
Source: Written for Hone Literacy. Original passage © Team AM, written for Hone Literacy.