Question

The greenhouse effect is caused by:

• A. Greenhouse gases in the lower atmosphere absorbing solar radiation
• B. Greenhouse gases in the lower atmosphere absorbing radiation from the Earth's surface, and preventing much of it escaping into space
• C. Too much heat in the atmosphere
• D. Too much sunshine reaching Earth

Answer 1

The correct option is B Greenhouse gases in the lower atmosphere absorbing radiation from the Earth's surface, and preventing much of it escaping into space

The greenhouse effect simply describes the fundamental role our atmosphere plays in sustaining life on Earth. Energy from the sun in the form of sunlight passes through our atmosphere and warms the surface of the Earth which then emits the energy back into the atmosphere in the form of infrared radiation. Greenhouse gases, which make up only about one per cent of the atmosphere, absorb and re-emit some of this heat, preventing much of it leaving the Earth's atmosphere. This keeps the blue planet at a comfy temperature to sustain life.
But over time, climate scientists argue, our atmosphere has accumulated more greenhouse gases, in particular carbon dioxide, methane, nitrous oxide and fluorocarbons. This increased concentration of atmospheric gases traps more heat close to the Earth's surface in the lower atmosphere and increases the average global temperature. This process, called the 'enhanced greenhouse effect', is fundamental to global warming.