Question

which of these processes has a cooling effect on earth?
a. rising carbon dioxide levels fuel the growth of algae and plants, which increases carbon dioxide absorption.
b. burning fossil fuels increases the concentration of greenhouse gases in the atmosphere.
c. when permafrost melts, methane is released into the atmosphere.
d. as snow and ice melt, the underlying surfaces absorb heat from solar radiation.

Explanation:

• Option A: Rising carbon dioxide levels fueling plant growth (which increases carbon dioxide absorption) can have a cooling effect. Plants and algae use carbon dioxide in photosynthesis. More carbon dioxide absorption can potentially offset some of the warming effects (though this is a complex interaction and not a simple one - way cooling).
• Option B: Burning fossil fuels increases greenhouse gas concentration. Greenhouse gases (like carbon dioxide from fossil - fuel burning) trap heat in the atmosphere, leading to a warming effect, not a cooling one.
• Option C: When permafrost melts, methane (a potent greenhouse gas) is released. Methane traps heat more effectively than carbon dioxide in the short - term, so this has a warming effect.
• Option D: As snow and ice melt, the underlying surfaces (which are usually darker, like soil or water) absorb more heat from solar radiation. This is known as the albedo effect (where snow and ice have a high albedo - reflect more sunlight, and darker surfaces have a low albedo - absorb more sunlight), and it leads to a warming effect.

Answer:

A. Rising carbon dioxide levels fuel the growth of algae and plants, which increases carbon dioxide absorption.