Answer:
The greenhouse effect is a natural process that occurs when certain gases in the atmosphere trap heat from the sun, making the planet warmer. This effect is important for regulating the temperatures on Earth, allowing it to be habitable for life. However, human activities have increased the concentration of greenhouse gases in the atmosphere, leading to an enhanced greenhouse effect, which is causing global warming and climate change.
Two gases that contribute to the greenhouse effect are carbon dioxide (CO2) and methane (CH4).
From a planetary perspective, the greenhouse effect is neither good nor bad, but rather a natural phenomenon that helps to regulate the temperature of a planet. However, when the greenhouse effect is intensified due to increased greenhouse gas concentrations, it can have negative impacts on the planet's climate, ecosystems, and human societies.
Mars, Earth, and Venus provide some contrasts regarding the greenhouse effect. Mars has an extremely thin atmosphere, which contains only trace amounts of greenhouse gases. Therefore, it experiences a weak greenhouse effect, resulting in cold temperatures below freezing. On the other hand, Venus' thick atmosphere is composed mostly of carbon dioxide, which causes an intense greenhouse effect, heating the planet's surface to over 460℃, hot enough to melt lead. Earth's atmosphere contains moderate levels of greenhouse gases, which keep the planet's average temperature at a comfortable 15℃. However, human activities have increased the concentration of greenhouse gases, leading to an enhanced greenhouse effect, causing global warming and climate change.