MEGA Elementary Education Multi-Content Practice Test

How do greenhouse gases primarily contribute to global warming?

1. Absorbing solar radiation and transferring it to Earth's surface

2. Increasing the rate of evaporation of the surface waters on Earth

3. Absorbing and trapping thermal radiation emitted from Earth's surface

4. Increasing the intensity of ultraviolet radiation hitting Earth's surface

The correct answer is: Absorbing and trapping thermal radiation emitted from Earth's surface

Greenhouse gases primarily contribute to global warming by absorbing and trapping thermal radiation emitted from Earth's surface. When solar energy reaches the Earth, a portion of it is absorbed and warms the planet. As the Earth's surface emits this absorbed energy back into the atmosphere as thermal radiation (heat), greenhouse gases, such as carbon dioxide, methane, and water vapor, absorb some of this radiation and re-radiate it in all directions, including back toward the surface. This process creates a warming effect known as the greenhouse effect, which is essential for maintaining the Earth's temperature and climate. The effectiveness of greenhouse gases in trapping heat is crucial in understanding how human activities, such as burning fossil fuels and deforestation, have led to increased concentrations of these gases in the atmosphere. As more greenhouse gases are released, they enhance this natural process, leading to a rise in global temperatures and contributing to climate change. The other options refer to processes that are either less directly related to the greenhouse effect or describe phenomena that do not accurately explain how greenhouse gases operate in the context of global warming. For example, while increased evaporation can influence climate, it is not the primary mechanism by which greenhouse gases trap heat. Similarly, the intensity of ultraviolet radiation is more related to ozone depletion than to greenhouse