Final answer:
Increasing the concentration of CO2 and decreasing the amount of water vapor would increase the greenhouse effect. CO2 and water vapor are potent greenhouse gases, while N2 does not significantly impact the effect, and CH4 is also a potent greenhouse gas that when reduced, lowers the effect.
Step-by-step explanation:
The greenhouse effect is a natural process that warms the Earth's surface. When the Sun's energy reaches the Earth's atmosphere, some of it is reflected back to space and the rest is absorbed and re-radiated by greenhouse gases. The absorption of this longwave radiation by greenhouse gases warms the atmosphere and the surface of the Earth. If the concentrations of these gases increase, the effect is enhanced, leading to more warming, which is known as the enhanced greenhouse effect.
Increasing the concentration of CO2 and decreasing the amount of water vapor would increase the greenhouse effect because CO2 and water vapor are potent greenhouse gases. Carbon dioxide traps heat by absorbing infrared radiation, and water vapor also has strong heat-trapping abilities. Conversely, increasing the number of N2 molecules would not significantly change the greenhouse effect as nitrogen does not absorb infrared radiation effectively. Decreasing the concentration of CH4 (methane) would actually reduce the greenhouse effect since methane is another potent greenhouse gas.
The approaches most effective in reducing the greenhouse effect include planting more trees and burning less fossil fuels. These actions can help decrease the concentrations of CO2 in the atmosphere.