Final answer:
Water vapor and CO₂ absorb and emit infrared energy, acting as a greenhouse blanket around Earth and keeping it warmer by trapping heat. This is a critical component of the natural greenhouse effect, which is intensified by human activities releasing more greenhouse gases into the atmosphere.
Step-by-step explanation:
Water vapor and CO₂ absorb and emit infrared energy and act as an insulating layer around Earth, keeping part of Earth's infrared radiation from escaping rapidly into space. This results in the Earth's surface and the lower atmosphere being much warmer than they would be without these gases. The major greenhouse gases, which include water vapor and carbon dioxide, play a crucial role in this process by absorbing and re-emitting infrared radiation. The presence of these gases is vital for maintaining the Earth's temperature, making it habitable.
The more CO₂ and other greenhouse gases like methane (CH4) there are in our atmosphere, the higher the temperature that the Earth's surface must reach to achieve a new balance of energy radiated to space with the energy received from the Sun. Conversely, the Earth would be significantly cooler without the greenhouse effect provided by these gases. The greenhouse effect is a natural phenomenon that is exacerbated by human activity, particularly the burning of fossil fuels which increases the concentrations of these gases and thus impacts global temperatures.