Final answer:
The phenomenon where longwave radiation is trapped by greenhouse gases in the atmosphere, causing the Earth's surface to heat up, is known as the Greenhouse Effect. Greenhouse gases absorb and re-emit infrared radiation, which increases Earth's surface temperature, and enhanced greenhouse gas concentrations can lead to global warming.
Step-by-step explanation:
The term used to describe the phenomenon where longwave (LW) radiation is bounced back and forth between the atmosphere and the ground, leading to the heating of the atmosphere from the ground up, is known as the Greenhouse Effect. This effect occurs when the Earth's atmosphere, similar to the glass of a greenhouse, allows visible radiation from the Sun to enter and be absorbed by the Earth's surface, which then re-emits this energy as infrared radiation. However, gases in the atmosphere, such as carbon dioxide (CO2), water vapor (H2O), and methane (CH4), are able to absorb and re-emit this longwave radiation, trapping heat and keeping the Earth's surface temperature warmer than it would be without these greenhouse gases.
Increased concentrations of greenhouse gases are believed to enhance the greenhouse effect, leading to a rise in Earth's surface temperature, which is a central concern in discussions about global warming and climate change. Visible light from the sun passes through the atmosphere, but when it is absorbed and transformed into longwave infrared radiation, it cannot pass through these gases as easily, resulting in more heat being retained.