Why does Temperature Decrease with Increasing Altitude?

Answer: The temperature decreases with an increase in altitude because the atmosphere becomes less dense at higher elevations, resulting in fewer air molecules to absorb and retain heat, leading to a decrease in the overall temperature.

The decrease in temperature with increasing altitude is primarily due to changes in atmospheric pressure and density. As one ascends to higher altitudes, the air pressure decreases because there is less atmospheric mass above.

In the troposphere, which is the lowest layer of the Earth’s atmosphere where weather events occur, the temperature typically decreases by about 6.5 degrees Celsius per kilometer of altitude gained. This is known as the lapse rate. As air rises, it expands and cools adiabatically, meaning without gaining or losing heat.

Additionally, the decrease in air density at higher altitudes means that there are fewer air molecules to absorb and retain heat. The molecules in the air have more space between them, making it less effective at trapping and transferring heat. This phenomenon is why mountainous regions are often cooler than lowland areas, and why temperatures generally decrease with altitude in the Earth’s atmosphere.