Atmospheric carbon dioxide is the primary source of carbon in life on Earth and its concentration in Earth's pre-industrial atmosphere since late in the Precambrian was regulated by photosynthetic organisms and geological phenomena.
At about 55 km, the mesosphere begins. In the mesosphere, the temperature decreases with height again, because there is very little ozone to warm up the air. Finally, the mesopause divides the mesosphere from the thermosphere, which is the section of the atmosphere higher than 90 km. In this region, the temperature increases again. This time, it is molecular oxygen (O2) that causes the temperature increase.
The rate of change of air temperature with height is called the lapse rate. In the troposphere, the lapse rate is generally about 6.5 deg C per kilometer increase in altitude. The temperature can increase with height in the lower troposphere. When this happens, it is called an inversion. If the temperature remains the same with height, it is called isothermal. The actual lapse rate varies with location, time of day, weather conditions, season, etc.