globally, what is the major cause of famine? pests flood armed conflict ozone depletion drought

Drought and Climate ChangeĬlimate change increases the odds of worsening drought in many parts of the United States and the world. On the downside though, because CFCs remain in the atmosphere so long, the ozone layer will not fully repair itself until at least the middle of the 21st century.A drought is “a deficiency of precipitation over an extended period of time (usually a season or more), resulting in a water shortage.” Indicators of drought include precipitation, temperature, streamflow, ground and reservoir water levels, soil moisture, and snowpack. With great forethought, the developed world has phased out the use of CFCs in response to international agreements, like the Montreal Protocol, to protect the ozone layer. Of all of the causes of ozone depletion, the release of CFCs is thought to have accounted for 80% of all stratospheric ozone depletion. While naturally occurring chlorine has the same effect on the ozone layer, it has a shorter life span in the atmosphere.

The chlorine then reacts again with the oxygen molecules to destroy the ozone and the process repeats 100,000 times per molecule. The net result is that two molecules of ozone are replaced by three of molecular oxygen leaving. The chlorine reacts with oxygen which leads to the chemical process of destroying ozone molecules. This causes them to release free chlorine. Because of their relative stability, CFCs rise into the stratosphere where they are eventually broken down by ultraviolet (UV) rays from the Sun. This is what happens: CFCs do not fall back to Earth with rain, nor are they destroyed by other chemicals. All the while they are destroying ozone molecules. They take from 20 to 120 years to break down. CFC’s are man made chemicals that are very stable in the atmosphere. Both come from the breaking down of chloroflourocarbons(freons) by photons in the atmosphere.Ĭhloroflourocarbons(CFC) are the ”big dog” as far as causes of ozone depletion are concerned. There are many causes for ozone depletion, but the most important process in both trends is catalytic destruction of ozone by atomic chlorine and bromine.

This yearly occurrence is called the ozone hole. The other is a much larger, although seasonal loss of ozone over the polar regions. This has been happening constantly since the 1970’s. The first one has been a slow, but steady ozone depletion of 4% per decade of the Earth’s stratosphere(ozone layer). There are two different types of ozone depletion, both are very similar.

Globally, what is the major cause of famine? pests flood armed conflict ozone depletion drought