The number of times heads comes up when you toss a coin, number of students present in class, number of times a person has attended therapy sessions-these are all discrete variables. To help see the difference between continuous and discrete variables, imagine a really tall mountain with a trail leading up to the top.
Climate changes resulting from greenhouse gas increases could also significantly affect water supply and demand. For example, a local increase in temperature of several degrees Celsius could decrease runoff in the Colorado River Basin by tens of percent (25, 48).
There is a natural greenhouse effect that keeps the Earth's climate warm and habitable. There is also the man-made greenhouse effect, which is the enhancement of Earth's natural greenhouse effect by the addition of greenhouse gases from the burning of fossil fuels (mainly petroleum, coal, and natural gas).bout 80-90% of the Earth's natural greenhouse effect is due to water vapor and clouds. Most of the rest is due to carbon dioxide, methane, and a few other minor gases.