We Are Carbon Based Life Forms Living On A Carbon Planet In A Carbon Cycle.
We are a carbon based life - the earth is carbon - and we cycle carbon. Even though there is much talk about global warming there seems to be little said about the Carbon Cycle.
CO2 falls to the earth because it is heavier than air and is photosynthesised into the planet - into trees and soil, into the oceans and rivers, but not ash felt and concrete. That's why cities are heat islands and trees and forests are cool. Carbon isn't always warming, in effect carbon plays a role cooling the planet since trees attract rain. Water is the thermoregulator.
Soil started out life covered with grasses and trees, but steadily land was cleared to make way for crops. The Industrial Revolution enabled great growth, populations exploded and industrial farming techniques shifted into high gear with ploughing and tilling on a massive scale... the unseen consequence brought on artificial fertilisers.
Ploughing exposed the soil (beneath the top soil) to the harsh elements, especially the sun - but at that time little was known about the microbial populations living just below the surface. In the race for food, farmers added artificial fertilisers and ploughed and tilled, tilled and ploughed adding more artificial fertilisers.
The resultant completely changed the cycle of soil and carbon.
Exposed soil decimated the microbial population - and without the billions of workers - systems broke down - billions upon billions of microbes died and soil released all its' stored carbon back into the atmosphere.
Note: a little known fact - soils have contributed nearly twice as much CO2 to global warming than all the power stations and cars put together. See PROF. RATTAN LAL
Due to the relentless effort to produce more and more food per acre, modern farming techniques slowly addicted soil to a man-made cocktail of artificial nutrients normally cultivated when soil is left fallow - ostensibly dispensing with the microbes, natures little workers. It became a vicious cycle resulting in the lowest nutrient rich soil in human history (which in turn effects human health), exemplified by the Great Dust Bowl storms of America.