If from the US asia is the continent that makes the most shoes for us
They big and pointy like really big and pointy
The main sources are humans which is why it is stated that the global warming is man made. The levels have increased beyond all measure, increasing since the 1950s by a 100 CO2 parts per million, and it keeps increasing by 2ppm on a yearly basis. The statistics from the industrial revolution era are not much different and show how much we've increased the CO2 in modern times.
Too much power in the central government
Crude oil simply because once used it gets exhausted
