Why should we be concerned that so much of our energy is coming from fossil fuels? First. the fossil fuel resource is limited in amount On a global scale, we will have some coal for a few centuries, but natural gas and oil will be in short supply in only a few decades 300 United States O100 Founded Pyramids Roman Middle Built Empire Ag 500040003000-2000-10000+1000+2000+3000+4000+5000 Years before and after present a relatively brief time in the 10,000 year period shown centered around the only Figure 1.2 The complete exploitation of the world s fossil fuels will spar presentWhy should we be concerned that so much of our energy is coming from fossil fuels? First, the fossil fuel resource is limited in amount. On a global scale, we will have some coal for a few centuries, but natural gas and oil will be in short supply in only a few decades. Figure 1.2 The complete exploitation of the world’s fossil fuels will span only a relatively brief time in the 10,000 year period shown centered around the present