Burning fossil fuel to generate electricity is the largest source of carbon dioxide emissions in the United States. Carbon dioxide (CO2) and other gases can have a negative impact on the quality of the air, increase global temperature, lead to the loss of ecosystems, and potentially cause harm to human health. Incandescent bulbs emit 4500 pounds of CO2 per year. CFL bulbs, on the other hand, emit 1051 pounds per year. LED bulbs emit just 451 pounds per year. How many years would it take for CFL bulbs to emit as much CO2 as one year of incandescent bulbs? Round your answer to the nearest whole number.
