As the use of fossil fuels has grown, so has the amount of
CO
2 entering the air. In 1980, burning fossil fuels released 18.5
billion metric tons of CO2. By 2006, more than 29 billion metric
tons was released. China burns a great deal of coal in power
plants. Between 1980 and 2006, China’s output of CO2 jumped
from 1.5 billion metric tons to 6.0 billion metric tons.
Biofuels and Global Warming
Because biofuels come from living things, they, too, contain
carbon. This presents a problem. When biofuels are burned,
is carbon released into the
atmosphere? If so, do biofuels
contribute to global warming?
Some scientists say no. They
believe that burning biofuels
instead of fossil fuels can actually
reduce the threat of global
warming. The explanation for this
is based on the carbon cycle.
Biofuel crops use CO
2 as they
grow. Biofuels release CO2 as they
burn. As long as people continue
to plant biofuel crops year after
year, some or all of the CO2 that
is released will be absorbed by
the growing plants. The result
is that less CO2 remains in the
atmosphere. The more CO2 that
biofuel crops absorb, the less stays
in the air to cause global warming.
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