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If we stopped using fossil fuels today
and millions of young trees were planted, the amount of CO2
in our planet’s atmosphere would be reduced, at least temporarily.
As they grow, trees and other plants extract and embody
carbon from the atmosphere
and thus reduce the amount of CO2 in the atmosphere.
But when plants die and decay or burn, the carbon they have embodied
is recombined with oxygen and released into the atmosphere as CO2.
A large percentage of atmospheric CO2 cycles through the biosphere
once every 20 to 30 years.1
Thus, if forests and other vegetation communities
are expanded permanently,
a permanent reduction of atmospheric CO2 would occur,
but only if the combustion of fossil fuels ends.
As plant communities become larger, they can store more carbon.
This storage can be more or less permanent
since the CO2 released by burning or decaying plants
will be absorbed by new growth.
However, if the use of fossil fuels continues,
the only way plants can be used
to reduce the buildup of CO2 in the atmosphere would be to harvest
them and store them in a place where they could not decay or burn.
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While photosynthesis is only one aspect of the carbon cycle,
it does illustrate the need to think through natural processes.
If we do this, we can better understand
whether a perceived solution is really going to be effective
or if we need a more comprehensive approach,
based on how our planet's life support system actually works.
Another way that this lack of whole planet or biospheric analysis
manifests is in how we focus on a problem.
Take the issue of increasing levels of atmospheric methane.
The media has made much of the fact that cattle
and other domestic ruminants are collectively releasing
large amounts of methane gas into the atmosphere
as part of their digestive processes.
Molecule for molecule methane gas is 20 to 30 times more effective
in trapping atmospheric heat as is CO2.2
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