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The
amount of carbon stored in croplands is the lowest of all land types
(with the
exception of deserts and semi deserts). Therefore, all land use change
to
cultivated land will result in a net emission of carbon. However, the
actual contribution
of land use change has a high uncertainty, but is estimated to be 5.9 -
2.9 Pg
CO2-eq. Land use change is mainly driven by economics and legislation,
but also
by the availability of land.
The main expansion of global croplands is thought to be over, though
expansion
into tropical forests continues to be a major problem. Global woodland
areas
are projected to decrease at an annual rate of ~43,000 km2, but
developed
countries are projected to increase their woodland area by 7,400 km2
per year. [1]
In this sector, the fundamental basis for GHG inventory estimates rests
upon
the fact that the flux of CO2 to or from the atmosphere is assumed to
be equal
to the changes in carbon stocks in existing biomass and soils, and that
changes
in carbon stocks can be estimated by first establishing rates of change
in land
use and the practices used, to bring about the change (e.g., burning,
clear
cutting and selective felling etc.). The IPCC approach involves four
estimates
of carbon stock changes due to; (a) changes in forest and other woody
biomass
stocks; (b) forest and grassland conversion; (c) uptake from
abandonment of
managed lands; and (d) emissions and removals from soils. [2]
The area under forests (including tree plantations) in India
was estimated to be 63.33 Mha in 1994. The forest area in India
is categorized into 22 strata according to the Forest Survey of India
(FSI). [3]
Changes in forest and other woody biomass stock, Forest
and grassland conversion, Uptake from abandonment of managed lands and
Emission
and removals from soils are the criteria which are used to measure how
GHG
emission increases with these activities. The emissions vary depending
on the
land use and the way land is managed. However, a quantified separation
of
intensive and extensive agriculture is difficult for a number of
reasons, a)
there are many complex interactions between different practices and
effects, b)
statistics on intensity of land use are rarely available (statistics
are
collected in a different form), and c) often, intensive and
non-intensive
farming practices are present on the same farm, making categorization
of farms
as intensive / non-intensive very difficult. For this reason, we focus
on the
individual practices known to influence GHG emissions to the
atmosphere, and where
possible we present information at the aggregated systems level to
examine the
impacts of intensive vs. non-intensive agriculture. [4]
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