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| Titel |
Potential climate forcing of land use and land cover change |
| VerfasserIn |
D. S. Ward, N. M. Mahowald, S. Kloster |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 14, no. 23 ; Nr. 14, no. 23 (2014-12-03), S.12701-12724 |
| Datensatznummer |
250119204
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| Publikation (Nr.) |
 copernicus.org/acp-14-12701-2014.pdf |
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| Zusammenfassung |
| Pressure on land resources is expected to increase as global population
continues to climb and the world becomes more affluent, swelling the demand
for food. Changing climate may exert additional pressures on natural lands
as present-day productive regions may shift, or soil quality may degrade,
and the recent rise in demand for biofuels increases competition with edible
crops for arable land. Given these projected trends there is a need to
understand the global climate impacts of land use and land cover change
(LULCC). Here we quantify the climate impacts of global LULCC in terms of
modifications to the balance between incoming and outgoing radiation at the
top of the atmosphere (radiative forcing, RF) that are caused by changes in
long-lived and short-lived greenhouse gas concentrations, aerosol effects,
and land surface albedo. We attribute historical changes in terrestrial
carbon storage, global fire emissions, secondary organic aerosol emissions,
and surface albedo to LULCC using simulations with the Community Land Model
version 3.5. These LULCC emissions are combined with estimates of
agricultural emissions of important trace gases and mineral dust in two sets
of Community Atmosphere Model simulations to calculate the RF of changes in
atmospheric chemistry and aerosol concentrations attributed to LULCC. With
all forcing agents considered together, we show that 40% (±16%)
of the present-day anthropogenic RF can be attributed to LULCC. Changes in
the emission of non-CO2 greenhouse gases and aerosols from LULCC
enhance the total LULCC RF by a factor of 2 to 3 with respect to the LULCC
RF from CO2 alone. This enhancement factor also applies to projected
LULCC RF, which we compute for four future scenarios associated with the
Representative Concentration Pathways. We attribute total RFs between 0.9 and
1.9 W m−2 to LULCC for the year 2100 (relative to a pre-industrial
state). To place an upper bound on the potential of LULCC to alter the
global radiation budget, we include a fifth scenario in which all arable land
is cultivated by 2100. This theoretical extreme case leads to a LULCC RF of
3.9 W m−2 (±0.9 W m−2), suggesting that not only energy
policy but also land policy is necessary to minimize future increases in RF and
associated climate changes. |
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