The Max Plank Institute has constructed CO2 maps based in the original work of
Richard A. Houghton from The Woods Hole Research Center, 149 Woods Hole.
CO2 Data Set Appendix The Max Plank Institute has constructed CO2 maps based in the original work of Richard A. Houghton from The Woods Hole Research Center, 149 Woods Hole Road, Falmouth, Massachusetts 02540, U.S.A. The dataset we are using has been constructed in the following way (extract from the original source whihc can be found here http://www.mpimet.mpg.de/en/wissenschaft/land-im-erdsystem/wechselwirkungklima-biogeosphaere/landcover-change-emission-data.html): All maps have the same regular grid with a resolution of 0.5 degree. The regional land use change emissions of Houghton (2008) are scaled, so that the sum of the ten regions exactly equals the global emissions. Within each region the emissions are weighted with the population densities also used in Klein Goldewijk (2000), which are linearly interpolated between the years 1850, 1900, 1910, 1920, 1930, 1940, 1950, 1960, 1970, 1980, and 1990. After year 1990 population density is assumed to stay constant. Weighting fossil fuel emissions with population density is a common method (see e.g. Andres et al. 1996). Certainly, this approach is more problematic for landuse change emissions than for fossil fuel emissions, because in urban centers most of the land use change has already been done in former times. Therefore, the population density has been reduced to a maximum of 20 persons per km2 before constructing the second dataset (carbon_emissions_landuse_20person.nc). This is the only difference between the two datasets. It should be kept in mind that in reality there are considerable land use change emissions in areas with very low population density (e.g. tropical rainforests), which are not reflected in the datasets described here. Overall, the weighting of land use change emissions within continental scale regions by gridded population data has the advantage to exclude large emissions from some areas, where there had been indeed no substantial emissions in reality (e.g. subtropical deserts, high northern latitudes). Nevertheless, the approach is not suited to provide realistic land use change emissions on a local basis. Therefore, the datasets should only be applied in global simulation (e.g. for a comparison with atmospheric CO2 concentrations at remote marine stations) and not in regional models. As regards the original work from Richard A. Houghton, replicating partly the original source [..., this database provides estimates of regional and global net carbon fluxes, on a year-by-year basis from 1850 through 2005, resulting from changes in 1
land use (such as harvesting of forest products and clearing for agriculture), taking into account not only the initial removal and oxidation of the carbon in the vegetation, but also subsequent regrowth and changes in soil carbon. The net flux of carbon to the atmosphere from changes in land use from 1850 to 2005 was modeled as a function of documented land-use change and changes in aboveground and belowground carbon following changes in land use. Annual rates of land-use change (for example, conversion of forest to cropland) and per hectare changes in carbon stocks (vegetation, slash, wood products, and soils) as a result of changes in land use were used in a carbon accounting model to calculate the annual net flux of carbon between land and the atmosphere that results from land management. The net flux includes both emissions of carbon from deforestation and sinks of carbon in forests recovering from harvests or agricultural abandonment. Changes in land use included the expansion and contraction of croplands and pastures, plantation establishment, and harvest of wood. Carbon budgeting included only those ecosystems converted to other uses or harvested; unmanaged ecosystems were not considered. Further, rates of growth and decomposition were ecosystem specific and did not vary in response to variations in climatic factors, CO2 concentrations, or other elements of environmental change. The analyses were spatially aggregated. Two to six types of ecosystems, with average carbon stocks, were
considered
for
each
of
ten
world
http://cdiac.ornl.gov/trends/landuse/houghton/houghton.html.
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regions.]
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