Land use change in California, 2001-2100

The SLEUTH urbanization and land use change model was used to produce
century-long forecasts of California’s land uses to the year 2100. We
describe how data were assembled and conflated for the model, how the
model was applied to the very large and high resolution dataset, and how
calibration of the model was performed using a genetic algorithm. The
calibration results showed that the model accuracy was high, and suitable
for simulations, which used Monte Carlo methods to capture both future
land uses and their modeling uncertainty. The simulations showed the
amount and location of anticipated futures changes in land use, dominated
by changes to urban and a few other pairs of land use transitions. The
proportion of urban land was 6.7% in 2001, 8.8% in 2011, and is forecast
to reach 14.5% in 2050 and 17.6% in 2100, converting some 4,456,160
hectares of land. Farmland lost 224,135 Ha. between 2001 and 2011, but is
projected to lose another 1,346,912 Ha by 2100, a decline over the century
from 10.05% to 6.76% of the total land area. Of the 15 top land
transitions by land area, accounting for 88% of the expected change by
area from 2001-2100, only 6 of them are expected to be transitions to
urban, the remainder are combinations of changes among shrublands,
grassland and forest that will also have major consequences for
California’s future. The authors hope that the projections of land use
change will be of use to other scientists, land managers and policy
makers.