IPCC Climate Change Data: CGCM1 B2a Model: 2050 Radiation

The first version of the Canadian Global Coupled Model,
CGCM1, and its control climate are described by Flato et al.
(1999). The atmospheric component of the model is essentially
GCMII described by McFarlane et al. (1992). It is a spectral
model with triangular truncation at wave number 32 (yielding a
surface grid resolution of roughly 3.7 degrees x3.7 degrees )
and 10 vertical levels. The ocean component is based on the GFDL
MOM1.1 code and has a resolution of approximately 1.8 degrees
x1.8 degrees and 29 vertical levels. The model uses heat and
water flux adjustments obtained from uncoupled ocean and
atmosphere model runs (of 10 years and 4000 years duration
respectively), followed by an `adaption' procedure in which the
flux adjustment fields are modified by a 14 year integration of
the coupled model. A multi-century control simulation with the
coupled model has been performed using the present-day CO2
concentration to evaluate the stability of the coupled model's
climate, and to compare the modelled climate and its variability
to that observed. An ensemble of four transient climate change
simulations has been performed and is described in Boer et al.
(1999a; b). Three of these simulations use an effective
greenhouse gas forcing change corresponding to that observed
from 1850 to the present, and a forcing change corresponding to
an increase of CO2 at a rate of 1% per year (compounded)
thereafter until year 2100. The direct forcing effect of
sulphate aerosols is also included by increasing the surface
albedo (as in Reader and Boer, 1999) based on loadings from the
sulphur cycle model of Langner and Rodhe (1991). The fourth
simulation considers the effect of greenhouse gas forcing only.
The change in climate predicted by a model clearly depends
directly on this specification of greenhouse gas (and aerosol)
forcing, and of course these are not well known. The
prescription described above is similar to the IPCC
"business as usual" scenario, and using a standard
scenario allows the results of this model to be compared to
those of other modelling groups around the world. Some initial
results from these simulations are presented below. The climate
sensitivity of CGCM1 is about 3.5 degrees C. From the IPCC website: The B2 world is one of increased
concern for environmental and social sustainability. Education
and welfare programs are widely pursued leading to reductions in
mortality and, to a lesser extent, fertility. The population
reaches about 10 billion people by 2100, consistent with both
the United Nations and IIASA median projections. Income per
capita grows at an intermediary rate to reach about US$12,000 by
2050. By 2100 the global economy might expand to reach some
US$250 trillion. International income differences decrease,
although not as rapidly as in scenarios of higher global
convergence (A1, B1). Local inequity is reduced considerably
through the development of stronger community support networks.
Generally high educational levels promote both development and
environmental protection. Indeed, environmental protection is
one of the few remaining truly international priorities.
However, strategies to address global environmental challenges
are less successful than in B1, as governments have difficulty
designing and implementing agreements that combine environmental
protection with mutual economic benefits. The B2 storyline
presents a particularly favorable climate for community
initiative and social innovation, especially in view of high
educational levels. Technological frontiers are pushed less than
in A1 and B1 and innovations are also regionally more
heterogeneous. Globally, investment in R& continues its
current declining trend, and mechanisms for international
diffusion of technology and know-how remain weaker than in
scenarios A1 and B1 (but higher than in scenario A2). Some
regions with rapid economic development and limited natural
resources place particular emphasis on technology development
and bilateral co-operation. Technical change is therefore
uneven. The energy intensity of GDP declines at about one
percent per year, in line with the average historical experience
of the last two centuries. Land-use management becomes better
integrated at the local level in the B2 world. Urban and
transport infrastructure is a particular focus of community
innovation, contributing to a low level of car dependence and
less urban sprawl. An emphasis on food self-reliance contributes
to a shift in dietary patterns towards local products, with
reduced meat consumption in countries with high population
densities. Energy systems differ from region to region,
depending on the availability of natural resources. The need to
use energy and other resources more efficiently spurs the
development of less carbon-intensive technology in some regions.
Environment policy cooperation at the regional level leads to
success in the management of some transboundary environmental
problems, such as acidification due to SO2, especially to
sustain regional self-reliance in agricultural production.
Regional cooperation also results in lower emissions of NOx and
VOCs, reducing the incidence of elevated tropospheric ozone
levels. Although globally the energy system remains
predominantly hydrocarbon-based to 2100, there is a gradual
transition away from the current share of fossil resources in
world energy supply, with a corresponding reduction in carbon
intensity. Data are available for the following periods:
1961-1990, 2010-2039; 2040-2069; and 2090-2099 Mean monthly and
change fields.