IPCC Climate Change Data: HADCM3 A1F Model: 2080 Minimum Temperature

The recent experiments performed at the Hadley Centre have
used the new Unified Model (Cullen, 1993). These experiments
represent a large step forward in the way climate change is
modelled by GCMs and raises new possibilities for scenario
construction. This experiment has overcome some of the major
difficulties that were associated with the previous generations
of equilibrium (circa IPCC 1990) and cold-start transient (circa
IPCC 1992) climate change experiments. HadCM2 has a spatial
resolution of 2.5 degrees x 3.75 degrees (latitude by longitude)
and the representation produces a grid box resolution of 96 x 73
grid cells. This produces a surface spatial resolution of about
417km x 278 km reducing to 295 x 278km at 45 degrees North and
South (comparable to a spectral resolution of T42). The
equilibrium climate sensitivity (DT2x) of HadCM2, that is the
global-mean temperature response to a doubling of effective CO2
concentration, is approximately 2.5 degrees C, although, this
quantity varies with the time-scale considered. This is somewhat
lower than most other GCMs (IPCC, 1992). In order to undertake a
'warm-start' experiment it is necessary to perturb the model
with a forcing from an early historical era, when the radiative
forcing was relatively small compared to the present. The Hadley
Centre started their experiments performed with HadCM2 with
forcing from the middle industrial era, about 1860 Mitchell et
al., 1995 and Johns et al., 1995. The greenhouse gas only
integrations, HadCM2GG, used the combined forcing of all the
greenhouse gases as an equivalent CO2 concentration. A further
series of integrations, HadCM2GS, used the combined equivalent
CO2 concentration plus the negative forcing from sulphate
aerosols. The HadCM2GG integrations simulated the change in
forcing of the climate system by greenhouse gases since the
early industrial period (taken by HadCM2 to be 1860). The
addition of the negative forcing effects of sulphate aerosols
represents the direct radiative forcing due to anthropogenic
sulphate aerosols by means of an increase in clear-sky surface
albedo proportional to the local sulphate loading (refer to
Mitchell et al., 1995 for details of this method). The indirect
effects of aerosols were not simulated. The modelled control
climate shows a negligible long term trend in surface air
temperature over the first 400 years. The trend is about +0.04
degrees C per century, which is comparable to other such
experiments. HadCM2CON represents an improvement over previous
generations of GCMs that have been used at the Hadley Centre
(Johns et al., 1995 and Airey et al., 1995). The experiments
performed have simulated the observed climate system using
estimated forcing perturbations since 1860. Johns et al., (1995)
and Mitchell et al., (1995) have established that HadCM2's
sensitivity is consistent with the real climate system. The
agreement between the observed global-mean temperature record
and that produced in these experiments is better for HadCM2GS
than for HadCM2GG. This implies that HadCM2Gs has captured the
observed signal of global-mean temperature changes better than
HadCM2GG for the recent 100-year record. The climate
sensitivity of HadCM2 is about 2.5 degrees C From the IPCC website: The A1 Family storyline is a case of
rapid and successful economic development, in which regional
averages of income per capita converge - current distinctions
between poor and rich countries eventually dissolve. In this
scenario family, demographic and economic trends are closely
linked, as affluence is correlated with long life and small
families (low mortality and low fertility). Global population
grows to some nine billion by 2050 and declines to about seven
billion by 2100. Average age increases, with the needs of
retired people met mainly through their accumulated savings in
private pension systems. The global economy expands at an
average annual rate of about three percent to 2100. This is
approximately the same as average global growth since 1850,
although the conditions that lead to a global economic in
productivity and per capita incomes are unparalleled in history.
Income per capita reaches about US$21,000 by 2050. While the
high average level of income per capita contributes to a great
improvement in the overall health and social conditions of the
majority of people, this world is not without its problems. In
particular, many communities could face some of the problems of
social exclusion encountered by the wealthiest countries in the
20th century and in many places income growth could come with
increased pressure on the global commons. Energy and mineral
resources are abundant in this scenario family because of rapid
technical progress, which both reduce the resources need to
produce a given level of output and increases the economically
recoverable reserves. Final energy intensity (energy use per
unit of GDP) decreases at an average annual rate of 1.3 percent.
With the rapid increase in income, dietary patterns shift
initially significantly towards increased consumption of meat
and dairy products, but may decrease subsequently with
increasing emphasis on health of an aging society. High incomes
also translate into high car ownership, sprawling
suburbanization and dense transport networks, nationally and
internationally. Land prices increase faster than income per
capita. These factors along with high wages result in a
considerable intensification of agriculture. Three scenario
groups are considered in A1 scenario family reflecting the
uncertainty in development of energy sources and conversion
technologies in this rapidly changing world. Near-term
investment decisions may introduce long-term irreversibilities
into the market, with lock-in to one technological configuration
or another. The A1B scenario group is based on a balanced mix of
energy sources and has an intermediate level of CO2 emissions,
but depending on the energy sources developed, emissions in the
variants cover a very wide range. In the fossil-fuel intensive
scenario group A1FI, emissions approach those of the A2
scenarios; conversely in scenario group A1T with low labor
productivity or of rapid progress in "post-fossil"
energy technologies, emissions are intermediate between those of
B1 and B2. These scenario variants have been introduced into
the A1 storyline because of its "high growth with high
tech" nature, where differences in alternative technology
developments translate into large differences in future GHG
emission levels Ecological resilience is assumed to be high in
this storyline. Environmental amenities are viewed in a
utilitarian way, based on their influence on the formal economy.
The concept of environmental quality might change in thisstoryline from"conservation" of nature to active
"management" - and marketing - of natural and
environmental services. Data are available for the following
periods: 1961-1990, 2010-2039; 2040-2069; and 2090-2099 Mean
monthly and change fields.