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The IPCC SRES scenarios contain various driving forces of climate change, including population growth and socio-economic development (figure 3). These drivers encompass various future scenarios that might influence greenhouse gas (GHG) sources and sinks, such as the energy system and land use change. The evolution of driving forces underlying climate change is uncertain. This results in a very wide range of possible emissions paths of greenhouse gases.
Figure 3: integrated framework of climate change by IPCC
Population
Population growth is determined by fertility and mortality rates. Global
population projections range from 7,1 to 15 billion people by 2100 across the
scenarios, depending on the rate and extent of the demographic
transition. Figure 4 shows that population growth is strongest in
the regional and material scenario (A2) for 1992 results.
Regionalization causes more population growth than does globalization.
Economic growth
Economic development is expressed in GNP (Gross
National Product). The SRES scenarios span a wide range of future
levels of economic activity. The highest overall prediction is for the
A1 scenario; an estimated GNP of US$529 trillion (1990 US dollars) in
2100. The
lowest overall prediction is for the B2 scenario; an estimated GNP of
US$235 trillion in 2100. This means that globalization combined with an
emphasis on wealth would generate the highest economic growth. This is
mainly because population growth is lower in a global scenario, causing a
narrower division of the GNP. The emphasis on wealth rather than on
sustainability also increases the
GNP.
It is estimated that the future income gap between developed and
developing countries will be smaller than was initially estimated in the
IS92 scenarios.
Figure 4: population growth according to the SRES scenario's of 1992
Energy system
The impact of future energy use will largely depend on the fuel type. Both
global scenarios depict a transition towards more non-fossil fuel sources.
In the regional sustainable scenario the transition towards non-fossil
fuel sources is much more gradual. The regional wealth scenario marks a
stark transition back to fossil fuels. In all scenarios the share of oil
and gas declines and more coal will be used for energy generation in the
future.
Land use change
There are many different land use types. The main land use types that are
considered by the IPCC are forests, arable land and grassland. Land use
change is largely related to demands for food by a growing population
and changing diets.
Currently there is a lot of deforestation. In most SRES scenarios, the
current trend of deforestation is eventually reversed because of slower
population growth and increased agricultural productivity. Reversals of
deforestation trends are strongest in the globalized scenarios. In the
globalized sustainable scenario pasture lands decrease significantly
because of increased productivity in livestock management and dietary
shifts away from meat.
References IPCC scenario presentations
à
http://www.ipcc.ch/present/graphics.htm IPCC SRES technical summary
à
http://www.grida.no/climate/ipcc/emission/015.htm RIVM, the Netherlands
à
file:///D:/Data/Temporary%20Internet20Files/Content.IE5/K5W3OJCV/IMAGE_model%5B1%5D.ppt Summary of the 1996 SRES report
à
http://www.grida.no/climate/ipcc/emission/014.htm
Related pages
Fossil fuels: characteristics and effects The greenhouse effect
mechanism Emissions and infrared
absorption by greenhouse gases
Explanation of the IPCC SRES scenarios
The IPCC SRES scenarios:
consequences of climate change
Overview of emission reductions for each country according to Kyoto
Possible policy measures to achieve Kyoto
targets
Trading emission permits to
achieve Kyoto targets |
