Geography Reference
In-Depth Information
ecosystems will change as climate changes during
the coming century and that past performance of
plant adaptation will apply in the future. There is
some anxiety that selected plant species may die
back before betteradapted species are established.
Such a transient hysteresis effect in vegetation may
produce a temporary peak or 'spike' in
atmospheric CO
2
concentrations (Smith and
Shugart 1993).
Forest fires have periodically posed a threat
through the unregulated additions of CO
2
to the
atmosphere (see Plate 2.2 on p. 30). Box 2.2
highlights the problems of forest fires during
1997-8.
CONCLUSION
There has been no attempt here to deal with all
the complex systems relating to global warming,
but this is not to imply that the impacts will be
restricted to changing sea levels and vegetation
patterns. Changes are also likely in hydrological
systems, agricultural practices, associated economic
Box 2.3
Policies for reducing carbon dioxide
The Climate Convention is an attempt by the
governments of the world to reach agreement on curbing
emissions of greenhouse gases. The UN Framework
Convention on climate change was signed by over 160
countries at the Rio Conference on Environment and
Development in 1992. Details are provided by Houghton
(1997). This was subsequently revised at the 1997 Kyoto
Conference after considerable lobbying. It is unclear how
effective the Kyoto agreement will be due to problems of
monitoring and implementation agreements on
greenhouse gas emissions. However, the aim of the
Climate Convention was to slow down and then stabilise
global emissions to 1990 levels. This was to be achieved
by switching to more energy-efficient fuels. Natural gas,
for example, generates 40 per cent less CO
2
than coal
for the same energy output, but such a switch of fuel is
not an option for many countries. There is also a vested
interest by a number of transnational companies in
increasing the consumption levels of oil in the drive
towards greater economic growth. By 1998, changes in
CO
2
emissions had less to do with energy saving than
with political changes, despite the attempt by some
industrial countries to stabilise emissions. Trends during
the 1990s indicate that the industrial countries (OECD)
showed increases of around 4 per cent, while the
increase in developing countries was about 25 per cent
but from a lower 1990 emission level. Only a decline of
25 per cent in Eastern Europe, associated with
economic collapse, allowed world emissions to remain
almost constant.
This 'accidental' stabilisation is unlikely to continue,
even if the 'tiger' economies of East Asia suffer
economic decline under a 'boom-bust' scenario.
Unfortunately, additional uncontrolled emissions (see
Box 2.2) have probably renewed the upward global
trend seen in the 1980s.
later— usually termed 'business-as-usual' or BaU.
There are possibilities between these two extremes, but
problems of economic inertia and political 'short-
termism' mean that these are relatively unattractive. In
any case, climate models such as the Dutch IMAGE 2
model point to good scientific reasons for acting now.
This is because waiting until 2010 to act will be too late
in attempting to curb the higher rate of expected
emissions. In opposition to this scientific and legal view,
the BaU lobby insists that waiting until 2010 is the only
viable option for industrial countries (referred to as
Annex 1 countries), since new technology will then
become available. Non-Annex 1 countries could wait
until 2030. There is partial scientific support for BaU
(Wigley et al. 1997).
OTHER ISSUES
•
The USA favours a 'net' approach, in which a
country's inventory of carbon emissions will include
forest burning as well as sequestration (afforestation)
programmes. It also supports a 'global bubble' solution
in which the trading of pollution credits would be
permitted.
•
The EU favours the 'basket' policy, in which the
combined effects of carbon dioxide, methane and
nitrous oxide are taken into account.
•
The G77 developing countries group is opposed to
the basket policy and wishes there to be targets for
individual gases to be achieved domestically. Most of
these countries are opposed to pollution quota trading,
want drastic reductions by 2020 and an economic
compensation fund.
•
Another approach that was considered at the Kyoto
Conference was the idea of a per capita emission rate
with convergence to a value of 1 tonne CO
2
per capita
per year by 2030. This would stabilise CO
2
concentrations at around 450 ppmv. Others favour 560
ppmv, since this represents a doubling of pre-industrial
levels and accords with model scenarios.
THE TIME COMPONENT
The basic options that are presented in the models of
global warming are (1) act now and (2) delay until
