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However, valuing ecosystems can be harder than for species because it is difficult
to quantify all the benefits arising out of an ecosystem's function and not every
ecosystem has a human population with an easily identifiable ecosystem demand
and associated opportunity cost (see Glossary, Appendix 1). This does not mean that
some far-flung piece of tropical forest has no ecosystem service to offer, because vast
tracts of tropical forest, for instance, affect the regional climate and the (fast) global
carbon cycle.
In short, even though many developed nations theoretically embrace the polluter-
pays principle, the reality is that much of such costs remain environmental external-
ities if only because we are not, when undertaking economic transactions, valuing all
existing ecological services.
Nonetheless, rough valuation attempts have been made to value ecosystem services
globally. These suggest that the global value of services provided by ecosystems, but
external to our human economy, is of the same order of magnitude as the 'real' human
economy, if not greater. One 1997 estimate was in the range of US$(16-54)
10
12
and
this range was considered by the researchers to be a minimum one. It does, though,
compare with the then global annual economy of $18
×
10
12
(Costanza et al., 1997)
even if some of the assumptions and methods caused some debate in the ecological
economics community. Subsequently, in the run-up to the 2002 UN Conference
on Environment and Development
×
10) summit (see section 8.1.9),
another assessment concluded that the benefit/cost ratio of conserving the Earth's then
remaining wildlife and natural systems was at least 100/1 (Balmford et al., 2002).
Although attempts to quantify the (largely unrecognised) value of ecological ser-
vices have proven difficult - other than to say that they probably contribute roughly
as much value as the conventional economy - it is possible to identify how such
services might be affected in a region due to climate change. One such assessment of
change in ecosystem service supply due to climate change in Western Europe identi-
fied both positive and negative service changes (Schroter et al., 2005). Positive ones
included increases in forest area and productivity. Negative ones included declin-
ing soil fertility (due to temperature and extreme rain-burst erosion) and increased
risk of forest fires. These positive and negative service changes respectively provide
opportunities (biofuel production or increased agriculture) or remove options (such
as traditional water use). This assessment particularly noted that among the Western
European countries, those around the Mediterranean appeared to be most vulner-
able, with multiple projected impacts primarily related to increased temperature and
reduced precipitation with resulting loss of agricultural potential.
Despite difficulties in assessing the value of ecosystem services, there is increasing
interest in this approach by policy-makers. One project, supported by the European
Commission, the United Nations Environment Programme and government depart-
ments responsible for the environment in the UK and Germany, is The Economics of
Ecosystems and Biodiversity (TEEB) study project that came out of a G8 summit in
2007. It published a relevant report,
Climate Issues Update
, in 2009 (TEEB, 2009).
This concluded that there is a compelling cost-benefit case for public investment
in ecological infrastructure (especially restoring and conserving forests, mangroves,
river basins, wetlands, etc.), particularly because of its significant potential as a means
of adaptation to climate change. This included, among other things, an assessment of
+
10 (UNCED
+
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