The human ecology of climate change - Climate Change: Biological and Human Aspects - page 370

the ecosystem service value of coral biomes at on average US$13 541 ha − 1 year − 1
but noted that in some instances this might be as high as $57 133 ha − 1 year − 1 .
Of biological note, it seems that high biodiversity is needed to maintain ecosystem
services as many species contribute to these services at different times of the year
and in different years due to climate variability (see, for example, Isbell et al., 2011).
However there frequently appears to be a mismatch between the conservation value
placed on some ecosystems and their ecosystem service value (Turner et al., 2007),
which of course is why the ecosystem service approach is useful. Of special relev-
ance to global climate change is the ecosystem service value of some systems' role
(ecosystem function) in carbon cycling and/or storage.
Assessing affluence ( A in the equation at the start of this section) can be hard
because, in the sense of Ehrlich-Holdren impacts, it does not equate with money,
although frequently it can approximate to it. Yet the currency of money is at the heart of
our economic system. A person's affluence, for example, might be considered in terms
of the size of their home (harking back to a previous example), together with diet,
material possessions and so forth. Yet property and even food prices across a nation
vary, and between nations they vary considerably. The price of a four-bedroomed
house in, say, Washington DC, USA, is different from the price of a similar-sized and
-constructed house in Timisoara, Romania. The same applies to a loaf of bread in
the two places. Yet an American living in an analogous dwelling and consuming
analogous goods and services to a Romanian will be paying far more in US dollar
terms than a Romanian. The Romanian may even pay the same proportion of his or
her financial income for a loaf of bread as the American, and so have similar so-called
purchasing parity. The problem comes when the Romanian wishes to purchase goods
sold only in US dollars, as the US dollar is stronger than the lei (the unit of Romanian
currency). To get around this problem economists sometimes use parity purchasing
prices.
Even parity purchasing prices are not a perfect way of measuring affluence and all
monetary, indeed all other, means have their own limitations and this subject has been
the focus of considerable debate among economists for many decades. Any monetary
measure of a society's GDP, even compared with making parity-pricing allowances
with another country's GDP, does not accurately reflect that society's affluence, let
alone enable true comparisons with other societies both economically and in terms
of environmental impact. This is in part because it is possible to employ someone to
create something, or provide a service, that enhances a citizen's well-being as well
as someone who does not. For example, those involved in oil-spill accidents as well
as those who clean them up are both paid a salary, but all these citizens' salaries
contribute to their nation's GDP. However, clearly their actions, taken together, have
a zero effect on well-being and a negative effect on the environment, which has
been disrupted. This is somewhat analogous to the problem (see below) as to what
size of population the Earth can support. Using genuine progress indicators (such as
literacy levels, longevity, health, etc.), as opposed to purely GDP-type indicators (of
economic wealth and growth), does lead to a different perspective. For example, one
such indicator suggests that genuine progress in the USA remained broadly static
between 1970 and 2000, even though total US GDP more than doubled and GDP per
capita increased by more than 60% (Worldwatch Institute, 2003).