Geology Reference
In-Depth Information
of the nearby drought-tolerant savannah. The heat released when the clouds condense
helps to configure the Earth's climate system as a whole into a state that favours forest
growth in the Amazon region. Herein lies a great lesson for living in peace with Gaia:
the very structure of an ecosystem—namely which species are present, the depths of its
roots, the extent of its leafiness, its albedo and its release of cloud-seeding chemicals to
the air—all have massive effects not only on climate both locally and globally, but also
on the great cycling of chemical beings around the planet.
We have seen how biodiversity is a key player in creating habitable conditions on the
Earth, including a climate that favours our own existence. Biodiversity also provides us
with a host of other benefits, such the stabilisation of soil, recycling of nutrients, water
purification and pollination. These benefits have been called 'ecosystem services' by a
new breed of economists who are attempting to calculate how much these services are
worth in financial terms. The results are staggering—in 1997 global ecosystem services
were worth almost twice the global GDP. Recently, the results of the most comprehens-
ive survey of the state of the world's ecosystem services were made public. The Millen-
nium Ecosystem Assessment, compiled by 1,360 scientists from 95 countries, deliber-
ately took the approach of looking for the interconnections between human well-being
and ecosystem health. The results make sobering reading—in all, 60% of the ecosystem
services investigated have been degraded. Human activity has changed ecosystems more
rapidly in the past 50 years than at any other time in human history. About 24% of the
planet's land surface is now under cultivation; a quarter of all fish stocks are over-har-
vested; 35% of the world's mangroves and 20% of its coral reefs have been destroyed
since 1980; 40%-60% of all available freshwater is now being diverted for human use;
forest has been completely cleared from 25 countries and forest cover has been reduced
by 90% in another 29 countries; more wild land has been ploughed up since 1945 than
during the 18th and 19th centuries put together; demands on fisheries and freshwater
already outstrip supply; and fertiliser runoff is disturbing aquatic ecosystem services.
The report makes it abundantly clear that the UN's Millennium Development Goals of
halving poverty, hunger and child mortality by 2015 cannot be met unless ecosystem
services are nurtured and protected, because it is the poor who are most directly depend-
ent on these services, particularly for fresh water and protein from wild fish and game.
Furthermore, it has become abundantly clear from a handful of successful projects that
the way forward lies with encouraging local people to become involved in protecting
their own ecosystem services. This has worked well in Fiji, where local fishermen es-
tablished restricted areas that reversed serious declines in fish stocks, and in Tanzania
where villagers now harvest food and fuel from 3,500 square kilometres of degraded
land that they were allowed to reforest.
