Environmental Engineering Reference
In-Depth Information
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Over the past fifty years, humans have changed ecosystems more rapidly and
extensively than in any comparable period of time in human history, largely to
meet rapidly growing demands for food, fresh water, timber, fibre and fuel. This
has resulted in a substantial and largely irreversible loss in the diversity of life
on Earth.
2
The changes that have been made to ecosystems have contributed to substantial
net gains in human well-being and economic development, but these gains have
been achieved at growing costs in the form of the degradation of many ecosystem
services, increased risks of non-linear changes and the exacerbation of poverty
for some groups of people. These problems, unless addressed, will substantially
diminish the benefits that future generations will obtain from ecosystems.
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The degradation of ecosystem services could grow significantly worse during the
first half of this century and is a barrier to achieving the Millennium Development
Goals, particularly regarding the eradication of hunger, reduction in child
mortality and disease control.
4
The challenge of reversing the degradation of ecosystems while meeting increasing
demands for their services can be partially met under some scenarios that the
MEA has considered, but these involve significant changes in policies, institutions
and practices that are not currently underway. Many options exist to conserve
or enhance specific ecosystem services in ways that reduce negative tradeoffs or
that provide positive synergies with other ecosystem services.
Around 60 per cent of the ecosystem services that support life on Earth - fresh
water, fish stocks, pests, natural hazards, regional regulation of climate - are either
degraded or are being exploited unsustainably. According to the MEA, the next fifty
years will probably witness the collapse of more fish stocks, the creation of dead
zones around some coastal areas, the emergence of new diseases, deterioration
in freshwater quality, river flooding, desertification, deforestation, increase in
invasive species, general species extinction, loss of biodiversity, habitat degradation
and increased pollution, especially nutrient loading due to the increases in artificial
fertilizer use in agricultural production - all leading to a decline in human well-
being and loss of capital assets that even the wealthiest populations will notice.
In 2008, the human demand on the natural world's capacity to meet this demand
exceeded the biosphere's regeneration rate by 50 per cent (WWF-Int, 2012). As a
result, the WWF argue that it is necessary to significantly expand the network of
global protected spaces of representative land, freshwater and marine areas necessary
for food, biodiversity, energy security, climate change resilience and adaptation
to 20 per cent. Of course, if we don't do this, it will be the poor who are likely to
suffer the most.
The MEA report also states that the total economic value associated with the
sustainable management of an ecosystem is usually higher than the value assumed
to come from the conversion of the ecosystem through farming, clear-cutting or other
intensive uses. Thus, the MEA (2005: 15) outlines four possible scenarios exploring
potential futures for both ecosystems and human well-being. These scenarios are
based on differing assumptions about the forces driving change and their interactions:
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Global orchestration
: A globally connected society that focuses on economic
growth, global trade and economic liberalization, and takes a reactive approach
