Geoscience Reference
In-Depth Information
the past decades bring new opportunities and challenges for environmental sustain-
ability. Increasing proportions of very old or very young people in a population,
for example, change the nature of susceptibility to emerging diseases and pathogens.
Informal settlements of migrant populations are often the most vulnerable to hur-
ricanes, landslides and earthquakes (Mitchell, 1999), and, because of the complexity
of cultural integration, addressing these vulnerabilities can themselves produce
challenging policy problems.
The actual movement of resources for energy, food and primary production has
both direct and indirect consequences. The food eaten at dinner tables across the
world, for example, has increasing environmental impact due to energy and fertilizer
inputs, food miles travelled to the table and land use changes associated with new
production because of the fl ows of commodities and materials. Agricultural and
economic policies in one part of the world have direct consequences on producers
in another part of the world, and the globalisation of consumer tastes is now driving
commodity production and economic decisions in local places. The consequences
of the movement of materials round the world also are increasingly apparent in
bio-invasive species (Perrings et al., 2005), demand for land that leads to habitat
conversion and over-exploitation of species, and even the emergence of new
diseases.
The susceptibility of populations and ecosystems to changes that affect their
resilience in particular places is not only comparable but are actually linked to vul-
nerabilities elsewhere. This is apparent in the realm of human health. Certain sec-
tions of all populations are more vulnerable to emerging diseases than others, but
global interdependence connects these vulnerabilities in new and surprising ways.
Over 30 infectious diseases new to medicine emerged between the mid-1970s and
2000 according to the World Health Organization (see Epstein, 2002). These
include HIV/AIDS, Ebola fever, Lyme disease, a new strain of cholera and toxic
E. coli
. In addition, there has been a resurgence and redistribution on a global scale
of well-known diseases such as malaria and dengue fever, both transmitted by
mosquitoes.
The factors infl uencing the observed emergence of new diseases include urbanisa-
tion, increased human mobility, changing land use patterns and the decline of public
health infrastructure in parts of the world (McMichael, 2001). The emergence in
2003 of SARS (a virus recognised in several animal species that has crossed into
human populations) in South East Asia illustrates the mechanisms for tele-
connections of nested vulnerabilities outlined above. First, the interdependence
of 'globalised fl ows' in this case of people increases the global scope of human
transmission of emerging diseases such as SARS. Second, the underlying environ-
mental drivers are common to the rise of emerging diseases (Ebola fever, SARS and
HIV), the global biodiversity crisis and signifi cant global environmental change
associated with land use.
Infectious diseases such as SARS are transmitted around the world through move-
ments of people. In early 2003, the SARS virus was recorded in Guangdong Province
in southern China. Within a month, it had spread to Vietnam, Hong Kong, Singa-
pore and Canada with over 8,000 cases and almost 700 fatalities worldwide. The
SARS case also highlights another aspect of nested vulnerabilities: the links between
environmental changes and emerging diseases. The cases of SARS were traced back
to individuals who handled animals sold live in food markets in Guangdong. The
SARS virus jumped the species barrier to humans, probably from masked palm civet
