Climate change futures: health, ecological and economic dimensions

CASE STUDIES 86 | NATURAL AND MANAGED SYSTEMS
genetically modified animals and native oyster populations
is yet to be determined.
Another recent development in the attempts to restore
Chesapeake Bay oyster populations is the proposed
introduction of a non-native oyster, the Suminoe oyster
(Crassotrea ariakensis) into Chesapeake Bay with the
intent of developing a viable population that can restore
ecosystem services (Daily 1997) and enhance the wild
fishery. The apparent rapid growth rate of the Suminoe
oyster and its resistance to local diseases makes this an
attractive species for introduction (NRC 2004).
The scientific basis for making informed decisions about
the potential biological and ecological effects of introductions
of non-native and/or genetically modified oyster
species needs much more thorough study. For example,
the potential of altering the genotype of the native
oyster species by interbreeding with the genetically
modified oysters represents an unknown that could
cause unforeseen and abrupt perturbations to the
ecosystem.
The concerns associated with introduction of this nonnative
species include the introduction and/or enhancement
of different diseases, the spread of the species to
non-target regions, the competition with native oysters
and other native species, and the potential for biofouling.
The present knowledge of the biology and ecology
of the Suminoe oyster is limited. There are now ongoing
research programs that are focused on studies of the
physiology and ecology of post-settlement and larval
Suminoe oysters. However, the introduction of this
species into Chesapeake Bay will take place prior to
the availability of the ecological data needed to fully
evaluate the impact of this species on the Chesapeake
Bay ecosystem (NRC 2004).
Specific measures include the following:
• Develop monitoring systems with sufficient data collection
frequency to differentiate between
natural variability and long-term climate
change effects.
• Provide funding, infrastructure and resources
for long-term monitoring of habitat quality.
• Undertake studies that can identify long-term
climate change processes that may result in
environmental changes that facilitate the spread of
bivalve diseases.
• Develop management and decision-making
structures/policies that include effects of environmental
variability and the potential effects of long-term
climate change.
WATER
THE EFFECTS OF CLIMATE CHANGE
ON THE AVAILABILITY AND QUALITY
OF DRINKING WATER
Rebecca Lincoln
BACKGROUND
Water is essential to life on Earth. Yet clean, safe
water supplies are dwindling as demand rises.
Population growth, increases in agricultural and industrial
demands for water, and increased contamination
have already put a strain on water resources. Global
climate change threatens to intensify that strain,
through decreased availability and quality of drinking
water resources worldwide, and through increased
demand on these resources due to rising temperatures.
According to the World Health Organization (McMichael
et al. 2003), an estimated 1.1 billion people, or one of
every six persons, did not have access to adequate supplies
of clean water in 2002 and at least 1 billion people
must walk three hours or more to obtain their water
(Watson et al. 2000). A country is considered to be
experiencing "water stress" when annual supplies fall
below 1,700 cubic meters per person and “water scarcity”
when annual water supplies are below 1,000 cubic
meters per person. By these measures, according to The
Irrigation Association (a consortium of businesses), 36
countries, with a total of 600 million people, faced either
water stress or water scarcity in 2004.
If present consumption patterns continue, the United
Nations Environment Programme estimates that two out
of every three persons on Earth will live under waterstressed
conditions by the year 2025. These dire projections
do not take into account a changing climate.
Many of the world's arid and semi-arid regions cover
developing countries, and water stress in these countries
is often compounded by poor infrastructure for collecting,
disinfecting and delivering water. A change in
climate could have a particularly severe impact on
water quality and available quantity in these regions.