On the other hand, recent work suggests that increased UVR at high latitudes
could have some population health benefits, helping to prevent certain autoimmune
diseases. Further research is needed to quantify the optimum dose of sunlight
exposure, depending on factors including age, ethnicity, behaviour, latitude,
cloud cover and stratospheric ozone depletion (SOD). The health impacts of
SOD are difficult to quantify, but broad projections of the burdens of skin cancer
and other UV-related disease under various scenarios of emission containment
have been estimated (see Figure 2).
A potentially more important, although much more indirect, health detriment
could arise from ultraviolet-induced impairment of photosynthesis on land
(terrestrial plants) and at sea (phytoplankton). Such an effect could both reduce
the world’s food production, and also harm the oceanic carbon sink. However,
few quantitative data are yet available.
Biodiversity – Destruction and Invasion
Through humankind’s reproductive and technological ‘success’, we have occupied,
damaged or eliminated the natural habitat of many other species. Biologists
estimate that this mass extinction may cause around one third of all species that
were alive in the 19th century to be gone before the end of the 21st century.
The loss of various key species weakens ecosystems, with many potential adverse
consequences for humans as ‘nature’s goods and services’ decline. Examples
include disturbing the ecology of vector-borne infections — for example, by
reducing or eliminating mosquito predators — thereby enhancing transmission of
infections such as yellow fever and malaria. Other examples include damage to
food-producing systems that depend on pollinators and the predation of pests,
and impairing the cleansing of water and the circulation of nutrients that
normally pass through ecosystems.
We would also lose a rich repertoire of genetic and phenotypic material. To
maintain the hybrid vigour and environmental resilience of ‘food’ species, a
diversity of wild species needs to be preserved as a source of genetic additives.
Similarly, a high proportion of modern medicinal drugs in western medicine has
natural origins, and many defy synthesis in the laboratory. Scientists test
thousands of novel natural chemicals each year, seeking new drugs to treat HIV,
malaria, drug-resistant tuberculosis, cancers and so on.
The other side of this coin is the accelerating spread of ‘invasive’ species, as
long-distance trade, tourism and migration increase in intensity. For example,
A.-L. Ponsonby, A. J. McMichael and I. van der Mei, Toxicology, 2001, in press.
H. Slaper, G. J. M. Velders, J. S. Daniel, F. R. de Gruijl and J. C. van der Leun, Nature, 1996, 384, 256.
J. Longstreth, F. R. de Gruijl, M. L. Kripke, S. Abseck, F. Arnold, H. Slaper, G. J. M. Velders, Y.
Takiwaza and J. C. van der Leun, J. Photochem. Photobiol. B: Biol., 1988, 46, 20.
P. J. Neale, R. F. Davis and J. J. Cullen, Nature, 1998, 392, 585.
C. B. Field, M. J. Behrenfeld, J. T. Randerson and P. Falkowski, Science, 1998, 281, 237.
S. L. Pimm, G. J. Russell, J. L. Gittleman and T. M. Brooks, Science, 1995, 269, 347.
G. C. Daily, in Nature’s Services: Societal Dependence on Natural Ecosystems, Washington DC, 1997.
P. A. Cox, Science, 2000, 287, 44.
T. Low, Feral Future: The Untold Story of Australia’s Exotic Invaders, Viking, 1999.
Global Environmental Changes and Human Health
149
could have some population health benefits, helping to prevent certain autoimmune
diseases. Further research is needed to quantify the optimum dose of sunlight
exposure, depending on factors including age, ethnicity, behaviour, latitude,
cloud cover and stratospheric ozone depletion (SOD). The health impacts of
SOD are difficult to quantify, but broad projections of the burdens of skin cancer
and other UV-related disease under various scenarios of emission containment
have been estimated (see Figure 2).
A potentially more important, although much more indirect, health detriment
could arise from ultraviolet-induced impairment of photosynthesis on land
(terrestrial plants) and at sea (phytoplankton). Such an effect could both reduce
the world’s food production, and also harm the oceanic carbon sink. However,
few quantitative data are yet available.
Biodiversity – Destruction and Invasion
Through humankind’s reproductive and technological ‘success’, we have occupied,
damaged or eliminated the natural habitat of many other species. Biologists
estimate that this mass extinction may cause around one third of all species that
were alive in the 19th century to be gone before the end of the 21st century.
The loss of various key species weakens ecosystems, with many potential adverse
consequences for humans as ‘nature’s goods and services’ decline. Examples
include disturbing the ecology of vector-borne infections — for example, by
reducing or eliminating mosquito predators — thereby enhancing transmission of
infections such as yellow fever and malaria. Other examples include damage to
food-producing systems that depend on pollinators and the predation of pests,
and impairing the cleansing of water and the circulation of nutrients that
normally pass through ecosystems.
We would also lose a rich repertoire of genetic and phenotypic material. To
maintain the hybrid vigour and environmental resilience of ‘food’ species, a
diversity of wild species needs to be preserved as a source of genetic additives.
Similarly, a high proportion of modern medicinal drugs in western medicine has
natural origins, and many defy synthesis in the laboratory. Scientists test
thousands of novel natural chemicals each year, seeking new drugs to treat HIV,
malaria, drug-resistant tuberculosis, cancers and so on.
The other side of this coin is the accelerating spread of ‘invasive’ species, as
long-distance trade, tourism and migration increase in intensity. For example,
A.-L. Ponsonby, A. J. McMichael and I. van der Mei, Toxicology, 2001, in press.
H. Slaper, G. J. M. Velders, J. S. Daniel, F. R. de Gruijl and J. C. van der Leun, Nature, 1996, 384, 256.
J. Longstreth, F. R. de Gruijl, M. L. Kripke, S. Abseck, F. Arnold, H. Slaper, G. J. M. Velders, Y.
Takiwaza and J. C. van der Leun, J. Photochem. Photobiol. B: Biol., 1988, 46, 20.
P. J. Neale, R. F. Davis and J. J. Cullen, Nature, 1998, 392, 585.
C. B. Field, M. J. Behrenfeld, J. T. Randerson and P. Falkowski, Science, 1998, 281, 237.
S. L. Pimm, G. J. Russell, J. L. Gittleman and T. M. Brooks, Science, 1995, 269, 347.
G. C. Daily, in Nature’s Services: Societal Dependence on Natural Ecosystems, Washington DC, 1997.
P. A. Cox, Science, 2000, 287, 44.
T. Low, Feral Future: The Untold Story of Australia’s Exotic Invaders, Viking, 1999.
Global Environmental Changes and Human Health
149