acid rain and the diffusion of persistent chlorinated organic chemicals, were
recognized several decades ago. In the last two decades several global-scale
environmental changes, historically unprecedented, have emerged — and have
been recognized as posing substantial risks to human health. These include
changing the gaseous composition of the lower and middle atmospheres;
reducing productive soils on all continents; depleting ocean fisheries; over-exploiting
and contaminating many of the great aquifers upon which irrigated agriculture
depends; and resulting in an unprecedented rate of loss of whole species and many
local indigenous populations. Anthropogenic activity is disrupting at a global
level many of the biosphere’s life-support systems, which provide environmental
stabilization, replenishment, organic production, the cleansing of water and air,
and the recycling of nutrient elements.
Assessments of these human-induced changes have concluded that humanity is
now incurring a significant and increasing ‘ecological deficit’, evidenced by an
increasing decline in global environmental and ecological resource stocks.
Today, we have reached a position where the aggregate human impact on Earth’s
natural capital has reached unprecedented levels, at national, regional and global
scales. Some of these impacts are likely to have longer-term, and commensurately
more serious, consequences for the health of human populations.
This article reviews how human activities are adversely affecting, at various
physical scales, the different media of the biophysical environment, and in turn
how these changes may affect human health — the focal topic of Section 2 of the
article. As human population density continues to rise, with a commensurate rise
in the material- and energy-intensity of economic activity, this will place
pressures on many natural resources, which have finite stocks. Such pressures
may lead to conflict and insecurity, with adverse consequences for human health;
this important subject is reviewed in Section 3.
Often our environmental heritage and dependency have been neglected,
through either a lack of motivation or simple ignorance. In today’s world where
human activities are having an impact at a global scale there is a need not only for
society to understand this heritage, but to ensure that our dependence on the
environment is managed in a sustainable manner, for both current and future
generations. There is therefore a need to provide a framework for a better
understanding of this heritage and dependency. In Section 4 the concept of the
environment as a global public good for health is introduced, and we consider
how this framework might be used to enhance the interface between research and
policy, with a view to a sustainable future for all.
2 Local, Regional and Global Environmental Changes
The complexity of the biophysical environment can be seen in terms of media —
air, water, soil and climate — and physical scale — local, regional, global, and
cross-scale. Cross-scale recognizes that the scale of an environmental health
impact may greatly exceed the scale of the initial exposure; an example is where
C. D. Butler, Global Change and Human Health, 2000, 1, 156.
M. Wackernagel and W. Rees, Our Ecological Footprint: Reducing Human Impact on the Earth, New
Society Publishers, 1996.
M. J. Ahern and A. J. McMichael
140
recognized several decades ago. In the last two decades several global-scale
environmental changes, historically unprecedented, have emerged — and have
been recognized as posing substantial risks to human health. These include
changing the gaseous composition of the lower and middle atmospheres;
reducing productive soils on all continents; depleting ocean fisheries; over-exploiting
and contaminating many of the great aquifers upon which irrigated agriculture
depends; and resulting in an unprecedented rate of loss of whole species and many
local indigenous populations. Anthropogenic activity is disrupting at a global
level many of the biosphere’s life-support systems, which provide environmental
stabilization, replenishment, organic production, the cleansing of water and air,
and the recycling of nutrient elements.
Assessments of these human-induced changes have concluded that humanity is
now incurring a significant and increasing ‘ecological deficit’, evidenced by an
increasing decline in global environmental and ecological resource stocks.
Today, we have reached a position where the aggregate human impact on Earth’s
natural capital has reached unprecedented levels, at national, regional and global
scales. Some of these impacts are likely to have longer-term, and commensurately
more serious, consequences for the health of human populations.
This article reviews how human activities are adversely affecting, at various
physical scales, the different media of the biophysical environment, and in turn
how these changes may affect human health — the focal topic of Section 2 of the
article. As human population density continues to rise, with a commensurate rise
in the material- and energy-intensity of economic activity, this will place
pressures on many natural resources, which have finite stocks. Such pressures
may lead to conflict and insecurity, with adverse consequences for human health;
this important subject is reviewed in Section 3.
Often our environmental heritage and dependency have been neglected,
through either a lack of motivation or simple ignorance. In today’s world where
human activities are having an impact at a global scale there is a need not only for
society to understand this heritage, but to ensure that our dependence on the
environment is managed in a sustainable manner, for both current and future
generations. There is therefore a need to provide a framework for a better
understanding of this heritage and dependency. In Section 4 the concept of the
environment as a global public good for health is introduced, and we consider
how this framework might be used to enhance the interface between research and
policy, with a view to a sustainable future for all.
2 Local, Regional and Global Environmental Changes
The complexity of the biophysical environment can be seen in terms of media —
air, water, soil and climate — and physical scale — local, regional, global, and
cross-scale. Cross-scale recognizes that the scale of an environmental health
impact may greatly exceed the scale of the initial exposure; an example is where
C. D. Butler, Global Change and Human Health, 2000, 1, 156.
M. Wackernagel and W. Rees, Our Ecological Footprint: Reducing Human Impact on the Earth, New
Society Publishers, 1996.
M. J. Ahern and A. J. McMichael
140