Climate Change and Human Health - Report
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UNEP Press Release
(Jointly issued by UNEP, WHO and WMO)
CLIMATE CHANGE AND HUMAN HEALTH
GENEVA/NAIROBI, 12 July 1996 - Climate change
is likely to disturb various natural and
ecological systems thus triggering off a whole
host of - mostly - adverse effects on human
health. This is the main conclusion of
CLIMATE CHANGE AND HUMAN HEALTH - a joint
publication of the World Health Organization
(WHO), the World Meteorological Organization
(WMO) and the United Nations Environment
Programme (UNEP), released today in Geneva at
the current session of the Conference of the
Parties of the United Nations Framework
Convention on Climate Change.
Most of our current environmental health
problems are of localized nature. However,
many of the anticipated health effects of
climate change would affect large populations
in many regions.
The most direct health effects would be those
caused by heatwaves, storms, and floods; the
least direct would be those due to
socioeconomic disruption caused by
environmental deterioration. Many of the
indirect public health effects would occur
slowly, via climatic impacts upon agriculture,
ocean fisheries, and infectious disease
transmission.
Climatic factors also effect the emergence and
resurgence of infectious diseases. Infectious
diseases include vector-borne diseases, many
of which are a major source of illness and
death in developing countries. An estimated
one in 20 people in the world are currently
infected with malaria, with approximately 350
million new cases occurring annually. About
100 million people are at risk of contracting
American trypanosomiasis (Chagas disease).
Its geographical distribution ranges from the
southern United States to southern Argentina
and Chile. Onchocerciasis, or river
blindness, is currently affecting 17.5 million
people in Latin America and West Africa.
The distribution and abundance of vectors and
intermediate hosts of these diseases are
determined by various physical factors
(temperature, rainfall, humidity, surface
water availability, and wind) and biotic
factors (vegetation, host species, predators,
competitors, parasites and human
interventions). An increase in ambient
temperature is anticipated to cause net
increases in the geographic distribution of
vector organisms such as malaria mosquitoes,
although some localized decreases may also
occur. At the same time, temperature-related
changes in the life-cycle dynamics of vectors
and pathogens would increase the potential
rate of transmission of vector-borne diseases
in many parts of the world. Incidence of
trematode infections, including
schistosomiasis, may also rise due to climate-
related changes in transmission dynamics and
effects on the abundance of snail intermediate
hosts.
It is estimated that the proportion of the
world population exposed to the potential
transmission of malaria could increase in a
hundred years time from the current 45% to
around 60%. Much of this increase would
affect populations currently at the margins of
malaria endemic areas in tropical,
subtropical, and some less well-protected
temperate zones. Increases in incidence of
other infectious diseases such as cholera, and
other water-related and food-related
infections, could also occur, particularly in
tropical and subtropical regions, following
climatic impacts on water distribution,
temperature and the proliferation of micro-
organisms.
Climate change would lead to increased
incidence of familiar, existing public health
problems. An increase in the frequency of
severity of heatwaves would translate into
greater heat-related mortality and illness.
Studies in North America, North Africa and
China indicate that in very large cities, this
would represent several thousand additional
deaths annually. This trend is not expected
to be counterbalanced by a possible slight
decrease in cold-related mortality. Climate
change is also likely to bring about major
regional shifts in rainfall patterns and, with
them, increased frequency or severity of
droughts, floods, and bushfires. Drinking
water supplies may also be affected.
Injuries, deaths, and psychological and social
disturbances attributable to these causes are
likely to increase in affected regions.
The production of some types of air pollutants
and, accordingly, incidence of their
associated health impacts, such as cardio-
respiratory disorders, would probably be
exacerbated by climate change. A warmer and
wetter climate in some regions could also
result in higher airborne concentrations of
various pollens and spores with a possible
impact on allergic disorders, such as hay
fever and asthma.
Climate change, via effects on soil,
photosynthesis, pests and diseases, would
affect agricultural productivity. Almost
certainly, important regional differences
would occur, with negative effects seen
principally in lower-latitude lower-income
countries. In those regions, malnutrition,
hunger and other health problems could
increase, particularly in children.
Sustained depletion of stratospheric ozone
(technically speaking, not a component of
climate change, but closely related to it),
resulting in increased ground-level exposure
to ultraviolet radiation, would cause an
increase in the incidence of skin cancer. It
may also increase the incidence of ocular
lesions (for example certain cataracts), as
well as suppression of the immune system.
Increased ultraviolet radiation would also
impair, to some extent, the photosynthetic
productivity of land plants and marine
phytoplankton -both of which are basic sources
of human food.
Other indirect effects on health would result
from the social-demographic disruptions caused
by rising sea-level and from those caused by
climate-related regional shortages in fresh
water, food and other natural resources.
"The inherent "newness" of this topic -
climate change as a hazard to human health -
means that there is an urgent need for an
expanded international effort", says Dr.
Hiroshi Nakajima, WHO Director-General.
"Health sciences must develop new and better
methods for clarifying the relationship
between public health and natural and human-
induced climate change. Attaining a greater
awareness of potential health impacts will
require activities to educate the public
health community and to encourage media
coverage of this subject".
"We have gone beyond the point where the
casual use of the atmosphere as a highly
mobile dump for man's waste is possible",
comments Professor G.O.P. Obasi, Secretary
General of the WMO. "Any change in climate
would have far-reaching environmental,
biological, socio-economic and public health
consequences".
"Climate change poses direct risks for both
human health and ecosystems", says Ms.
Elizabeth Dowdeswell, UNEP Executive Director.
"Much of the damage to ecosystems could have
additional consequences for human well-being,
such as reduced water supplies in certain
regions and increased storm damage".
The Intergovernmental Panel on Climate Change
concluded in a recent report that "... the
balance of evidence suggests that there is a
discernible human influence on global
climate".
For more information:
Mr. Robert Bisset
Information Officer, UNEP Nairobi
Tel: 254-2-62-3084, Fax: 254-2-62-3692
Mr. Valery Abramov
Health Communications and Public Relations,
WHO Geneva
Tel: 41-22-791-2543, Fax: 41-22-791-4868
UNEP News Release 1996/43
Robert G. Bisset
Media/Information Officer
Information and Public Affairs
United Nations Environment Programme
PO Box 30552, Nairobi, Kenya
Tel: +254-2-623084
Fax: +254-2-623692
Email: Robert.Bisset@unep.org
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