MARK D
TITLE
Global Changes in Climate and Health
AUTHOR
Dragana Stojisavljević, MD
Prof. Miroslava Kristoforović-IlićProf. MD, PhD,
ADDRESS FOR
CORRESPONDENCE
(incl. fax and email)
KEYWORDS
Assistant Dragana Stojisavljević
Institute of Public Health, Medical Faculty Banjaluka
Jovana Ducica 1, 51000 Banjaluka
Republic of Srpska, Bosnia & Herzegovina
Tel. +387 51 216 509; Fax +387 51 216 510
E-mail: dada.bl@inecco.net
and
Prof. Miroslava Kristoforović-IlićProf. MD, PhD,
Institute of Public Health Novi Sad,
Medical Faculty Novi Sad
Futoska 121,
21000 Novi Sad, FR Yugoslavia
Tel. +381 21 42 22 55; Fax +381 21 61 39 83
E-mail: kristof@eunet.yu
climate changes, health, effects of climate changes on
human health
Postgraduates students and
the public health
professionals should be familiar with different types of
climate, climatic elements and their individual influence on
human health (direct and indirect), environmental,
agriculture, trade and tourism. Man's different discoveries,
some considered to be of historic importance (i.e.
discovery of freon) had a strong impact on climate
changes. Increased urbanisation, population migration,
need for opening new jobs, development of industry and
agriculture, and ruthless deforestation have brought about
LEARNING OBJECTIVES changes in global climate.
(expected outcomes)
The student should be at the end of this topic familiar
with:
- different types of climate
- climate elements
- relationship between man-climate
- air pollution and climate changes-"Greenhouse gases"
- legislation of air quality controllig, and definition of
standards for air pollutants according to WHO
recommendations
- climate factors' effects on human health
1
SYNOPSIS
This topics covers:
- climate, microclimate, urban climate, man and climate
- climatic elements and their influence on health
- indirect effects climate on human health
- NEHAP
CONTENTS
1. Introduction
1.1. Microclimate
1.2. Urban climate
2. Man and climate
3. Climatic elements and their individual influence on
human health
3.1. Air temperature
3.1.1. The influence of air temperature on human
organism
3.1.2. Health effects of high temperatures
3.1.3. Health effects of low temperatures
3.2. Air pressure
3.2.1. Health effects of high atmospheric pressure
3.2.2. Health effects of low atmospheric pressure
3.3. Air humidity
3.4. Air movement
3.5. Indirect effects of climatic factors on human health
4. Conclusions and directions
5. References
The teaching method recommended by the author is:
TEACHING METHODS
SPECIFIC
RECOMMENDATIONS
ASSESSMENT OF
STUDENTS






work in the small groups (5 students)
discussion about problem within each group
decide about the best way for considering of problem
the discussion among groups
presentation of work each group
Read this document and find artical with similar text in
your country (data about temperature, pressure,
movement, humidity, cloudiness and precipitation).
 Find in your country data abaut direct and indirect
effects of climate changes on human health
 write on a seminar abaut problem which you are
considering
Written or oral test
(type of examination)
2
Global Changes in Climate and Health
Stojisavljević Dragana Ass.1, Kristoforović-Ilić Miroslava Prof. Dr.2
1. Introduction
The climate of one place is characterized by the regime of climatic types, which
includes the moving in, staying, and replacing of an air mass by a new, physically and
chemically different, air mass. The climate of one region is defined on the basis of longterm observations of climatic elements, such as: temperature, air humidity, cloudiness,
duration of solar insolation, precipitation, wind direction, frequency and velocity. On the
basis of climatic elements, general climatology distinguishes seven major climate regions:
equatorial, two tropical, two temperate and two polar. Between them there are also six
transitive types.
1.1. Microclimate
Microclimate is the climate of a small site, in the air two meters above the ground. It's
mainly influenced by the local relief, flora, as well as by the water surface. The
differences in microclimate are bigger in clear and calm weather, and less distinct in
windy and cloudy weather.
1.2. Urban climate
Urban climate is significantly different from the climate of the surrounding area. A
city has lots of buildings, large concrete and asphalt surfaces, few green surfaces, heavy
traffic, developed industry, etc. With more industrial plants and without adequate filters at
the sources of air pollution, with adequate weather conditions (presence of temperature
inversions) that last longer in the air, a cloud of pollutants is formed over the city,
gathering beneath the inversive layer, blocking the penetration of radiation and preventing
the vertical movement of air, which leads to impaired health (as described in some cities
in Europe and America). Together with the above-mentioned factors the particles of air
pollutants can increase the condensation of water vapor causing increased precipitation,
which can also be very harmful (acid rains), depending on the emitted fumes, which
again, directly or indirectly, affects human health, i.e. toxic fog or smog in big cities. Due
to the above-mentioned reasons, the average annual temperatures are higher in urban
surroundings, both in winter and summer, than in the surrounding areas. The air humidity
is lower and air movement is slower inside than outside the city. We often find big
climatic differences from one town to another, which is due to geographical
characteristics and general city planning. The cities with more green surfaces, broader
streets, big squares with fountains, lying on a river or a lake, have a more favorable
climate. With regard to an increased migration of the population to urban areas, which has
been the case in both entities of Bosnia and Herzegovina during the last decade, heavier
traffic and a great number of old vehicles, petrol of varying quality, different industrial
plants, it is of great importance to put an emphasis on the importance of air conditions and
less air pollution. EPA warns that the global climate changes are caused by the
accumulation of «Greenhouse gases» in the lower layers of the atmosphere. Together with
deforestation the above-mentioned activities of man are the main causes of this increase.
USEPA informs that since the industrial revolution the concentration of the following
«greenhouse» gases has increased: CO2=+30%, methane=+100%, NOx=+15%. It is
assumed that the concentration of these gases will have doubled by 2060 in comparison to
the preindustrial level of concentration. Many of these gases remain in the atmosphere for
a long time. With regard to these changes WHO argues that the global average
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temperature will rise by 1.5-3.5 degrees C, which, due to the melting of glaciers, will
bring about the rising of the sea level from 15 to 95 cm in the year 2100, thus changing
the width of the geographic zones by 150-550 km. The emission (EPA; IPCC, 1995) of
CO2 is to be 250% higher by the end of the century than it was in the beginning. Table 1
illustrates the expected changes in the concentration of some pollutants that make the
«greenhouse gases» phenomenon (USEPA)
Table 1. The illustration of the expected changes in the concentration of some pollutants
that are part of the «Greenhouse gases» phenomenon (USEPA)
Concentration in the
preindustrial era
Concentration in
1994
Assessment of the change in
concentration1
Atmospheric life –
expressed in years
Legend:
CO2
CH4
N2O
280 ppmv
700 ppbv
275 ppbv
358 ppmv
1720 ppbv
312 ppbv/2
1,5 ppmv/god
10 ppbv/god
0,8 ppbv/god
50-200*
12**
120
1
time when changes take place
expected on the basis of the data taken in 1992-1993
*individual lifetime of CO2 cannot be determined owing to different assessments conditioned by different
processes
**defined as time regulation which takes place owing to indirect effects of methane during its lifetime
2
2. Man and climate
Climatic changes, such as the rise and drop of temperature, have occurred on our
planet throughout its geologic history. The effect of climate changes on human health has
been a matter of special interest since it was first brought up in the First Assessment
Report of IPCCU in 1992. The Second Assessment Report ( Mc Michel et al.1996)
designed a special chapter on health. At the same time WHO, WMO and UNEP together
formed a working group, which started working on the first large-scale assessment of the
effects of climate changes on human health (WHO, WMO, UNEP, 1996). The Third
Assessment Report of IPCC (published in 2001) deals with the influence of the
environment on the health of the whole population. Man’s different discoveries, some
considered to be of historic importance (i.e. discovery of freon) had a strong impact on
climate changes. Increased urbanization, population migration, need for opening new
jobs, development of industry and agriculture, and ruthless deforestation have brought
about changes in global climate. The global effects of air pollution are brought into a
direct relationship with climate changes on earth. It is assumed that airborne particles can
disperse sun’s rays, thus decreasing insolation. Man burns enormous quantities of fossil
fuels, which releases huge amounts of carbon dioxide and water into the atmosphere. A
long-term observation of carbon dioxide points to an increase in its concentration even in
the atmosphere of the Antarctic. The problem is that this could cause the “greenhouse”
effect with an increase in average annual temperature, the melting of snow in Polar
Regions, as well as long periods of drought on earth.
Bioclimatology is a science that deals with the influence of the external environment
on men and other living beings. It includes the elements of physics, meteorology, biology
and medicine.
Climate can have both direct and indirect influence on human health:
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The direct influence of climate on man’s health was described in many books and
bioclimatology is well acquainted with it. Today, it is often talked about when speaking of
global changes, especially in urban surroundings. Epidemiological studies have proved
that physiological functions of a healthy organism are under the influence of climatic
factors on both daily and seasonal bases (body temperature, glycemia, the number of
erythrocytes and leukocytes is higher during the second half of the day). Different
seasonal variations in physiological functions within cardiovascular, neurovegetative and
endocrine system (meteothropic disorders) have been found. In spring, there are more
cardiovascular disorders, especially thromboembolic states, neurosis, psychosis, ulcer
cases, even tuberculosis fatalities. Many allergens are present in the air during a certain
time of the year (spring, late summer), so different allergic reactions are season
conditioned. A great number of infective diseases are seasonal, which is influenced by the
virulence of the causative agent, organism immunity and lifestyle.
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3. Climatic elements and their individual influence on human health
The basic climatic elements that determine the weather and climate of one region are:
solar radiation, (insolation), air temperature, air pressure, air movement (winds). air
humidity, cloudiness and precipitation. All these elements are interrelated and
interdependent. In the further text we’ll discuss the direct and indirect influence of
individual factors on human health.
Figure 1. Direct and indirect influence of climatic elements on human health
Heat/Cold
Temper atur e
Humidity
Wind
Radiation
Infr ar ed
Light
UV
Air
pollution
Par ticles
Liquids
Gases
Noise
3.1. Air temperature
The atmosphere absorbs only 15% of solar radiation, so it receives very little heat in
this way. Land and water surfaces absorb the greatest part of solar thermic energy and
thus get warm. At the same time these surfaces start emitting the heat, so the air is
warmed from the ground upwards. Air temperature is a thermic condition of air measured
by thermometers and expressed mainly in Celsius, Kelvin, and Fahrenheit thermometric
scale.
3.1.1. The influence of air temperature on human organism
Body temperature is regulated by complex thermoregulatory mechanisms ranging from
36.1 to 37.5 degrees C. The human organism emits heat by physical methods of
thermoregulation, which are: heat radiation around 45%, convection and conduction,
evaporation around 25% of heat. All the mentioned physical methods of heat emission are
greatly influenced by the microclimatic conditions of one’s surroundings. The chemical
form of thermoregulation is controlled by the thermoregulation center in the
hypothalamus. The change of air temperature causes a change in the intensity of oxidative
processes in the human body. In lower temperatures the oxidative processes are
intensified and temperature is preserved by way of vasoconstriction, whereas in higher
temperatures the process is reversed.
3.1.2 Health effects of high temperatures
High temperature, together with other microclimatic factors, can have the following
effects on health:
 Heatstroke – caused by impaired thermoregulation.
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 Cardiovascular disorder – which manifests as hypotension and tachycardia, caused
by a big loss of water and electrolytes through sweating.
 Heat spasms, which can ensue due to the prolongation of the previous state or in
very hostile microclimatic conditions together with hard physical labor and a lack of
adequate rehydration.
 Gastrointestinal disorders, due to a quick intake of too much water when the
organism has been exposed to high temperatures, which leads to hypoacidity
followed by loss of appetite and dyspepsia.
 Functional changes in the central nervous system manifesting as loss of
concentration, fatigue, sleepiness, decreased attention, precision and reflex
responses of the organism.
 Thermic exhaustion – thermic collapse resulting in fatigue, dizziness, tachycardia,
due to the inability of the organism to overcome the hypovolemia as a result of a big
loss of fluid.
 Sunstroke is the outcome of a direct head exposure to sun’s rays. The pathogenesis
of this disorder is characterized by vasodilatation in the head region and brain
edema. The symptoms develop acutely: headache, vomiting, tachycardia,
hypertension, loss of consciousness and spasms.
 A chronic exposure of the organism to high environment temperatures can lead to
urolithiasis.
 A chronic exposure to high temperatures and direct solar radiation can lead to
different forms of skin cancer, which, due to greater frequency in certain parts of the
world, attracts more and more attention.
Figure 2. Demonstration of high temperature effects on KVS in some USA cities.
200
NEW Y ORK
NEW ORLEA NS
100
90
80
70
60
50
CHICA GO
40
Average number of deaths f rom K V I (log)
30
SA N FRA NCISCO
20
M I NNEA POLI S
10
9
8
7
6
5
4
DA LL A S
ATLA NTA
M EM PHIS
3
2
1
-20
-29
0
-18
20
-7
40
4
60
16
80
27
100 F
38 C
Average daily temperature
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3.1.3 Health effects of low temperatures
Human organism shivers in its reflex reaction to low temperature, which is a reflex
defense mechanism at the start of exposure. This involuntary activity is enhanced by
conscious activities: stamping, hopping, etc. Vasoconstriction is another reaction,
followed by raised blood pressure and increased activity of the anterior pituitary lobe,
adrenal and thyroid gland so that the redox processes in the body can be increased up to 57 times. Under the influence of low temperatures thermic emission usually occurs at the
uncovered body parts (hands, nose, ears) by way of convection and conduction. Low
temperature makes cells less motile, causes the formation of transudates and, due to
stagnation, enhances the development of respiratory diseases. Furthermore, low
temperature causes leukopenia with decreased phagocytic capacity of leukocytes, which
accounts for more frequent infections of respiratory tracts in winter months. Elderly
people and small children are the most vulnerable category.
 Frostbites – form at the exposed parts of the body due to decreased blood circulation.
They can be of 1st and 2nd degree when reversible and of 3rd and 4th degree when
the tissue is permanently damaged or has even become gangrenous.
 Trench foot – it was named after the place where it’s usually found – trenches. This
phenomenon is caused by multiple factors – low temperature, increased air humidity,
lack of movement, tight footwear. In the beginning the changes resemble frostbites of
1st and 2nd degree, but later the changes become irreversible with the onset of stasis,
edema and foot gangrene.
3.2. Air pressure
Atmospheric pressure is the force per unit area exerted on all surfaces by the
atmosphere. It’s expressed in millibars. It decreases in higher altitudes and when
temperature and relative air humidity increase, and increases below the sea level and
when temperature and relative air humidity drop.
Atmospheric pressure acts on man mechanically – it is exerted on the surface of the
body, and is also partially exerted by some gases.
An increase in pressure in cold weather suits healthy people and they feel full of
energy. But such weather conditions don’t suit those with hypertension, angina pectoris,
atherosclerosis and serious lung diseases.
As opposed to the above-mentioned, when the air pressure drops in cloudy weather,
the increase in temperature and air humidity has a negative effect on the health of those
suffering from hypotension, anemia, chronic bronchitis and asthma.
In those with neurovegetative disorders negative effects are present in both cases.
3.2.1 Health effects of high atmospheric pressure
 High atmospheric pressure acts by the high pressure mechanism itself, mechanically
causing dented tympanic membrane, pain, hearing problems, faster pulse and
breathing.
 Professional scuba divers and caisson workers can develop caisson disease –
Decompression Syndrome.
3.2.2 Health effects of low atmospheric pressure
When atmospheric pressure is decreased there is a proportional decrease in the partial
pressure of the gases that make up the normal composition of the air. Human organism is
most sensitive to the drop of partial oxygen pressure, which manifests in deeper and faster
breathing; the heart volume per minute is increased, there is a mobilization of blood from
8
the storages and faster erythropoiesis. This phenomenon is made use of when sending
children or anemic, weak, exhausted patients into the mountains for recovery, or for the
training of athletes.
3.3. Air humidity
Air humidity means the presence of water vapor in the air due to the evaporating of
water from the land and sea. The evaporating speed is determined by the air temperature
and the velocity of air movement.
 Increased air humidity is a favorable condition for the development of
microorganism. If increased air humidity is followed by low temperatures and faster
air movement, the human body feels colder. If temperature is high and there is no
movement of air, increased humidity prevents heat emission and leads to the
overheating of the body.
 Decreased humidity is also harmful to the human body – the skin and mucous
surfaces become dry and chapped and are prone to infections.
3.4 Air movement
Air moves due to the difference in air pressure, which depends on the air temperature
and the relief. The horizontally directed movement of air in the atmosphere from
anticyclone towards cyclone is called wind. The wind rose is a diagram showing for a
given place the frequency of winds over a shorter or longer period. The wind rose is of
special importance when it comes to the planning and zoning of urban places, i.e. the
making of general and detailed urbanistic plans, which has become more significant for
urban areas in modern times as regards the global climate changes. Besides the horizontal
movement of air (winds), it can also move vertically – air turbulence, caused by the
difference of air temperature on the ground and in the higher atmospheric layers. This
movement is especially important for urban and industrial areas because pollutants move
from lower to higher atmospheric layers, directly influencing microclimatic changes.
Some winds can have a depressive, irritating effect on human organism, causing
headaches, insomnia and decreased working capacity.
3.5. Indirect effects of climatic factors on human health
So far we have been dealing mainly with direct effects of climatic factors on human
health. As far as indirect effects are concerned, we’ll be dealing with agricultural,
socioeconomic, political and environmental aspects, as well as with the source and
development of certain vector transmittable diseases.
9
Figure 3. A diagram of climatic factors’ effects on human health
Termic shock
Nutricion
H
U
M
A
N
Food production
Organic diseases
Fishery
Agriculture
Urban areas
Air heating
Vectors
Allergic disorders
r tal
Allergens
Vector caused diseases
Chronic diseases
mo
Forests
Moist soils
and
The forming of pollen
Infectuous diseases
i ty
C
H
A
N
G
E
S
i ty
Reproduction effects
mo
r bi d
C
L
I
M
A
T
E
When speaking of indirect effects of climate changes on human health through
agriculture, we speak of the effects of various climatic factors that reduce agricultural
crops (long droughts, rain periods, floods, increased humidity). A shortage of necessary
food and drinkable water leads to malnutrition and famine, which in turn leads to the
second segment of indirect effects of climatic factors on human health – the
socioeconomic segment. It brings about the migration of population, which are looking
for food and water, leading in turn to the third segment of indirect effects – the diseases
transmitted by vectors (mosquitoes, ticks). In the past different populations were protected
against vectors of infectious diseases and crop pests. Today, the global interconnection,
overpopulation and the frequency of international traveling make the separation of risk
factors impossible (e.g. a dangerous carrier of Aedes albopictus disease was brought into
the USA in a cargo of car tires coming from the East Asia and spread all over the
continent, four different serotypes of virus, each from a different geographic range, are
now distributed all around the world). Vectors are sensitive to high temperature and
increased humidity, floods and winds, i.e. climatic changes. Human influence on such
diseases is enormous. There is a great danger of the distribution of these diseases to the
areas that have never been affected but have weather conditions similar to those regions
they come from. Malaria is one of the most serious and complicated public health
problems, and is consider today as a disease most likely to appear due to climatic changes
(WHO, WMO; UNEP, 1996). Countries facing the greatest risk of malaria are the
countries touching the edges of the countries with the permanent distribution of malaria
and the countries with a failed program for malaria control (The Central Asia and East
Europe). It is important to mention dengue, an infectious disease caused by an arbovirus
and transmitted by mosquitoes. More than half of the world’s population live in places
that are at risk of this infection and 100 million new cases is reported every year (RigauPerez et al. 1998). First of all, dengue is a disease of urban areas in tropical countries with
considerable demographic changes. The migration of population from rural areas to cities
and towns has resulted in the spreading of urban areas and a lack of adequate housing and
water supply systems. These are ideal conditions for the development of vectors (Gubler
and Clark, 1995). Schistosomiasis is caused by flat worms whose intermediate host is a
small water snail. The prevalence of this disease is increasing all around the world due to
the developing of irrigation systems in the warm regions with a population of snails as
human parasite transmitters of the disease.
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4. Conclusions and directions:
The primary aim of adaptation to climatic changes is to reduce the
development of a disease, its consequences, the accompanying disabiliti es,
pain and fatality.
Many effects of climatic changes, including health effects, can be
reduced or avoided by different adaptations (Mac Iver and Klein, 1999). The
mechanisms of adaptation include different sectors: healthcare, water supplies, education,
agriculture, purchase and sale, tourism, transportation, development. Not having these
aspects in mind, the improvement of public health is going to be an extremely hard job.
The primary and secondary adaptation measures, a strategy of adaptation based on
cooperation between similar and different sectors are all necessary for the reduction of the
effects that climatic changes have on human health.
In these areas it is necessary to monitor the course of climatic changes and make
predictions of possible consequences for human health accordingly. The more data we
have on potential climatic changes the better we can prepare for the future events. These
preparations should be aimed at the reduction of those human activities that have been
proved as a potential threat to climatic conditions and human health under certain
circumstances.
By examining the quality of the soil, as part of agricultural research, and with the
help of the data about climatic tendencies, it is possible to plan which crops can be grown
successfully in the given area. By keeping track of certain vectors, adequate measures can
be taken to prevent their spreading and adequate immunization campaigns can be
conducted. As part of general urbanistic plans in city developments, the esthetic aspect
should be of great concern (more green surfaces and vegetation), new codes of practice
and design standards should be introduced for building. Educational programs should
include instructions for the population on how to protect themselves from natural disasters
and how to protect and improve (prevent pollution) their environment. A list of polluters
should be made and penalties imposed on them unless they take the necessary measures to
stop the emission of harmful gases. The principles of the trash disposal strategy are to be
strictly followed. The population is to be informed through media about the tendencies of
climatic changes and their possible effects on their health. As part of scientific research
there should be a monitoring of the course of climatic changes, diseases and vector
control.
11
Recommended readings:
1. WHO (2000) Climate change and human health: Impact
RESOURCES
recommended readings et
al.)
and adaptation. Prepared by London School of Hygiene and
Tropical Medicine, World Health Organization, European
Centre for Environment and Health Roma, Protection of the
Human Environment Geneva. R. Sari Kovats Bettina
Menne Anthony J. McMichael Carlos Corvalan Roberto
Bertollini.
2. WHO: Health 21: the impact for all policy framework for
the WHO Europen Region, Europen Health for All Series;
No. 6, Regional Office for Europe, Copenhagen, 1999., 64112.
3. WHO: The World Health Report 1998.: Life in the 21st
century A vision for all, Report of the Director-General,
Geneva, 1998., 124-126.
5. References
1. Gubler DJ and Clark GG (1995) Dengue and
haemoralgic fever: the emergence of a global health
problem. Emerging Infectious Diseases, 1:55-57
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(WHO/EHG/96.7).
8. WHO (2000) Climate change and human health: Impact
and adaptation. Prepared by London School of Hygiene
and Tropical Medicine, World Health Organization,
European Centre for Environment and Health Roma,
Protection of the Human Environment Geneva. R. Sari
Kovats Bettina Menne Anthony J. McMichael Carlos
Corvalan Roberto Bertollini.
EVALUATION OF UNIT
BY STUDENTS
(student questionnaire)
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