Impact of Weather on Population

Weather is the state of the air at a particular place and time – warm or cold, wet or dry, cloudy or windy or the likes. Climate is the normal pattern of weather experienced in a particular area over a long period.

The weather and climate of a place has always affected populations. Throughout history, humanity has always been in awe of the weather, and weather still plays a big part in our lives today. It affects many of the things that we do, from the clothes we wear and the food we eat, to where we live and how we travel.


Since the dawn of history human settlements, migrations and growth has depended on weather conditions. All the great civilizations and empires have flourished near rivers and oceans, where the weather is moderate and suitable for the cultivation of crops and domestication of animals.

Just to cite some instances from history, it is the pleasant climate of England that attracted the various invaders of the past like Normans, Danes and others to settle down, and gradually over the years assimilate to form what is now the English population. The harsh climate of the Arabian deserts have prevented the interiors of the land from being invaded by an external force in the annals of history, and moreover was an added incentive for the Arabs to burst out from that hot and barren land to establish one of the largest empires during the medieval period. The Arabs landed in Spain initially on an expedition, and attracted by the weather, stayed and ruled there for 800 years! Many once thriving cities are now abandoned ghost towns primarily because the weather changed and people could no longer continue with their lives there. A big tsunami in the Indian Ocean in 1341 CE wrecked havoc of most of the well-established ports and led to the formation of new natural harbors in places like Cochin and Karachi, which soon developed into big cities.


Weather has an impact on the physical and mental make up of the populace as well. The culture, the way of life, the dietary habits, the clothing trends, the behavior of people coming from places where the weather in harsh differs significantly from that of people who live under docile climates. It is possible to stereotype the populace of cities and even nations based on weather related factors.


Weather also has a profound effect on human health and well-being. The hypothalamus in the human brain controls the body’s main functions like mood, activity, sleep, temperature, appetite, and sex drive. This hypothalamus is stimulated by natural light that passes through the retinas in our eyes, and when there is less light, these functions slow down. This is why people tend to feel better when the sun is shining and the lack of lack of sunshine can cause ‘winter blues’ or Seasonal Affective Disorder (SAD).

People generally perform at their best when they are not under stress from the surroundings, and that includes the weather. Researchers in the Ukraine have found that slight low-frequency atmospheric oscillations that cause changes in atmospheric pressure can influence human mental activity, causing significant changes in attention and short-term memory functions.

Hot humid days are generally associated with decreased general activity, lethargy, a tendency to procrastinate, poor reaction times and performance, sleeplessness and irritability, and heat waves usually bring out an increase in crimes and violence. Cooler days, with lower humidity, tend to increase alertness and general activity, and improve moods.


People call seasonal winds like the fohn in the Alps, Mistral in southern France, Chinooks in western Canada and the USA, and the Sharav in Middle East as “ill winds” as such winds herald feelings of anxiety, stress, depression, and sleepless nights among the vast majority of the populace. When these winds blow, temperatures increase rapidly and negative electric charges or eons dominate the air. Studies have linked these winds to an increase in traffic accidents, crime and suicide rates. Schoolteachers notice that children tend to be more irritable and that there are more playground ‘upsets’ when it is windy. Heating and air-conditioning depletes negative ions, leaving the positive ones to re-circulate and improve moods.

Higher air temperatures also increase the concentration of ozone at ground level, and in the lower atmosphere, ozone is a harmful pollutant that damages lung tissues. The heart would have to work harder to keep the body cool during the hot weather, leading to heat exhaustion, respiratory problems, and eating disorders. Seasonal variations in temperature and excessive humidity also lead to medical disorders such as bronchitis, pneumonia, influenza, peptic ulcer, adrenal ulcer, glaucoma, goiter, eczema, and herpes zoster and several viral infections. These are the reasons why people generally go on vacations to hill stations and cool areas to beat the summer heat.


Research has proved that weather is associated with changes in birth rates and sperm counts. In addition, several atmospheric phenomena like atmospheric pollutants and pollen concentrations, indirectly related to weather also have an impact on the mortality rates of a populace.

Heat Waves lead to large-scale mortality. The 1980 heat wave accounted for an estimated 1327 deaths in the USA through heart failures and cerebrovascular accidents. Humidity also has an important impact on mortality since it contributes to the body’s ability to cool itself by evaporation of perspiration. The World Heath organization estimates 150,000 deaths annually because of climate change.


Today, Global warming may lead to sea levels rising by six feet and this threatens to inundate many coastal areas of the world, including Beijing, Bombay, and even the entire island nation of Maldives. Global warming would also convert vast swathes of fertile lands to hot and uninhabitable deserts and conversely throw open many sub-freezing lands like Greenland for human habitation. All these are likely to cause large-scale population shifts and changes in the way of life. Already people in the Arctic lives find their way of life changed due to scarcity of their traditional food sources, thanks to the melting of polar ice caps.

Global warming also causes changes in the life cycles and behavior patterns of animals, and this again has a significant impact on how people live. Rising temperatures could lead to a major increase in insect-borne diseases in Britain and Europe, as per the report of the World Health Organization.