Human Population and the environment: How human population, intervention,Activities affect environment ?

 Human Population and 

the environment 

Human Population and the environment:

                           

How human population, intervention,Activities affect environment ?

Humans  are present almost everywhere.  The number of peoples living in an area is somewhat called population. It may be higher in some area like Delhi,India or lower in parts of ladakh.Anywhere humans live they have to rely on environment for food,shelter,energy etc. But in the search of proper livelihood, humans somewhat compromise with the environment. In this article by HavePrasad, we will know 

                        

How human population, intervention,Activities                               affect environment ?

Human Population and the environment

The population of a species in an ecosystem depends primarily on the birth rate and the death rate (also called mortality). The birth rate is the number of individuals born in a fixed period of time, say a year. The death rate is the number of individuals that die in a fixed period of time. If the birth rate is greater than the death rate, the population increases, and if it is the other way round, the population decreases. There is another factor that influences population. Individuals may come from another place and join a population, or immigrate. They may also leave the population or emigrate.

What controls the birth rate, the death rate and migration? The birth rate depends on the species one is considering. For example, a dog may have seven or eight puppies at one time, while a human being may have two or three children in a lifetime.

The death rate depends on environmental pressures like shortage of food, air, light or water, sudden change in climate, natural disasters, an increase in the number of predators, and diseases. Many of these conditions are population-linked, or affected by the population of the species. For example, when the population of a particular species  rises due to favourable environmental conditions, there may be overcrowding. And overcrowding may lead to a shortage of food, air, light, and so on.

Under natural conditions, though the populations of different species in an ecosystem may rise or fall due to environmental conditions, a kind of stability is maintained over time. Say, the population of rabbits in a particular area rises due to favourable conditions, including a fall in the number of foxes, which prey on them. As the population of rabbits rises, so will that of foxes because they will have more rabbits to eat. As the foxes increase in number and kill off more rabbits, the rabbit population will fall, and so on .Thus, a natural balance of both populations will be maintained over time.

Migration is also linked to environmental conditions. When there is overcrowding in an area, individuals of a species may move on to another area in search of better conditions.

Growth of human population

The human population, as you have learnt already, has grown tremendously over the last 200-300 years.  In fact India's  population grew by more than 78 million in the last century. This is primarily due to the following reasons.

1. Increase in food production

2. Protection from predators and from climatic factors

3. Advances in medicine, which have increased life span, or brought down the death rate.

Impact on ecosystems

From the dawn of civilisation, our aim has been to protect ourselves from environmental pressures and to let our species grow at any cost-even at the cost of the environment on which our survival depends. This Telugu poem by Cherabandaraju expresses, in a very simple way, how we look upon our environment.

I will not stop cutting down trees,

 though there is life in them

I will not stop plucking out leaves, 

though they will make nature beautiful

I will not stop hacking off branches, 

though they are the arms of a tree

Because -

I need a hut

Forests As the human population has grown, so have our needs. And that has been due not only to growing numbers, but also changing lifestyles. We cut down forests to meet our growing need for land, which we use for  agriculture, industries and our settlements (towns and villages). We also destroy forests to meet our requirement of timber, paper and fuel. We build dams to irrigate our crop fields and produce electricity. In the process, large tracts of forests get submerged. They also get destroyed when we build roads through them and use them down to extract minerals.

Wetlands

Most migratory birds visiting India in inter take a break in Kashmir, before proceeding to other parts of the country. They used to earlier, and now they have started doing so again. In the middle, the birds had turned away, because the famous wetlands of the state were getting destroyed by human activities. A part of one wetland, for example, was cut off by a bund (embankment) to make room for paddy fields.

Wetlands are rich in biodiversity, or variety of species. They are the home of migratory and other birds. They serve many functions other than providing us with resources. Wetlands provide a natural way of treating sewage and controlling floods. They help to recharge groundwater and release water vapour into the atmosphere. Yet, they are being destroyed all over the world-being used as landfills, or reclaimed for agriculture or human settlement (as in Kolkata).

Ecosystems serve us in many ways. They maintain the natural cycles of matter. They protect us from drastic fluctuations in climate and purify the air. They stop soil erosion and control floods. They provide us with many valuable resources. A team of leading scientists and economists of the world has estimated the value of the services provided by ecosystems as $ 36 trillion per year.

Do you remember the story of the foolish man who killed the goose that laid golden eggs? That is precisely what we are doing with ecosystems. We are killing them to get quick gains, and thus, depriving ourselves of long-term benefits. The following example shows just what we are doing. The people of New York get their water supply from the Catskill watershed. A watershed, put simply, is the area from which water flows into a river. Some time back, when the quality of the water started declining, the people realised that they had only two options. They could build a water purification plant at the cost of more than $6 billion or restore the forests of the watershed at the cost of $1 billion. They decided to do the second, but it would have been the best not to have destroyed the forests in the first place.

It is not just forests and wetlands that we are destroying, but oceans, lakes, rivers, coasts-we are degrading ecosystems all over the world by overusing the resources they offer and dumping more wastes than they can handle. Even Antarctica and the Southern Ocean, which surrounds it, have not been left unpolluted. Pesticides and other chemicals have been found in the waters around Antarctica.

Biodiversity

 One of the permanent losses due to the destruction of ecosystems is the loss of biodiversity. Scientists estimate that we are loosing three species every day and that about 20% of the species living on the earth now will be gone in another 25 years. Many species will become extinct before we even know of them.

Loss of biodiversity has been caused not only by the destruction of ecosystems, but also hunting, fishing, pollution and urbanisation.

Human settlements

Human settlements have changed a lot over the centuries. This is partly due to growth in population and partly due to other factors. The first settlements were small clusters of homes around crop fields, or villages. Each village produced what it needed. Life was slow and at one with nature. There was no shortage of space and there was greenery all around. Then, as people started 'trading', or buying and selling, towns came up. The people living in towns did not depend on agriculture. They made their living through trade, so they did not need too much land. More people started living together in smaller areas. Roads, markets, houses, offices, and so on, replaced the surrounding greenery.

Industrialisation was the next big change. As large factories came up, small industries, especially village industries died, because factories could produce on a larger scale and at a cheaper rate. More and more people started flocking to towns and cities to look for work because no one bought the things they made any more. People left villages also because as the population grew, there were less resources to share, and the crops they produced no longer brought them enough money

The shift from villages to towns is still going on, especially in developing countries like ours. People come to a town or city looking for a job. Then they settle down, get married and have children. So the town's population keeps rising. In recent years, cities and towns which are centres of business and industry have become particularly overcrowded, with people flocking to them not only from villages, but also other towns.

Towns and cities have spread out, gobbling up neighbouring woodlands, croplands, forests and wetlands. They have become congested, with all available open spaces being used up for buildings. Multi-storeyed buildings have replaced spacious, single-storeyed houses Slums, with people crowded together in small shacks, have come up on common land)

The look of villages has changed too. The forests, grasslands and woodlands around them are being destroyed to fulfil our need for resources. The water bodies that people depended on are dying due to overuse and pollution. The waste produced is growing with the population, and is polluting the land, air and soil. Nature is no longer able to recycle it. And factories in the neighbourhood are destroying the ecosystems that used to provide the villagers with many of the resources they needed.

Land distribution

The term land distribution' means how land is divided among different people or for different uses. The growth in population has affected land distribution in many ways. The most obvious is that land has been taken away from natural cover to be put to use for various human  activities. Let us discuss the other ways in which land distribution has changed.

In recent years, the urban population has grown at a faster rate than has the total population of the world. This has led not only to overcrowding of urban areas, but also to the spreading out of towns and cities. Since urban areas grow at the cost of surrounding villages, cropland and land under natural cover, this too constitutes a change in the distribution of land.

The distribution of land within towns and cities is changing too. The greenery around houses is vanishing, as every bit of land is being used to accommodate more people. The open spaces, parks and playgrounds are being used up to make markets, houses, hotels, offices, parking lots, and so on. In general, more land is being brought under concrete cover. The distribution of land in the villages is also changing. The patches of green around houses are being used to extend houses or make new ones to accommodate more people. The greenery in the common areas is being replaced by shops or small business units. The woodlands and forests around villages are being replaced by plantations, factories, mills, and so on.

Stress on facilities and services

Stress on facilities and services 

So far, we have discussed how towns and cities are getting more crowded, and how more and more land is being brought under concrete cover. There are other problems related to the increase in urban population. When the population grows too fast, a town often grows in an 'unplanned' way. That means houses come up too close to each other, with narrow alleys between them. There is no space left for broad streets or roads with pavements for pedestrians Shops and offices come up in residential areas, making these more congested There is no space to park vehicles in markets, outside offices or even in residential arts Nor is there enough space for children to play or people to hold meetings, community celebrations, and so on. Slums come up on public land, along roads, next to railway lines, near railway stations and monuments, and so on.

(When a town or city grows fast in an unplanned way, the facilities or services that the people are supposed to be given do not suffice For example, the civic bodies do not have the means to provide drinking water for everyone or dispose of all the waste generated by the people The supply of electricity does not match the requirement and there are frequent power cuts Buses and other modes of public trampod get overcrowded. Hospitals de not have enough beds for patients. There are traffic jams because the roads are not made for the increasing number of vehicles)

Loss of heritage

Encroachment on monuments

Old buildings and monuments and the pride not only of a city or town, but of the entire country As the population grows, the need for space pushes people to bring down old buildings and build space-saving multi-storeyed butdings This is happening in the old parts of every city. Old office buildings, post offices, town halls, havelis, cafeterias, and so on, are being replaced by modern highrises, Old buildings are often symbols of pride that people identify with. When they are brought down, that collective sense of identity gets hurt. It is a historical loss too.

Old temples, mosques, palaces and forts, that have not yet been brought down are often used by people for various purposes. Nobody maintains them and the parts left intact are used as shelters by people and animals. Some are used to store goods, and others as hide-outs by criminals. Even big tourist attractions, like the famous fort in Jaisalmer, are not free from encroachment. To encroach means to intrude into someone else's property. These old buildings are the property of the entire nation. We should preserve them for future generations, and not use them as shelters, shops and stores or let them get destroyed.