Urboecology is a science that studies the interaction of human activities with the environment in settlements. In the 21st century, cities become a place of concentration for most of the world's population. So, in 2001, for the first time, the number of urban residents exceeded 50% of the total population of the Earth. It is assumed that by the 30s of this century, there will be 2 times more urban residents than rural residents. Therefore, urban ecology and urban problems affect the interests of more and more people. Particularly relevant are the developments to improve the urban environment proposed by urban ecologists for residents of megacities.
Fundamentals of Urban Ecology
Urboecology is a science that uses the data of technical, engineering, medical, biological, geographical, social and economic sciences to solve its problems. The objects of study of urban ecology are territories developed by man, which include individual buildings, quarters, cities, regions and even entire countries. The subject of the study of urban ecology is the mechanisms of interaction between the urbanized and the natural environment. The task of urban ecology is to develop a plan for the development of the settlement, ensuring a high quality of human life, protecting health, protecting litho, hydro, atmosphere and biota from the harmful effects of urban development. The implementation of the development of urban ecology in life largely depends on state policy.
It is often said that urban ecology is urban sprawl and the problem of overpopulation. But there are other environmental problems associated with cities:
- the increase in urban pollution, the ingress of pollution into the environment around cities;
- “Sprawling” of cities and the number of inhabitants, too high population density, turning cities into giant megacities with a population of tens of millions of people;
- crowding out the natural landscape with an artificial one;
- loss by a person of direct contacts with nature (tactile, sound, visual, olfactory);
- the effect on the natural daily biorhythms of a person (night work, lighting of cities at night, noise).
The problem of "sprawling" cities
The highest percentage of urban population is observed in the economically developed countries of Europe and North America - more than 70%. The most gigantic urban development called Boswash consumed more than 500 cities on the territory between Boston and Washington. About 20% of the total US population lives here. “Bosvash” in the photographs taken from Earth’s satellites at night, looks like a solid luminous spot. And there are more and more such agglomerations in the world.
And now, at an active pace, urban enlargement in poor countries is taking place. If in the first half of the 20th century 20 of the 30 largest megacities of the world were located in developed countries, in 2017 there were only 5 such cities (Tokyo, New York, Los Angeles, Osaka, Paris), the remaining 25 are in developing countries. The largest of them are Bombay, Lagos, Shanghai, Jakarta.
Anthropogenic pollution of the urban environment
Inadequate management of city development leads to an increase in the negative impact on the natural environment of cities. These include:
- pollution;
- exhaustion of natural resources;
- global climate change associated with human activities;
- change or destruction of natural landscapes.
The most dangerous type of anthropogenic impact is pollution. The main sources are: motor transport, industrial enterprises, especially the petrochemical industry, ferrous and nonferrous metallurgy, thermal power plants, waste incinerators.
Chemical pollution is caused by the ingress of new chemicals into the environment or an increase in the concentration of compounds present in it. Xenobiotics are a particular danger to human health - substances that are not characteristic of nature (heavy metals, nitrosoamines, polycyclic hydrocarbons), which lead to metabolic disorders in the body, have a carcinogenic and mutagenic effect.
Physical pollution is divided into thermal, noise, light, electromagnetic, radioactive. Mechanical pollution occurs with substances that do not have a physical or chemical effect on nature. These include mainly waste from the production of building materials. Biological and microbiological pollution - the most dangerous infectious diseases are recorded precisely in places of the greatest concentration of people.
Environmental impact of the city
The abiotic components of the environment include litho, hydro and atmosphere. The most important part of the lithosphere for humans is soil. It takes a very long time to form - only 2-3 cm in 200 years. The soil is most easily destroyed under the influence of erosion and its swelling by the wind, and the most valuable areas, agricultural land, are affected first of all. Of great danger is the inept use of various pesticides, which cause the death of flora and fauna of the soil, as well as pollute groundwater. Negatively affect the soil and municipal solid waste, which every year becomes more and more. Annually, 1 billion tons of garbage are thrown out on the planet, most of which are synthetic materials that are not destroyed in nature and pollute the soil for millennia.
The main factors of the negative impact of the city on the hydrosphere are the high water consumption associated with farming in the suburbs, and wastewater pollution. Megacities annually dump about 350 million tons of polluted wastewater containing phosphates, nitrogen, heavy metals, petroleum products, and detergents.
The most common air pollutants are dust, sulfur oxides, carbon dioxide, nitrogen oxides, and hydrocarbons. The air above a large city contains 25 times more harmful impurities than the air of the countryside. The cities located in mountain valleys suffer most from air pollution. Polluted air causes approximately 30% of all diseases of urban residents. Allergens in the air (hydrogen sulfide, formaldehyde, nickel, chromium) cause bronchial asthma, rhinitis and other respiratory allergies. In addition, residents of urban areas located next to the enterprises of the petrochemical, chemical or metallurgical industries have 2 times more frequent pathologies of pregnancy and childbirth and 6-7 times more births of children with pathologies or developmental abnormalities.
The functioning of the city affects the flora and fauna. Plants play a special role in the city - they absorb carbon dioxide and produce oxygen. Deforestation of 1% of the forest leads to a decrease in river flow by 2.5% and is fraught with shallowing of rivers. Forests protect the soil from erosion, swelling by the wind, and purify the air. 1 ha of pine forest absorbs up to 32 tons of dust per year. And if the vegetation benefits the city, then the city itself adversely affects it. Moreover, small arrays along the roads suffer the most. For example, linden in the forest lives up to 400 years, in city parks - up to 150, on the streets - only up to 60 years. A number of factors have a negative effect: air, soil and groundwater pollution, soil compaction, vibration from transport, violation of the temperature regime.
The influence of the urban environment on the animal world is ambiguous. For some species of animals and birds, existence in the city is impossible - there is no food or habitual conditions of existence and reproduction. For other species, the city provides food and protects from natural enemies. The city is dominated by birds that can twist nests under the roofs, on the cliffs - pigeons, sparrows, swifts, jackdaws.
Urboecology offers solutions to the environmental problems of the city
1. Greening the urban environment
It is necessary to ensure the ecological balance between the urban and natural environment, to preserve the natural surface of the Earth along with soil, vegetation, wildlife, and relief. This is possible when building cities with several dense buildings and powerful landscaping.
2. Energy Saving
It is necessary to build energy-efficient buildings, use technologies that do not require energy.
3. Reducing the negative impact of the urban environment on human health
It is necessary to improve the quality of air and water, save water consumption. Best of all, green spaces - forests, parks, green corridors - cope with the issue of improving the environment. They purify the air, regulate the microclimate, isolate noise, retain nutrients, provide biodiversity, and enable pollination and dispersal of seeds.
4. Waste reduction and disposal
It is necessary to introduce a waste management system, to reduce the adverse impact of waste by reducing and recycling it.
5. Resource Saving
One of the problems of cities is the cost overrun of fresh water, so it is necessary to introduce systems for collecting rainwater. For construction, it is necessary to choose materials with a high service life.
The main idea of creating an urban environment, proposed by urban ecology, is a “replacement” ecological reconstruction of cities, restoration of landscapes. This is the mildest way, which does not require large-scale interventions in the life of existing cities.