Climate Change and Extreme Cyclones
Cities are the colonized places of high-dense population, where the inhabitants enjoy easy livelihood, communication, healthcare, education, security and recreation facilities. Due to climate change effects, the basic ingredients namely air, space, light, water and other logistic support and services of a citizen are increasingly hampered and the cities are becoming inhabitable. The present study analyzes the magnitude of climate change effects on city lives and works out the ways of adaptation to reduce the risk of the anticipated disasters. It is found that migration towards the cities for livelihood is increasing at a very high rate and the cities are increasingly facing various crises like accommodation, energy, transportation, pollution, wastes, insecurity, crimes and social unrest. Resource management and biomass recycling have been seriously affected. It has also been investigated that the poor planning and administrative weakness aggravate the crises. However, it has been found that the cities are the ultimate shelters during major disasters like floods, tidal surge, cyclones, tornadoes and famine. To keep the cities safe and habitable, the ways for mitigation of climate change effects are focused, and appropriate ways are recommended for better adaptations.
Urbanization is an inevitable process which occurs because of various factors. The number and size of cities has grown particularly rapidly in the twentieth century in all countries. In highly industrialized countries, the urban population has already reached 70 to 80%. Global proportion of urban population was 220 million (13% of total) in 1900 which has increased to 732 million (29%) in 1950, to 3.2 billion (49%) in 2005 (Hafiz, 2009). In the very near future, an overwhelming majority of the world’s population will live in cities.
A similar process is taking place in Bangladesh. In 1950, the population was less than 5% in urban and 95 % in rural areas of Bangladesh. The rapid industrial development and work opportunities have speeded up the process of urbanization. Today, more than 20% of the population of Bangladesh lives in cities, and old cities has expanded and many new ones appeared.
Fig. Rising Dhaka City
Some of the urban agglomerations are very large; the population of the world’s top ten cities is:
1. Tokyo, Japan 28,025,000
2. Mexico City, Mexico 18,131,000
3. Mumbai, India 18,042,000
4. Sáo Paulo, Brazil 17, 711,000
5. New York City, USA 16,626,000
6. Shanghai, China 14,173,000
7. Lagos, Nigeria 13,488,000
8. Los Angeles, USA 13,129,000
9. Calcutta, India 12,900,000
10. Buenos Aires, Argentina 12,431,000
Source: World Atlas http://www.worldatlas.com/citypops.htm
The number of cities in Bangladesh was 70 in 1950 but now it is 522 including 6 city corporations viz. Dhaka, Chittagong, Khulna, Rajshahi, Barisal and Sylhet and total urban population is about 30 million (Nazem 2009). Dhaka is now a mega city; from 1951 to 2001, the population of Dhaka city increased 25 times and the area has increased by 18 times (Jahan 2009 and Rahman 2010). Present population of Dhaka city is around 12 million and is projected to grow 20 million in 2020, making it the world’s third largest city (Satu and Ovi, 2009).
Scientific and technological progress and urbanization process raise the level of cultural and the daily services for the population, the comfort of housing and general prosperity. The urban way of life has many advantages, and they are preferred by many people. But urbanization is also involved with many shortcomings, above all, air pollution and deterioration of the climate. The principal sources of air pollution in the cities are industry and motor transport. Polluted city air is more opaque, reduces solar energy and in large cities causes a poisonous gas to occur. The hurried way of life and constant nervous tension, the stress experienced by the inhabitants of big cities, combined with little physical exertion, polluted air and long time spent indoors have caused an increase in nervous, heart, lungs, liver, metabolism, and other diseases.
The basic shortcomings of life in cities have to do with deficiencies in man’s biological environment. Efforts are therefore, being made to reduce pollution and make the elements of nature in cities as close as possible to the natural environment. The main factor here is the planning of greenery.
Greenery plays a major role in cities. Trees and shrubs trap as much as 72% of the suspended dust and up to 60% of the sulfur-dioxide. They regulate air temperature and humidity, enrich the air with oxygen, and emit phytoncides killing microorganisms. In the hottest weather, the air temperature among green plants is 4 to 8°C lower than among buildings. Plants help man to fight noise in the cities. Tree leaves absorbs up to 26% of the sonic energy which fall on it. A street which is lined with trees is five times quieter than one without trees (Astanin and Blagosklonov, 1983).
Experts estimate that for an optimal life there must be about 50 m² greenery/person and another 300 m² in recreational forest zone. Plants not only create a favorable microclimate in the city and improve the sanitary condition of the air, but are also an important part of the urban landscape.
Methods and Materials
The present study was conducted by analyzing the ongoing situation of the urban areas of Bangladesh taking the references of scientific data from research and publications. For clear expression, photographic and electronic media were used. Personal experiences and evidences of circumstances are the main support of the present study.
Observation and Discussion
In the recent years, most of the cities of Bangladesh are being experienced with many crises due to climate change effects. Most of the rivers in or along the cities have lost their perennial water flows and there is a severe water crisis in the cities. Moreover, refuses including polythene and plastics from the homes and industries are often thrown into the drains and water bodies and these create serious pollution problems of water. The pollution problem is so serious that water of the rivers around Dhaka city is not recyclable. The cities are mostly using underground water and the water table is going down every year which has aggravated the situation (Rahman, 2009).
Fig. Street hawkers on the footpath Fig. Flood in Dhaka city, July 28 2009
obstructing the passersby’s movement
Fig. What a crowd of migrants? Fig. No greenery but slums
Occasional cyclonic storms, cloud outbursts, floods, tidal surges and epidemics have been experiencing by the countries which have driven millions of climate change refugees to the cities. Climate change refugees mostly from the poverty prone flood and drought affected Monga areas have gathered in the cities and taken shelters in the slums, which is one of the biggest problems of the cities. They are so poor that, at best, they can hire basic accommodation in crowded slums (Jahangir 2009). About 12% population of Dhaka is living in the slums with a concentration more than 247,000 people per sq km which is 16 times higher than the average population density in the city (Hafiz and Islam 2009). Due to unhygienic sanitary condition, most of the people are vulnerable to various diseases like cholera, typhoid, food poisoning, dysentery, skin diseases and worms etc., which also causes serious water pollution when human excreta is discharged directly into to the water bodies.
Fig. Landslide in Chittagong, Jun 2007 Fig. Flood and Tidal Surge in Chittagong
It has been observed that, due to lack of sufficient drainage facilities of discharging surface runoff, during the monsoon the city roods get overflowed. In the wet season, water table rises and trees are dying due to water logging. The heaps of garbage often go down under water and create serious pollution problems in the cities; as a result, huge biomass which could be valuable as organic fertilizers is lost.
Moreover, it has been observed that most of the Real Estate companies like Asian city, Modhumati, Concord, Eastern Housings and the RAJUK are establishing so-called city parks in Dhaka by land filling of the water bodies and catchments. The rivers, canals and lakes are being encroached and disturbed the water flows and the basins are being raised, thus creating a great surface water crisis in the dry season and flooding in the wet season.
Fig. Green garbage along with plastics, polythenes, metals and what not?
Fig. Land-filling in the heart of river Turag Fig. Power connection or a death trap?
There is a very little or no greenery in the cities especially in Dhaka. Most of the buildings do not have enough space for raising avenue plantations and also for home gardening. Although some plantations are made here and there, but in most cases people do not raise plantations according to the habit and habitats. Rather plantations are raised under the high tension lines or very proximate to the buildings, drains or sewerage. Spacing and plants’ habit and habitats, are seldom considered. As a result, during strong winds it has been found that serious power failure, road blocking due to uprooted plants, and sometimes people get trapped and die. So, the utility-men have to often fell down or pollard the trees to tackle the situation.
However, from the study it has been studied that most of the city homes are concrete structured and multistoried. They can easily resist cyclonic storms and there is a very little evidence such structures collapse during the cyclonic storms and strong winds. Reinforced concrete buildings can easily withstand wind speed of 300-500km/hour, but the highest speed of cyclonic storms was recorded 225km/hour (Chowdhury, 2008, Tarikhi 2008). During high floods and tidal surges, the cities are the safest places as the homeless people can take shelter in the multistoried buildings, even on the rooftops. So, there is a little chance of loss of lives in the cities. It has been observed that hundreds of thousands of floods and tidal surges affected coastal and rural people took shelter in the nearby cities during the cyclones of 1970, 1988, 1991, 1998, 2007 and 2008. So, for the safety, the peri-urban and rural people can take shelter in the city buildings during floods.
The cities can be considered safer zones than the present rural areas for the birds and insects as the farmers are indiscriminately applying pesticides for cropping culture. Consequently, chirpings of birds are heard in the city trees in the morning and evening. Therefore, more attention should be paid for establishing plantations and arboretums. The plantations should be made keeping safe distances from the structures, transmission lines and bridges etc. according to the canopy height. Evergreen fruits, nuts and palms and ornamental plants with straight boles and less branches, should be established, according to their growing habitats.
Everyday about 5000 tons of wastes are being accumulated in Dhaka city only of which 80% are of agricultural origin. These agricultural wastes are the biomass and of course valuable fertilizers. Only 1300 tons are being processed at Matuail and the rest is dumped here and there, the sites of origin of their organic matters have been deprived as these are not recycled to their source of origin throughout the country. These organic valuable fertilizers could have been served the purpose of fertilization (Rahman 2010). However, it has been observed that hundreds of tons of vegetables are produced in the periurban zones of Dhaka city like, Kanchkura, Ashkona, Ashulia and Kamrangir Char etc. utilizing only a portion of organic wastes of the city. This can be an option for using of agricultural wastes through urban agriculture to feed huge population of the city especially with the green vegetables and fruits.
Although the cities are considered as safe and comfortable places for living, the present city lives are full of mischief. Due to lack of proper planning and implementation of code of practices, the climate change effects are seriously damaging the lives and properties. To overcome the situation, proper adaptation is needed. Spacious and aerated buildings, wider roads, easy and mass transports, running drainage, clean water bodies, greenery and parks, shelterbelts, quick and separate disposal of garbage and security etc. are essential. Urban forests and greeneries are the lung of the cities and the water bodies and catchments are considered as the heart. Urban gardening or agriculture can provide organic and fresh foods.
To mitigate the power crisis, all buildings must have their own solar systems at their roof tops which should be mandatory for the building code of practices. Safety measures like fire-fighting, security access to emergency services should be ensured. Every building should have enough space for gardening and vegetation.
1. Astanin, L.P. and Blagosklonov, K.N., 1983: Conservation of Nature; Progress Publishers, Moscow
2. Chowdhury, M.R., 2007; Cyclone Sidr: Impact of Climate Change; The Daily Star, December 8, 2007
3. Hafiz, R. and Islam, I., 2009: World Town Planning Day 2009: Planning for Livable Communities: World Planning Day 2009, Bangladesh Institute of Planners
4. Jahangir, S., 2009: Sustainable Water Supply and Sanitation System in Urban Slums: A Case Study on North Begum Bari Slum of Dhaka City; World Planning Day 2009, Bangladesh Institute of Planners
5. Nazem, N.I., 2009: Future Planning of Our Cities; Planning for Livable Communities; World Planning Day 2009, Bangladesh Institute of Planners
6. Rahman MA, 2010, Climate Change hits Drastically; The Bangladesh Observer December 13, 2009
7. Rahman MA, 2010, Organic Fertilizers can be produces from Garbage; The News Today, Jan 9, 2010.
8. Tarikhi, P., 2008; Cyclone Sidr; ASM: Asian Surveying and Mapping January 2008
Climate Change Adaptation for Cities
Asian Disaster Preparedness Center (ADPC)
Bangladesh Disaster Preparedness Center (BDPC)
In collaboration with
The Ministry of Food and Disaster Management of
Professor M Alimullah Miyan, PhD
South Asian Disaster Management Center (SADMC)
Founder & Vice Chancellor of IUBAT—International University of Business Agriculture and Technology
4 Embankment Drive Road, Sector No 10,
Uttara Model Town, Dhaka-1230, Bangladesh
Co-author: Mohammed Ataur Rahman, Director Cntre for Global Environmental Culture, IUBAT, Uttara Model Town, Dhaka, Bangladesh
February 17-18, 2010