Scientists have been measuring the amount of carbon dioxide in the atmosphere for about 40 years, over which time the concentration has risen by about 15%. Older records of carbon dioxide, obtained from air bubbles trapped in Antarctic ice go back 300,000 years. Scientists have found that carbon dioxide levels now are 32% higher than before the Industrial Revolution, higher than they have been for 160,000 years. Other greenhouse gases have also increased: methane levels have more than doubled and nitrous oxide levels have risen by 15%.
Humans have also introduced greenhouse gases into the atmosphere that did not exist until this century, such as chlorofluorocarbons. We are changing the atmosphere faster than ever before!
Rising Temperatures. Additional greenhouse gases add to the natural greenhouse effect and are likely to make the planet warmer than it would otherwise be. Records show that the Earth is about 0.6C warmer than it was a century ago, with most of the temperature increase occurring in the last 40 years. The warmest year ever recorded was 1998.
Changes in natural phenomena can also indicate changes in temperature over a longer period of time. Evidence of warming includes melting glaciers, accelerated coral growth, and the varying width of tree rings. These records show the 1900’s to have been the warmest century in over 1000 years.
Acid Rain. This phenomenon is caused principally by the release into our atmosphere of sulphur dioxide and oxides of nitrogen. These gases dissolve into pure rainwater and cause it to become acidic. The burning of fossil fuels, such as coal, which contains high quantities of sulphur, forms Sulphur dioxide; nitrogen oxides are contributed from various industries and from car exhaust fumes.
These alarming shifts in our global environment could manifest themselves in many ways around the planet:
- Global temperature increases
- Melting of glaciers and polar ice
- A rise in sea levels
- Extreme weather conditions
- Damage to forests by acid rain
- Spread of diseases such as malaria
- Famine as crops fail in dry soils
LOCAL CHANGES
In the UK we can expect to experience much more of the flooding we have seen in recent years. Our summers are likely to be hotter and drier, while the winters become much more wet and windy.
Sea levels are likely to rise by as much as 200mm in the next 20 years. This may not sound like much but we will see an increase in coastal erosion and flooding as a result; especially on the East Yorkshire coast where the boulder clay cliffs are particularly susceptible.
The dramatic swing between dry summers and very wet winters will have a marked effect on soil and local habitats; we can expect more frequent shortages of water in summer months, which are likely to coincide with a higher demand for water services. Farmers may have to adapt the crop they sow to the drier soils we can expect, as the land may be unable to support traditional plants and trees.
The gradual loss of wetlands such as marshes, reed-beds and peat lands will devastate populations of wildlife that inhabit them; many of the species which do survive may be forced to migrate in search of ever-dwindling habitats.
The Impact of the Built Environment
While the world population continues to expand at a terrific rate, life expectancies lengthen, and habitable land area becomes less and less due to global pollution issues such as rising sea levels and changing habitat, the burden on the planet intensifies as areas are developed for habitation.
World Population Growth (In billions)
Year 1950 1994 2000 2050(projected)
Pop. 2.250 5.630 6.168 9.857
Our planet is taxed almost to breaking point by the burden placed upon it by civilization; every citizen of Planet Earth requires these basic commodities to survive:
- Food
- Water
- Breathable air
- Shelter
- Sanitation
Add to these the secondary comforts most of us demand in the 21st century, such as heating/air conditioning, transportation, clothing, entertainment etc and you begin to realise the impact that mankind has on the world’s resources.
Our settlements are connected by thousands upon thousands of miles of roads and railways, power and communication cables. We build houses and factories, schools and churches; each building connected to water and power supplies as well as drains and sewers. We travel to, from and around our cities in cars, motorcycles, buses and aeroplanes. Lorries deliver our commodities and take away our waste. Over the years our factories have polluted the land and the air around them, our waste has found it’s way into the waterways and the noise made by traffic and industry has become the soundtrack to our busy lives.
Agriculture and forest clearances have changed the very appearance of the country in which we live and mining and quarrying has left craters and tunnels in the ground from Scotland to Wales to Cornwall. Particles of dust in the atmosphere from traffic and heavy industry mean our children are more likely than not to suffer some form of respiratory disease. Furthermore, it is strongly suspected that there is a link between the presence of high voltage overhead power-cables and the incidence of childhood leukaemia.
Insurance companies are now refusing to provide cover for homes which are deemed liable to flooding. Many residents of the UK have had their houses damaged by floodwaters in recent years. As our climate changes to a wetter one due to the effects of global warming, our ancient systems of drainage are becoming increasingly unable to cope. We are now seeing vast areas of land in flood plains submerged every winter, forming huge temporary lakes. Town planners in years gone by couldn’t have foreseen that the very methods of draining our roads and streets that they pioneered are now a contributing factor to the problem of flooding, as heavy rainwater is channelled too rapidly into rivers and waterways causing them to burst their banks.
Before Victorian engineers opened a new canal, they would first drive herds of sheep through the cuts. The hooves of the sheep would compact the ground, thus preventing the canal water from draining away into it. There are nowadays up to 5 times the number of sheep on any given area of Welsh hillside than there were a century ago. The hooves of these animals have had the same effect on the ground in Wales that the Victorian engineers made good use of 150 years ago, the result being that when rain falls heavily on these hills, the rain is not absorbed into the ground in a natural way, pouring instead into the valleys and contributing to the already swollen rivers.
These are some of the many ways in which the progression of mankind from a tribal creature who was at one with his natural environment, to the city-dwelling modern being of the 21st century, who uses science to bend the forces of nature to his will for his own benefit, has wrought a world of steel and concrete which would be unrecognisable to our not-so-distant ancestors.
Sick Building Syndrome
Sick Building Syndrome is a malaise first diagnosed in the early 1980’s and largely afflicting office workers. Some of the more usual symptoms are:
- Eye, nose and throat irritations
- Dryness of throat and sinuses
- Breathing difficulties and chest tightness
- Headaches, nausea and dizziness
- Mental fatigue
- Skin rashes
- Aching muscles
- Flu-like symptoms
Companies which use buildings where cases of SBS have been recorded have experienced a dramatic loss of productivity in their staff; up to 40% in some cases, as well as an increase in absenteeism – as much as 30% over the acceptable “norm”. This ultimately leads to a loss in profits for the affected company.
Research shows that there are patterns to cases of SBS. Buildings where SBS occurs are usually:
- Mechanically ventilated
- Have windows sealed for energy efficiency
- Of lightweight construction
- Carpeted and have surfaces of ‘soft’ finish
- Warm, controlled-temperature environments
Looking at the above list of common factors, one might well assume that SBS is caused by a combination of exposure to solvents used in the construction and fittings of the building and poor ventilation. However, it has also been noted that clerical staff are more likely to succumb than managerial level personnel and that the symptoms of SBS are more likely to occur in an afternoon than in a morning.
It seems evident that the way staff feel about their working environment is as likely to have an effect on their health at work as the physical construction of the building itself. The conclusion that can be drawn from this observation is that SBS is about people. The occupants of a building need to feel that they are involved in the creation and control of their own environment.
Specific health risks.
Radon Gas – A colourless, odourless gas that occurs naturally in rocks below the ground. It can slowly filter through to the surface and accumulate inside buildings and is a cause of lung cancer.
There are measures reduce the effects of Radon gas (outlined in Building Regulations, Approved Document C). These are:
- Seal floors and walls
- Ventilate spaces below floors
- Install a pump where radon can accumulate, then extract it safely
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Use positive pressure ventilation systems
Legionella – Also known as ‘Legionnaires Disease’, this is caused by bacteria which breed rapidly in warm water (such as in air-conditioning systems). These bacteria release airborne particles, which cause pneumonia-like symptoms, often fatal if contracted by the elderly.
Legionella can be easily avoided by regular maintenance of air-conditioning and heating systems; systems which are operating correctly are usually operating at temperatures that are too high for the legionella bacteria to breed in.