Weather: Human Aspects

Every aspect of our lives is affected by weather; the table below summarises the effects on various areas of economic and social activity.

Effects on the economy

• Agriculture - Animals and livestock get distressed in excessive heat or cold, particularly young animals. Fodder and grazing need to be available at all time for animals, this is difficult in winter. Crops. Few grow above 60° N or S. Most crops can be affected by variations in day-to-day weather fluctuations. A late frost affects the coffee crop. Droughts are threat to crops. Pests tend to be weather dependent (locusts).
• Fishing - Is completely weather dependent. Icing of the superstructure leads to disasters, as do storm conditions.
• Construction - Concrete laying and groundwork cannot take place in extreme cold or wet periods. Tenders are often adjusted to allow for weather risks. Using the services of the weather forecaster saves £120 million/yr for the construction industry in the UK.
• Transport - Bad/adverse weather causes delays and accidents. In the UK airlines can save millions of pounds per year, local highway divisions can save by only gritting where necessary, and shipping can save fuel and time, all by using forecasting to help them be more efficient.
• Power - There is a strong and obvious link between weather and fuel used. Most utilities estimate, using past weather records, when greatest demand will be.
• Television - Reception is affected by rapid changes in temperature and humidity. Anticyclonic conditions in particular affect reception.
• Business and Retail - Most businesses would be unwise to ignore the weather. E.g. in summer, supermarkets stock up on BBQ fuels and foods, salad products and fruit. Cinemas lose their attraction. DIY enthusiasts buy equipment and plants. Ice cream sellers do a roaring trade. In winter, stocks of antifreeze and batteries for cars sell quickly. Plumbers attend more leaks and bursts. Pharmacists dispense more medicine. Wet weather equates to more business for retail outlets in tourist areas, and so on.
• Leisure and Sport - By using forecasting we can plan our activities for maximum enjoyment and safety. In the UK indoor parks (Centre Parcs) and covered stadia (Millennium Stadium in Wales / the Millennium Dome and the new Wembley Stadium Complex) are all responses, perhaps, to our unreliable weather.
• Health - Housing, dress and way of life all relate to the weather and climate of our respective home area. Our comfort (addressed by air conditioning or heating), activity (i.e. cold restricts activity) and health (asthma, heat-stroke, hypothermia and hayfever) are all affected.

Threats to our ecosystems

Too much UV can cause cataracts and crop yield drop, and plankton are damaged. The latter not only save food chains, but also have a regulatory exchange effect on CO₂. Plankton can regulate global temperatures. They can affect global warming!

The ozone layer

Ozone is a thin layer found in the stratosphere, 10 km to 50 km above the ground. Being very unstable, ozone is easily broken down by high-energy UV light; the process of breakdown causes absorption. This blocking effect is beneficial to us because high intensity UV can cause skin cancer.

Ozone is being depleted by mans use of CFCs (chloroflourocarbons) in industry, as a coolant in refrigerators and in aerosol propellants. Once released, CFCs rise high in the atmosphere, releasing chlorine. Chlorine is the destroyer of ozone.

Chlorine is released readily in the cold (below –80°C) sunless skies of the Poles.

By April 1992 UK and European scientists confirmed the American Upper Atmosphere Research Institute’s fears that chlorine levels were high, and rising, and that ozone was being destroyed more rapidly than ever before. If levels of ozone could be reduced or frozen at 1986 levels, as in the Montreal Protocol, then ozone levels might recover by the end of this century! What seems certain is that ozone levels will certainly deteriorate further before they improve.

A 1% decrease in ozone causes 70,000 new skin cancers and 100,000 new cataracts.

N.B. Ozone depletion was first noted in 1975 by the British Antarctic Survey.

Smog

The smogs we experience today are vastly different from those of the 1950s. London, for instance, was known as ‘Old Smokey’ or the ‘Smoke’ because of the thick smoky fogs that would often envelop the city. These only disappeared in the early 1960s when legislation and smokeless fuels ended the polluting effects of bituminous coal. Today we have to deal with photochemical smog, the more lethal relation of smog. Photochemical smog, produced by the exhaust gases of vehicles

and industry, in still, warm, clear sunny conditions contributes to a build up of poisonous ground level ozone. Small amounts at ground level are lethal, affecting breathing, causing conjunctivitis-type irritations and affecting plant and animal tissue.

The greenhouse effect and global warming

• We add 10 tonnes/person/year of CO₂ to the atmosphere.
• Current values = 240 ppm, during the last ice age there were 200 ppm

N.B. Our memories are short, in the 1970s we were warned about a return of the ice to the land! During the periods between the last four ice ages temperatures were 5°C warmer than today!

Warming near the Earth’s surface results in the atmosphere trapping the Sun’s heat: without the greenhouse effect the Earth would be 33°C cooler. CO₂ is a major contributor to the greenhouse effect and with water vapour it absorbs vast amounts of heat. Since the Industrial Revolution we have dumped vast amounts of CO₂ into the atmosphere. Once emitted, a CO2 molecule stays active in the atmosphere for about 200 years. Some computer models estimate a 1.5°C to 4.5°C

increase in temperature over the next two centuries because of global warming.

CO₂ from human activity is therefore a major cause of global warming, along with methane from termite colonies, flatulent cattle and rice paddy fields.

It should be remembered that global warming has been widely debated, that climate varies naturally and that in fact actual data that really does support the theory is difficult to come by and verify. Certainly some areas in the world have been hotter and drier and river flows have varied. However, many people believe that the data suggest a new ice age is upon us!

Best scientific evidence supports a significant increase in the Earth’s temperature over the last 100 years (this is well within normal averages/fluctuations of the Earth’s atmosphere). This increase will affect sea level; the Marshall Islands, Maldives and Kiribati islands, lower areas of the Nile and Bengal deltas could all be threatened by increases in sea level.

In the developed world we are attempting to reduce levels of CO2, for instance, by using energy efficient lights we might reduce CO2, sulphur dioxide and nitrogen dioxide emissions. Burning leaner and cleaner fuels and the implementation of energy efficiency campaigns will reduce the amounts of greenhouse gases released into the atmosphere.

Acid rain

Quantities of sulphur dioxide and oxides of nitrogen are emitted into the atmosphere from industrial activity and vehicles. In the atmosphere chemical changes turn rain into weak acids (in the order of pH 4.3). Why is it a problem? In the late 1960s lakes became acidic and fish populations plummeted in Scandinavia, caused by pollution from Western Europe. Germany has been particularly affected, in the mid-80s 58% of trees showed some signs of damage. Over the last twenty years Germany has spent £300 million, attempting to sort out its problem forests.

Acid rain also ‘rots’ buildings, the Houses of Parliament being a prime example. The future? Various Clean Air Acts in the Westernised countries have reduced the problem significantly. Remedially, lakes can be limed to neutralise acids.

Aspects of local climate

Air flow in mountains (anabatic and katabatic winds)

During the day when conditions are calm, warm air blows up the valley in response to the heating of the air in contact with the valley slopes. At night the reverse happens. A return wind at night completes the circulation. Accumulations of cold air in valley bottoms can cause frost hollows to form.

Land and sea breezes

On warm days air over the land heats up and expands. This tilts the pressure gradient. The result is that a small landward blowing circulatory system develops, with compensating outblowing wind aloft. The reverse happens at night. These breezes have a marked effect on coastal climates.

Mountain climates

Few mountain climates fit into any climate scheme easily. For instance, in tropical areas increases in height are the equivalent of an increase in latitude. In Africa and other equatorial continents and countries, mountains are important for their effect on precipitation patterns and for the moderating effect they have on temperatures.

Urban climates

Buildings interfere with both wind and airflow patterns and they change temperature regimes. In the high-rise cities of the world, wind is channelled down streets, the so-called venturi effect. These effects cause massive turbulence in city streets, particularly at night and especially in winter. Cities tend to have lower humidity rates, because of a lack of vegetation. Evaporation tends to be high, combined with turbulence; thunderstorms over or near cities are common. Increased light precipitation over and around cities is an observable feature, and may contrast markedly to the surrounding countryside.

Heat island effect

The contribution of industry, central heating, the heat retaining and emitting properties of the fabric of the city, and the blanket of pollution, cause temperatures recorded over the city to be one or two degrees higher than the surrounding countryside. If plotted on an isotherm map, temperatures show a marked decline from the central area to the edge of the city.