The Impact of Weather on Human Activity
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The Impact of Weather on Human Activity
The weather and climate play a huge role in defining what human activities can and cannot occur. For instance farming types are directly influenced by the climate. Some of the more extreme weather conditions are shown below to describe how they might affect human activity.
Britain doesn't tend experience extremes of weather too often. Fog is common,and we usually have at least one bad flood each year. However, droughts and tropical storms (hurricanes) are much more rare.
In the last 25 years Britain has experienced drought conditions in the summer of 1976 and 1995. Both caused great problems for local water supplies, after months of below average rainfall caused the reservoirs to run out.
Although these two summers were very hot, dry and caused problems they were nothing comparable to the extreme droughts recently experienced in Africa.
The United Kingdom is not in the normal line of tropical storms or hurricanes either. In 1987 a hurricane hit southern England causing millions of pounds worth of damage, but this was a freak occurrence rather than something we should expect every year.
Droughts are times when there has been below average rainfall for a period of time, causing water supplies to dryup and run out. In countries such as the United Kingdom and America they cause inconveniences for the local people. Farmers probably will be affected andwater supplies might be more tightly controlled, but in general the countrywill cope pretty well. During the mid 1990's California suffered a 3-year drought, and yet life continued almost as normal.
However in some less developed countries the threat of drought is a very dangerous one that could result in millions of people starving to death. People in places such as Ethiopia and Sudan rely on the rains for their crops. Most of them are subsistence farmers, which means that they grow enough for themselves,and maybe a little to sell. If the rains fail they are left with no food and no means to buy any.
Equally Africa is a very hot and dry continent, so drinking water is always very valuable. No rains mean that quickly people run out of water. Serious droughts have affected areas of Africa for the past 30 years, killing millions of people.
Fog can cause great problems when it occursin the United Kingdom, Anyone who has been in a car on the motorway in fog will appreciate this fact. Accidents are frequently caused by people driving too fast in patches of thick fog where the poor visibility means that they cannot really see the cars in front.
Other methods of transport such as ships and planes are also badly affected by the poor visibility associated with fog.
Otherwise known as hurricanes, cyclones, typhoons, and wily willies (the Australian name!). These are very intense areas of very low pressure, approximately 500 to 1000 kilometres in diameter.
Tropical storms form over water that is above 26.5°C in temperature. The warm water heats the air above it, causing it to rise rapidly. Cooler air from elsewhere rapidly moves in to replace the rising air and the process starts again.
The rapidly rising moist air, cools as it ascends and forms tall cumulo-nimbusclouds. These slowly spin around the central point. Jet streams above thestorm clouds continue to suck the air up.
Cooling air sinks down through the spiralling mass of clouds to produce acentral eye of the storm.
Tropical storms move quickly over water, as long as it is warms enough to keep the storm energised. Once over land, where there is less moisture and the surface is cooler, tropical storms quickly calm down.
The main effects of a tropical storm are the very strong winds, torrential rain and storm surges. These all can cause massive damage and huge loss of life.
The sequence of events as a tropical storm travelled overhead would be:
- As the storm approached there would be a drop in temperature and pressure. Wind speeds would begin to increase and clouds would form.
- As the storm is overhead the pressure would fall rapidly, as would the temperature. Wind speeds would be in excess of 150km/hr and the rain would be torrential. The wind would whip up waves that could swamp entire coastal areas, or drown entire coral islands in the Pacific.
- The eye of the storm is overhead. Skies are clear, the temperature and pressure increase, and the wind dies down. Unfortunately this is only a brief lull in the storm.
- The storm hits again. Temperature and pressure falls. Torrential rain and wind speeds of over 100km/hr occur. The winds are now coming form the opposite direction than they were before.
- After the storm the temperature and pressure rise again. The rain becomes showers, and the winds die down. The clean up operation begins!
Example: Hurricane Floyd, September 1999
- Hit the coast of Florida and then moved North towards Georgia and South Carolina.
- Torrential rain and 155mph winds battered the area, bringing down power and phone lines and snapping trees.
- It whipped up 20-foot waves along the coast.
- Anxious holidaymakers and local residents fleeing the storm jammed roads. Over a million people were evacuated from Key Biscayne, Miami Beach and Fort Lauderdale.
- Floyd was more than 600 miles in diameter and was the biggest storm to hit Florida since Hurricane Andrew in 1992 (that left 26 dead, 160,000 homeless and caused $25billion of damage). Floyd was estimated to be three times as strong as Andrew.
Hurricanes since, such as Katrina in August 2005 (Over 1800 deaths / $108 Billion USD worth of damage) and more recently Sandy in October 2012 (over 200 deaths / $71 Billion damage) have claimed many more lives and caused more damage.