Fig 1: Factors Affecting Climate

Natural Vegetation and Soil: Natural vegetation affects the temperature of the region significantly. Often areas with dense forest cover like areas in thick foliage of Amazon jungles receive less insolation and are, often, cooler than the areas in open space. Light soils reflect more heat than darker soils which are better absorbers. Such soil differences may give rise to slight variations in the temperature of the region. As a whole, dry soils like sands are very sensitive to temperature changes, whereas wet soils, like clay, retain much moisture and warm up or cool down more slowly.

Slope, Shelter and Aspect: A steep slope experiences much rapid change in temperature as compared to a gentle slope. Mountain ranges that have an east-west alignment like the Alps show a higher temperature on the south-facing 'sunny slope' than the north facing 'sheltered slope'. The greater insolation of the southern slope is better suited for vine cultivation and has a more flourishing vegetative cover. Consequently, there are more settlements and it is better utilised than the 'shady slope'.

El Niño Effect: El Niño, which affects wind and rainfall patterns, has been blamed for droughts and floods in countries around the Pacific Rim. El Niño refers to the irregular warming of surface water in the Pacific. The warmer water pumps energy and moisture into the atmosphere, altering global wind and rainfall patterns. The phenomenon has caused tornadoes in Florida, smog in Indonesia, and forest fires in Brazil. El Niño is Spanish for 'the Boy Child' because it comes about the time of the celebration of the birth of the Christ Child. The cold counterpart to El Niño is known as La Niña, Spanish for 'the girl child', and it also brings with it weather extremes.

Human Influence: The factors above affect the climate naturally. However, we cannot forget the influence of humans on our climate. Early on in human history our effect on the climate would have been quite small. However, as populations increased and trees were cut down in large numbers, so our influence on the climate increased. The number of trees being cut down has also increased, reducing the amount of carbon dioxide that is taken up by forests.