2.7: Causes of Drought are Complex

Match each of the definitions to the correct key term.

• Nomadic herdsman

• An area of grassland which has a few shrubs and trees; it can be found in tropical areas.

• Pastoral farming

• A period of below-average precipitation resulting in prolonged shortages in water supply.

• Savannah ecosystem

• People raising animals for their own food; they move around and have no fixed land.

• Drought

• The artificial watering of land for farming.

• Irrigation

• The rearing of sheep, cattle, pigs or any other animal on a farm.

Complete the paragraph below to show the difference between being an arid environment and an area in drought.

Areas suffering from drought can be in arid (​ (a)   ) environments but can also be in other climate regions. The main characteristic of a drought is the gradual ​ (b)   in available water, whereas arid environments ​ (c)   have low amounts of available water. Low precipitation in arid regions is because they are dominated by ​ (d)   pressure where air cannot rise, so condensation doesn't occur. As a result ​ (e)   don't form and so it doesn't rain.

• dry
• reduction
• high
• clouds
• always

Match each description to the correct cause of drought.

• Human - deforestation

• This can help areas near rivers by providing electricity and water. But places further downstream might get less water, which can lead to drought.

• Meteorological

• When there isn’t enough water for crops to grow properly. It’s caused by less rainfall or if farming methods change (e.g. use of irrigation).

• Hydrological

• • Fewer trees means less CO² in the air, causing global warming, reducing rainfall in some areas.

  • Trees also help create rain. They release water into the air through transpiration, creating clouds and therefore rain. Fewer trees means less transpiration and therefore less rain.

• Human - agriculture

• A reduced amount of water in rivers, lakes, reservoirs. Water levels drop below what’s normally expected because of less rainfall or because people are using more water.

• Human - dams

• When an area gets much less rain than usual for a long time, leading to a shortage of water.

Sort the statements into the correct order to explain why global atmospheric circulation makes some locations more vulnerable to drought than others.

• Warm air rises at the Equator causing thunderstorms and a lack of moisture.

• When it reaches approximately 30°N or S, the dry air sinks and warms.

• The drier air then moves towards the mid-latitudes.

• This gives reason for the location of many of the World's arid areas.

• High pressure is created by the sinking air, resulting in clear skies/no rain.

Fill in the gaps to explain a reason why some areas are likely to experience drought in the future.

Global ​ (a)   patterns are shifting. Jet streams are moving toward the poles, and the tropical zone has ​ (b)   since the 1970s. As a result, dry (​ (c)   ) areas are changing. Places that used to get more rain are getting ​ (d)   , leading to more ​droughts. For example, the Upper Colorado River Basin in the USA has had much less rain than normal and is now facing ​ (e)   .

• wind
• expanded
• arid
• drought
• less

Match each of the explanations to the correct ending to explain some of the human causes of drought.

• downstream resulting in possible drought

• On a regional scale, fewer trees results in less transpiration. Therefore, there's less water in the atmosphere...

• water stores, such as lakes and rivers.

• On a global scale, deforestation results in less CO2 being absorbed, causing global warming. This results in some areas ...

• becoming warmer and drier.

• Agricultural practices can cause drought. For example, irrigation can use too much water leaving below average levels in ...

• resulting in less rainfall.

• Building a dam holds water back in a reservoir, resulting in less water ...

Sort the reasons for why droughts are hazardous, into the correct category.

Groups:

(a) Social

,

(b) Economic

,

(c) Environmental

• Soil becomes dry and cracked, and so no longer supports plants.

• Wild animals suffer from a lack of water.

• Water companies have to spend large amounts on new supplies & pipe systems = higher bills.

• Industries such as those building farming equipment, see a drop in income.

• Ill health caused by low supply or poor quality of water.

• Habitats, particularly river habitats, are damaged or lost.

• Migration away from affected areas.

• Poorest are at risk of malnutrition due to an increase in food prices.

• Endangered species could become extinct.

• Safety risks as fires and dust storms are more likely.

• Wildlife might migrate away from the area.

• Depression and anxiety over economic impacts.

• Industries, such as farming and forestry, unable to support jobs, leading to mass unemployment.

Study Figure 8. Identify which one of the following countries has the largest arid environment.

• South Africa

• Ghana

• Angola

• Madagascar

Study Figure 5a. identify the amount of winter rainfall in 1995.

• 155mm

• 220mm

• 325mm

• 400mm

Study Figure 5a.

Calculate the range of winter rainfall.

Only write the answer (not the workings) so that the computer doesn't get confused marking it.

Mathematical Equivalence

ON