2.7: Causes of Drought are Complex

Match each of the definitions to the correct key term.

• Nomadic herdsman

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

• Savannah ecosystem

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

• Drought

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

• Pastoral farming

• The artificial watering of land for farming.

• Irrigation

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

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.

• Hydrological

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

• Human - deforestation

• 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.

• Meteorological

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

• Human - agriculture

• • 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 - dams

• 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).

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

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

• 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.

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.

• becoming warmer and drier.

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

• resulting in less rainfall.

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

• 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.

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

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

Groups:

(a) Social

,

(b) Economic

,

(c) Environmental

• Wild animals suffer from a lack of water.

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

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

• Wildlife might migrate away from the area.

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

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

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

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

• Depression and anxiety over economic impacts.

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

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

• Endangered species could become extinct.

• Migration away from affected areas.

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