S2 geography Taming the sand 10.2

Desertification refers to___ ___of drylands.

Answer in(Abc abc)

Dryland(e.g.semi-desert and savanna).There, the precipitation is___but the evaporation rate is___.

• Low/high

• High/low

• Hot/cold

• Cold/hot

Dryland. They lose their productivity and the vegetation becomes___.

• Rare

• Sparse

• Scarce

• High

___had the largest desertified area.

• Africa

• Asia

• Oceania

• North America

What are those physical factors?

• Decrease in rainfall

• Global warming

• Over-cultivation

• Overgrazing

What the (decrease in rainfall) cause?

• Drought occurs

• Lower land productivity and kills vegetation (soil erosion)

• Most of humans dead

• 2A become happier

___ ___refers to an increase in global average(平均) air temperature.

Answer in(Abc abc)

What are those human factors?

• Over cultivation

• Overgrazing

• Deforestation

• Misuse of water resources

• Overspending

What the Global warming caused?

• It lowers the relative humidity.This hinders the formation of rain.

• It leads to a higher evaporation rate.This increase the loss of soil moisture.Soil becomes dry

• Whatever la give up geog(dont choose this)

Grow too many crops on existing farmland cause___

• Farmers may shorten the fallowing period, this reduces the time for the soil to replenish its moisture and nutrients

• Topsoil exposed to erosion

• Bye bye world(don’t choose this)