Climate and Human Activities

25 min

Let's begin

Every Rwandan farmer plans the year around the rain. The National Institute of Statistics of Rwanda (NISR) measures farming in three seasons: Season A from September to February and Season B from March to June are the two main growing seasons, and Season C, from July to September, is a small season, mainly for vegetables and sweet potatoes in the marshlands and Irish potatoes in the volcanic zone. Compare those dates with Kigali's rainfall and the link is obvious. Climate shapes what people grow, where they live, how they build, travel and earn a living, all over the world.

Figure 6. Kigali rainfall and Rwanda's three farming seasons. Drawn by Ganzaa.

Worked example

Worked example 1: reading Figure 6. Explain why Season C is a small season and is farmed mainly in marshlands.

Season C (July to September) covers the long dry season: Kigali averages only 10.2 mm in July and 30.2 mm in August.
Rain-fed crops on the hillsides would dry out, so farming moves to places where water is still available: marshlands and valley bottoms, where the water table is near the surface, or irrigated land.
NISR also lists Irish potatoes grown in the volcanic zone of the north-west; being high, it is cooler, which suits potatoes.

Climate and people around the world

Climate	Farming and work	Homes, health and problems
Equatorial (Congo Basin, Amazon)	Tree crops all year (cocoa, oil palm, rubber); forestry; shifting cultivation	Hot, humid; insects and diseases such as malaria thrive; dense forest makes roads costly
Savanna (Kano, northern Australia)	One crop season: maize, sorghum, millet, cotton, groundnuts; cattle herding; wildlife tourism	Water is short in the dry season; droughts when the rains fail
Semi-arid and desert (Sahel, Sahara, Australia)	Nomadic herding of camels, goats and cattle; farming only at oases or with irrigation; mining; great potential for solar power	Thick-walled, small-windowed houses keep out the heat; dust storms; desertification
Mediterranean (Tunis, southern Europe, California)	Olives, grapes, citrus fruit and wheat; summer tourism	Summer drought and wildfires; irrigation needed for summer crops
Tropical highland (Rwanda, Ethiopia)	Tea, coffee, potatoes, dairy cattle; two farming seasons where there are two rainy seasons	Pleasant climate attracts dense settlement; heavy rain on steep slopes causes landslides
Temperate (London, Moscow)	Mixed farming, wheat and dairying; in continental areas a short growing season	Houses must be heated in winter; snow and ice disrupt transport in continental winters
Arctic (Resolute)	Traditionally hunting and fishing; today also mining and research; almost no farming	Buildings raised on piles so they do not thaw the permafrost; months of darkness and extreme cold
Mountain (Alps, Andes)	Moving herds to high summer pastures; skiing and mountain tourism; hydro-electric power	Avalanches; cold limits crops at height

Worked example

Worked example 2: an "explain" answer. "Explain how the climate of Kano affects farming."

Kano has one rainy season, from May to September (about 1,149 mm in a year, 400 mm in August alone), so rain-fed crops such as sorghum, millet and groundnuts are planted when the rains begin and harvested at the end of the wet season.
From November to February no rain falls and the dry harmattan blows from the Sahara, so without irrigation the land lies fallow and herders must move cattle to find water and grass.
High temperatures all year (21–32 °C) mean crops grow fast whenever water is available, so irrigation can allow a second, dry-season crop.

Warning

Climate influences; it does not decide everything. People change what climate allows. Egypt farms in a desert by irrigating from the Nile; greenhouses grow vegetables in cold countries; air conditioning makes hot cities comfortable. In an "evaluate" question, show both sides: the limits set by climate, and the ways technology and money overcome them, often at a cost in water or energy.

Tip

Link, not list. For every activity, name the climate feature that causes it: "because there is only one rainy season (May to September), farmers grow quick-maturing grains". The figures from the climate graph are your evidence.

Practice

Name Rwanda's three farming seasons and give the months of each.
Using Figure 6, explain why Season B starts in March.
Give two ways in which a desert climate affects how people build their houses or earn a living.
Why do equatorial regions have problems with diseases such as malaria?
Name two crops suited to a Mediterranean climate and explain why the climate suits them.
Why are buildings in the Arctic often raised on piles?
Describe two ways in which people overcome the limits that climate places on farming.
"Climate is the most important influence on how people live." Using examples from at least two continents, discuss this statement.

Show answersHide answers

Season A: September to February; Season B: March to June; Season C: July to September (NISR).
March is the start of the long rains: rainfall jumps from 83.9 mm in February to 129.1 mm in March, giving enough moisture to plant crops.
Any two: thick walls and small windows keep houses cool; flat roofs; nomadic herding follows water and grass; farming only at oases or with irrigation; solar power can be developed.
Heat and humidity all year, with standing water from frequent rain, allow mosquitoes that carry malaria to breed in every month.
Olives and grapes (or citrus, wheat): they need warm, sunny summers to ripen and can survive the summer drought with deep roots, while the mild, wet winters let them grow.
Heat from the building would thaw the permafrost below; the ground would become soft and the building would sink or crack. Piles let cold air pass underneath and keep the ground frozen.
Any two: irrigation (e.g. from the Nile in Egypt); greenhouses; drought-resistant crop varieties; farming in marshlands in the dry season (Season C in Rwanda); water harvesting and storage.
For: climate sets the farming calendar (Rwanda's seasons A, B and C), limits crops (none in the Arctic), shapes houses and health (malaria in equatorial areas). Against: technology and wealth overcome climate (irrigation in Egypt, heating in Moscow, greenhouses), and relief, soils, history and the economy also matter. A good conclusion weighs the two.

1Climate and people around the world

Climate and people around the world