Climate and Human Activities in Rwanda – Climate in Rwanda (Senior 4 Geography) | Ganzaa

Climate in Rwanda

Lessons

Senior 4 · Geography

Climate in Rwanda

3 lessons

Lesson 3 of 3

Climate and Human Activities in Rwanda

25 min

When the rain does not follow the calendar

Late January is usually part of the short dry season. Yet on 28 January 2020, roads in Kigali were under water, and people paid to be carried across. Climate shapes almost everything people do in Rwanda, and when the weather departs from the usual pattern, farming, transport, health and safety all feel it.

Climate and farming

Most of Rwanda's farming is rain-fed, so the agricultural year follows the rains. NISR's Seasonal Agricultural Survey divides it into three seasons: Season A from September to February, Season B from March to June, and Season C from July to September, a shorter season mainly for vegetables and sweet potato in swamps and Irish potato in the volcanic zone (NISR, 2024).

Figure 6: the agricultural seasons used by NISR's Seasonal Agricultural Survey, set against the two rainy seasons. Seasons A and B are rain-fed; Season C, in the long dry season, depends on swamps, irrigation and the cool, moist volcanic zone.

Climatic zone	Farming it favours	Evidence
Cool, moist volcanic highlands	Irish potato, even in the dry Season C; pyrethrum, vegetables	NISR (2024) names Irish potato in the volcanic zone in Season C
Cool, wet Congo–Nile highlands	Tea, which needs high, reliable rainfall and cool temperatures	Tea factories in the highlands depend on fuel wood from their own plantations (REMA, 2009)
Valley marshlands everywhere	Rice, vegetables and sweet potato, with water available in the dry season	Rice cooperative of Bugarama (REMA, 2009); swamps in Season C (NISR, 2024)
Warm, semi-arid east	Livestock, bananas, maize, beans; irrigation needed in dry spells	Improved pasture and irrigation proposed for Nyagatare's Eastern Savannah (REMA, 2021)

Irrigation shows how farmers adapt to the dry season: in 2024, 7.5% of farmers irrigated in Season A, 12.1% in Season B and 58.2% in Season C (NISR, Seasonal Agricultural Survey 2024).

Definition

Rain-fed agriculture: farming that depends only on rainfall for water. Climate variability: year-to-year differences from the average climate (a wet year, a late season). Climate change: a long-term change in the average climate, such as a warming trend over decades.

Adaptation: changes that reduce harm from climate (terraces, irrigation, new crop varieties). Mitigation: actions that reduce the causes, mainly greenhouse-gas emissions.

Climate and other activities

Activity	Positive effects of climate	Problems
Energy	Rain and relief feed hydroelectric stations such as Ntaruka	Low flows cut power: REMA notes that when the Rugezi marsh above Lake Burera was degraded, water reaching Ntaruka was not enough to generate electricity (REMA, 2021)
Water supply	High rainfall in the west and north recharges springs and rivers	Shortages in the dry east during long dry spells; muddy water after storms
Transport and building	Dry seasons are good for construction and road works	Floods and landslides cut roads: after the rains of 2–3 May 2023, 29 bridges and many roads were damaged (ReliefWeb)
Tourism	Mild temperatures all year; misty forests and volcanoes	Heavy rain makes trails slippery and roads difficult
Health	Cool highlands are healthier for people and livestock	REMA lists more water-borne and vector-borne disease, and flood and landslide deaths, as risks of climate change (REMA, 2021)
Settlement	Mild climate supports dense rural settlement	Homes on steep, wet slopes and in flood-prone valleys are at risk

A changing climate

REMA's 2021 report analysed Meteo Rwanda's records from 1981 to 2020 for rainfall and 1983 to 2020 for temperature. It found an increasing trend in mean temperatures over the last 40 years, and in 2020 minimum temperatures were above normal at all 14 stations studied, by between 0.2 °C at Bugarama and 2.3 °C at Busogo. The year 2020 was also very wet: 11 of the 14 stations recorded rainfall above their long-term average. Serious landslides with loss of life were recorded in Rulindo and Gakenke (2016), Karongi and Ngororero (2018), many parts of the country (2019), and Nyabihu, Gakenke, Ngororero, Kigali and Muhanga (2020) (REMA, 2021).

REMA also notes a sharp contrast: Rwanda ranked 185th out of 188 countries for greenhouse-gas emissions per person, yet the Global Climate Risk Index placed it among the ten countries most affected by climate change in 2018 (REMA, 2021, citing Germanwatch, 2019).

Worked example 1: how wet was 2020 in Kigali?

Data (REMA, 2021, Table 10-1). In 2020 Kigali Aero recorded 226 mm more rain than its long-term average, an anomaly of +24%.

Problem. Find the long-term average and the 2020 total.

Solution. If 226 mm is 24% of the average $\bar{R}$ :

\bar{R} = \frac{226}{0.24} = 942\ \text{mm}, \qquad R_{2020} = 942 + 226 = 1\,168\ \text{mm}

The same method for Rubengera (Karongi), +461 mm or +38%, gives an average of $\frac{461}{0.38} = 1\,213$ mm and a 2020 total of about 1,674 mm.

Worked example 2: how much does Season C depend on irrigation?

Data (NISR, 2024). 7.5% of farmers irrigated in Season A and 58.2% in Season C.

\frac{58.2}{7.5} = 7.8

A farmer is almost eight times as likely to irrigate in the dry Season C as in the rainy Season A: a direct measure of how the climate's dry season shapes farming.

Responding to climate hazards and change

Forecasts and warnings: Meteo Rwanda publishes seasonal forecasts, weather warnings and services for agriculture, health and transport.
Land and water management: terraces, agroforestry and reforestation of steep land (Unit 5); rain-water harvesting; irrigation for dry seasons.
Disaster risk reduction: mapping high-risk zones, moving households away from them, and keeping buffer zones along rivers.
Climate-smart farming: crop varieties suited to shorter or less reliable rains; diversified crops and livestock.
National strategy: Rwanda's Green Growth and Climate Resilience Strategy and its updated Nationally Determined Contribution to the UN Framework Convention on Climate Change set out adaptation and emission-reduction plans (REMA, 2021).

Warning

One wet year is not climate change. A single flood or drought is weather or variability. Climate change is shown by long-term trends, such as the 40-year rise in mean temperatures in Meteo Rwanda's records. Use the right word in your answers.

RwandaTV: "Farmers in Rwanda turn to irrigation to deal with climate change". A model farmer explains how he adapted to drier, less reliable seasons. List the adaptations he names and link them to this lesson.

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Practice

Explain why Rwanda's agricultural year is divided into Seasons A, B and C.
Why can Irish potato be grown in the volcanic zone during Season C?
In 2020, Nyagatare had a rainfall anomaly of +287 mm, or +34% (REMA, 2021). Find its long-term average and its 2020 total.
Explain two ways in which climate affects energy supply in Rwanda.
Distinguish climate variability from climate change, with a Rwandan example of each.
Describe three ways in which Rwanda can adapt to heavier rains.
"Rwanda suffers from a climate problem it did little to cause." Discuss, using REMA's evidence.

Show answersHide answers

Farming is mostly rain-fed and follows the two rainy seasons: Season A uses the short rains (September–February), Season B the long rains (March–June), and Season C (July–September) uses swamps, irrigation and the moist volcanic zone in the long dry season.
The volcanic highlands are cool and moist, with fertile, water-holding volcanic soils, so potatoes can grow even in the dry season.
$\bar{R} = \frac{287}{0.34} = 844$ mm; 2020 total $= 844 + 287 = 1\,131$ mm.
Hydroelectricity depends on river and lake levels, which fall in droughts and dry seasons (Ntaruka); floods and landslides damage power lines and stations; heat increases demand for cooling in towns.
Variability: a single unusually wet year such as 2020, or a late rainy season. Change: the 40-year rising trend in mean temperatures in Meteo Rwanda's records.
For example: terraces and contour drains; reforestation of steep slopes; rain-water harvesting and storm drains in towns; early warnings and moving families from high-risk zones; protecting wetlands that store flood water.
Rwanda ranked 185th of 188 for emissions per person but among the ten countries most affected by climate change in 2018 (REMA, 2021): it suffers rising temperatures, floods and landslides caused mostly by others' emissions. But local actions (deforestation, farming steep slopes, building in risky places) also increase the damage, so both international support and national adaptation are needed.

Quick check

Match each NISR agricultural season to its months.

Tap one on the left, then its partner on the right.

Key points

Farming follows the rains: Season A (September–February), B (March–June), C (July–September, swamps and volcanic zone) (NISR); irrigation rises to 58.2% of farmers in Season C (2024).
Climate zones favour different activities: potatoes in the volcanic zone, tea in the wet highlands, rice in marshlands, livestock in the semi-arid east.
Climate affects energy, water, transport, tourism, health and settlement.
Meteo Rwanda's records show rising mean temperatures over 40 years; 2020 was very wet (REMA, 2021). Responses include warnings, terraces, irrigation, relocation from high-risk zones and the Green Growth and Climate Resilience Strategy.

1When the rain does not follow the calendar

2Climate and farming

3Climate and other activities

4A changing climate

5Responding to climate hazards and change

When the rain does not follow the calendar

Climate and farming

Climate and other activities

A changing climate

Responding to climate hazards and change