Rwanda
Rwanda has a tropical climate with four seasons:
a short rainy season (September to mid-January), a short dry season (till February), a long rainy season (mid-March to mid-June) and a long dry season (June to mid-September). The rainy seasons are primarily determined by the Inter-Tropical Convergence Zone (ITCZ).
It has been observed that the Eastern part of Rwanda, being the precipitation-deficit region, has recently experienced lower rainfall than usual in the last 30 years.
Recently, there has been a changing pattern in rainy seasons. At times, the total number of annual rainy days is reduced with short periods of more intense rainfall. Other times, frequent torrential rainfall on a daily basis exceeds the total monthly quantity. Also, there are times when there is a late onset of rainfall or an early cessation of the same.
According to the Rwandan Ministry of Finance and Economic Planning, since 2002, there has been low food production due to irregular rain and dislocation of rainy seasons. In 2003 and 2004, the agricultural sector was significantly impacted due to inadequate and unreliable rainfall. From late 2005 to early 2006, there was a famine in the Eastern and Southern provinces due to irregular rainfall that caused harvest failure during farming season. In 2006 and 2008, Bugesera witnessed severe droughts.
Rwanda is a fast warming country. In the last 50 years, there has been a 0.7°C to 0.9°C increase in temperature, thereby increasing the number of warm days. short dry season (December to January) and a long dry season (June to mid-September).
In the last 65 years, it has been noted that there have been alternating rainfall periods of surplus and deficit every ten years.
By 2050, it is estimated by some experts that there will be an overall increase of 3 per cent to 10 per cent in rainfall; however, there will be a decrease of 4 per cent to 15 per cent in May and October.
By 2050, it is estimated that there will be an increase of 1.9°C rise in temperature.
Tanzania
Tanzania has a tropical climate along its coast, and semi-temperate in the inlands.
There have been seasonal shifts, such that some parts of Tanzania receive more rainfall in comparison to the rest of the country like the Central region, wherein there is less rainfall early in the season and stronger rains later in the season.
By 2075, it is estimated that there will be an increase of 5 per cent to 45 per cent in rainfall in the Northern and South eastern parts, especially near Mt. Kilimanjaro. However, there will be a decrease of 5 per cent to 15 per cent in rainfall in the Central, Western, South western, Southern and Eastern parts of Tanzania.
For the last 35 years, there has been a consistent rise in temperature.
By 2050, it is estimated that there will be a rise in temperature by 1.5°C to 2°C.
Kenya
Kenya has a tropical climate although 80 per cent
30 Climate Change
of it is arid and semi-arid, and drought prone.
Kenya has disparate effects of climate change.
For instance, in 2011, there were flash floods in Northwest Kenya and the Turkana region. On the other hand, major droughts occur every ten years, and minor ones every 3-4 years in the arid and semi-arid lands.
Uganda
Uganda has an equatorial climate with small regional variations due to temperature and humidity.
As a result of erratic rainfall, the North-eastern part of Uganda experiences droughts between October and December.
As a result of decrease in rainfall over the years, Lake Wamala has shrunk by one metre in the last decade.
Since the 1960s, a decrease in rainfall has been observed in the North and Northeast parts of Uganda.
Since the 1960s, the mean annual temperature has risen by 1.3°C.
Eritrea
Eritrea has a temperate climate on the Highland Plateau while it is hot and arid along its coast.
As a consequence of climate change, there is expected to be a 29.5 per cent decrease in the runoff of River Mereb-Gash, which will impact the water flow into Sudan.
By 2050, a 4.1°C rise in temperature is expected due to global carbon dioxide levels.
Ethiopia
Ethiopia has diverse climatic zones that translate into varied vegetation zones. These include hot
arid, hot semi-arid, tropical with distinct dry winter, tropical monsoon with short dry winter, warm temperate rainy with dry winter, warm temperate rainy without distinct dry season.
In the last 10 years, there has been an increase in rainfall during the wet season and decrease in rainfall during the dry seasons, thereby resulting in floods and droughts.
By 2045-55, a 23 per cent rise in rainfall is expected during the wet season or a 15 per cent decline in rainfall during the dry season.
By 2070, rainfall is expected to decrease in the North while the South may witness a rise in precipitation by 20 per cent. Also, rainfall will decrease during the growing season between February and May.
It is estimated that climate change will reduce the annual runoff of River Nile tributaries Abbay and Awash by up to one-third.
Ethiopia has a historical pattern of rainfall variability; therefore, it is uncertain whether rainfall variability is an effect of climate change or a general trend of the country.
By 2050, a 1.7°C to 2.1°C rise in Ethiopia’s mean temperature is expected.
Sudan and South Sudan
Sudan and South Sudan have a varied climate, which is arid in the North and tropical wet-and-dry in the Southwest.
Since the mid-1970s, the summer rains have reduced by 10 per cent to 20 per cent in Western and Southern Sudan.
Studies in 2007 have suggested that there will be a decrease of 6mm of rainfall each month during the rainy season in the coming years.
By 2060, it is estimated that there will be a 1.5°C to 3.1°C rise in temperature in August, and 1.1°C to 2.1°C rise in January.
Blue Peace for the Nile 31
Egypt
Egypt has a semi-desert climate comprising hot dry summers, moderate winters and scanty rainy seasons.
On average, Egypt receives 24mm of rainfall every year, of which the Northern coastal region receives some while the South receives almost none. In Cairo, it is driest in July and August with no rainfall and wettest in December with 5mm of rainfall.
In the future, a steady rise in temperature with slight inter-modal variance is expected, causing summers to warm faster than winters.
The River Nile is the longest river in the world with high inter-annual and decadal water resource variability as a result of several factors. One such factor is evapotranspiration - a natural and pertinent phenomenon across the Nile Basin, especially in Uganda, Ethiopia, South Sudan and Sudan. The Nile Basin’s geographic location, varied climate and erratic weather patterns make it highly susceptible to evapotranspiration, which has a strong impact on the hydrology and variable flow of the Nile. Evapotranspiration is affected by a range of factors such as rising temperatures, humidity, direction and speed of wind, type of vegetation, and soil characteristics.
Climate Change in the Nile River Basin