When it comes to climate change Africa is in the eye of the storm. This is partly because of human factors – but the continent’s climate also makes it extremely vulnerable.
Africa is faced with a number of interlinked challenges. These include land degradation, poverty and climate change. These are referred to as “wicked problems” since they are complex and caused by a number of factors, many of which have global dimensions.
In the case of climate change, Africa is vulnerable because it is exposed to damaging climate risks including extreme droughts, flooding and storms.
The continent also has low adaptive capacity making it particularly vulnerable and exposed because of high rates of poverty, financial and technological constraints as well as a heavy reliance on rain-fed agriculture.
Solving these challenges can seldom be achieved with a one-size-fits-all approach.
Africa has one thing in common with the rest of the world: the certainty that rising temperatures will exacerbate existing problems and vulnerabilities.
The global focus is on getting agreement to halt the rise in the world’s temperature. The outcome of the Paris Climate Summit later this year will be particularly important for Africa because of the changes that may accompany climate change.
An increased number of droughts is possible. Flooding is also a very real threat and we could experience more frequent and severe storms.
With climate change and climate variability occurring, the poorest communities are set to suffer the most.
African climate systems
The engine of the global climate system is a linked set of ocean currents and circulating air masses. These are powered by the greater warming of the earth near the Equator than at the poles. As the planet rotates, the air masses curve when they blow north or south.
This forms large swirling air masses. Where the air is descending it is dry and clear. When ascending it produces clouds and rain. For example, the rising air in the Equatorial region generates huge thunderstorms, whereas subtropical descending air creates the Sahara and Kalahari deserts.
The climates of Africa are a direct result of the spread of the continent across the Equator. The general zonal pattern of climates worldwide is a warm and moist rainforest-covered equatorial belt; savannahs and hot, arid lands surrounding the tropics of Cancer and Capricorn; and temperate, cooler lands north and south of about 30 degrees.
This basic pattern is altered in Africa by the influence of the ocean masses on the western and eastern coasts (the Atlantic and Indian Oceans). For instance, in southern Africa, the climate zones are oriented east-west rather than north-south, with the western part much drier than the eastern part.
The climate of the southern portions of the continent is influenced by waves of cold, polar air from the Southern Ocean while the influence of the Mediterranean ocean impacts North Africa. The air streams that flow out of Eurasia – the monsoons – also influence the climate of the continent. An example of this is East Africa’s double rainy season.
A warming world results in the strengthening of these atmospheric patterns. Africa, straddled as it is across the equator, is generally hot. The climate in many areas, exhibits a wet-dry seasonality.
Current projections indicate that we can possibly expect warmer and drier conditions in the interior of the sub-continent, and an increase in the magnitude and frequency of thunderstorms in southern Africa.
Semi-arid areas fringing the deserts are particularly vulnerable. Changes in ocean circulation, often thousands of kilometres away, will possibly see these areas more prone to spells of drought followed by floods over consecutive years.
Some climate model projections also suggest a pole ward displacement of the westerly waves, leading to more summer rain and less winter rain in the south-western Cape.
Efforts are being made to better understand Africa’s climate as a system and possible implications for ecosystems and humans. This will equip us to better meet the challenges posed by climate change. But there is only so much we can do. This is a global threat that needs a global response.
This article was co-authored by Robert Scholes, a Professor at Wits in the School of APES and in the Global Change and Sustainability Research Institute.