By Blair Trewin, Lead Author of the World Meteorological Organization’s 2019 State of the Climate report for Africa
Africa is highly vulnerable to the influence of the climate. The continent contains many of the world’s least developed countries, who have limited capacity to mitigate against the impacts of extreme events. The continent is also highly dependent on rain-fed agriculture which is at the mercy of fluctuations in rainfall from season to season. Amongst the most vulnerable areas are the semi-arid regions of the Sahel and the Greater Horn of Africa; many of these regions also suffer from unstable security situations, and in the worst cases, drought and conflict can combine to trigger famine, as in Somalia in 2011-12.
Like the rest of the world, Africa is warming. 2019 was likely the third-warmest year on record for the continent, after 2010 and 2016. Over the last 30 years, the continent has been warming at a rate of 0.3 °C to 0.4 °C per decade, a similar rate to the global average for land areas. 2019 was an especially warm year in southern Africa, where parts of South Africa, Namibia and Angola had temperatures more than 2 °C above the 1981-2010 average.
As described in the 2019 State of the Climate report for Africa, 2019 started with significant drought in many parts of east Africa, especially Kenya and Somalia. Dry conditions continued through the first half of 2019, but this changed abruptly in the second half of the year, which brought exceptionally wet conditions (with seasonal rainfall more than four times average in many areas) and widespread flooding, continuing into early 2020. A major driver for this shift was a strong positive phase of the Indian Ocean Dipole, which produced unusually warm sea surface temperatures off the equatorial African coast and unusually cool conditions in the eastern tropical Indian Ocean (which contributed to severe drought in Australia and parts of south-east Asia). The combination of drought and flood saw widespread food insecurity in the region, with the number of people affected in Somalia and Kenya increasing from 2.3 million in late 2018 to 5.2 million in late 2019.
Long-term drought persisted in parts of interior southern Africa, although near-average rainfall in southern South Africa saw the abatement of the water crisis which had affected Cape Town in 2018. Conversely, a number of regions suffered from flooding, including Sudan and South Sudan, the Central African Republic, and parts of the Niger River basin.
Tropical Cyclone Idai struck Mozambique in March 2019. The cyclone caused massive destruction through wind damage and storm surge around its landfall point, near the city of Beira, and went on to cause disastrous floods in parts of interior Mozambique and Zimbabwe. More than 1200 lives were lost, the worst casualties in any southern hemisphere tropical cyclone in at least the last century. Tropical cyclones are a regular occurrence in the south-west Indian Ocean, and affect Madagascar and smaller Indian Ocean islands such as those of Mauritius and La Réunion in most years, but major cyclone landfalls on the mainland African coast are relatively rare. A few weeks later, Cyclone Kenneth struck northern Mozambique at an even higher intensity than Idai, but had much less impact as it hit a sparsely populated region.
One of the major challenges in monitoring climate in Africa is the limited availability of data. Many African countries have only sparse meteorological observing networks, and maintaining those networks is a major challenge. Even where those observations are made, they are often not communicated to international data networks from which regional and continental analyses are made. Satellite-based observations can fill some, but not all, of this gap. The situation is gradually improving, however, with several African countries building the capacity of their national meteorological services significantly in the last few years, and regional centres such as the African Centre of Meteorological Applications for Development (ACMAD) also playing an important role. The World Meteorological Organisation also recently established a Systematic Observations Financing Facility, which provides a vehicle for donors to support improved systematic observations in Least Developed Countries, many of which are in Africa, and other parts of the world with sparse observing networks, such as the island nations of the Pacific.
The climate of Africa, as with the rest of the world, is expected to continue to warm, with the strongest warming in regions away from the coasts. Expected rainfall changes are more mixed and uncertain, although projections point to a likely decrease of rainfall in many parts of southern Africa, whilst global sea-level rise will continue to have an impact on low-lying coastal regions.
The World Meteorological Organization’s 2019 State of the Climate report for Africa report is the first of its kind, but is expected to begin a series of similar reports in Africa and other regions. It is hoped that these annual reports will combine with longer-term assessments such as those of the Intergovernmental Panel on Climate Change (next due to report in 2021-22) to give policymakers around the world the best possible, and most up-to-date, information available on the state and impacts of the climate in their region, and how it is expected to evolve into the future.