In this first of a nine-part serial, EnviroNews Nigeria examines the implications of the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC) on the African continent
The Fifth Assessment Report presents strong evidence that warming over land across Africa has increased over the last 50 to 100 years. This warming trend is very likely to continue. Surface temperatures have already increased by 0.5–2°C over the past hundred years (Figure 1). However, as shown by the white space covering much of the map in Figure 1, over large areas of Africa there is not enough historical data to show observed trends. The absence of this data is problematic. Planners have to deal with considerable uncertainty about future conditions.
Investment in strengthening climate services – such as climate monitoring and national meteorological agencies – is assumed to be money well spent.
Most areas of Africa lack sufficient data to draw conclusions about trends in annual rainfall over the past century. But where data is available, these indicate that rainfall patterns are changing. A very likely decrease in average annual rainfall has occurred in some parts of western Africa, with an observed drop in average annual rainfall of approximately 25–50 mm each decade from 1951–2010.18 Some parts of southern and eastern Africa have very likely experienced increases in average annual rainfall of 5–50 mm each decade (Figure 2). However, rainfall trends in eastern Africa vary greatly over time and location. Some assessments suggest that wet seasons will be more intense and droughts less severe over eastern Africa by the end of the century, which indicates a reversal of the observed increase in droughts and heavy rainfall during the past 30 to 60 years.
The implication of the changing rainfall trends is that it will become increasingly important to put adaptation measures in place to manage and reduce the risks of changing rainfall on productive systems such as agriculture and forestry – and to build resilience.
Even today, climatic risks threaten lives and prosperity across many parts of Africa and there are clear signs that the impacts of climate change are already being felt. The health, livelihoods and food security of people in Africa have been affected by climate change. There is evidence that temperature changes have played a role in the increased incidence of malaria in parts of eastern Africa, and have already driven changes in the practices of South African farmers. Production of wheat and maize in parts of Africa has been impacted by climate change, as has the productivity of fisheries of the Great Lakes and Lake Kariba and fruit-bearing trees in the Sahel.
The impacts from recent weather-related extremes, such as heat waves, droughts, floods, cyclones and wildfires, reveal the exposure and vulnerability of some African people and economies to climate. Following droughts in the 1970s and 1980s, recurrent droughts and floods affected the Sahel in the 1990s and 2000s, often destroying crops and compounding food security problems. Floods in the Zambezi River Valley displaced 90,000 Mozambicans in 2008, some permanently. The experiences of extreme weather events in different parts of Africa highlight the risks to human wellbeing. The Fifth Assessment Report expects such events to become more frequent and more intense as the climate changes, though with large regional variations and differing degrees of confidence depending on the type of climate event. The economic losses due to extreme weather events are also rising with the increasing frequency of events and increasing exposure of assets.
The impacts of recent extreme weather events also demonstrate the vulnerability of some African ecosystems. The geographic range, seasonal activities and migration patterns of many terrestrial, freshwater and marine species have shifted in response to ongoing climate change. The abundance of species has changed, as have interactions among species. The pace of change has been rapid. Climate change has already led to changes in freshwater and marine ecosystems in eastern and southern Africa, and terrestrial ecosystems in southern and western Africa.