Climate variability and change

Climate change is a major threat to atmospheric resources and is resulting in climatic variations that have effects at multiple scales – temporal and spatial. It is closely linked to global patterns of energy consumption and production. Its impacts are increased by poor natural resource management.

Climate change has multiple impacts, at diverse scales and in particular affects ecosystems, which in turn affect livelihoods and human well-being. Even a temperature rise of as little as 1°C will affect land, coastal and marine, freshwater, and forests and woodland resources. Biodiversity will also be affected, as will human settlements. New health challenges are expected as vector-borne diseases, such as malaria, are predicted to increase. Environmental change affects food production systems, contributing to malnutrition, famine and starvation, and insect ranges and numbers, increasing the incidence of diseases such as malaria. Climate change contributes to population displacement, undermining social cohesion and cultures. The impacts of climate change are also considered in Chapter 3: Land and Chapter 5: Coastal and Marine Environments.

Several factors, including an over-dependence on rain-fed agriculture and the high incidence of poverty, make Africa’s people particularly vulnerable to climate variability. Poor people have little protection against extreme climatic events: they have few resource reserves, poor building structures, and depend directly on natural resources for their livelihoods. Extreme weather events have serious economic and business implications. Floods and droughts cause damage to property and loss of life that affect the opportunities available and that increase the cost of business through higher insurance premiums and claims.

Climatic variations manifest themselves as extreme weather variations, such as floods and droughts. These events are increasing in magnitude and frequency over the years. The mean annual rainfall has been decreasing over the decades. Many countries, including Botswana, Burkina Faso, Chad, Ethiopia, Kenya, Mauritania and Mozambique, experience drought at regular intervals. The 1997-98 El Niño floods caused heavy damage to roads, buildings, bridges, railway lines and other property including schools. Incidences of epidemic diseases such as malaria increased during this period. This is related to improved conditions for mosquito breeding; mosquitoes transmit many viruses, over 100 of which are known to infect humans, including malaria, dengue, yellow fever and severe and sometimes fatal encephalitis and dengue haemorrhagic fever (Akhtar and others 2001). Cholera, which is transmitted by water or food, could aggravate health problems in many parts of the world including Africa. During the 1997-98 El Niño event, excessive flooding is reported to have caused epidemics in Djibouti, Somalia, Kenya, Tanzania and Mozambique (Hassan and others 2005).

Mean global temperatures are rising, slowly but surely (Christy and others 2001). This rise in global temperature is attributed to anthropogenic emission of GHG, particularly carbon dioxide. Greenhouse gas emissions result from the burning of fossil fuels in industry, transport vehicles, waste disposal and in households. Africa contributed 341 836 m³ of CO2 in 1970, or 2.2 per cent of global emissions (WRI 2005); by 2000 this had risen to nearly 3.6 per cent of global emissions (UNSTATS/CDIAC 2006). Although African emission levels are low, their steady increase demands increased investment in clean production processes and the fulfilment of the commitment made by industrialized countries at WSSD to support Africa in this through partnership and investment.

Climate change is causing the rapid melting of snow caps and a concomitant rise in sea level. For example, the glaciers on Kilimanjaro have shrunk by 73 per cent over the century (Mastny 2000). This process may result in the displacement of people, loss of lowland areas, reduced agricultural production, health problems and enhanced climate variability. The challenges associated with climate change are discussed in relation to land resources in Chapter 3: Land.