Past Climate Change Impacts
Rising fossil fuel burning and land use changes have emitted, and are continuing to emit, increasing quantities of greenhouse gases into the Earth’s atmosphere. These greenhouse gases include carbon dioxide (CO2), methane (CH4) and nitrogen dioxide (N2O), and a rise in these gases has caused a rise in the amount of heat from the sun withheld in the Earth’s atmosphere, heat that would normally be radiated back into space.
This increase in heat has led to the greenhouse effect, resulting in climate change. The main characteristics of climate change are increases in average global temperature (global warming); changes in cloud cover and precipitation particularly over land; melting of ice caps and glaciers and reduced snow cover; and increases in ocean temperatures and ocean acidity – due to seawater absorbing heat and carbon dioxide from the atmosphere
Over the next decades, it is predicted that billions of people, particularly those in developing countries, face shortages of water and food and greater risks to health and life as a result of climate change concerted global action is needed to enable developing countries to adapt to the effects of climate change that are happening now and will worsen in the future.
Climate change will have wide-ranging effects on the environment, and on socio-economic and related sectors, including water resources, agriculture and food security, human health, terrestrial ecosystems and biodiversity and coastal zones. Changes in rainfall pattern are likely to lead to severe water shortages and/or flooding. Melting of glaciers can cause flooding and soil erosion.
Rising temperatures have already caused shifts in crop growing seasons which affects food security and changes in the distribution of disease vectors putting more people at risk from diseases such as malaria and dengue fever. Temperature increases will potentially severely increase rates of extinction for many habitats and species (up to 30 per cent with a 2° C rise in temperature).
Particularly affected are coral reefs, boreal forests, and Mediterranean and mountain habitats. Increasing sea levels mean greater risk of storm surge, inundation and wave damage to coastlines, particularly in Small Island States and countries with low lying deltas. A rise in extreme events have shown effects on health and lives as well as associated environmental and economic impacts.
Regional impacts of and vulnerabilities to climate change
Many factors contribute and compound the impacts of current climate variability in Africa and will have negative effects on the continent’s ability to cope with climate change. These include poverty, illiteracy and lack of skills, weak institutions, limited infrastructure, lack of technology and information, low levels of primary education and health care, poor access to resources, low management capabilities and armed conflicts.
The overexploitation of land resources including forests, increases in population, desertification and land degradation pose additional threats (UNDP 2006). In the Sahara and Sahel, dust and sand storms have negative impacts on agriculture, infrastructure and health. Climate change is an added stress to already threatened habitats, ecosystems and species in Africa, and is likely to trigger species migration and lead to habitat reduction.
Up to 50 per cent of Africa’s total biodiversity is at risk due to reduced habitat and other human-induced pressures (Boko et al. 2007). Future sea level rise has the potential to cause huge impacts on the African coastlines including the already degraded coral reefs on the Eastern coast.
National communications indicate that the coastal infrastructure in 30 percent of Africa’s coastal countries, including the Gulf of Guinea, Senegal, Gambia, Egypt, and along the East-Southern African coast, is at risk of partial or complete inundation due to accelerated sea level rise. In Tanzania, a sea level rise of 50 cm would inundate over 2,000 km2 of land, costing around USD 51 million (UNEP 2002a). Future sea level rise also threatens lagoons and mangrove forests of both eastern and western Africa, and is likely to impact urban centers and ports, such as Cape Town, Maputo, and Dar Es-Salaam.
Asia is the largest continent on Earth and spreads over four climatic zones (boreal, arid and semi-arid, tropical and temperate). The region faces formidable environmental and socio-economic challenges in its effort to protect valuable natural resources. Land and ecosystems are being degraded, threatening to undermine food security. In addition, water and air quality are deteriorating while continued increases in consumption and associated waste have contributed to the exponential growth in the region’s existing environmental problems.
Climate change will affect many sectors, including water resources, agriculture and food security, ecosystems and biodiversity, human health and coastal zones. Many environmental and developmental problems in Asia will be exacerbated by climate change.
Under climate change, predicted rainfall increases over most of Asia, particularly during the summer monsoon, could increase flood-prone areas in East Asia, South Asia and Southeast Asia.
Latin America includes much of the world’s biological diversity, as well as a wide variety of ecosystems, climatic regions, topographies and land-use patterns. Particularly vulnerable to climate change are the water, agriculture and health sectors, the Andean glaciers, the Amazon region and regions vulnerable to extreme climatic events (UNFCCC 2006d).
The region has already been experiencing climate-related changes with the frequency and intensity of extreme events, particularly those associated with the ENSO phenomenon.
Torrential rains and resulting floods, including those associated with tropical cyclones, have result in tens of thousands of deaths and severe economic losses and social disruption in the region in recent years18, for example in 1998 hurricane Mitch caused 10,000 deaths and severe damage to infrastructure, with Honduras and Nicaragua the worst hit. Northeast Brazil, on the other hand, is particularly affected by drought and its associated socio-economic impacts (Charvériat 2000).
Small Island Developing States
The small island developing States comprise 51 States and Territories spread over the Pacific, Indian and Atlantic Oceans and Caribbean Sea, and are highly vulnerable to the effects of climate change and already feeling its impacts. For example, in the Pacific islands region, cyclones accounted for 76 per cent of the reported disasters between 1950 and 2004, with the average costs relating to damage caused per cyclone standing at USD 75.7 million in 2004 value (World Bank 2006a). In the Caribbean region, the 2004 hurricane season alone caused damages estimated at USD 2.2 billion in four countries: the Bahamas, Grenada, Jamaica and the Dominican Republic.
Adaptation to climate change in developing countries is vital and has been highlighted by them as having a high or urgent priority. Although uncertainty remains about the extent of climate change impacts, in many developing countries there is sufficient information and knowledge available on strategies and plans to implement adaptation activities now.