Climate Change Impacts on Water Resources in Ghana

Transcription

1 Climate Change Impacts on Water Resources in Ghana By K. Kankam-Yeboah Research Scientist B. Amisigo Research Scientist E. Obuobi Senior Research Scientist CSIR Water Research Institute Introduction Although climate change is not a new phenomenon, in this present age, it has taken the centre stage in the development agenda of both the developed and developing countries. This is, perhaps due to the compelling evidence which roll in by the day supporting the existence of the phenomenon, making it difficult for countries that are conservative when it comes to climate change issues and some climate change deniers to openly ignore it. Climate change simply refers to increase in the average global surface temperatures caused mainly by anthropogenic increase in concentration of greenhouse gases, particularly carbon dioxide (CO 2 ), in the earth s atmosphere. Throughout history, the earth s climate has varied, sometimes very significantly. This is caused by natural mechanisms including: continental drift which has changed the features of the earth s landmass, their position and the position of water bodies, and consequently changing the flow of ocean currents and winds; large volcanic eruptions which throw out large amounts of sulphur dioxide (SO 2 ), water vapour, dust and ash into the atmosphere which could influence climate patterns for years; orbital variations which can affect the severity of climate seasons (e.g., summer, winter, harmmattan); changes in atmospheric composition which can lead to global warming; and ocean circulation. Except for volcanic eruptions, climate variations caused by natural mechanisms are slow and sometimes take millions of years to happen, by which time the earth s systems would have adjusted to the change. 65

2 Causes of present climate change Today s climate change, however, is caused by recent increasing trend in carbon dioxide emissions into and consequent increase in temperature in the earth s atmosphere. This situation can be attributed to human industrialization process that began in the 1750s, as shown in the two (2) graphs from NASA (Figure 1) and CDIAC (Figure 2). Over the past 40 years, human activities such as burning of fossil fuels for energy and transportation, changing land use, deforestation, land clearing, oil drilling, coal mining and agriculture have accelerated the release of CO 2 into the atmosphere, way beyond the rate of release from natural processes. This has thereby speeded up the warming of the earth within a short period of time, to the extent that the earth s systems are increasingly unable to adapt. scarce and poor quality of fresh water resources, moisture stress or excess leading to poor crop yields, loss of biodiversity, poor health conditions and increased risk of contracting water related diseases. Even though large amounts of the CO 2 emissions come from industrialized countries such as the USA, Canada, Europe and Russia and fast developing countries such as China and India; the impact is most felt by the poor in developing countries, particularly in Africa including Ghana. There is also the consensus that climate change will hit agriculture hardest. Again, developing countries will be the most affected since their economies are heavily dependent on agriculture, which is largely rainfed. How is climate change impacting in Ghana? There is no doubt that the climate in Ghana has changed significantly with impacts (EPA), showed that, there is: 1 C increase in temperature over a 30-year period from the historical records, increased evaporation, decreased and highly variable rainfall pattern, and frequent and pronounced drought spells. Another study led by EPA in 2008 on Ghana Climate Change Impacts, Vulnerability and Adaptation Assessment reported that, over the past 40 years ( ), average annual temperatures have been rising steadily in 5 of the 6 agro-ecological zones of Ghana. This trend is projected to continue into the future. The impacts of the rising temperatures are already happening. These include: the drying of some rivers in the dry season which were hitherto perennial rivers, more intensive rainfall events such as the rainfall and flood events of 23 rd April 2008 and 24 th June 2009 in parts of Fig 1 - Comparison of atmospheric CO 2 before and after the industrial revolution. (Source: NOAA). Fig 2 - Global CO 2 emission from 1751 (beginning of industrial revolution) to Climate change impacts Climate change holds possible threats to all countries of the world; some of the threats are already being experienced. They include sea level rise, increased frequencies of extreme weather events such as floods and droughts, being felt everywhere in the country. Studies conducted by the CSIR Water Research Institute (CSIR WRI) in 2000, under the United Nations Framework Convention on Climate Change (UNFCC) and co-ordinated by the Environmental Protection Agency Accra (Fig. 3) that wrecked havoc on life and properties, frequent events of drought (e.g., the drought that led to power rationing in 2006), due to low levels of water in the Akosombo dam, floods, such as the one that occurred in 2007 which 66

3 Fig. 3 Flooding in Accra (April 2008). affected about 332,600 people and caused the death of 56 persons in the Upper East, Upper West and Northern regions and parts of Western region, and unpredictable weather, especially late start of the rainfall season and or shorter rainy season. All these are evidence of the impact of climate change in Ghana. In northern Ghana, for instance, high temperatures that were previously recorded in March (peak of the dry season) are now being recorded also in January. The start of the rainy season has become more difficult to predict. In the past, the rainy season started in April and ended around late September or early October. However in recent times, the rainy season starts in June or July with extreme heavy rainfall in September or October, often resulting in floods that destroy crops, life and properties or ending abruptly and resulting in drought conditions (Fig. 4). With projected average temperatures showing a rising trend, the impacts of climate change are likely to be more severe in the future. Studies done by the International Food Policy Research Institute (IFPRI) show that, even though food prices in Ghana will rise in the near future, climate change will make it worse. The price of rice that is projected to increase by 60 % without climate change could go up by as much as 121 % due to climate change. Prices of maize are projected to increase by up to 153 % in 2050 with climate change, instead of just more that 60 % without climate change. Consequences of climate change for water management Studies at CSIR-WRI show that even without climate change considerations, Ghana is predicted to become a water stress country by In the face of increases in the frequency and severity of extreme weather events in the future, it is most likely that climate change will worsen future water scarcity in many places in the country. Frequent floods have the potential to wreck havoc on expensive water infrastructures for domestic water supply, irrigation and hydropower generation. The CSIR-WRI 2000 report on climate change and water resources estimated: a general reduction in annual river flows in Ghana by % for the year 2020 and % for the year 2050, a reduction in groundwater recharge of 5-22 % for 2020 and 30-40% for 2050, an increased irrigation water demand of % for 2020 and % for 2050, a reduction in hydropower generation of 60 % for 2020 and, by the year 2020, all river basins will be vulnerable and the whole country will face acute water shortage. Under climate change, the quality of freshwater in rivers and other water bodies will also be impacted negatively as the expected increased floods would carry pollutants into water bodies, restricting their use and putting further constraint on water availability to meet growing demand. Women and children will be affected the most as they will have to spend more time travelling longer distances in search of good quality water. Fig. 4 Drought resulting in loss of cereal harvest in Bolgatanga, Upper East Region (2006). 67

4 Climate change comes with great challenges for water management in Ghana and certainly, adaptation and innovative management will be a necessary response. For, instance, water managers may be required to change design criteria of water facilities, planning and allocation decisions, to incorporate the impacts of climate change. The general perception in the populace that water is an infinite resource would also have to change through mass education on water utilization practices. Need for continuous research on climate change Similar to else where in the world, the need for continuous research on climate change and water resources in Ghana cannot be overemphasized. Water is life and fundamental input for many sectors of Ghana s economy and therefore any impact of climate change on water resources has a direct impact on the economy of Ghana. It is important, therefore, that accurate assessment of the impacts of climate change is periodically carried out to inform appropriate choice of adaptation options which are then accounted for in the development agenda of government. Accurate assessment of climate change in Ghana is faced with challenges. It is a well known fact that the science of the climate in West Africa including Ghana is not well understood, compared to other areas of the African continent. As a result, the Global Climate Models (GCMs) of the Intergovernmental Panel on Climate Change (IPCC) produce varying projections for rainfall change over the West African area. While some models project wet conditions for the future, others project dry conditions; any of them is plausible. The IPCC scenarios of global situation in the future (the so called story lines), upon which climate projections are made with GCMs, are revised from time to time to reflect current knowledge generated in the scientific community. As part of the IPCC and the world scientific community and given the uncertainty regarding the prediction of the West African weather, it is only proper that research on climate change in Ghana is continuous so as to take advantage of the new knowledge that becomes available from time to time, and to revise the choice of adaptation options, which then feeds into government s agenda. Support from government and development partners The government of Ghana has very strong interest in climate change issues and is working through the research institutions, universities and ministries to address the challenge. The World Bank is leading a major country case study on Economics of Adaptation to Climate Change (EACC) in Ghana, among others. The study will help inform the debate in the international community on economic issues related to adaptation, as well as contribute to advancing the methodology of linking climate impact models and economic models within a coherent framework for evaluating policies related to climate change. The United Nations agencies through frameworks such as the UNESCO Participation Project, International Hydrological Programme (IHP) and, Intergovernmental Oceanographic Commission (IOC) are supporting various programmes and projects to quantify the impacts, identify appropriate adaptation options, assess economic cost of adaptations and incorporate the adaptations in its development agenda of the country. Current research at CSIR Water Research Institute Against the back drop that climate change research needs to be continuous, the CSIR-WRI in 2009 and with support from the Ghana National Commission (GNC) for UNESCO under the UNESCO Participation Project started a study on climate change effects on hydrology and water resources and adaptation strategies in Ghana. Among other objectives, the study seeks to: assess the vulnerability of rainfall and river flows to climate change in selected river basins, and recommend appropriate adaptation strategies for coping with water stress under changing climate. The goals are to: document the evidence of hydrologic effects of climate change in Ghana; improve the awareness of policy makers and other stakeholders on the consequences of climate change on water resources; scientifically support the preparation of an action plan on climate change for the country; and, contribute to adaptation strategies to climate change. The proposed study is a contribution to the Main Line of Action 1 of 34/C5 Activities of Major Programme II 68

5 (Natural Sciences) of UNESCO and the Theme 1 of Phase VII of the International Hydrological Programme (IHP). When completed, the study will be an update to the surface water hydrology component of the climate change study done by the same institute in Conclusion There is broad scientific consensus that the climate of the earth is really changing and the earth is becoming warmer due largely to anthropogenic emission of greenhouse gases, especially, CO 2. If nothing substantial is done to slow down the fast warming of the earth, future climate will no longer be the same as the past. Much of the CO 2 emission that is changing the earth s climate originates from the industrialized countries. However, the negative impacts of climate change such as droughts and floods are most felt in developing countries, Ghana being no exception. We therefore need to put in place appropriate adaptation measures to deal with the impacts of climate change. The water sector in Ghana is one major area that is and will be impacted by climatic change and therefore water planners and managers can no longer rely only on past climatic conditions for the design of water facilities, water allocation, planning and management decisions. Improper land and water use practices should be curtailed by the enforcement of national legislations and traditional rules on water resources, as the knowledge base in climate change and its impact is deepened and sustainable adaptation are sought for through research. Considering the uncertainties that surround climate change studies and the importance of accurately quantifying the impacts of climate change and therefore choosing appropriate adaptation measures to be included in government s development agenda, it is only right to say that climate change research, and for that matter scientific research in general, needs to be continuously supported by all. It is in this light that the support from UNESCO through the Ghana National Commission for UNESCO to the current study at the CSIR-WRI is very much appreciated. Decision-Making Support for Coastal Zone Management, Water Resources and Climate Change in Africa The Pan-African Workshop on Decision-Making Support for Coastal Zone Management, Water Resources and Climate Change in Africa was held in Cotonou, Benin, from February The event was a joint initiative of, inter alia, the Global Ocean Observing System in Africa (GOOSAFRICA) sponsored by the Global Ocean Observing System (GOOS) of the Intergovernmental Oceanographic Commission (IOC) of the UN Educational, Scientific and Cultural Organization (UNESCO), the International Hydrological Programme (IHP) of UNESCO, the GEO Coastal Zone Community of Practice (CZCP) and the African Association of Remote Sensing of the Environment (AARSE). The African regional institutions, the United Nations Environment Programme (UNEP) and the African Large Marine Ecosystems Commissions and programmes are also key partners and sponsors of the Workshop. Participants included marine, water, climate and environmental scientists and resource managers, from Africa and elsewhere. One of the workshop s objectives was to focus on identifying gaps in capabilities of Earth observation systems, as well as scientific and research infrastructures needs, to respond to concerns surrounding modeling of coastal oceans, water resources and climate change in Africa while addressing socioeconomic issues and fostering capacities for decision making. The event included a high-level Governance Forum, which provided a venue for African leaders to consider frameworks for addressing critical water issues in Africa, as well as to assess the results and implications for the economies and populations of Africa subsequent to the Copenhagen Climate Change Conference. 69