THE IMPACT OF CLIMATE CHANGE ON GROUNDWATER BY STUDYING CLIMATE PARAMETERS OF THE SOIL AND ATMOSPHERE
CHAPTER ONE
INTRODUCTION
1.1 BACKGROUND OF STUDY
Water is indispensable for life, but its availability at a sustainable quality and quantity is threatened by many factors, of which climate plays a leading role (IPCC, 1995). Groundwater is the major source of drinking water in Africa and has a rapidly expanding role in irrigation to combat growing food insecurity. This module deals with both the impact of climate change on groundwater resources, It is important to recall the global extent of climate change, and to consider the impacts on the scale of the global hydrologic cycle.
Of Africa’s population of 1 billion, roughly 60% live in rural areas. Around 80% of them rely on groundwater-based community or household supplies for domestic and other water needs (WHO/UNICEF, 2008).
Currently there are more than 300 million people in Africa without access to safe drinking water, many of whom are amongst the poorest and most vulnerable in the world (MacDonald, A.; Bonsor, H.C.; Dochartaigh, B.E.O.; Taylor, R.,, 2012). Climate variability and change influences groundwater systems both directly through replenishment by recharge and indirectly through changes in groundwater use. These impacts can be modified by human activity such as land-use change (Taylor, Nature Climate change, 2013).
Climate change is “an altered state of the climate that can be identified by change in the mean and/or variability of its properties and that persists for an extended period, typically decades or longer”. It may be due to “natural internal processes or external forcing, or to persistent anthropogenic changes in the composition of the atmosphere or in land use” (IPCC, 2007).
Climate change affects water resources around the world in generally unknown ways. Potential impacts of climate change on surface water particularly projected regional climate patterns and trends (i.e., climate variability and change) have been studied in some detail. Yet, little is known about how subsurface waters will respond to climate change coupled with human activities
We refer to all subsurface water as ‘‘groundwater’’, including soil water and unconfined and confined aquifer waters. Distinctions can be made between these components of groundwater, noting interactions between them and surface water.
The challenges of understanding climate-change impact on groundwater are unprecedented because climate change may affect hydrogeological processes and groundwater resources directly and indirectly (Allen, D. M., Mackie, D. C., Wei, M., 2004). In ways that have not been explored sufficiently
Observational data and climate predictions provide abundant evidence that freshwater resources (both surface and groundwater resources) are vulnerable and have the potential to be strongly affected by climate change, with wide-ranging consequences for society and ecosystems (Calow, R.; MacDonald, A, 2009).
Today, climate change may account for approximately 20% of projected increases in water scarcity globally (Bouraoui, F., Vachaud, G., Li, L. Z. X., Le Treut, H,, Chen, T., 1999).
Thus, there is a need to evaluate and understand climatic variability over the long term to better plan and manage groundwater resources well into the future, while taking into consideration the increasing stresses on those resources from population growth and industrial, agricultural, and ecological needs (Warner, S.D., 2007).
In this project we appraise the state of the science of global change related to all components of groundwater. Scientific issues and methods are placed in the context of global programs aimed at assessment of groundwater resources and adaptation to climate change. The current emphasis is on regional case studies with the potential for global analogues to inform decisions where detailed studies are not presently feasible. In this synthesis of results to date, we provide the type of soft information needed to generalize scientific knowledge and the controlling factors specific to each case study.
