Richard C. Carter and Alison Parker, “Climate Change, Population Trends and Groundwater in Africa,” Hydrological Sciences Journal, vol. 54, no. 4 (2009), pp. 676–89, https://doi.org/10.1623/hysj.54.4.676.
While the effects of climate change on African groundwater are likely to be significant, they are uncertain in both direction (they could decrease or increase the amount of water in aquifers) and magnitude, these authors conclude. Based on a review of climate and population projections for the continent, they find the impact of demographic change to be more-likely and larger than that of climate change. Roughly half of Africa’s population currently relies on shallow or deep groundwater, they estimate. And they note that development increases per capita water use for hygiene, food security, and improved livelihoods.
Roughly half of Africa’s population currently relies on shallow or deep groundwater
Comparing scenarios of climate change without population growth, and scenarios of population growth without climate change, the authors find much more impact on groundwater from the latter. The combination of population growth and urbanization with rising food demands and energy costs will “dwarf the likely impacts of climate change on groundwater resources, at least in the first half of the 21st century,” they write.
Key quotes: “Africa’s population is increasing rapidly [and] will place massively increased and concentrated demands on water resources, both for domestic and industrial use in the towns and cities, and for agricultural use in the rural areas and urban fringes. This increase in demand is likely to dwarf any likely reductions in renewable fresh water resources consequent upon climate change. . . .
“Research into the likely future impact of climate change on groundwater recharge is needed, but an equal priority should be placed on: (i) monitoring of groundwater levels over the long term to establish actual change, as a reality check on models and projections; (ii) developing sound conceptual and quantified models that explicitly link climate variability and change, population growth and water demand, land use and land cover change, hydrology and water resources; (iii) quantifying likely future urban and agricultural demands on fresh water resources, and on groundwater in particular; (iv) finding environmentally and functionally sustainable solutions for the present and near-future water emergency represented by the massively expanding need for domestic, industrial and (especially) agricultural water in Africa.”
The availability of fresh water for present and future generations reflects a complex combination of multiple factors that are hard to untangle and project for the future
Assessment: The availability of fresh water for present and future generations reflects a complex combination of multiple factors that are hard to untangle and project for the future. Groundwater is especially challenging, with inadequate data on current supplies around the world and gaps in understanding about the mechanisms and time scales for recharging groundwater supplies as they are drawn down for irrigated agriculture and other uses. This paper explores these questions in detail, considering, for example, how climate change might alter not just the amount of rainfall in Africa, but its timing and intensity. These strongly influence how much water runs off in surface streams and how much it recharges aquifers.
Given the uncertainty in projections on how climate change will affect Africa’s groundwater, the authors place far more confidence in population projections, which indicate much faster growth in Africa than in any other major world region throughout the 21st century. More people, and especially more urban residents, they reason, will place far more demands on groundwater, especially as the continent industrializes and its agriculture relies increasingly on irrigation.
The paper may be subject to criticism based on strong subjective wording (they call their findings “cause for alarm” three times) and on the authors’ obvious concern about the risks of Africa’s rapid population growth. Skeptical readers might wonder if their research is subject to a predetermined conclusion. We found no evidence that this was the case, however. In their analysis of available data and the logic of their argument, the authors point the way for future research comparing potential determinants of future water supply and demand. They may place too much confidence in population projections, however. These do attract more scientific consensus than do the more-diverse projections of climate change impacts, which rely on a range of possible emissions scenarios interacting with natural systems that are still not well understood. Population, however, is also subject to unpredicted developments and could unfold differently than expected.
The following annotation and assessment is excerpted from the forthcoming report of the Family Planning and Environmental Sustainability Assessment (FPESA) project. The report will contain selected annotations from more than 930 peer-reviewed articles reviewed for potential relevance to the hypothesis that family planning supports environmental sustainability. The annotations are written by project director Robert Engelman with input from members of the project team and, where indicated, members of the project’s international network of research assessors.