Each year, the fresh water the Earth loses—324 billion cubic meters—could meet the annual needs of about 280 million people. This loss has been measured and documented in the World Bank’s latest Global Water Monitoring Report, which explicitly speaks of “continental drought”: a persistent, long-term decline in the earth’s water reserves.
The problem, revealed thanks to a new analysis of two decades of satellite data (GRACE and GRACE-FO missions) combined with economic and land use data, is no longer confined to desert areas, but involves vast continental masses. The picture that emerges is that of a global water system that is reaching a tipping point.
When withdrawal beats deposit
Fresh water is stored on the continent like in a “giant bank account”. The report reveals that, globally, withdrawals are systematically exceeding deposits, leading to a deficit. This loss has reached 3% of the basin-wide annual renewable freshwater supply; however, in arid areas already in the drying phase, it reaches a critical threshold of 10%.
In addition to global warming and intensifying drought, the crisis is directly fueled by concrete human choices. Agriculture, which consumes 98% of the total human water footprint, is at the heart of the problem: in non-glacial regions, aquifer depletion (68% of water loss) and intensive land conversion for irrigation are among the major culprits in the loss of reserves. Land use decisions, such as rapid urbanization and intensive irrigation, are indeed a key driver of continental drought.
Furthermore, the undervaluation and underpricing of water, especially in agriculture, incentivizes excessive use and inefficiency. In countries that rely heavily on irrigation, lower prices for energy, often subsidized for pumping groundwater, are associated with a more rapid depletion of water reserves. Last but not least, in countries with weak implementation of Integrated Water Resources Management (IWRM), reserves are being depleted at a rate two to three times higher than in nations with more effective management.
Work, food and biodiversity
Continental drought is not a problem that only affects cubic meters, but triggers knock-on consequences that directly affect people’s lives and global environmental stability.
Water scarcity seriously compromises agricultural productivity, leading to job losses and reduced incomes. In sub-Saharan Africa, drought shocks left between 600,000 and 900,000 people without work each year between 2005 and 2018, an impact that was particularly acute among women and low-skilled workers. Virtual water, i.e. water embodied in traded goods, means that local water scarcity can have global economic repercussions, as demonstrated by the estimate that a 100mm decrease in rainfall in India could reduce real global income by around $68 billion.
Environmentally, the drying up of water supplies significantly increases the likelihood and severity of forest fires. In areas of high biodiversity, a one standard deviation increase in the rate of freshwater depletion raises the probability of fire by 50%. The analysis highlights a worrying “point of no return”, caused by a non-linear synergy: drying makes adaptation to warming more difficult, and vice versa, exponentially accelerating damage.
The solutions
Despite the severity of the situation, the report indicates that there are significant opportunities for savings, especially by improving water use efficiency in agriculture. Bringing low-efficiency producers in desiccation-prone regions to median global water management standards, for example, could reduce annual irrigation water use by 137 billion cubic meters.
The report recommends a three-pronged strategy to address the crisis: managing demand by adopting efficient technologies and extraction limits; increase supply, through recycling, desalination and improved storage; and improve the allocation of scarce resources.
To make all this effective, it is necessary to act on five transversal levers: strengthen institutions, reform tariffs and subsidies, adopt water accounting (accurate measurement of consumption and supply), exploit technological innovation and give a value to water in trade. Only through the integration of real-time data and policies that reflect the true value of this resource can we ensure that continental drought does not accelerate towards irreversible consequences.
