GWSP Archive: Achieving Water Security in the Arid Americas: Emerging Challenges at the Beginning of the Anthropocene

Image of DroughtContemplating the Earth from the space gives us the impression that this blue planet would never suffer from water availability problems. However, as in any down-scaling exercise, it is only when we perform a detailed examination we begin to realise that, in many places of the world, water abundance is rather a privilege than a normal operating condition.

Water is at the very basis of biophysical and socioeconomically processes, so that whenever we trespass thresholds of water availability their functioning is seriously affected. That is why, the availability of sufficient quantities and adequate quality of water to meet societal needs and build resilient ecosystems, a concept known as water security, represents a fundamental precondition to achieve sustainability. This integration of societal and ecological needs broadly represents an aggregated demand that must be seen as dynamic in nature, since societal requirements are often reexamined and adjusted to respond to population growth, technological changes and the accommodation of multiple and more sophisticated aspects of water demand such as recreational and spiritual needs. Freshwater supply is also subject of considerable modes of variability (from seasonal to interannual) so the difference between this supply and demand at a given time is a preliminary indicator of the level of water security.

Dynamic global processes, such as climate change, land-use change, urbanization, population growth, and economic development (characteristic symptoms of the arriving era) produce evident biophysical effects that can seriously threaten water security. The latter two, if not accompanied by increasing efficiency, can produce unidirectional changes in water demand increasing pressure over existing freshwater resources.  Climate change and land use change, on the other hand, can have effects on both total demand and on the magnitude (and seasonality) of freshwater supply. The result is however, not easy to anticipate. In some scenarios such as the ones obtained from precipitation reductions along with increased deforestation in mountain areas, significant changes in land cover can overcome climate change impacts, resulting into an increase in surface water availability, usually at the expense of water quality due to erosion.

Water (in)security is not only the result of supply/demand interactions driven by global change. Societal conditions such as institutional rigidity and regulatory aspects can aggravate this problem as they affect stakeholder’s capacity to adopt long term horizons in their planning process and/or impede the incorporation of adaptive water management strategies. There is growing recognition of the importance of institutions and adequate legal frameworks to ensure water security.  In this sense, researchers and policymakers are expected to establish interdisciplinary science-policy dialogues to distill basic scientific knowledge and transform it into actionable information for policy making.

Western North America, central Andes, and north east Brazil are three regions that collectively represent the Arid Americas and share common features in terms of water security. Here severe water scarcity shapes landscape and constraints socioeconomic development. Global economic integration has accelerated growth and urbanization in the region, increasing water use, and changing consumption patterns.

The region also exhibits a significant El Niño Southern Oscillation (ENSO) footprint in its climatic regime, showing significant correlation between the occurrence of droughts and floods and the magnitude of the anomalies of the ENSO index. In addition, the Intergovernmental Panel on Climate Change (IPCC) projects increasing temperatures and drier conditions in sixty percent of the Latin American region. As a consequence it is expected that the number of people living in water-stressed conditions would increase by 2100.

From the ecosystem stand point, projected changes in precipitation, increases in evapotranspiration result in diminished groundwater recharge. As a consequence, riparian areas are modified, affecting ecosystem services that determine water quality and wildlife habitat.

Numerous approaches have been applied to address problems of water insecurity in this region. Some of them focus on the supply side, favoring the investment in infrastructure to better regulate seasonal streamflows and make water available when it is needed. Others like cloud seeding, artificial infiltration of aquifers, and water reuse enrich the portfolio of alternatives. From the demand side, most of the approaches emphasize strategies that increase efficiency (either sectorial or at a basin level).  Systems to allocate water, assign rights, establish priority uses, and balance human and ecosystem needs are also explored to complement the abovementioned policies, but they depend strongly on historical, political, and institutional context.

In view of the critical challenges faced by the Arid Americas to achieve water security, a network of researchers funded by the Inter-American Institute for Global Change Research (IAI), has launched AQUASEC, the IAI Center of Excellence for Water Security (  In 2012 IAI provided some initial support to encourage networking among AQUASEC partners across the American continent. AQUASEC ’s objectives are to promote water security through adoption and innovation with adaptive governance and management approaches that are innovative and adaptive.  Integrated research and strong science-policy dialogues are two of the most important and distinctive elements of this initiative since they are regarded as necessary conditions to strength water security. Taking a comprehensive approach we aim to study and represent the full range of uncertainties (social, ecosystem, and hydroclimatic), as well as to explore effective adaptation alternatives, facilitating decision making at all scales.

We have identified several case examples using comparative, cross-basin and multi-country approach to extract most salient lessons and have engaged relevant decision makers and stakeholders in a collaborative and integrated modeling framework.

Water security is a cornerstone for sustainable development. As we enter the Anthropocene, more critical it becomes to view water management through the lens of flexible strategies and to gain insights by working within communities of practice, with scientists and stakeholders.

By Francisco Meza
Director of the Centro de Cambio Global at Pontificia Universidad Catolica de Chile and co-Director of the Inter-American Institute for Global Change Research (IAI) Center for Water Security in the Americas AQUASEC.