"A primary goal for the future is to develop ways to provide dryland residents with a much larger set of livelihood options, including at least some that do not depend on agriculture and are not vulnerable to local climate variability."

• State of knowledge: mid-20th century
• State of knowledge: early 21st century
• 2007 and beyond: Where to now?
• References
• Author information
• Additional web resources

[ Editor's note: In 1955, the "International Arid Lands Meetings" were held in New Mexico, USA, sponsored by UNESCO and the American Association for the Advancement of Science. These meetings brought together a panel of experts whose aim was to discuss what were then considered the major problems facing drylands and to develop a research agenda for addressing these problems. The presentations from these meetings were published by the AAAS in 1956, in the book The Future of Arid Lands, edited by Gilbert White.

Fifty years later, the United Nations declared 2006 the International Year of Deserts and Drylands. In connection with the IYDD, UNESCO commissioned a team headed by Dr. Charles Hutchinson, Director of the Office of Arid Lands Studies at the University of Arizona, to reassess the contents of the 1956 book in light of what has changed since then and to speculate on what all this might mean for the future of today's drylands. The resulting manuscript, tentatively titled The Future of Arid Lands Revisited, is scheduled to be published in late 2007.

This article provides a brief summary of major points made in the upcoming book, as they are particularly relevant to the theme of this issue of ALN. Readers who are interested by this short overview and would like to learn more are urged to seek out copies of the forthcoming work once it is published (an event that will of course be announced in the ALN book review column). ]

State of knowledge: mid-20th century

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At the 1955 International Arid Lands Meetings in New Mexico, USA, drylands were considered mainly as a resource to be used. The aim of the meetings was to figure out ways to make this use more productive; the purpose of identifying gaps in then-current knowledge about drylands was not so much to increase understanding of dryland dynamics as to determine better ways of exploiting dryland resources. Thus, the meeting participants focused primarily on understanding the variability of water supply and developing new sources of supply; how to improve overall resource use in drylands; and how to improve animal and plant adaptations to drylands--all with an overall focus on agricultural production.

The overall mood that informed the meetings, and the papers in the subsequent 1956 book, The Future of Arid Lands (White 1956), can be characterized in several important ways:

First, belief in the overall benefits of science and technology was very strong. The prevailing view was that technology could bring much larger portions of drylands into productive use. For example, the early 1950s were the beginning of the era of construction of large dams. This was entirely in accord with the view of that time that irrigated agricultural production (rather than "less valuable" uses such as grazing or forestry) was the best use to which drylands could be put; "greening the deserts" through development of surface water resources and large-scale irrigation projects was a goal to be vigorously pursued. Other uses were regarded as less desirable, even to the point of being actively discouraged.

Second, little data available was available that allowed full understanding of biosphere processes, particularly at regional and global scales. The science of complex systems had not yet been developed, and the tendency then was to consider the various components of drylands ecosystems quite separately from each other. A corollary to this was the feeling that these "discrete" problems might be solved by the development of a single, powerful "magic bullet" solution. A good example of this is the many programs that were then under development to modify the weather and bring rains by various cloud-seeding techniques. Optimism was high that weather modification could be developed to a point where it would reliably produce rains in wide swaths of dryland regions.

Another example of this compartmentalized approach to drylands was the general lack of emphasis, during the 1955 meetings, on economics, social issues or traditional human livelihood systems. What attention was paid, especially to these livelihood systems, tended to be negative: for example, pastoralism was seen as a primitive and ineffective land use, highly discouraged by most governments.

A third characteristic of mid-20th century views was that there was very little recognition of the possibility of unintended consequences. This probably reflected the belief in technological solutions that characterized the time. When discussing water resources development and agriculture, for example, little notice was given to the potential for large-scale irrigation to create severe problems of salt accumulation in the soil, even though that potential had been recognized as far back as the days of the ancient civilizations of the Fertile Crescent. The prevailing belief in the 1950s appeared to be that, if such problems did occur, they would be easy to reverse.

State of knowledge: early 21st century

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Today, many of these viewpoints are seriously questioned. One of the most important drivers of this change is the growing scientific understanding of the complexity and interconnectedness of all aspects of the biosphere. Climate modeling is one area that demonstrates how this understanding of complexity has grown. In the 1950s, climate modeling by computers had just gotten its start. Up to the mid-1970s, only atmospheric data were included in these models; by the mid-1980s, land surface data were also added; by the late 1990s, data on land and sea ice and on phosphate aerosols were incorporated. Current climate models have been even further expanded to incorporate data on non-sulphate aerosols and the carbon cycle.

The emergence of complex systems science, and advances in our understanding of such systems, have furthermore led to a shift of focus from individual components of dryland ecosystems to the study of the relations and interactions among all of these components.

Another change is a shift away from thinking that the "equilibrium model" describes drylands ecosystems. This model states that each ecosystem has a natural "climax state" that it will eventually and inevitably reach; after that, if disturbances occur that cause changes to the ecosystem, it will naturally (if perhaps eventually) revert to that climax state once the disturbances are removed. Now, scientists understand that drylands are better described by non-equilibrium models driven by variability, uncertainty and disturbance. Drylands ecosystems may more often be in a state of transition than in a state of equilibrium. Not only that, a given ecosystem, if disturbed beyond a certain "tipping point", may never return to its previous state; instead, it may be changed in ways that cannot be reversed, no matter what management strategies are used.

Current science also recognizes that no truly viable, long-term solution to drylands problems can be achieved without considering humans as an integral part of ecosystems. In terms of agriculture, for example, attention is now focused on regional or household-level land use systems that may incorporate more than one economic land use. In addition, land value is no longer seen as merely economic, but as incorporating other aspects such as social, cultural, historical, spiritual and environmental values, as well.

This perspective also treats traditional land use systems with new importance. Pastoralist strategies are now respected as highly successful adaptations to particular ecosystems, for example. This change in attitude leads to the possibility of integrating modern science with traditional knowledge to make incremental changes to existing local systems--an approach that has shown great promise for enabling sustainable development and alleviating poverty.

Globalization is another radical shift that has changed perspectives on drylands in numerous ways in the past 50 years. First, seemingly local environmental problems (e.g. dust storms in the Gobi Desert or the Sahel) may have far-reaching, even global effects that will take international efforts to address. On a more positive note, globalization has also opened new opportunities for drylands in sectors like tourism and the information industry.

2007 and beyond: Where to now?

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Over the course of the next 50 years, drylands can be expected to assume more importance in the evolving world economy. Drylands are in a good position to benefit economically from the development of new markets and products based on intangible values like recreation or provision of ecosystem services like nutrient cycling and maintenance of biodiversity. Land uses with low demands on water but high demands on space, like solar energy, may provide particularly interesting opportunities.

Some things certainly will not change. Water will continue to be the major constraint on drylands development, and current, often unsustainable pumping of groundwater in drylands is of particular concern. Well-planned policies will always be needed to support the long-term success of local development efforts, and the inherent variability of arid climates will continue to be a major challenge.

A primary goal for the future is to develop ways to provide dryland residents with a much larger set of livelihood options, including at least some that do not depend on agriculture and are not vulnerable to local climate variability. That dryland inhabitants themselves favor such an approach is reflected in the growing numbers of rural drylands residents who are migrating to urban areas in drylands. In fact, if policies and techniques can be developed to make cities more resource-effective, and if land values change sufficiently, this trend might be a positive one: in a global economy, it is not necessary for every area to strive for agricultural self-sufficiency, and non-agricultural uses (e.g. cities, factories, recreation) may be more appropriate for drylands than water-intensive crop production.

The challenges are great, but there is reason for cautious optimism. One potential path to the future is to link local ingenuity and productivity to local, regional, and national markets; such efforts need to be fostered by:

• developing policies and institutions that facilitate access to markets;
• providing access to physical and institutional infrastructure;
• valuing, managing and building on local knowledge; and
• diversifying opportunities in the form of ways to generate income from non-farm work.

Locally successful strategies that follow this path can already be found, as for example in the refinement of "zai" farming techniques in Burkina Faso during the 1980s. This development arose in the Yatenga region when a local farmer began to modify the traditional small planting pits (the zaï), making them larger than usual and adding manure to them. This concentrated both water and nutrients around his crops with such excellent results that the new techniques were quickly adopted, first by his neighbors, and then by local NGOs who spread them throughout the region.

Another possible path, less well developed at present, is through global efforts to provide the world's energy needs while reversing greenhouse gas emissions. Solar energy is a prime example of this possibility.

In either case, though, it can be expected that drylands will continue to be increasingly integrated into and connected with the world as a whole. Some people, perhaps romantically, may see this as a loss; but others will see it as the future for which drylands have long been destined.

References

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Hutchinson, Chuck and Stephanie Herrmann. Forthcoming. The future of arid lands revisited. Paris: UNESCO.

White, Gilbert (ed). 1956. The future of arid lands: Papers and recommendations from the International Arid Lands Meetings. Washington, D.C.: American Association for the Advancement of Science.