The arid and semi-arid regions account for approximately 30% of the world total area and are inhabited by approximately 20% of the total world population. Issues of present and future climate variability and change on agriculture and forestry in the arid and semi-arid tropics of the world were examined and discussion under each of these issues had been presented separately for Asia, Africa and Latin America.

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Impacts of Present and Future Climate Variability and Change on Agriculture and Forestry in the Arid and Semi-Arid Tropics

Drylands cover 41 percent of the earths terrestrial surface. The urgency of and international response to climate change have given a new place to drylands in terms both of their vulnerability to predicted climate change impacts and their potential contribution to climate change mitigation. This book aims to apply the new scientific insights on complex dryland systems to practical options for development. A new dryland paradigm is built on the resources and capacities of dryland peoples, on new and emergent economic opportunities, on inward investment, and on the best support that dryland science can offer.

Dryland opportunities : a new paradigm for people, ecosystems and development

The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations, of the United Nations Development Programme or of the United Nations Environment Programme concerning the legal statue of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries.

Land degradation in South Asia: Its severity, causes, and effects upon the people

Drought is among the most damaging, and least understood, of all “natural” hazards. Although some droughts last a single season and affect only small areas, the instrumental and paleoclimate records show that droughts have sometimes continued for decades and have impacted millions of square kilometers in North America, West Africa, and East Asia. To cross the spectrum of potential drivers and impacts, drought information systems have multiple sub-systems which include an integrated risk assessment, communication and decision support system of which early warning is a central component and output. An early warning system is much more than a forecast – it is a linked risk information (including people׳s perception of risk) and communication system that actively engages communities involved in preparedness. There are numerous drought systems warning systems being implemented at different scales of governance. We draw on the lessons of over 21 drought early warning systems around the world, in both developing and developed countries and at regional, national and community levels. The successes illustrate that effective early warning depends upon a multi-sectoral and interdisciplinary collaboration among all concerned actors at each stage in the warning process from monitoring to response and evaluation. However, the links between the community-based approach and the national and global EWSs are relatively weak. Using the rich experience of information systems across the globe, this paper identifies pathways for knowledge management and action at the relevant scales for decision-making in response to a changing climate.

https://www.droughtmanagement.info/literature/WCE_Information_Systems_in_a_Changing_Climate_2014.pdf

Information systems in a changing climate: Early warnings and drought risk management

Current theory presumes that natural selection on vascular traits is controlled by a trade-off between efficiency and safety of hydraulic architecture. Hence, traits linked to efficiency, such as vessel diameter, should show biogeographic patterns; but critical tests of these predictions are rare, largely owing to confounding effects of environment, tree size and phylogeny. Using wood sampled from a phylogenetically constrained set of 28 Eucalyptus species, collected from a wide gradient of aridity across Australia, we show that hydraulic architecture reflects adaptive radiation of this genus in response to variation in climate. With increasing aridity, vessel diameters narrow, their frequency increases with a distribution that becomes gradually positively skewed and sapwood density increases while the theoretical hydraulic conductivity declines. Differences in these hydraulic traits appear largely genotypic in origin rather than environmentally plastic. Data reported here reflect long-term adaptation of hydraulic architecture to water availability. Rapidly changing climates, on the other hand, present significant challenges to the ability of eucalypts to adapt their vasculature.

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Climate determines vascular traits in the ecologically diverse genus Eucalyptus

The author describes the contents and participation of former Soviet republics in the compilation of a global atlas of desertification, published under the auspices of the United Nations. Translated by H. L. Haslett, Leamington Spa, UK, from: Izvestiya Akademii Nauk SSSR, seriya geograficheskaya, 1991, No. 6, p. 130.

A. Y. Levintanus

Papers

World atlas of thematic maps of desertification