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Dust transported by Southern Hemisphere mid-latitude westerly winds from Australia and deposited in the Tasman Sea shows no evidence for stronger winds during the last glacial maximum (LGM), compared to the Holocene. Features of the particle-size distributions of the dust do, however, indicate enhanced dry deposition of dust in the LGM changing to rainfall scavenging during deglaciation and the early Holocene as climate ameliorated. From these results it appears that activation of desert dunefields over 40% of Australia during the LGM was the result of a reduction in stabilizing vegetation and more frequent episodes of sand movement rather than of increased wind strength. The LGM climate of inland Australia must have been considerably more stressful for plants as a result of lower precipitation and/or carbon dioxide stress to achieve the implied levels of surface destabilization. Enhanced atmospheric dust loads in the Southern Hemisphere and deposition over Antarctica were most likely the result of greatly expanded source areas in the mid-latitude southern continents and a weaker hydrological cycle rather than greater entrainment or more efficient transport by stronger winds. During the LGM wind strength appears to have varied regionally, and predominantly in high latitudes, rather than uniformly for all zonal winds.

To date, the principal constraint upon the implementation of a dust monitoring programme for desertification control in West Africa, is our limited knowledge of the dust processes to be monitored. A review of the state of dust research in Africa and over the Atlantic reveals a strong imbalance in favour of the latter, and resolves some misconceptions concerning dust source-areas and the relative importance of winter and summer dust. The results of Atlantic Ocean dust research are here brought together with the recent results of Harmattan dust research in Nigeria to demonstrate, at least tentatively, that the Harmattan and winter dust comprise a contiguous aeolian process system referred to as the Harmattan aeolian system.The Harmattan aeolian system is used here as a conceptual framework for the dust monitoring programme. Three dust process-zones are identified, within which three basic aeolian processes operate: dust entrainment (primary and secondary), dust transport, and dust deposition (primary and secondary). Within each dust process-zone, standardized dust collection, measurement, and analysis techniques, are proposed for a network of monitoring sites. Entrainment and transport can be measured — directly using aerosol pump-samplers and indirectly by relating dust-aerosol concentration to solar radiation and visibility. The indirect approach has the advantage that it opens up a large body of historical data on dust and, therefore, desertification. Deposition can be measured using dust-traps. The importance of such aspects as site characteristics, measurement period, and laboratory methods, are also discussed. Finally, a minimal administrative structure is suggested, allowing for the possibility of UNEP or other major support.