Dust Aerosols And Climate: A Brief Review Rabia S. Sa’id Department of Physics, Bayero University, PMB 3011, Kano, Nigeria (Submitted: October 6, 2011; Accepted: May 27, 2012) Abstract In Africa and particularly in areas prone to desertification, dust aerosols are impacting considerably. The Third Assessment Report (TAR) of the Intergovernmental Panel on Climate Change (IPCC) reported that the Radiative Forcing (RF) due to anthropogenic dust lies in the range of +0.4 to –0.6 Wm –2 . Although, the RF efficiency of anthropogenic dust has not been differentiated from that of natural dust, it is assumed to be equal. In this paper, journal articles dealing with different aspects of dust aerosol effects on climate have been reviewed. Particular attention has been paid to research articles on the effect of dust aerosols on climate. The review shows that majority of studies indicate that dust aerosols have a direct and indirect effect on climate. The review further highlights the recent research findings that the optical properties of the mineral constituents of dust aerosols play an important role in determining the physical and chemical equilibrium of the atmosphere. Keywords: Dust Aerosols, Radiative Forcing, Climate Advances in Science and Technology, Vol. 6, No. 2S, August 2012, pp 115 - 122 1.0 Introduction A vast body of literature on dust aerosol research is now readily available and research is still ongoing. On the effect of dust aerosols on incident radiation, current literature available are also many and deal with different aspects of dust aerosol interactions with incident radiation. A review of past and current research on the subject is presented. Dust aerosols are tiny solid and liquid particles suspended in the atmosphere. Depending on their size, type and location, aerosols can either cool the surface of the atmosphere or they can cause warming. Dust aerosol sizes range between 1–10 microns. Fine or accumulation mode dust aerosols are in the range of 1-2 microns, while larger particles (coarse mode) have radial sizes greater than 2 microns. Dust aerosols also help in cloud formation. Although dust aerosols occur naturally in the atmosphere and are useful in climate processes where they influence radiative forcing directly through reflection and absorption of solar infrared radiation in the atmosphere, the increase in anthropogenic dust aerosols have been shown to have significant net (direct and indirect) global mean radiative forcing (Ingold, 2001). The IPCC report (2007); surmises the likelihood that more solar radiation is now being reflected from earth’s surface as a result of dust resulting from human activities. These changes have been shown to result in negative radiative forcing (Forster, et al. 2007). However, there are uncert- ainties particularly due to the uneven distribution of dust aerosols in the atmosphere. Sokolik et al. (1998) show that the uncertainties in radiative forcing of dust aerosols are due to: mineralogy, size distribution and albedo effects. Prospero et al. (1996) in their research, show that the uncertainties are also due to difficulty in quantifying the human impact of dust aerosols in the atmosphere. Dust aerosol that originate as surface windblown dust and from specific landscapes such as desert areas, which are then transported annually to different regions by air masses are referred to as natural dust. Natural dust would therefore refer to dust resulting from Aeolian processes that mobilize and suspend large quantities of dust into the atmosphere. The Sahara Desert is a major source of natural mineral dust aerosols transported across the Caribbean, Mediter- ranean, the Americas and Europe, while the Gobi Desert is the source of natural dust that affects eastern Asia and the western part of North America. If the dust emanate from land use, cultivation and road construction, then it is referred to as anthropogenic dust aerosol. Human activities contribute about 30% (Ge, et al. 2010) of dust load in the atmosphere. Author’s E-mail: rssaid2001@yahoo.co.uk, saidur2776@buk.edu.ng