Climate change and dust generation

The projected impact of climate change on dust generation is seldom considered in the planning and framework of the design for pavement construction, mining activities, recreational facilities, agricultural activities just to mention a few. Often times, the approach taken is based on the past and present without much investment in the future. Given the recurrence and frequency of natural phenomenon such as floods leading to elevated soil moisture susceptibility and droughts resulting in more dry seasons consequentially the future must be taken into account in the initial stages of any project. Of particular interest to our conversation is dust in its various forms and how much more prevalent it will be as a result of the effects of climate change. We pose three key questions: 

• What is the worldview on climate change and dust generation? 
• What is the Australian view on climate change and dust generation? 
• Of the products currently available for dust suppression how do they meet sustainable development goals? 

The article will evaluate and seek to answer the questions whilst highlighting the synergy with sustainable development in tackling dust generation for the future based on climate change. 

What the modelling can show us?

Predictive modelling from climate models suggests a rise in drought conditions resulting in unmatched aridity in the next half century. The burden on health and the society is forecasted to be devastating and unfortunately it’s not always the case of forewarned is forearmed as for most of the world. Globally, the predictive tools for climate change and its effects on dust generation in the last few years have been faced by large uncertainties in dust modelling. For example projection of American dustiness in the late 21st century did not yield any specific information for the United States given the difficulty for models to properly reproduce observed dust variability over North America. Presently, they have been suggestions for application of modulated dust source strength to fit the data however this has limitations in projection of future dust change. Most recently, researchers from Princeton University evaluated key controlling factors of dust activity using satellite data. They used key projected changes controlling these factors from climate models to project future dust activity due to climate change with their model parameters working on a worst-case scenario of extreme droughts and associated dust generation. 

What the data tells us?

Over the past five decades, climate change detection in Australia has improved remarkably. Observations in maximum daytime temperatures and average minimum night-time temperatures depicts a rise almost all over the country. Annual rainfall rose in the northwest as a summer singularity but reduced in the southwest. In addition, rise in warming due to greenhouse gas concentrations and decreased rainfall in southwest Western Australia is attributed to natural climate variability and land-use changes. Marked increase in summer rainfall in northwest Australia was due to aerosols resulting from human activities. The climate change monitoring in Australia has been made much easier with availability data sets from 50 to 200 stations distributed evenly from over the Australian continent and prepared by the Australian Bureau of Meteorology. Generally, drought conditions obtained from the precipitation minus evaporation have been more common. The recent droughts of 1994 and 2002 did not show significant changes in total precipitation but temperatures have been very high in the recent droughts in Australia. 

Intensification of dust generation as a result of drought can be examined from variation in precipitation, surface wind, surface bareness. Precipitation which is also related to soil moisture reduces dust generation by dislodging airborne dust and increasing soil moisture in the dust source area, it also curbs the rise of dust particles due to winds. A lack of precipitation owing to drought therefore favors dust generation with dust events correlated to frequency in dry episodes. Surface wind is related to transport of dust as a result of wind speed leading to increase in dust emissions. Surface bareness considers mostly the area covered by vegetation and how it contributes to reducing soil erosion by wind. These variations are described broadly but an example in farming considers the effect of change in land use or cover for instance from grasslands to non-irrigated croplands, the lack of vegetative cover, improper farming methods also contribute to dust generation and can be accelerated by climate change. All these factors lead to intensification of dust generation, which in turn affects air quality. 

UNCSD – Kicking Goals

The follow-up of the 2012 Rio+20 United Nations Conference on Sustainable Development has driven the post-2015 development agenda through coordinated and concerted strategies and actions to minimize potential trade-offs and conflicts whilst maximizing synergies to contribute to multiple Sustainable Development Goals. Reduction of dust generation in a more controlled environment such as a mine or farm is interlinked to achieving development goals and targets. For example use of environmentally friendly dust suppressants enables achievement of: 

• Goal 3: good health and well-being
• Goal 8.4: improve progressively global resource efficiency in consumption and production and endeavor to decouple economic growth from environmental degradation
• Goal 8.8: promote safe and secure working environments 
• Goal 12.4: achieve the environmentally sound management of chemicals and all wastes throughout their life cycle 

Looking forward, looking back

The view on climate change and dust generation varies from one country to the other. A lot of this is due to the disagreement regarding the level that human activities are driving climate change. Regardless of the why, the effects of climate change are universal, and incidence of dust generation is correlated to natural phenomenon culminating from climate change. Australia like any other country has experienced changes in climate and inevitably this has led to further increase in dust generation. Environmentally friendly dust suppression products meet the sustainable development goals in promoting safe working environments through sound management of chemicals obtained from green feedstocks and harness the power of the circular economy approach to dust mitigation. Climate change mitigation strategies must factor in air quality co-benefits to application of effective dust suppression methods as part of the framework with assessments from an economic, health and environment point of view. Imperative to the policy making is consideration of past climate changes and how the global dust cycle responded to projected future climate changes. In as much as the future is important the past can also be used to benchmark and even improve climate modelling tools and sensitivities to enhance prediction capabilities of the future climate models. 

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REFERENCES 

• Delworth, T.L., and Zeng, F. 2014. Regional rainfall declines in Australia attributed to anthropogenic greenhouse gases and ozone levels. Nature Geoscience. 7. 583-589.
• Haines, A., Amann, M., Borgford-Parnell,N., Leonard, S., Kuylenstierna, J., and Shindell, D. 2017. Short-lived climate pollutant mitigation and the Sustainable Development Goals. Nature Climate Change. 7. 863-869. 
• Kok, J.F., Ward, D.S., Mahowad, N.M., and Evan, A.T. 2018. Global and regional importance of the direct dust climate feedback. Nature Communications. 9:241, 1-11. 
• Nemet, G.F., Holloway, T., and Meier, P. 2010. Implications of incorporating air-quality co-benefits into climate change policymaking. Environ. Res. Lett. 5. 1-10.
• Nicholls, N. 2006. Detecting and attributing Australian climate change: a review. Aust. Met. Mag. 55. 199-211. 
• Pu,B., and Ginoux, P. 2017. Projection of American dustiness in the late 21st century due to climate change. Scientific Reports. 7:5553. 1-10. 
• Shindell, D et al. 2017. A climate policy pathway for near- and long-term benefits: Climate actions can advance sustainable development. Science AAAS. 356:6337. 493-494.