Anthropogenic dust in the climate system
What role do soil dust particles from sparsely vegetated, dry surfaces play in the climate system? And can that role become more pronounced in the future as humans and climate change affect the land surface? These are the key questions that will be tackled through the project ARIDITY.
Dust plays a key role in the Earth system, affecting climate, air quality, and ecosystems. While mineral dust from deserts is the largest source, soil particles emitted from sparsely vegetated surfaces in semi-arid regions are suggested to give a substantial contribution to the total amount of dust in the atmosphere. Because these regions are often influenced by agriculture and other human activities, this type of dust is typically referred to as “anthropogenic dust”. However, the role of anthropogenic dust remains poorly understood. This in turn hampers our ability to represent the dust cycle, quantify dust environmental impacts, and project the full consequences of land-use/land cover change. Advancing the state-of-knowledge about anthropogenic dust is becoming increasingly urgent as its sources are likely to respond to the large and concurrent changes in climate, socioeconomic development and land-based climate mitigation that are projected as society strives to meet the Paris Agreement and Sustainable Development Goals.
ARIDITY aims to reduce the uncertainty in how much anthropogenic dust there currently is in the atmosphere and its subsequent climate impact, and to provide future projections that are consistent with the most recent generation climate scenarios, the Shared Socioeconomic Pathways. The project will bring together experts in aerosol modeling and observations from Norway and the US and is positioned to deliver knowledge of relevance for climate mitigation.
Dust is the most abundant species of aerosol in the atmosphere. While mineral dust from deserts is the largest source, an important but less well-studied component is soil dust from sparsely vegetated surfaces. Commonly referred to as “anthropogenic dust”, arising from the influence of human activities on land surfaces and subsequent increase in wind erosion and dust emissions, this source is believed to contribute a substantial fraction to the total global dust load. However, the contribution and climate impact of anthropogenic dust, through interactions with radiation, clouds and precipitation, is poorly quantified. Concurrently, large changes in the environmental and socioeconomic drivers of anthropogenic dust emissions are projected in the coming decades, including land-based climate mitigation measures. The uncertainties surrounding anthropogenic dust hamper our ability to accurately model global dust levels, quantify aerosol radiative forcing and project climate implications of anthropogenic pressures on the land surface. ARIDITY will constrain this uncertainty by rigorously exploring sensitivities to poorly known physical dust parameters, leverage a growing body of observations, and integrate the resulting insights with the Shared Socioeconomic Pathways to provide a novel bound on the potential future climate influence of anthropogenic dust. ARIDITY sits at the nexus of two of the critical challenges for climate science: Reducing aerosol radiative forcing uncertainty, and understanding land-atmosphere-climate interactions. By bringing together experts in aerosol modeling, observations and process parameterization, and developing novel methodologies and tools, ARIDITY will deliver knowledge beyond the current scientific frontier, and bridge science-policy gaps in climate mitigation.