Inadvertent Weather Modification

Inadvertent weather modification refers to short-term changes in weather resulting from human activities conducted for purposes other than altering the weather. Inadvertent weather modification is distinct from changes in weather resulting from long-term modification of the Earth's climate as a result of human-caused greenhouse gas emissions. Human activities unintentionally change many facets of weather experienced at and near the Earth's surface. Urban areas, for example, change weather such as temperature, wind, precipitation, cloudiness, and visibility over and downwind of their locations. Changes to land-surface use, such as deforestation and large-scale irrigation, can influence where and when storms may form. Installation of large solar arrays and wind turbine farms may also impact local weather. Emissions from human activities have dramatically altered air quality and visibility, and have led to acid precipitation. Jet aircraft produce contrails that spread to create cirrus clouds, increasing cloud cover, while ships leave tracks of bright stratocumulus clouds over the oceans in their wake. This article describes the scientific basis underlying current understanding of inadvertent weather modification.