Atmospheric brown clouds (ABCs), observed as widespread layers of brownish haze, are regional scale plumes of air pollutants, consisting of mainly aerosol particles (such as black carbon (BC) and non BC), and precursor gases (e.g. CH4, CO,NMVOCs, NOx), which produce aerosols and ozone in the atmosphere. ABCs and their interaction with build-up of greenhouse gases (GHGs) significantly affect the regional climate, hydrological cycle, glacial melting, agriculture production, and human health.
Studies reveal that light absorbing aerosol components of the ABCs reduces a significant a mount sunlight reaching to Earth surface by as much as 10 to 15%, and enhances atmospheric solar heating by as much as 50%. Thus, the ABCs on one hand mask the greenhouse warming by surface dimming, while on the other hand enhance the greenhouse warming of the atmosphere.
The Indian Ocean experiment (INDOEX) was the first to discover the nature and extent of ABCs, widespread over several continents. Scientific findings of the INDOEX indicated that ABCs significantly affects earth radiative balance, chemistry, and dynamics of the atmosphere which in turn impacting the regional climate, human health, water resources, and agriculture production
The United Nations Environment Programme (UNEP) commissioned the Atmospheric Brown Cloud (ABC) Programme in 2002, with a team of renowned scientists, to further continue the studies to understand the impacts of ABCs on climate and health and equip the policy makers with science-based information in order to underpin the actions on mitigation of ABCs at regional and global levels.
ABC Programme implemented through three sub-programmes:
1. Observatory and Capacity Building Programme: Established a network of ABC Climate Observatories in Asia-Pacific region with networking of atmospheric and climate scientists and built the capacity of participating countries in terms of infrastructure, instruments, and skilled manpower to carry out observations of the ABCs.
3. Mitigation and Awareness Programme: Commissioned Project Surya for demonstrating mitigations options for emission reduction of ABCs from biofuels through technological innovation and creating awareness among policy makers and common people through organizing awareness and training programmes and presenting ABC issues at the high level meetings.
The ABC programme has established a strong science team of renowned scientists, those including from India, China, Japan, America, Germany, Sweden, Korea and ex-officio of the World Meteorological Organization (WMO). The members of science team includes experimentalists, modelers, and policymakers who are continuously providing guidance and technical support to observatory and capacity building, impact assessment, mitigation activities. They are providing science-based information to policy makers to underpin the issues of ABCs at national and international levels.
The ABC Programme was evaluated by independent experts twice in the year 2007 and 2013. The evaluators were highly satisfied with the scientific findings and the way ABC programme was implemented. In their view, the science-based knowledge immensely generated by ABC programme has high prospects and potential to contribute in environmental policy making at national, regional, and international levels. [Read more...]
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