Last week’s UN Environment Program Report concluded that Atmospheric Brown Clouds are darkening cities on several continents, destroying crops and killing hundreds of thousands of people.
The report also warned that brown clouds are enormously important climate changers and that poorly planned efforts to eliminate the clouds would accelerate global warming.
In the Himalayan-Tibetan plateau, brown clouds enhance greenhouse warming and are thus accelerating the retreat of the Hindu Kush-Himalayan-Tibetan glaciers. These glaciers feed the four great rivers of Asia which provide water to 2.5 billion people. The matter carries “serious implications for the water and food security of Asia,” said Professor Veerabhadran Ramanathan, head of the UNEP scientific panel.
But warming of the Himalayas is an unfortunate regional anomaly. The UNEP scientific panel in fact concludes that brown clouds dampen the pace of global warming by 20-80% by reducing the amount of sunlight that reaches the Earth’s surface.
This means that tackling the pollution linked with brown cloud formation without simultaneously delivering big cuts in greenhouse gases may increase global temperatures 2 degrees Celsius, which is nearly three times the rise in world temperatures measured during the entire 20th century.
Professor Veerabhadran Ramanathan, head of the UNEP panel said, “Our preliminary assessment, published in 2002, triggered a great deal of awareness but also skepticism. That has often been the initial reaction to new, novel and far reaching, counter-intuitive scientific research.
“We believe today’s report brings ever more clarity to the ABC phenomena and in doing so must trigger an international response – one that tackles the twin threats of greenhouse gases and brown clouds and the unsustainable development that underpins both.”