Atmospheric Brown Cloud Watch:

The first fully-researched and detailed report on the environmental impact of South Asian Haze was released by UNEP and the Center for Clouds, Chemistry and Climate (C4) in August 2002. The report is mainly based on the studies of the Indian Ocean Experiment (INDOEX) and its team of 200 scientists. It provides a summary of the large brownish haze layer and its impact on the radioactive heating of the atmosphere and surface for South Asia and the Indian Ocean. It also discusses early findings with respect to the effects of the haze on regional temperatures, rainfall, agriculture and health.

Findings are based on limited sets of modeling studies. Because definitive conclusions cannot yet be drawn, these studies emphasize the importance of the haze on climate and the great need for further research into the problem of brown haze.

Quick facts
  • brown haze extends over South, Southeast and East Asia
  • haze is concentrated 3 kilometers above the surface and can travel halfway around the globe in less than a week
  • large earth surface cooling due to reduced sunlight throws off the hydrological cycle
What is in the Brown Haze?
  • black carbon and ash
  • sulfates
  • nitrates
  • mineral dust
  • 75% of the cloud is man-made
Causes
  • forest fires
  • inefficient cooking fuels
  • factories
  • motor vehicle use
Effects
  • significant reduction of solar radiation to the earth’s surface by as much as 15%
  • changed regional monsoon patterns (less sea evaporation from sunlight means less rain)
  • less rain in northwest India, Pakistan, and Afghanistanby as much as 40%
  • more rain and flooding in other areas
  • reduction of photosynthesis (drop in agricultural productivity)
  • acid rain and plant damage
  • breathing problems and diseases

Source: UNEP and C4. The Asian Brown Cloud: Climate and Other Environmental Impacts UNEP, Nairobi

Giant Atmospheric Brown Cloud Has Intercontinental Reach

NASA scientists announced a giant, smoggy atmospheric brown cloud, which forms over South Asia and the Indian Ocean, has intercontinental reach. The scientists presented their findings today during the American Geophysical Union Fall meeting in San Francisco.

The scientists discussed the massive cloud's sources, global movement and its implications. The brown cloud is a moving, persistent air mass characterized by a mixed-particle haze. It also contains other pollution, such as ozone.

"Ozone is a triple-threat player in the global environment. There are three very different ways ozone affects our lives," said Robert Chatfield, a scientist at NASA's AmesResearchCenter, Moffett Field, Calif. "A protective layer of good ozone, high in the atmosphere, shields us from deadly ultraviolet light that comes from the sun. Second, bad or smog ozone near the surface of Earth can burn our lungs and damage crops. In our study, we are looking at a third major effect of ozone, that it can warm the planet, because it is a powerful greenhouse gas," Chatfield said.

"We found both brown cloud pollution and natural processes can contribute to unhealthy levels of ozone in the troposphere where we live and breathe. Some ozone from the brown cloud rises to high enough altitudes to spread over the global atmosphere," Chatfield explained. Ozone from the Earth's protective stratospheric layer, produced by natural processes, can migrate down to contribute to concentrations in the lower atmosphere, according to the scientists.

The researchers studied the intercontinental smog ozone processes associated with the brown cloud over South Asia. They used a NASA technique that combines data acquired by satellites with ozone data measured by instruments on special weather balloons.

The ozone-monitoring instrument on NASA's Aura satellite is providing data about the brown cloud. "The beautiful, high-detail images from this instrument promise to help us sort out our major questions about how much of the tropospheric ozone is from pollution and how much is from natural factors," Chatfield said.

Analysis shows ozone in the lower atmosphere over the Indian Ocean comes from the intensely developed industrial-agricultural areas in the region. The southern pollutant buildup has long-range effects, often traveling across Africa, further than the brown cloud of particles, according to researchers.

Massive Pollution Documented Over Indian Ocean

An international group of scientists participating in a climate field experiment has documented widespread pollution covering about 10 million square kilometers of the tropical Indian Ocean -- roughly the same area as the continental United States. The finding raises serious questions about what impact the extensive pollution is having on climate processes and on marine life in the ocean below.

The scientists are participating in the Indian Ocean Experiment (INDOEX), a $25 million project, sponsored in part by the National Science Foundation, to investigate how tiny pollutant particles called aerosols are transported through the atmosphere and their effect on climate. The team of scientists was shocked by the extent of pollution they encountered during the six-week field experiment that began in early February and continued through the end of March 1999. "There was a brownish haze layer all over the Indian Ocean almost 1,000 miles off the coast," he said. "That was what really stunned us -- how pervasive these aerosols were and how they could survive at such long distances from where they originated." The INDOEX scientists reported finding a dense, brown haze of pollution extending from the ocean surface to altitudes of 2 miles in the air.

The haze layer covered much of the research area almost continually during the six-week experiment. The affected area includes most of the northern Indian Ocean, including the Arabian Sea, much of the Bay of Bengal, and spills over into the equatorial Indian Ocean to about 5 degrees south of the equator. "It appeared as if the whole Indian subcontinent was surrounded by a mountain of pollution," agreed Ramanathan. "At times, we couldn't even see the low clouds because the haze layer was so thick."

The haze is caused by high concentrations of small particles known as aerosols that are usually less than a few micrometers in diameter. Comprised primarily of soot, sulfates, nitrates, organic particles, fly ash and mineral dust, the particles often reduced visibility over the open ocean.The haze layer also contains relatively high concentrations of gases, including carbon monoxide, various organic compounds, and sulfur dioxide, providing conclusive evidence that the haze layer is caused by pollution. "There is little doubt that future levels of pollution from India and other nations bordering on the Indian Ocean region are going to grow substantially in the future.

Asia and the Indian subcontinent, which together have a population of more than 2 billion people, emit large quantities of pollutants that can be carried to the Indian Ocean during the northern hemisphere winter by monsoon winds from the northeast. "If you cut the amount of sunlight going into the ocean, you will also impact the amount of moisture evaporating from the sea surface either regionally or globally and, consequently, the amount of rainfall that will be generated," Ramanathan said. "So the entire hydrological cycle is being perturbed."

A reduction in the amount of sunlight reaching the ocean surface can also have a detrimental effect on plant life that depends on photosynthesis, including plankton, which provides a key link in the marine food chain. Early results indicate that the pollutants play a dual role in that they have both warming and cooling effects. The tiny particles produce a cooling effect in that they scatter sunlight back to space. By acting as seeds for cloud condensation, they also produce an indirect cooling effect by increasing both the longevity and reflectivity, or albedo, of clouds. The pollutants have a warming effect, however, in that they absorb a large amount of sunlight. The airborne particles over the northern Indian Ocean are unusually dark because they contain large amounts of soot and other materials from incompletely burned fuels and wastes. Dark aerosols lead to the increased absorption of solar radiation.

"The soot contributes a substantial amount of heating of the atmosphere, but it also reduces the amount of sunlight reaching the ocean," Ramanathan said. "So, it is just too early to say at this point whether the net effect is one of cooling or warming." The dark airborne particles over the Indian Ocean appear to be markedly different from those over North America and Europe, where advanced pollution control technologies remove much of the dark material and yield particles that are relatively brighter. "What INDOEX has pointed out very dramatically is that the long-range transport of aerosols can be extremely important and that we should be looking more closely at what impact this is having on global climate."

Asia's brown clouds 'warm planet'

Clouds of pollution over the Indian Ocean appear to cause as much warming as greenhouse gases released by human activity, a study has suggested.

US researchers used unmanned aircraft to measure the effects of the "brown clouds" on the surrounding area.

Writing in Nature, they said the tiny particles increased the solar heating of the lower atmosphere by about 50%.

The warming could be enough to explain the retreat of glaciers in the Himalayas, the scientists proposed.

The clouds contain a mixture of light absorbing aerosols and light scattering aerosols, which cause the atmosphere to warm and the surface of the Earth to cool.

The main sources of the pollutants came from wood burning and fossil fuels, the team added.

Aerosols, also known as particulates, cool the land or sea below because they filter out light from the Sun.

While this process, known as "global dimming", is fairly well understood, the effect aerosols have on the surrounding atmosphere is still unclear.

The scientists, from the University of California San Diego and the NasaLangleyResearchCenter, said there remained a degree of uncertainty because, until now, estimates had largely been derived from computer models.

Solar heating

For their study, the team of researchers used three unmanned aircraft, fitted with miniaturised instruments that were able to measure aerosol concentrations, soot amounts and the flow of energy from the Sun.

The crafts flew over the polluted region of the Indian Ocean at varying heights between 500m (1,640ft) and 3,000m (9,840ft).

"During 18 flight missions, the three unmanned aerial vehicles were flown with a separation of tens of metres or less and less than 10 seconds (apart), which made it possible to measure the atmospheric solar heating rates directly," they wrote.

"We found that atmospheric brown clouds enhanced lower atmospheric solar heating by about 50%.

"[The pollution] contributes as much as the recent increase in anthropogenic greenhouse gases to regional lower atmospheric warming trends," they suggested.

"We propose that the combined warming trend of 0.25 Kelvin per decade may be sufficient to account for the observed retreat of the Himalayan glaciers."

Seasonal glacier and snow melt from the mountain range feeds rivers that supplies water to about 40% of the world's population.

The United Nations Environment Programme (Unep), in its latest Snow and Ice Outlook report, said the ice sheets in the region could retreat by up to 81% by the end of the century.

Story from BBC NEWS:

Published: 2007/08/01 18:34:48 GMT© BBC MMVII

Asian Brown Cloud Activity

Essential Question: How have humans altered their environment?

The Asian Brown Cloud is a giant brown haze as large as a continent and 2 miles thick. It was created from factory’s smoke, forest fires, automobiles and inefficient cooking fuel.

Task: Choose one of the activities below to demonstrate your knowledge of the “Asian Brown Cloud.”

  1. Pretend that you are a student in India and make a poster to make people aware of the dangers of the “Asian Brown Cloud” and how to help alleviate the problem.
  2. Write a commercial that explains the dangers of the “Asian Brown Cloud”
  3. Write a news article that illustrates a story of how someone or something has been affected by the “Brown Cloud”
  4. Write a letter to a public official and propose a law that will demand Indian citizens take action to reduce the effects of the “Asian Brown Cloud”
  5. Write a song that explains the dangers of the Asian “brown” cloud.

Asian Brown Cloud Rubric

1 2 3 4

Wrote the words Asian “brown” cloud but do not write any thing that is true about the “Asian Brown Cloud”. / Includes elements in the definition that are wrong. / Gives the basic definition without explaining the “Asian Brown Cloud”. / Demonstrates a clear understanding of the “Asian Brown Cloud”.
Simply wrote one reason why the “Asian Brown” Cloud” exists. / Included some of the definition but also concluded false reasons why the Asian Brown” Cloud” exists. / Gave the basic reasons why the Asian “brown” cloud exist that you learned in the notes. / It is clear by the work of what caused the “Asian Brown Cloud”.
Attempted to explain where the cloud is located but got confused and thought it was coming to Woodland. / Only told part of the location. / Copied the location from the notes. / Utilized knowledge of geography and explained where the “Asian Brown Cloud” is located.
Explained fictional problems the “Asian Brown Cloud” has created. / Only explained part of what the “Brown Cloud” is doing to Asia. / Copied what was stated in the notes. / The project exemplifies the students understanding of why the “Brown Cloud” is so dangerous.