Cloud formation affected by human activity, study says

September 12, 2006

University of Toronto researchers and their collaborators have discovered that solid ammonium sulphate aerosol – an airborne particle more prevalent in continental areas - can act as a catalyst to the formation of ice clouds, suggesting that cloud formation is another aspect of the global climate system that can be affected by human presence. The findings were published last week in Science.

With European climate scientists and cloud physicists, U of T atmospheric chemists Jon Abbatt and Zamin Kanji investigated whether ammonium sulphate aerosol in its crystal form could act as the ice nuclei to form cirrus clouds, the thin, wispy ice clouds that cover one quarter of the globe at any given time.

Cirrus clouds are important to the climate system because they scatter incoming sunlight, trap outgoing heat radiation and control the amount of water vapour in the upper troposphere. “Water vapour is a greenhouse gas, so any change in the ratio of ice cloud to water vapour affects the overall system,” says Abbatt. “So knowing how ice clouds form helps us better understand the system, and put together a better climate model.”

Studies of cirrus formation in different parts of the world have found that the clouds form more efficiently in the moderately polluted air of the Northern hemisphere than in the clean oceanic air of the Southern hemisphere. Abbatt’s team found a correlation between the amount of sulphate aerosol in the air and the efficiency of cloud formation in the regions. Because atmospheric ammonia now mainly comes from livestock and nitrogen-based fertilizer, the study provides evidence that human agricultural practices impact how and what kind of clouds form in the sky.

Source: University of Toronto

Explore further: Stellar nursery blooms into view

Related Stories

Stellar nursery blooms into view

December 13, 2017

The OmegaCAM camera on ESO's VLT Survey Telescope has captured this glittering view of the stellar nursery called Sharpless 29. Many astronomical phenomena can be seen in this giant image, including cosmic dust and gas clouds ...

Mars upside down

December 14, 2017

Which way is up in space? Planets are usually shown with the north pole at the top and the south pole at the bottom. In this remarkable image taken by ESA's Mars Express, the Red Planet is seen with north at the bottom, and ...

Why is massive star formation quenched in galaxy centers?

November 29, 2017

The current cosmological model to explain the universe, the "Big Bang" model, aims to describe all observable phenomena, including the evolution of galaxies from earliest times to the present day. One of the major problems ...

Recommended for you

Fish to benefit if large dams adopt new operating approach

December 18, 2017

Thousands of dams built along U.S. rivers and streams over the last century now provide electricity for homes, store water for agriculture and support recreation for people. But they also have significant downstream impacts: ...

Heavy oils and petroleum coke raising vanadium emissions

December 15, 2017

Human emissions of the potentially harmful trace metal vanadium into Earth's atmosphere have spiked sharply since the start of the 21st century due in large part to industry's growing use of heavy oils, tar sands, bitumen ...

Climate change made Harvey rainfall 15 percent more intense

December 14, 2017

A team of scientists from World Weather Attribution, including researchers from Rice University and other institutions in the United States and Europe, have found that human-caused climate change made the record rainfall ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.