How the atmosphere above the Amazon rainforest – the purest air on Earth – can help to cool the planet

Amazon-tntmagazine
Scientists from Harvard and São Paulo University (USP) carried out a research to try and find out how the planet’s climate was before the industrial revolution. For this they were searching for the purest air in the planet and found it in the atmosphere above the Amazon rainforest. The study is crucial to understand cloud formation and, ultimately, changes in the climate.

To make predictions about future climate, it is fundamental to understand the past and present climate, explained the study coordinator, Paulo Artaxo, from USP. The Amazon is one of the few regions in the world, the other being the Antarctic, where it is still possible to find atmospheric conditions similar to those before the Industrial Revolution, i.e. before pollution.

Artaxo explained that the aim of the investigation was to understand the mechanisms of cloud formation in an atmosphere free from pollutants. This is important to find out how the atmospheric conditions will be in respect to cloud formation and precipitation if the temperature of the Amazon region increases in future with global warming.

The scientists used 40 metre high towers and sophisticated sampling equipment and managed to isolate aerosols in pristine conditions for the first time. In the Amazon basin in the area north of Manaus, the concentration of suspended particles formed in the Amazon ecosystem was 200-300 per cm3 and the samples were free from any anthropogenic influence. This figure is typically tens of thousands in an industrial region.

Atmospheric particles are essential for cloud formation; it is around these that the nucleus begins to gather and group to form clouds. In a polluted atmosphere, clouds form from pollution particles. In the Amazon, the particles in the atmosphere are formed in the atmosphere, as opposed to being emitted from anthropogenic sources, as is the case in the cities. Before this latest research, it was believed that the forest emitted these particles, but now it is clear that the particles in the Amazon atmosphere are secondary particles formed from gaseous compounds emitted by the vegetation.

Implications for global warming

If the forest is cut down and replaced with pasture we will lose the most important mechanism of cloud formation in the Amazon basin, because pasture plants do not emit these volatile organic compounds, which form clouds, explained Artaxo. However, if the forest is maintained as forest, with the warming of the planet, as predicted by models, the rate of conversion to particles of these gases emitted by the vegetation will increase and more clouds will form. This does not mean more rain, as rain depends on the water vapour flux. However, more importantly, this increase in clouds over the Amazon will help to cool the Earth because these clouds are white and, therefore, will reflect the solar radiation back into space, a mechanism which would help to balance the temperature in the Amazon region, at least.

The results of the study were published in Science and will be incorporated in models to predict the future of the Amazon.

Link to source article in O Globo newspaper website.

One thought on “How the atmosphere above the Amazon rainforest – the purest air on Earth – can help to cool the planet

  1. Chris Holehouse September 26, 2010 / 1:52 am

    Hi there,
    Just following up from my recent comment about your RSS feed being published to Before It’s News.
    I’m the Environment editor at Before It’s News. Our site is a People Powered news platform with over 1,000,000 visits a month and growing fast.
    We would be honored if we could republish your blog RSS feed in our Environment category. Our readers need to read what CABI Blogs has to say.
    Syndicating to Before It’s News is a terrific way spread the word and grow your audience. Many other organizations are using Before It’s News to do just that. We can have your feed up and running in 24 hours. I just need you to reply with your permission to do so. Please include the full name and email of the person who will be attached to the account, and let me know the name you want on the account (most people have their name or their blog name).
    You can also have any text and/or links you wish appended to the end or prepended to the beginning of each of your posts on Before It’s News. Just email me the text and links that you want at the beginning and/or ending of each post. If you know html you can send me that. If not, just send me the text and a link to your site. It should be around 200 characters or less (not including links).
    You can, if you like, create a custom feed for Before It’s News that includes multiple links back to your blog or web site. We only require that RSS feeds include full stories, not partial stories. We don’t censor or edit work.
    All the best,
    Chris Holehouse
    Editor, Before It’s News
    http://www.beforeitsnews.com
    chris.h@beforeitsnews.com

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