Howard County Maryland Blog

Local Politics and Current Events

Sahara desert frontiers turn green

Posted by David Keelan on Monday, June 18, 2007

Sahara desert frontiers turn green

Satellite pictures of northern Africa show that areas lost to the Sahara desert during decades of drought are turning green again.

Analysis of images show deserts retreating in a broad band stretching from Mauritania to Eritrea, according to research in British magazine New Scientist.

The driving force behind the retreat of the deserts is believed to be increased rainfall.

Compare that to this headline:

Climate change behind Darfur killing: UN’s Ban

UN Secretary General Ban Ki-moon said that the slaughter in Darfur was triggered by global climate change and that more such conflicts may be on the horizon, in an article published Saturday. “The Darfur conflict began as an ecological crisis, arising at least in part from climate change,” Ban said in a Washington Post opinion column.

What is a person to think. Are we expected to accept that global warming real when we are constantly presented with such conflicting information and reports?

Meanwhile trying to explain the behavior of deserts is just as difficult as explaining the behavior of a teenager.  Here is an article on the formation of the Sahara desert.

Sahara desert born 4,000 years ago

Using a new computer simulation of the Earth’s climate, German scientists say that the Sahara underwent a brutal climate change about 4,000 years ago.

Over a very short time scale – possibly as short as 300 years – it went from grasslands with low shrubs to the desert we are familiar with today. Summer temperatures increased rapidly and rainfall almost ceased. The change devastated many ancient cultures and caused those that did survive to migrate elsewhere.

Scientists at the Potsdam Institute for Climate Research say that the desertification of the Sahara was one of the most dramatic changes in climate over the past 11,000 years.

The loss of agricultural land to the desert may have been one of the reasons why early civilisations developed along the valleys of the Nile, the Tigris and the Euphrates.

Feedback mechanism

Slight climate alterations caused by subtle changes in the Earth’s orbit around the Sun were amplified by a climatic feedback mechanism.

Some 9,000 years ago the tilt of the Earth’s axis was 24.14 degrees; today it is 23.45 degrees. Today, the Earth is closest to the Sun in January. Nine thousand years ago, our planet was closest to the Sun at the end of July.

The changes in the tilt of the Earth occur gradually. However, the interplay of atmosphere, ocean and landmass can react to these changes in abrupt and severe ways.

The climate model suggests that land use by man was not an important factor in the creation of the Sahara.

What is my point?  The information is contridictary and we don’t know what is going on.  Of course the researchers could be wrong.  I have not seen their models and really have no idea if and when the earth’s axis changed.  So if you have these models please share them with us.

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3 Responses to “Sahara desert frontiers turn green”

  1. An interesting article you might want to expand on:

  2. Sorry, didn’t mean to screw up the layout. Feel free to correct it so that it doesn’t screw up the page.

  3. John Bradbury said

    http://www2.cnrs.fr/en/516.htm have a read of this site for an explanation of how the Sahara desert has cycled through green and desert periods for millions of years and this has occured without the help of modern man and machinery. Does climate change theory help to contribute to the maintenance of high oil prices? Just a thought.

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