Free Republic

The global extent and distribution of forest trees is central to our understanding of the terrestrial biosphere. We provide the first spatially continuous map of forest tree density at a global scale. This map reveals that the global number of trees is approximately 3.04 trillion, an order of magnitude higher than the previous estimate. Of these trees, approximately 1.39 trillion exist in tropical and subtropical forests, with 0.74 trillion in boreal regions and 0.61 trillion in temperate regions. Biome-level trends in tree density demonstrate the importance of climate and topography in controlling local tree densities at finer scales, as well...

Every so often you will see articles warning that some species is going extinct. And usually it's not really a species -- you never hear about "leopards" going extinct, usually it's "purple dotted left handed bisexual Nepalese leopards" or some subvariety.  We are assured they are going extinct because fewer have been seen recently. But the Earth is so big, how can we really be sure that some subspecies is going extinct just because we see fewer of them? After all, only three percent of the land mass of the Earth is urbanized. Animals could easily be hidden in...

It seems that scientists were a little off in calculating the number of trees on the planet. You remember trees: they turn CO2 into oxygen and water. In fact, if you buy a “carbon credit,” you are paying to plant trees to buy an indulgence for your private jet travel -- just like Al Gore and Robert F. Kennedy Jr. supposedly do. Well, all those calculations of doom over purported CO2-caused global warming may be a little more unsettled. The Wall Street Journal reports:

There are just over three trillion trees in the world, a figure that dwarfs previous estimates, according to the most comprehensive census yet of global forestation. Using satellite imagery as well as ground-based measurements from around the world, a team led by researchers at Yale University created the first globally comprehensive map of tree density. Their findings were published in the journal Nature on Wednesday. A previous study that drew on satellite imagery estimated that the total number of trees was around 400 billion. The new estimate of 3.04 trillion is multiple times that number, bringing the ratio of trees...

The global map of tree density at the square-kilometer pixel scale. Credit: Crowther, et al A new Yale-led study estimates that there are more than 3 trillion trees on Earth, about seven and a half times more than some previous estimates. But the total number of trees has plummeted by roughly 46 percent since the start of human civilization, the study estimates. Using a combination of satellite imagery, forest inventories, and supercomputer technologies, the international team of researchers was able to map tree populations worldwide at the square-kilometer level. Their results, published in the journal Nature, provide the most comprehensive...

OSLO (Reuters) - The once-green Sahara turned to desert over thousands of years rather than in an abrupt shift as previously believed, according to a study on Thursday that may help understanding of future climate changes. And there are now signs of a tiny shift back towards greener conditions in parts of the Sahara, apparently because of OSLO (Reuters) - The once-green Sahara turned to desert over thousands of years rather than in an abrupt shift as previously believed, according to a study on Thursday that may help understanding of future climate changes. And there are now signs of a...

World's poorest must change lifestyles as Earth dries up.Many of the world's dry regions, currently home to some 2.1 billion people, are in danger of becoming useless for growing food, according to the latest in a series of reports on the world's ecosystems. It blames climate change and human activities. The report's authors estimate that 10-20% of these 'drylands' have already lost some plant life or economic use, and they say the situation is getting worse. Hundreds of thousands of people will be in need of new homes and lifestyles over the next 30 years, they estimate. The report, titled...

UNITED NATIONS (AP) The world is turning to dust, with lands the size of Rhode Island becoming desert wasteland every year and the problem threatening to send millions of people fleeing to greener countries, the United Nations says. One-third of the Earth's surface is at risk, driving people into cities and destroying agriculture in vast swaths of Africa. Thirty-one percent of Spain is threatened, while China has lost 36,000 square miles to desert an area the size of Indiana since the 1950s. This week the United Nations marks the 10th anniversary of the Convention to Combat Desertification, a plan aimed...

Kazakh dam condemns most of the shrunken Aral Sea to oblivion Desperate step after water row with Uzbeks Paul Brown, environment correspondent Wednesday October 29, 2003 The Guardian (UK) A seven-mile dam is being built across a small northern section of the shrunken Aral Sea in Central Asia, which is described as the world's worst environmental disaster. The saline inland sea, divided between the former Soviet states of Kazakhstan and Uzbekistan, has been drying out for 25 years, since the USSR began a vast irrigation scheme drawing water from its two tributary rivers to grow cotton and rice in the...

...the Garamantes - a mysterious desert people of Greco-Roman date (broadly 500 BC AD 500)... Inhabiting a region that had already been for several thousand years a hyper-arid desert environment, with negligible rainfall, elevated summer temperatures and blistering expanses of barren sand and rock... have long been an enigma. They were depicted by Roman sources as ungovernable nomadic barbarians, who raided the settled agricultural zone and cities of the Mediterranean littoral. Following up earlier work by Daniels, the current project allows a different picture of the Garamantes to be drawn. Archaeological evidence shows them to have been a complex and...

Britain's airspace was closed under false pretences, with satellite images revealing there was no doomsday volcanic ash cloud over the entire country. Skies fell quiet for six days, leaving as many as 500,000 Britons stranded overseas and costing airlines hundreds of millions of pounds. Estimates put the number of Britons still stuck abroad at 35,000. However, new evidence shows there was no all-encompassing cloud and, where dust was present, it was often so thin that it posed no risk. The satellite images demonstrate that the skies were largely clear, which will not surprise the millions who enjoyed the fine, hot...

Wet spells in the Sahara may have opened the door for early human migration. According to new evidence, water-dependent trees and shrubs grew there between 120,000 and 45,000 years ago. This suggests that changes in the weather helped early humans cross the desert on their way out of Africa... While about 40 per cent of hydrocarbons in today's dust come from water-dependent plants, this rose to 60 per cent, first between 120,000 and 110,000 ago and again from 50,000 to 45,000 years ago. So the region seemed to be in the grip of unusually wet spells at the time. That...

A plan to build a 6,000km-long wall across the Sahara Desert to stop the spread of the desert has been outlined. The barrier - formed by solidifying sand dunes - would stretch from Mauritania in the west of Africa to Djibouti in the east. The plan was put forward by architect Magnus Larsson at the TED Global conference in Oxford. A 2007 UN study described desertification as "the greatest environmental challenge of our times".

On top of the world! Sensational collection of satellite images captures Earth's natural wonders from space CHER THORNHILL 25th July 2009 For decades, man has gazed up at the stars and marvelled at the wonders of the universe. But, as this amazing selection of images shows, there are many mind-blowing sights to behold from the other direction. [Pics in URL] Pictures taken by astronauts and Nasa satellites give a fascinating bird's-eye view of Earth's natural wonders - including hurricanes, volcanoes and other powerful weather formations - from space. A mosaic of Nasa satellite images gives the most detailed true-colour image...

The African source of the Amazon's fertilizer Sid Perkins In the winter months in the Northern Hemisphere, massive dust storms from the African Sahara waft southwest across the Atlantic to drop tons of vital minerals on the Amazon basin in South America. Now, scientists have pinpointed the source of many of those dust storms and estimated their dust content. ON THE WAY. Satellite photo shows dust (arrow), bound for the Amazon, blowing away from the Sahara's Bodélé depression. NASA The Amazonian rainforest depends on Saharan dust for many of its nutrients, including iron and phosphorus (SN: 9/29/01, p. 200: http://www.sciencenews.org/articles/20010929/bob9.asp)....

DESERTIFICATION threatens to drive millions of people from their homes in coming decades while vast dust storms can damage the health of people continents away, an international report said today. "Desertification has emerged as a global problem affecting everyone," said Zafar Adeel, assistant director of the UN University's water academy and a lead author of a report drawing on the work of 1360 scientists in 95 nations. Two billion people live in drylands vulnerable to desertification, ranging from northern Africa to swathes of central Asia, he said. And storms can lift dust from the Sahara Desert, for instance, and cause...

Could dandruff be altering the world’s climate? Along with fur, algae, pollen, fungi, bacteria, viruses and various other “bio-aerosols” wafting around in the atmosphere, it may well be. A global study has found that tiny fragments of biological detritus are a major component of the atmosphere, controlling the weather and forming a previously hidden microbial metropolis in the skies. Besides their climatic influence, they may even be spreading diseases across the globe. Scientists have known for some time that aerosols of soot, dust and ash can influence climate by reflecting or absorbing the Sun’s rays and by providing the condensation...

As little as 30 years ago the talk wasn’t about global warming, it was about an imminent ice age. Is an ice age likely? Even possible? Consider this: There have been more than 20 glacial advances, or ice ages, in just the last two million years. And we know from geological evidence that each glaciation lasted anywhere from 20,000 to 100,000 years—no one knows why the disparity—separated by warm periods that last some 10,000 to 15,000 years. What we can be reasonably sure of is that we’re now in one of the warm periods, and this one is already 13,000...

Out Of AfricaDust, the Thermostat How tiny airborne particles manipulate global climate Sid Perkins On April 15, 1998, Mongolia's Gobi Desert lay between an area of low atmospheric pressure on the eastern end of the country and a zone of high pressure to the west. As swift winds rushed across the desert floor, they lofted sand and dust into the heart of a storm system racing southward into China. During the next 2 days, a yellow, muddy, acidic rain fell in a wide swath that covered Beijing and the Korean peninsula. On April 16, 1998, a strong storm system passing ...