7 Billion People by 2011

Earth's population will reach 7 billion people in 2011, a new report predicts. That's sooner than had been expected.

We hit 6.5 billion in February, 2006. The U.S. Census Bureau keeps a running projection of population, and at that time, the Bureau predicted we'd reach 7 billion on on Oct. 18, 2012 at 4:36 p.m. Eastern Daylight Time.

The new report, from Population Reference Bureau, forecasts that 97 percent of the population growth over the next four decades will occur in Asia, Africa, Latin America and the Caribbean.

In the year 1900, there were just 1.6 billion people. Back in the year 1000, there were only 310 million. Some 261 people are born every minute. As of this writing, the Census Bureau says there are 6,777,348,371 in the world.
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Submitted by LiveScience Staff
posted: 13 August 2009 08:46 am ET
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Fire Used to Make Better Tools 75,000 Years Ago

Early humans crossed a threshold around 75,000 years ago, when they started painting symbols, carving patterns and making jewelry. A new study found they also began to use fire to make tools around that time.

Until now, this complex, multi-step process for tool making was only known to occur as recently as 25,000 years ago in Europe. But the new findings show this breakthrough occurred much earlier, and in Africa, not Europe.

By heating up stones in a fire before chipping away at them to make blades, early humans could make tools sharper and produce them more efficiently.

Scientists think this advancement represents a link between the earlier use of fire for cooking and warmth, and the later production of ceramics and metals.

"Around 800,000 years ago we see some of the first evidence for hominid controlled use of fire," said study leader Kyle Brown, a graduate student in archaeology at the University of Cape Town in South Africa and at Arizona State University. "And then at about 10,000 years ago we see evidence for production of ceramics. And at about 5,000 years ago we see metal working."

"The heat treatment of tools is sort of a bridging technology," he said.

The development of this skill may represent a level of complex cognition that was just beginning in humans at this time.

Brown and colleagues discovered the remains of tools that had been made using fire at archaeological sites in South Africa. The tools were made out of a stone called silcrete. Some of the earliest examples could date back to 164,000 years ago, and the researchers found that by 72,000 years ago this technique was seemingly common for silcrete tools.

The heat-treated tools look almost like stone razor blades, and are small enough that they could have been set into a handle.

"It’s a big debate to figure out what people were doing with these things," Brown told LiveScience. "Some people argue that they are the first arrowheads. Other people argue that they were set in a handle and used as knives."

To make the tools, early humans would have had to bury the stone beneath a fire, then slowly heat it up, keep it at a high temperature for hours, and then let it cool. The process was complicated and could take one to two days of continuous heating.

The heat transforms the stone so that it's harder and more brittle, which allows it to be more easily chipped away into a sharper edge. It also gives the stone a special sheen, which helped the archaeologists identify the tools as resulting from fire treatment.

"The most noticeable thing about heat-treated stone is that it has a luster or a gloss to it that’s fairly distinctive," Brown said. "A stone that's heated will only show that gloss if it's been flaked after it's heated."

The researchers then confirmed that the tools had been warmed in a fire with a technique called archaeomagnetics, which measures the realignment of iron particles in stone that results from heating. Another chemical process called thermoluminescence provided further proof that the stones had been heated.


Fire pit and sand both used for heat treatment experiments. Silcrete is placed beneath a layer of sand and then a fire is built over the top. The temperature is gradually increased and then slowly decreased to avoid cracking the stone.

Caffeine Causes and Cures Headaches

Norwegian scientists' large, cross-sectional study of more than 50,000 people has found that caffeine seems to both cause and prevent hurting heads.

In a study published in the Journal of Headache Pain, scientists at the Norwegian University of Science and Technology (NTNU) in Trondheim, Norway, concluded that people who consume high amounts of caffeine each day are more likely to suffer occasional headaches than those with low caffeine consumption.

However, they also found that low caffeine consumption was associated with a "greater likelihood of chronic headaches, defined as headaches for 14 or more days each month."

After noting that there was no obvious reason for the differences in the effect of caffeine on people, the researchers advised those who suffer from occasional headaches to try cutting back on caffeine. Those who suffer from chronic headaches may reduce the amount and frequency of headaches they receive by drinking caffeine.

Pollution Reduces Rain Vital to Crops

Air pollution in China has cut the amount of light rainfall by 23 percent over the past 50 years, a new study finds.
The cause: Particles in air pollution cause smaller drops of water to form, and smaller drops have a harder time making rain clouds.

The result: Bad air could hamper the country's ability to grow food.

It is the first such study to link pollution to altered climate that can directly affect agriculture.

"People have long wondered if there was a connection, but this is the first time we've observed it from long-term data," said study leader Yun Qian at the U.S. Department of Energy's Pacific Northwest National Laboratory. "Besides the health effects, acid rain and other problems that pollution creates, this work suggests that reducing air pollution might help ease the drought in north China."

The study is detailed in the Aug. 15 in the Journal of Geophysical Research-Atmospheres.