Earth ChangesS


Meteor

Dinosaur-killing impact set Earth to broil, not burn

Image
© Don Davis/NASADebris kicked up by a large asteroid rained back down on the Earth, heating up as it fell. But new research suggests that the first debris to re-enter the atmosphere shielded the surface from the heat of later infalling debris, preventing the world's forests from igniting
The asteroid impact that ended the age of dinosaurs 65 million years ago didn't incinerate life on our planet's surface - it just broiled it, a new study suggests. The work resolves nagging questions about a theory that the impact triggered deadly wildfires around the world, but it also raises new questions about just what led to the mass extinction at the end of the Cretaceous period.

The impact of a 10-kilometre asteroid is blamed for the extinction of the dinosaurs and most other species on the planet. Early computer models showed that more than half of the debris blasted into space by the impact would fall into the atmosphere within eight hours.

The models predicted the rain of shock-heated debris would radiate heat as intensely as an oven set to "broil" (260 °C) for at least 20 minutes, and perhaps a couple of hours. Intense heating for that long would heat wood to its ignition temperature, causing global wildfires.

Sun

Copenhagen climate summit: global warming 'caused by sun's radiation'

Image
© Reuters
Global warming is caused by radiation from the sun, according to a leading scientist speaking out at an alternative "sceptics' conference" in Copenhagen.

As the world gathered in the Danish capital for the UN Climate Change Conference, more than 50 scientists, businessmen and lobby groups met to discuss the arguments against man made global warming.

Although the meeting was considerably smaller than the official gathering of 15,000 people meeting down the road, the organisers claimed it could change the course of negotiations.

Bulb

The climate-change travesty

With 20,000 delegates, advocates and journalists jetting to Copenhagen for planet Earth's last chance, the carbon footprint of the global warming summit will be the only impressive consequence of the climate-change meeting. Its organizers had hoped that it would produce binding caps on emissions, global taxation to redistribute trillions of dollars, and micromanagement of everyone's choices.

China, nimble at the politics of pretending that is characteristic of climate-change theater, promises only to reduce its "carbon intensity" -- carbon emissions per unit of production. So China's emissions will rise.

Barack Obama, understanding the histrionics required in climate-change debates, promises that U.S. emissions in 2050 will be 83 percent below 2005 levels. If so, 2050 emissions will equal those in 1910, when there were 92 million Americans. But there will be 420 million Americans in 2050, so Obama's promise means that per capita emissions then will be about what they were in 1875. That. Will. Not. Happen.

Bizarro Earth

US: Big Storm Brings Heavy Snow and Strong Winds to Upper Midwest

Image
© AP PhotoScotti Carver sweeps snow from the roof and windshield of his truck.
A fierce winter storm was moving into the nation's midsection Tuesday, promising to wallop the region with heavy snow and strong winds.

Officials were warning residents in parts of the west and Midwest to stay close to home.

"Anybody traveling tomorrow morning is really taking a huge risk I would say - a risk of being stranded and not having anybody be able to help you for 6 or 12 hours, probably," Karl Jungbluth, a meteorologist with the National Weather Service in Johnston, Iowa, said Tuesday.

The storm already blanketed much of the mountain west with snow and drenched Southern California with rain. In the Phoenix area, fierce wind brought down power lines, left four hospitals temporarily without power and created wide outages.

Fish

Blue whale songs are getting deeper, say baffled scientists

Image
Blue whales are famed for their haunting songs that travel thousands of miles under the ocean. Now scientists have discovered the world's largest mammals are singing in deeper voices every year - and they are not sure why.

A study in the journal Endangered Species Research, has found male blue whales all over the world have lowered their tone. Mark McDonald of WhaleAcoustics first noticed the change about eight years ago when he had to shift automated blue whale song detectors off California to lower frequencies.

He decided to compare the songs in areas ranging from the North Atlantic to the Indian Ocean with the help of researchers from the Scripps Institution of Oceanography in California.

Igloo

US: Up to 4 inches of snow in the foothills coming, a light dusting in Sacramento

Image
© Paul Kitagaki Jr.
Snow is coming to the Sacramento Valley -- but only a light dusting is expected on the streets of Sacramento. The National Weather Service said today that 2-4 inches of snow is expected to fall at the 1,000-foot elevation, below Auburn and El Dorado Hills.

Cindy Matthews, forecaster, said a dusting of snow is likely to start in the pre-commute hours in Sacramento and should continue off and on throughout the day.

The cold storm system dropping from the northeast out of Canada will be unusual since the coldest temperatures will bypass Northern California communities such as Red Bluff and Redding but drop Sacramento Valley temperatures Monday to a record 27 degrees.

Bizarro Earth

Samoan Tsunami wave was 46 feet high

The tsunami that killed more than 200 people in the Samoan islands and Tonga earlier this year towered up to 46 feet (14 meters) high - more then twice as tall as most of the buildings it slammed into, scientists said Friday.

New Zealand scientists studying the size, power and reach of the tsunami as part of efforts to guard against future disasters said they found up to three destructive waves were caused by the magnitude 8.0 undersea earthquake in September.

The massive waves that struck Samoa, American Samoa and Tonga totally destroyed traditional wooden buildings, many of them singly story, along the coast while reinforced concrete buildings sustained only minor damage, said Stefan Reese, a risk engineer with New Zealand's National Institute of Water and Atmospheric Research.

The waves were up to 46 feet (14 meters) high, Reese told The Associated Press. The scientists measured watermarks on buildings and trees to help confirm the height of the waves.

"In some areas there was virtually nothing left" after the waves reached up to 765 yards (700 meters) inland, Reese said.

Magnify

Humans Wonder, Anybody Home?

Image
© Bill O'Leary/The Washington PostTo prevent Shania the octopus from becoming bored, keepers at the National Aquarium in Washington, D.C. gave her a Mr. Potato Head filled with fish to snuggle.
Brain structure and circuitry offer clues to consciousness in nonmammals

One afternoon while participating in studies in a University of Oxford lab, Abel snatched a hook away from Betty, leaving her without a tool to complete a task. Spying a piece of straight wire nearby, she picked it up, bent one end into a hook and used it to finish the job. Nothing about this story was remarkable, except for the fact that Betty was a New Caledonian crow.

Betty isn't the only crow with such conceptual ingenuity. Nor are crows the only members of the animal kingdom to exhibit similar mental powers. Animals can do all sorts of clever things: Studies of chimpanzees, gorillas, dolphins and birds have found that some can add, subtract, create sentences, plan ahead or deceive others.

To carry out such tasks, these animals must be drawing on past experiences and then using them along with immediate perceptions to make sense of it all. In other words, some scientists would say, these animals are thinking consciously.

Magnify

By Feeding the Birds, You Could Change Their Evolutionary Fate

Image
© iStockphoto/Andrew HoweBlackcap (Sylvia atricapilla) male at a bird feeder.
Feeding birds in winter is a most innocent human activity, but it can nonetheless have profound effects on the evolutionary future of a species, and those changes can be seen in the very near term. That's the conclusion of a report published online on December 3rd in Current Biology, showing that what was once a single population of birds known as blackcaps has been split into two reproductively isolated groups in fewer than 30 generations, despite the fact that they continue to breed side by side in the very same forests.

The reproductive isolation between these populations, which live together for part of the year, is now stronger than that of other blackcaps that are always separated from one another by distances of 800 kilometers or more, the researchers said.

"Our study documents the profound impact of human activities on the evolutionary trajectories of species," said Martin Schaefer of the University of Freiburg. "It shows that we are influencing the fate not only of rare and endangered species, but also of the common ones that surround our daily lives."

Bug

How a Brain Hormone Controls Insect Metamorphosis

Image
© iStockphoto/Cathy KeiferVarious views of a monarch butterfly emerging from its chrysalis.
A team of University of Minnesota researchers have discovered how PTTH, a hormone produced by the brain, controls the metamorphosis of juvenile insects into adults.

The finding, published in the Dec. 4 issue of Science, will help scientists understand how insect body size is programmed in response to developmental and environmental cues and offers the opportunity to develop a new generation of more environmentally safe ways to control agricultural pests as well as insects that carry human pathogens.

Scientists have known for 100 years that a brain-derived neuropeptide known as PTTH controls metamorphosis and although its specific sequence was identified 20 years ago, the way it signaled endocrine tissue has remained elusive until now.