Earth Changes
Researchers at the University of Birmingham found that 630 million years ago the earth had a warm atmosphere full of carbon dioxide but was completely covered with ice.
The scientists studied limestone rocks and found evidence that large amounts of greenhouse gas coincided with a prolonged period of freezing temperatures.
Such glaciation could happen again if global warming is not curbed, the university's school of geography, earth and environmental sciences warned.

A close-up view of the inch-long "snow worms" Bill Thornton found in his parent's Port Orchard backyard clearly shows the segments, which look like an earthworm. The running theory is they they're juvenile earthworms, but samples have been sent to a scientist for review.
Bill Thornton of Port Orchard certainly didn't, until he noticed something in his parents' backyard early Christmas morning.
"The more I looked, the more I found, and they were literally crawling up out of the snow," he said.
Worms - "snow worms," as he's started calling them - squiggled by the thousands atop the backyard snow.
That discovery launched Thornton on an odyssey as he tried to figure out what the worms are and where the came from.

Introduced mice are responsible for declines in Tristan Albatross and Gough Bunting.
The mice are also affecting Gough Island's other Critically Endangered endemic species, Gough Bunting Rowettia goughensis. A recent survey of the bunting's population revealed that the population has halved within the last two decades. Now there are only an estimated 400-500 pairs left.
"We've known for a long time that the mice were killing albatross chicks in huge numbers. However, we now know that the albatrosses have suffered their worst year on record", said Richard Cuthbert, an RSPB scientist who has been researching the mice problem on Gough Island since 2000. "We also know that the mice are predators on the eggs and chicks of the Gough bunting and mice predation is the main factor behind their recent decline."

A successful coral transplant site in Aceh, Indonesia, some four years after the tsunami.
The WCS team, working in conjunction with the Australian Research Council Centre of Excellence for Coral Reef Studies (ARCCoERS) along with government, community and non-government partners, has documented high densities of "baby corals" in areas that were severely impacted by the tsunami.
The team, which has surveyed the region's coral reefs since the December 26, 2004 tsunami, looked at 60 sites along 800 kilometers (497 miles) of coastline in Aceh, Indonesia. The researchers attribute the recovery to natural colonization by resilient coral species, along with the reduction of destructive fishing practices by local communities.
Wind gusts near 60 mph in some areas hurled trees and branches onto roads and disabled traffic lights, The Washington Post reported Thursday.
Officials said a priest died Wednesday when he was struck by a falling tree as he tried to remove debris from traffic lands. A 2-year-old boy was hospitalized after he was hit by a tree limb while in his back yard, the Post reported.
The gusty conditions forced municipalities along the eastern seaboard to cancel New Year's Eve fireworks displays because conditions were hazardous.
In McLean, Va., a gust sent the "U" of the high-rise USA Today building's sign toppling to the streets below.
Over the weekend, the mercury at Fairbanks International Airport dropped to 39 degrees below zero. Areas in the Interior outside the city were even colder; 46 below on the Yukon Flats, 41 below in Fort Yukon and 44 below in Central, according to the weather service.
Rick Thoman, lead forecaster at the National Weather Service office in Fairbanks, said temperatures rose a few degrees on Sunday, but that was it.
"The temperature will probably continue to go up and down randomly," he said. "With no clouds and no wind on the valley floor, temperatures are pretty much probably going to be stuck."
Fairbanks had experienced a relatively mild winter prior to Christmas. It had only dropped to 30 below once, in early December.
Magnitude 4.9
Date-Time
* Thursday, January 01, 2009 at 02:54:05 UTC
* Thursday, January 01, 2009 at 02:54:05 AM at epicenter
* Time of Earthquake in other Time Zones
Location 80.884°N, 2.923°W
Depth 10 km (6.2 miles) set by location program
Region NORTH OF SVALBARD
Distances 270 km (165 miles) ESE of Nord, Greenland
It happened at 12:34 a.m., the USGS reported. There were no reported injuries.
It's the second earthquake in the midstate in the past few weeks. A quake measuring 3.3 on the Richter Scale hit Lancaster County on Saturday night.
As we've noted, 2008 has been a year of records for cold and snowfall and may indeed be the coldest year of the 21st century thus far. In the U.S., the National Oceanic and Atmospheric Administration registered 63 local snowfall records and 115 lowest-ever temperatures for the month of October.
The most recent quake, a 2.7-magnitude tremor, was recorded at 2:46 p.m. Tuesday, three mines northeast of the tiny community and about 7.5 miles below it.
The swarm of quakes began at 4:20 a.m. on the 26th with a 4.5-magnitude shaker that was distinctly felt in many areas of Butte County.
Comment: Current Extreme Temperatures from here:
Last Updated: Thu Jan 1 06:51:02 UTC 2009
PFYU: Fort Yukon, Fort Yukon Airport, AK, United States [-49°C, -56.2°F]
PABI: Delta Junction/Ft Greely, Allen Army Airfield, AK, United States [-42°C, -43.6°F]
PABT: Bettles, Bettles Airport, AK, United States [-43°C, -45.4°F]
PAEG: Eagle, Eagle Airport, AK, United States [-44°C, -47.2°F]
PAEI: Fairbanks, Eielson Air Force Base, AK, United States [-44°C, -47.2°F]
PAFA: Fairbanks, Fairbanks Intl Arpt, AK, United States [-41°C, -41.8°F]
PAFS: Nikolai, AK, United States [-41°C, -41.8°F]
PAGK: Gulkana, Gulkana Airport, AK, United States [-42°C, -43.6°F]
PAIN: McKinley Park, McKinley National Park Airport, AK, United States [-40°C, -40.0°F]
PALR: Chandalar Lake, Chandalar Lake Airport, AK, United States [-44°C, -47.2°F]
PAMX: McCarthy, AK, United States [-42°C, -43.6°F]
PANN: Nenana, Nenana Municipal Airport, AK, United States [-42°C, -43.6°F]
PAOR: Northway, Northway Airport, AK, United States [-41°C, -41.8°F]
PATA: Tanana, Calhoun Memorial Airport, AK, United States [-40°C, -40.0°F]