Earth ChangesS

Better Earth

Anthropogenic Global Warming, or just natural variation?

For the past 1.3 million years there have been 13 ice ages, average duration 90,000 years, and each followed by an interglacial period, average duration 10,000 years. During both ice ages and interglacial periods, there will be numerous briefer cycles of warming and cooling. A 65 million year review of climate and related information is available at JoNova.

If this one million+ year trend continues, we are now nearing the end of our current interglacial period. The actual duration will likely vary somewhat from the 10,000 year average. Even assuming that the ice age cycle again repeats, its start date will probably not be easy to recognize in real-time.

During our current interglacial period there have been several periods when it was warmer than now. The most recent prior warming, and hence best documented, was about 1,000 years ago, spanning the period from about 800 to 1300 AD, and is referred to as the Medieval Warming Period (MWP).


Flashback Abrupt Climate Change: Should We Be Worried?

Are we overlooking potential abrupt climate shifts?

Most of the studies and debates on potential climate change, along with its ecological and economic impacts, have focused on the ongoing buildup of industrial greenhouse gases in the atmosphere and a gradual increase in global temperatures. This line of thinking, however, fails to consider another potentially disruptive climate scenario. It ignores recent and rapidly advancing evidence that Earth's climate repeatedly has shifted abruptly and dramatically in the past, and is capable of doing so in the future.

Fossil evidence clearly demonstrates that Earth's climate can shift gears within a decade, establishing new and different patterns that can persist for decades to centuries. In addition, these climate shifts do not necessarily have universal, global effects. They can generate a counterintuitive scenario: Even as the earth as a whole continues to warm gradually, large regions may experience a precipitous and disruptive shift into colder climates.

This new paradigm of abrupt climate change has been well established over the last decade by research of ocean, earth and atmosphere scientists at many institutions worldwide. But the concept remains little known and scarcely appreciated in the wider community of scientists, economists, policy makers, and world political and business leaders. Thus, world leaders may be planning for climate scenarios of global warming that are opposite to what might actually occur.1


Best of the Web: Dramatic rescue of 1,000 people trapped on ferries as 50 ships get stuck in Baltic Sea ice after worst winter in 50 years

© Agence France-PresseNo way through: A passenger ferry attempts to power its way through pack ice off Sweden's east coast. The Baltic Sea is experiencing its coldest winter in 50 years
Nearly 1,000 people trapped on a ferry were dramatically rescued today after 50 ships got stuck in heavy pack ice in the Baltic Sea, officials said.

The passenger ferry Amorella was returned safely to Stockholm harbour after ice breakers helped release it from large masses of ice off Sweden's east coast.

A total of 50 ships and boats had been stuck for hours as gale-force winds built up the ice along the coastline north of Stockholm.

Rescue helicopters and military hovercraft had been placed on standby to evacuate passengers if needed. No one was injured.

'It arrived in the port during the morning,' sea rescue spokeswoman Christel Englund said.

The Swedish Maritime Administration said the Amorella had 753 passengers and 190 crew on board.

The 10-deck ship belongs to Viking Line, which operates Baltic Sea cruises between Sweden and Finland.

Bizarro Earth

Volcanoes Erupt Side by Side in New Satellite Picture

© Jesse Allen, NASA Earth ObservatorySeen via satellite, two Russian volcanoes—the third "plume" at center is just cloud cover—erupt on February 13.
In a satellite image released today by NASA, two neighboring Russian volcanoes are seen erupting at the same time.

Surprising as the picture may be, the simultaneous eruptions of the Kamchatka Peninsula's Klyuchevskaya and Bezymianny volcanoes isn't all that shocking, according to geologist James Quick of Southern Methodist University in Texas.

"Kamkatcha [map] volcanoes are very active, so it's not uncommon for more than one of these volcanoes to be erupting at the same time," Quick said.

In fact, the volcanoes' close proximity makes it more, not less, likely that they'd explode in unison, he said.

Though there's no "great pool or pipe of lava connecting them," he said, the volcanoes lie above the same active subduction zone, an area where one tectonic plate is diving under another. So if the gnashing of the plates sends heat, lava, gas, or ash up through the earth toward one of the volcanoes, chances are the other might get it too. (See plate tectonics pictures.)


Flashback Failing ocean current raises fears of mini ice age

© Mark Daly The photo above showing ice at the docks in Galway, Ireland was captured in the early afternoon of January 9, 2010. The Atlantic coast of Ireland hasn't experienced seawater freezing in its dock area since the early 1980s. Ireland is still freezing in its coldest and longest winter since 1963. Is it a canary in the goldmine in terms of the North Atlantic Drift ocean current?
The ocean current that gives western Europe its relatively balmy climate is stuttering, raising fears that it might fail entirely and plunge the continent into a mini ice age.

The dramatic finding comes from a study of ocean circulation in the North Atlantic, which found a 30% reduction in the warm currents that carry water north from the Gulf Stream.

The slow-down, which has long been predicted as a possible consequence of global warming, will give renewed urgency to intergovernmental talks in Montreal, Canada, this week on a successor to the Kyoto Protocol.

Harry Bryden at the Southampton Oceanography Centre in the UK, whose group carried out the analysis, says he is not yet sure if the change is temporary or signals a long-term trend. "We don't want to say the circulation will shut down," he told New Scientist. "But we are nervous about our findings. They have come as quite a surprise.

Bizarro Earth

Philippines: 4 earthquakes strike in 4 places

Manilla - Four moderate tremors struck the country Thursday, just hours after a strong quake hit Taiwan and two days after a strong earthquake occurred in the Cagayan area.

A magnitude 4.9 earthquake hit the region around Batanes, the Philippines' northernmost province, at 10:08 a.m. Thursday, with the epicenter estimated at 48 kilometers southeast of Basco, the capital.

The quake had a shallow depth of 7 kilometers, according to the Philippine Institute of Volcanology and Seismology (Phivolcs).

It was tectonic in origin and was felt as intensity 3 in Basco.

The second earthquake with a magnitude of 3 occurred near the island province of Camiguin at around 12:16 a.m.

Bizarro Earth

Chinese expert says Chile quake part of new activity phase

An anecdote from the ancient Chinese book Liezi tells a story about a man from the state of Qi who was so obsessed with the thought that the sky might fall that he had no appetite for food nor could sleep well.

Recently some people have developed a similar anxiety over a hypothesis no less catastrophic to mankind. And the threat lies beneath our feet.

Xu Xiangyu, a 6-grader at Beijing No 2 Experimental Primary School, cried out "2012" when he first heard about the Chile earthquake, associating it at once with the Hollywood movie, which depicts a doomsday-like situation caused by strong earthquakes.

And his worry is by no means unfounded.

Extreme weather has been reported this winter in many places around the world: blizzards in Northern Europe, America and Asia, heat waves in South America and Australia, heavy snows in North China and severe droughts in the South. Now, Chile has been hit by a massive earthquake registered 8.8 on the Richter scale, less than two months after the devastating Haiti quake of 7.3 magnitude claimed nearly 290,000 lives.

Sun Shihong, a senior researcher with CEA China Earthquake Networks Center (CENC), said the world did look like it was entering a new phase of earthquake activity. The latest movements of the earth's crust undoubtedly demonstrated an "active state." "They are not abnormal, though. The earth has its life cycle, guided by it own rules," he said.

Bizarro Earth

Quake aftershocks trigger new terror in Chile

Talca - Three powerful aftershocks Friday spread new terror among weary Chileans traumatized by a huge quake and tsunami as UN chief Ban Ki-moon was due to arrive to assess the damage.

A first 6.2-magnitude quake jolted people awake at 6:20 am (0920 GMT), just six days after Saturday's record 8.8-quake and ensuing tsunami waves killed over 800 people and left some two million homeless.

That was then followed Friday by a 6.8-magnitude tremor -- one of the most powerful of more than 200 to rattle Chile since the weekend -- followed swiftly by another measuring 6.6.

Buildings in Concepcion, the country's second city, already damaged in the disaster collapsed, although the national emergency services said Friday's quakes caused no injuries or serious damage.


Study finds methane bubbling from Arctic

© iStockphoto
Large amounts methane are bubbling up from a long-frozen seabed north of Siberia, raising fears of far bigger leaks, say scientists.

But it is unclear if the emissions are new or have been going on unnoticed for centuries - since before the Industrial Revolution of the 18th century.

The study, which appears today in the journal Science, says about 8 million tonnes of methane a year, equivalent to the annual total previously estimated from all of the world's oceans, were seeping from vast stores long trapped under permafrost below the seabed north of Russia.

"Subsea permafrost is losing its ability to be an impermeable cap," says study co-author Dr Natalia Shakhova, a scientist at the University of Fairbanks, Alaska.

The experts measured levels of methane, a gas that can be released by rotting vegetation, in water and air at 5000 sites on the East Siberian Arctic Shelf from 2003 to 2008. In some places, methane was bubbling up from the seabed.

Bizarro Earth

6.5 Earthquake Hits Off Sumatran Coast

A 6.5 magnitude earthquake struck off the Indonesian island of Sumatra at 11:06 p.m. local time (16:06 GMT) yesterday but a widespread tsunami was not predicted.

The quake hit about 165 km west of Bengkulu, Sumatra at a depth of about 22 km, the US Geological Survey said.

The US National Oceanic and Atmospheric Administration said there was no widespread threat of a tsunami in the Indian Ocean.

But, it added, "there is a very small possibility of a local tsunami that could affect coasts located usually no more than a hundred kilometers from the earthquake epicentre.