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Bizarro Earth

Mini Ice Age Took Hold Of Europe In Just Months

Image
© Tancrediphoto.com/Stone/Getty
Big freezes can happen fast
Just months - that's how long it took for Europe to be engulfed by an ice age. The scenario, which comes straight out of Hollywood blockbuster The Day After Tomorrow, was revealed by the most precise record of the climate from palaeohistory ever generated.

Around 12,800 years ago the northern hemisphere was hit by the Younger Dryas mini ice age, or "Big Freeze". It was triggered by the slowdown of the Gulf Stream, led to the decline of the Clovis culture in North America, and lasted around 1300 years.

Until now, it was thought that the mini ice age took a decade or so to take hold, on the evidence provided by Greenland ice cores. Not so, say William Patterson of the University of Saskatchewan in Saskatoon, Canada, and his colleagues.

The group studied a mud core from an ancient lake, Lough Monreagh, in western Ireland. Using a scalpel they sliced off layers 0.5 to 1 millimetre thick, each representing up to three months of time. No other measurements from the period have approached this level of detail.

Carbon isotopes in each slice revealed how productive the lake was and oxygen isotopes gave a picture of temperature and rainfall. They show that at the start of the Big Freeze, temperatures plummeted and lake productivity stopped within months, or a year at most. "It would be like taking Ireland today and moving it up to Svalbard" in the Arctic, says Patterson, who presented the findings at the BOREAS conference in Rovaniemi, Finland, on 31 October.

Bizarro Earth

Volcanoes Played Pivotal Role In Ancient Ice Age, Mass Extinction

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© Matthew Saltzman, courtesy of Ohio State University
Researchers at Ohio State University have discovered that volcanoes played a pivotal role in a deadly ice age that occurred nearly half a billion years ago. This photograph shows volcanic ash beds - formed around 455 million years ago - layered in the rock of the Nashville Dome area in central Tennessee.
Researchers here have discovered the pivotal role that volcanoes played in a deadly ice age 450 million years ago. Perhaps ironically, these volcanoes first caused global warming - by releasing massive amounts of carbon dioxide into the atmosphere. When they stopped erupting, Earth's climate was thrown off balance, and the ice age began.

The discovery underscores the importance of carbon in Earth's climate today, said Matthew Saltzman, associate professor of earth sciences at Ohio State University.

The results will appear in the journal Geology, in a paper now available online.

Previously, Saltzman and his team linked this same ice age to the rise of the Appalachian Mountains. As the exposed rock weathered, chemical reactions pulled carbon from Earth's atmosphere, causing a global cooling which ultimately killed two-thirds of all species on the planet.

Better Earth

Hunting Banned in Parts of Austria After Hailstones Kill 90 Percent of Wild Game

Hunting has been banned in parts of Austria after freak storms with tennis ball-sized hailstones killed up to 90 per cent of the wild game population.

Sepp Eder, the hunting chief, said : "Animals sought shelter in farms, in fields of grain but the hail was so heavy it smashed right into them. It may take five years for animal numbers to recover, if they ever do so."

Farmers are believed to have suffered more than £60 million in damages to crops and buildings.

Hundreds of deer were discovered either dead or so badly injured they had to be put down by wildlife experts.

In the country's rural Salzburg province, 90 per cent of pheasants and 80 per cent of hares were killed in the hail storms.

Telescope

Ice age on Mars: New evidence points towards recent ice age on Mars

In a new research, scientists have found evidence on the Martian terrain that points towards a recent ice age on the Red Planet.

The research, by Samuel C. Schon and James W. Head from the Department of Geological Sciences, Brown University, was carried out to explain the distribution of ice in the near subsurface at middle to high latitudes on Mars.

Two hypotheses emerged out of the research.

While one theory suggested diffusion of water vapor into porous regolith, the other indicated atmospheric deposition of ice, snow, and dust during recent ice ages.

To determine which of these hypotheses is correct, Schon and his team used data from the High Resolution Imaging Science Experiment (HiRISE) to examine the structure of exposed subsurface mid-latitude Martian terrain.

The researchers observed that the terrain is characterized by layered deposits multiple meters thick that stretch over many hundreds of meters.

Blackbox

Ice Ages Linked To Slight Shifts In Solar Radiation

Image
© Unknown
Sometime around now, scientists say, the Earth should be changing from a long interglacial period that has lasted the past 10,000 years and shifting back towards conditions that will ultimately lead to another ice age unless some other forces stop or slow it. But these are processes that literally move with glacial slowness, and due to greenhouse gas emissions the Earth has already warmed as much in about the past 200 years as it ordinarily might in several thousand years, Clark said.
A team of researchers says it has largely put to rest a long debate on the underlying mechanism that has caused periodic ice ages on Earth for the past 2.5 million years - they are ultimately linked to slight shifts in solar radiation caused by predictable changes in Earth's rotation and axis.

In a publication to be released Friday in the journal Science, researchers from Oregon State University and other institutions conclude that the known wobbles in Earth's rotation caused global ice levels to reach their peak about 26,000 years ago, stabilize for 7,000 years and then begin melting 19,000 years ago, eventually bringing to an end the last ice age.

The melting was first caused by more solar radiation, not changes in carbon dioxide levels or ocean temperatures, as some scientists have suggested in recent years.

"Solar radiation was the trigger that started the ice melting, that's now pretty certain," said Peter Clark, a professor of geosciences at OSU. "There were also changes in atmospheric carbon dioxide levels and ocean circulation, but those happened later and amplified a process that had already begun."

Sherlock

Peru: Global Warming freezes 20,000 alpaca

Climate change continues to wreck havoc in Peru's southern Altiplano, where the arrival of freezing temperatures since March - almost three months earlier than usual - have killed at least 20,000 alpaca, reported Peru's National Agriculture and Sanitation Service, or Senasa.

Since January, approximately 20,000 alpaca - a number that still remains within normal limits - have died, and 73,000 others have suffered from various illnesses due to the cold, said Senasa Director Reinaldo Llano Flores.

Alpacas, or vicugna pacos, is a domesticated species of South American camelid, and resembles a small llama. These animals are mostly kept in herds, and bred specifically for their high-quality fiber.

Magnify

At 9,000 years old, Britain's oldest house gives a glimpse of post-Ice Age domesticity

Built 3,000 years before the miracle of Stonehenge, this is Britain's oldest and best preserved house.

The remains of the strongly built shelter, discovered on the Isle of Man, provide a rare window into the domestic life of hunter-gatherers 9,000 years ago.

Unearthed by accident during extension work to the island's airport runway, the 23ft wide pit is giving up extraordinary archaeological secrets.

Most exciting is the revelation that the people of the mesolithic age, long regarded as nomads who wandered ancient Britain in search of food, were actually very good at settling down.
9000 Year old house
© Oxford Archaeology North
Excavation nears completion of the Mesolithic house, defined by a ring of holes which once contained wooden posts

Pumpkin

US: Nebraska tomatoes over a month late ripening

green tomatoes
© unknown
This year, the prize of gardening — a juicy tomato, ripe by the Fourth of July — has remained stubbornly green and hard.

Talk about frustration.

By now, many vegetable gardeners would be layering fat slices of tomatoes on a plate and eating them like watermelon.

But not this year.

The prize of gardening - a juicy tomato, ripe by the Fourth of July - has remained stubbornly green and hard.

"This is as slow as I've seen it, and I've been growing tomatoes since 1972," said Bob "The Tomato Man" Green.

A Sarpy County farmer, master gardener and longtime competitor at the county fair, Green has 67 plants - 27 varieties - this year at his farm outside Springfield, Neb. And they just aren't ripening.

Blame it on the cool weather, he said. Tomatoes need warm days and warm nights to ripen. So far, though, much of eastern Nebraska is running about 4 to 6 degrees below normal for July.

Bizarro Earth

Long debate ended over cause, demise of ice ages - may also help predict future

A team of researchers says it has largely put to rest a long debate on the underlying mechanism that has caused periodic ice ages on Earth for the past 2.5 million years - they are ultimately linked to slight shifts in solar radiation caused by predictable changes in Earth's rotation and axis.

In a publication to be released Friday in the journal Science, researchers from Oregon State University and other institutions conclude that the known wobbles in Earth's rotation caused global ice levels to reach their peak about 26,000 years ago, stabilize for 7,000 years and then begin melting 19,000 years ago, eventually bringing to an end the last ice age.

The melting was first caused by more solar radiation, not changes in carbon dioxide levels or ocean temperatures, as some scientists have suggested in recent years.

Blackbox

Did an ice age boost human brain size?

Image
© Doug Allan/Getty
Letting off some steam.
It is one of the biggest mysteries in human evolution. Why did we humans evolve such big brains, making us the unrivalled rulers of the world?

Some 2.5 million years ago, our ancestors' brains expanded from a mere 600 cubic centimetres to about a litre. Two new studies suggest it is no fluke that this brain boom coincided with the onset of an ice age. Cooler heads, it seems, allowed ancient human brains to let off steam and grow.

For all its advantages, the modern human brain is a huge energy glutton, accounting for nearly half of our resting metabolic rate. About a decade ago, biologists David Schwartzman and George Middendorf of Howard University in Washington DC hypothesised that our modern brain could not have evolved until the Quaternary ice age started, about 2.5 million years ago. They reckoned such a large brain would have generated heat faster than it could dissipate it in the warmer climate of earlier times, but they lacked evidence to back their hypothesis.

Now hints of that evidence are beginning to emerge. Climate researcher Axel Kleidon of the Max Planck Institute for Biogeochemistry in Jena, Germany, modelled present-day temperature, humidity and wind conditions around the world using an Earth-systems computer model. He used these factors to predict the maximum rate at which a modern human brain can lose heat in different regions. He found that, even today, the ability to dissipate heat should restrict the activity of people in many tropical regions (Climatic Change, vol 95, p 405).