Geologists Just Discovered 260-Million Year Old Forests In Antarctica

Huffington Post - Lara Pearce

And they could provide a glimpse into a climate-changing future.

The 260 million-year-old tree fossils provide an insight into a warmer, greener Antarctica. Erik Gulbranson

Antarctica wasn't always a barren and largely uninhabitable landscape of snow and ice.
Almost 260 million years ago, the world's coldest and driest continent was awash with lush, thriving forests -- and a group of geologists have just found one.
The University of Wisconsin–Milwaukee paleoecologists spent last summer climbing Antarctica's Transantarctic Mountains.
High above the ice fields, they combed the mountain's gray rocks for fossils from the continent's green, forested past.
By January, they had found the fossil fragments of 13 trees.



"People have known about the fossils in Antarctica since the 1910-12 Robert Falcon Scott expedition," explained research team leader and paleoecologist, Assistant Professor Erik Gulbranson.
"However, most of Antarctica is still unexplored. Sometimes, you might be the first person to ever climb a particular mountain."

The trees are estimated to be around 260 million years old -- older than the world's first dinosaurs.
And even though the trees died out many millennia before our ancestors were swinging through the treetops, they could provide some clues into how our landscape will alter as a result of human-induced climate change.

Geologist Erik Gulbranson is studying the tree fossils to see how they survived Antarctica's harsh landscape. UWM Photo/Troye Fox

The researchers believe the trees proliferated in Antarctica at the end of the Permian Period, when the continent was warmer and more humid than today.
At the time Antarctica was part of Gondwana, a supercontinent spanning the Southern Hemisphere that included Australia as well as South America, Africa and India.
But around 251 million years ago, the Permian Period ended as the planet rapidly moved from icehouse to greenhouse conditions, bringing about a mass extinction which killed more than 90 percent of species on Earth, including the polar forests.
Many scientists now believe this mass extinction was caused by a massive increase in greenhouse gases, such as carbon dioxide and methane, from a huge number of volcanic eruptions in Siberia.
"This forest is a glimpse of life before the extinction, which can help us understand what caused the event," Gulbranson said.
"The geologic record shows us the beginning, middle and end of climate change event. With further study, we can better understand how greenhouse gases and climate change affect life on Earth."



The geologists also hope to get an insight into how the hardly plant species survived months of sunlight followed by months of complete darkness in the polar region.
"There isn't anything like that today," Gulbranson said.
"These trees could turn their growing cycles on and off like a light switch.
"We know the winter shutoff happened right away, but we don't know how active they were during the summertime and if they could force themselves into dormancy while it was still light out."
In other Antarctica-related news, NASA has just released the first photographs of the enormous Larsen C iceberg since it split from mainland Antarctica in July, becoming one of the largest icebergs in recorded history.
The jaw-dropping images are a sobering reminder of what is in store for the world's coldest continent as we face a warmer future.

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Links

• Climate Change Is Turning Antarctica Green
• Iceberg Bigger Than Bali Breaks Off Antarctica
• Australia And US Scientists To Search For Antarctica's 'Super-Cooled' Clouds
• Astonishingly, Indonesia Has A Glacier. But It's About To Disappear Forever
• Australia's Climate Performance Ranks Fourth Last On Long List
• How The Shipping Industry Bullied Its Way Out Of Doing Anything To Fight Climate Change

La Nina Likely To Develop In The Pacific By December, Bureau Of Meteorology Says

Fairfax - Peter Hannam

A La Nina is almost certain to develop in the Pacific this summer, as all eight models used by the Bureau of Meteorology anticipate threshold levels for the key climate pattern will be reached or exceeded by next month.
The bureau's latest fortnightly assessment of conditions in the Pacific and Indian oceans rates the likelihood of a La Nina this summer at about 70 per cent – triple the usual level – prompting it to issue a La Nina alert on Tuesday.

La Ninas tend to result in above-average rainfall for eastern Australia and more cyclones than usual crossing the coast. Photo: Glenn Hunt

During La Nina years, eastern Australia tends to have wetter than usual summers, as equatorial trade winds strengthen, shifting rainfall westwards.
While the added cloud cover can moderate temperatures, there is also an increased chance of prolonged warm spells for south-eastern Australia during La Ninas, the bureau says. The cyclone season can also be more active than usual.
But, as reported by Fairfax Media last week, the Indian Ocean's influence is tending to counter some of the typical La Nina characteristics, prompting the bureau to predict much of the country may yet get a warmer and drier than average summer.

"Climate models suggest that any [La Nina] event is likely to be weak and short-lived," the bureau said. "This means it is expected to be very different [from] the strong 2010-12 La Nina."
All eight of the main models used by the bureau point to La Nina thresholds being reached or exceeded next month, while most suggest the event will last until at least February. (See bureau chart below.)

Much of southern Australia has been in a grip of early season heat so far this November. Photo: Daniel Munoz

But the Indian Ocean's influence of late has favoured drier-than-usual conditions over the Australian continent.
Sea-surface temperatures in the eastern Indian Ocean have been cooler than average, which "may be limiting the feed of moisture over Australia, and opposing more typical La Nina influences", the bureau says.

'Blocking high'
In the near term, conditions have contrived to generate exceptionally warm conditions over much of southern Australia.
A large blocking high has set up in the Tasman, allowing cities such as Melbourne and Hobart to experience extended early season heat.

"It's unusual to get such a persistent blocking in November," Blair Trewin, senior climatologist at the bureau, said.

Record tumble
Melbourne, for instance, has posted its eighth day of 30 degrees this spring, with as many as three more to come. That compares with an average of just two pre-summer days of that heat.
The city has also notched four days above 28 degrees in a row, including Tuesday, a tally that could stretch to seven or eight before the hot spell ends. The current record for November is six such consecutive days, Dr Trewin said.
Nights, too, are likely to break records, with the number above 15 degrees in a row on course to reach at least 14. The existing record for November is nine such consecutive nights of 15 degrees or warmer.
Hobart may collect its most days in a row above 25 degrees for any time of the year. Including Tuesday, the city clocked up its fourth such days, matching the November record.
The current run of Hobart days above 25 degrees could reach six or more, setting a record for any time of the year, Dr Trewin said.
But the same system is directing onshore winds along the east coast, keeping a lid on temperatures such as in Sydney.
Daytime temperatures in the Harbour City have been running about a degree below the November norm, although a late burst of warmth can close the gap, and maintain Sydney's run of above-average months for maximums.
The last time Sydney had a below-average month for maximums was in March 2012, almost six years ago, Dr Trewin said. February 2013 and February 2014 matched the average.

Links

• BOM Climate outlook overview December to February
• La Nina likely to develop in the Pacific by December and last until February: Australia's Bureau of Meteorology
• BOM announces short, weak La Nina probability for summer lacking rainfall but packing heatwaves
• One Ocean, Two La Nina Forecasts: A Look Behind the Numbers
• Australia's weather bureau issues La Nina alert
• La Nina event almost certain to occur in southern Pacific: scientists
• Unusual climate mix has summer tilting to warmer times