Last edge of Greenland ice sheet to resist global warming is now unstable

March 17, 2014 by admin  
Filed under Global Warming

The last edge of the Greenland ice sheet that had resisted global warming has now become unstable, adding billions of tonnes of meltwater to rising seas, scientists said.

In a study published on Sunday in the journal Nature Climate Change, they said a surge in temperature from 2003 had eased the brakes on a long “river” of ice that flows to the coast in northeastern Greenland. Known as an ice stream, the “river” takes ice from a vast basin and slowly shifts it to the sea.

In the past, the flow from this ice stream had been constrained by massive buildups of ice debris choking its mouth. But a three-year spell of exceptionally high temperatures removed this blockage - and like a cork removed from a bottle helped accelerate the flow, the study said.

The stream, called Zachariae, is the largest drain from an ice basin that covers 16 per cent of the Greenland ice sheet.

From 2003 to 2012, northeastern Greenland disgorged 10 billion tonnes of ice annually into the ocean, the study found.

“Northeast Greenland is very cold. It used to be considered the last stable part of the Greenland ice sheet,” said Michael Bevis, an earth sciences professor at Ohio State University who led the study. “This study shows that ice loss in the northeast is now accelerating. So, now it seems that all the margins of the Greenland ice sheet are unstable.”

Greenland is estimated to contribute 0.5mm to the 3.2 mm annual rise in global sea levels.

The study’s main tool was data from a network of 50 Global Positioning System (GPS) sensors along the Greenland coast.

They use earth’s natural elasticity as a stethoscope of the ice sheet. When the ice melts in massive quantities the land rebounds and the sensor positions change.

To get a wider picture, the GPS data was then overlaid with data from four satellites that measured ice thickness from space.

“The Greenland ice sheet has contributed more than any other ice mass to sea level rise over the last two decades and has the potential, if it were completely melted to raise global sea level by more than seven metres,” said Jonathan Bamber, a professor at Britain’s University of Bristol.

Article source: http://www.scmp.com/news/world/article/1451095/last-edge-greenland-ice-sheet-resist-global-warming-now-unstable

Melting sea ice blamed for UK Arctic weather

December 25, 2010 by admin  
Filed under Global Warming

Scientists are claiming melting sea ice in the Arctic Ocean is the cause of the bitter polar weather causing chaos across Europe.

Recent meteorological reports claim a high pressure area over the Atlantic resulting in the repositioning of the jet stream combined with the influence of La Nina are responsible for the current bleak midwinter. Scientists in Germany, however, are forming a complementary theory, with climate experts at the Potsdam Institute suggesting melting sea ice could be the cause.

The institutes Vladimir Petoukov believes the big freeze is a result of global warming causing sea ice in the Arctic to melt, changing wind patterns across the northern hemisphere and bringing icy blasts of freezing air across the UK. He expects the trend to continue, with Britain shivering in the grip of longer and colder winters.

Petoukov states the disappearing sea ice will have an unpredictable effect on the climate in the northern hemisphere due to a complex and powerful feedback mechanism detected in the Barents-Kara Sea. He adds that colder winters are not disproving the global warming theory, but are supplementing it.

The Arctics floating ice cover is though to have diminished by around 20 per cent in recent years, with temperatures rising at up to three times the global average. As the ice melts, the comparatively warm sea water loses its heat to the atmosphere, causing an area of high pressure to form. This creates clockwise Arctic winds which sweep southwards over northern Europe and the UK.

Although the climate research institute states its too early to link the last two years bitter winters to changes in the Arctic, it believes the theory resulting from the research is strong. and predicts freezing winters will continue for around 50 years, after which warmer winter conditions will develop.

Article source: http://news.carrentals.co.uk/melting-sea-ice-blamed-for-uk-arctic-weather-34230354.html

As the Arctic Ocean Melts

December 22, 2010 by admin  
Filed under Global Warming

22 Dec 2010: Interview

With the Arctic Ocean heading toward a largely ice-free state in summer, scientists are looking for areas that may help preserve ice-dependent creatures. In an interview with Yale Environment 360, geologist Stephanie Pfirman talks about the need for a refuge north of Canada and Greenland that researchers say could be a kind of Noahs Ark in the age of global warming.

As scientists from around the world tracked the rapid decline of Arctic sea ice in recent years, they couldnt help but notice that one part of the Arctic basin is a repository for the oldest and thickest polar ice. Stetching across northern Greenland and the Canadian Arctic Archipelago, this band of reasonably sturdy ice forms as prevailing wind and ocean currents drive sea ice from Siberia, across the Arctic, and up against the opposite shore.

Stephanie PfirmanStephanie Pfirman

Leading Arctic sea ice specialists believe that this strip of ice could become a crucial ice refuge as summer sea ice all but disappears in most other parts of the Arctic by mid- to late-century. One of those researchers is Stephanie Pfirman, co-chair of the Environmental Science Department at Barnard College in New York City, who, along with several colleagues, presented the concept of the Arctic sea ice refuge at the recent meeting of the American Geophysical Union.

In an interview with Yale Environment 360, Pfirman described how the refuge could become a key habitat for polar bears, ringed seals, and other ice-dependent Arctic creatures. While these species are likely to suffer major population declines in other parts of the Arctic, the ice refuge zone could harbor substantial numbers of these creatures until the end of the 21st century and, possibly, beyond.

The good news, says Pfirman, is that if humanity begins to significantly reduce its emissions of greenhouse gases, the ice refuges could preserve Arctic species and enable them to repopulate the region if ice levels recover in the future.

Yale Environment 360: Can you tell me where the concept of the Arctic sea ice refuge came from?

Stephanie Pfirman: With the summer sea ice projected to decline, the more we looked at the models, the more we realized that in the latter half of this century most models project that there will still be some ice. And so that got us thinking. Where will that ice be? And where would it come from? The observations show that right now the oldest ice is right up along the northern flank of Canada and Greenland. The oldest ice has been there for a long time, and we know that from our analysis of the way the ice moves. And it makes sense that its there because the winds come from Siberia. They blow across the Arctic, and the Russian currents do, too, and it basically piles up ice in northern Canada and Greenland. So in the future, as you continue to freeze the ocean during the wintertime, the winds will blow that winter ice over toward Canada and Greenland. So its likely that youll continue to have ice there even when you have less and less ice in the summertime.

Then we looked at the model projections and they were showing the same thing. So theres a real scientific consensus saying that this is likely to be the place thats going to have the most persistent ice into the future. So then once you know that, then you say, well, what does that mean?

e360: I want to get into the details of this so-called refuge, but could you first describe the rate of melting, both in terms of extent and thickness, that is driving the necessity to even think about having an ice refuge?

Pfirman: When I first started working on ice up in the Arctic back in 1980 or so, ice tended to be in equilibrium and was around three meters thick. Thats at least twice as thick as it is now.

e360: Throughout the Arctic basin?

Pfirman: Yes, but even more so in this [refuge] area. When you ridge the ice, when you deform it, you pile it up and then you have much, much thicker ice. Ice would form and then it would get transported in this big gyre, the Beaufort Gyre, kind of like a whirlpool, to the one side of the Arctic. And the ice just circulates around and around in that area and can stay there for over a decade.Then on the other side theres the Transpolar Drift Stream that goes from the middle of Siberia, sweeps all the way across and over the North Pole. So you had these two systems and right in the middle of the two is kind of this dead zone where the ice is very slow and sluggish and its up against the Canadian Arctic archipelago and Greenland. And thats the likely place of the refuge.

e360: And one of your colleagues said that based on the rate of melt and the continued pouring of greenhouse gases into the atmosphere, that in the 2030s and 2040s you could see a really precipitous drop of Arctic sea ice?

Pfirman: Yes. So the [steep] drop that we saw in 2007, something like that had actually been projected by Marika Holland, Cecilia Bitz, and Bruno Tremblay, who had done some work earlier where they had said that theres no reason why, with the warming that were having, the decline of ice has to happen gradually. It could happen precipitously. And those are

A new study says if we do act to reduce greenhouse gas emissions, then it looks like the sea ice can come back.

called rapid ice loss events. They were analyzing a lot of models and they said, you know, there is potential for this to happen and it could result in much diminished ice cover. Theres a really neat new study that just came out [in Nature], which shows that if we do act to reduce greenhouse gas emissions, then it looks like the sea ice can come back. Its kind of a bookend on our refuge analysis, because what were saying is, if we dont act, whats the base case? Where is the most persistent ice likely to be? What are the sources of it? But what they did was they said,

Article source: http://e360.yale.edu/feature/as_the_arctic_ocean_melts_can_refuge_save_polar_bears/2355/

Preserving sandy beach ecosystems – the way forward

March 4, 2009 by admin  
Filed under Featured, Protecting Habitats

European Commission DG ENV, Science for Environment Policy Environment News Alert Service
Special Issue 8, Sept 2008

European sandy beach.

The combined impacts of climate change and increasing population pressures on coastal areas for living and recreation have placed beach ecosystems under severe pressure. New research suggests efforts to preserve the biodiversity of sandy beach ecosystems should be undertaken within the framework of Integrated Coastal Management(1). The aim is to integrate the physical protection of coastlines with the conservation of threatened ecosystems.

As key recreational sites, sandy beaches are of prime social, cultural and economic importance and dominate the world’s coastlines. They also provide critical and irreplaceable ecosystem services and there is a growing recognition of the ecological value of beaches. However, current beach management is largely concerned with managing sand budgets and erosion, while ecological aspects are rarely considered.

Co-operation between beach managers and ecologists is therefore important, according to the researchers. They produced 50 ‘key statements’ summarising how essential features of sandy beach ecosystems function and are structured, which include defining the physical features of beaches, the functioning of beaches as ecosystems and incorporating the protection of beach ecosystems with wider management practices.

The researchers suggest that climate change will have a significant impact on the ecology of sandy beaches. It is
anticipated that climate change will affect the following:

  • Sea levels – Average sea levels have risen by 0.17 metres in the last century and there are more occurrences
    of damaging high seas during storms. Continued loss of beaches will severely impact on coastal habitats and
    communities.
  • Extreme weather events – It is likely that changes in cyclone and storm behaviour will produce higher and more
    powerful waves, increasing beach erosion.
  • Precipitation - the pattern of precipitation is changing with more incidences of floods and altered freshwater flow
    to the oceans and this will affect the ecology of the beaches.
  • Changes in the ENSO (El-Niño-Southern Oscillation) events cause alterations to precipitation and this may
    affect beach ecosystems.
  • Within decades, acidification of the oceans will negatively affect marine organisms that need calcium carbonate to form shells, such as urchins and snails.


Four principles have been proposed by the researchers to integrate the ecological and physical aspects of management strategies for sandy beaches, which will help beach ecosystems withstand the pressures of climate change. It is suggested that ecologists, managers and policy makers work together at all levels of decision making in implementing effective and enduring strategies to conserve coastal ecosystems. There is also a need for further development of modelling techniques to study the impacts of climate change on beach ecology and to combine this with the effects that various management strategies will have on beach systems.

A further issue highlighted by the study are the special difficulties caused by tidal conditions for scientists trying to study beach organisms. The researchers have consequently produced a code of ‘best practice’ which contains 11 recommendations to help ecologists develop the most appropriate methods when collecting samples.

1. See http://ec.europa.eu/environment/iczm/ for information on Integrated Coastal Zone Management in Europe

Source: Schlacher, T.A., Schoeman, D.S., Dugan, J. et al. (2008). Sandy beach ecosystems: key features, sampling issues, management challenges and climate change impacts. Marine Ecology. 29(Suppl. 1): 70-90.
Contact: tschlach@usc.edu.au

Sea levels set to rise faster than expected

November 27, 2008 by admin  
Filed under Featured, Global Warming

Geneva, Switzerland: Even warming of less than 2°C might be enough to trigger the loss of Arctic sea ice and the meltdown of the Greenland Ice Sheet, causing global sea levels to rise by several metres.

Ahead of next week’s meeting of governments in Poznan, Poland for UN climate talks WWF analysis of the latest climate science comes to the dire conclusion that humanity is approaching the last chance to keep global warming below the danger threshold of 2°C.

”The latest science confirms that we are now seeing devastating consequences of warming that were not expected to hit for decades,” said Kim Carstensen, WWF Global Climate Initiative leader.

“The early meltdown of ice in the Arctic and Greenland may soon prompt further dangerous climate feedbacks, accelerating warming faster and stronger than forecast.

“Responsible politicians cannot dare to waste another second on delaying tactics in the face of these urgent warnings from nature.

“The planet is now facing a new quality of change, increasingly difficult to adapt to and soon impossible to reverse.

“Governments in Poznan must agree to peak and decline global emissions well before 2020 to give people reasonable hope that global warming can still be kept within limits that prevent the worst.

“In addition to constructive discussions in Poznan we need to see signals for immediate action.”

The CO2 storage capacity of oceans and land surface – the Earth’s natural sinks – has been decreasing by 5 per cent over the last 50 years. At the same time, manmade CO2 emissions from fossil fuels have been increasing – four times faster in this decade than in the previous decade.

WWF is urging governments to use the Poznan talks for an immediate U-turn away from the fatal direction the world is heading in.

“We are at the point where our climate system is starting to spin out of control,” said Carstensen. “A single year is left to agree a new global treaty that can protect the climate, but the UN talks next year in Copenhagen can only deliver this treaty if the meeting in Poznan this year develops a strong negotiation text.”

Article copyright WWF