Tag Archives: Arctic

Arctic warming accelerating according to new report

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*See related video at the bottom of page*

This year’s Arctic Report Card from NOAA is in, and the grades aren’t good. The theme for this year is that it is clear that the Arctic is experiencing the impacts of a prolonged and amplified warming trend, highlighted with many record-setting events. The report also reminds us that deviations from the average air temperature are amplified by a factor of two or more in the Arctic relative to lower latitudes.

Walrus and other iconic species are at high risk due to prolonged Arctic warming.

Walrus and other iconic species are at high risk due to prolonged Arctic warming.

To this I would add that it is now apparent (due to the inertia inherent in the global climate system) that the  warming effects currently being observed are due to the greenhouse gasses released 30-40 years ago -back when climate change was barely known to the general public. The amount of warming built into the system (based on real-world observations like the ones in this report) that is still to come is quite terrifying – suggesting to me that the most recent IPCC predictions for warming and sea-level rise are remarkably optimistic (let alone the claims of the climate denialists!).

It is also worth noting that while a reduction in the ice-albedo effect leading to enhanced warming is described, accelerated GHG release from thawing permafrost, along with methane hydrates, are not mentioned in this report card (despite the evidence that permafrost is warming up around the Arctic rim). Either could act as additional positive feedback mechanisms – causing accelerated warming – if and when large amounts of gas are released (UPDATE – New article about accelerated methane release from permafrost).

Now to the findings of the report card. The “highlights” include:

*A new record minimum in springtime snow cover duration.

*Increased permafrost temperatures around the Arctic rim.

*Increased river discharge to the Arctic Ocean (could this affect the thermohaline circulation?)

*Increased greenness of Arctic vegetation.

Sea Ice

The Arctic summer sea ice extent and mass is rapidly decreasing.

The Arctic summer sea ice extent and mass is rapidly decreasing.

*September Arctic sea ice extent was the third smallest of the past 30 years (the four smallest recorded September ice extents have occurred in the past four years, and eight of the ten lowest summer minimums have occurred in the last decade).

*Third smallest ever extent of older, thicker multiyear ice.

*Both the Northern Sea Route and the Northwest Passage were ice-free in September.

Greenland

*Record warm air temperatures were observed over Greenland in 2010. This included the warmest year on record for Greenland’s capital, Nuuk, in at least 138 years.

*Melt period on Greenland’s inland ice sheet 1 month longer than the 30 year average.

*Glacier loss along the Greenland margins was also exceptional in 2010, with the largest single glacier area loss (110 square miles, at Petermann glacier) equivalent to an area four times that of Manhattan Island.

“There is now no doubt that Greenland ice losses have not just increased above past decades, but have accelerated – the implication is that sea level rise projections will again need to be revised upward.”

Outcomes

“It is increasingly unlikely (at least for the foreseeable future) that the Arctic will return to conditions that were considered normal in the later part of the 20th century…and very likely that Arctic climate warming will continue and we will continue to see records set in years to come.”

*Progressive reduction in the ice albedo effect, exposing darker ocean and increasing heat absorption – this in turn leads to accelerated melting and a progressive acceleration of this cycle (in a classical example of positive feedback).

*With the expectation of continued warming air temperatures, Arctic species that have adapted to the Arctic environments are expected to be displaced by the encroachment of more southerly (sub-Arctic) species and ecosystems.

“While we see somewhat direct relationships between warming and ice cover melt, it is more difficult, due to the complex nature of ecosystems, to predict and understand how these biological systems are and will respond to this amplified warming trend.”

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Arctic Multi-Year Ice Effectively Gone

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According to a Reuters report published 29.10.2009, the multi-year ice covering the Arctic Ocean has effectively vanished.

The disappearance of Arctic multi-year ice is a disaster for polar ecosystems

The disappearance of Arctic multi-year ice is a disaster for polar ecosystems

This is important news for several reasons:

    *It is some of the best (or worst?) evidence yet of the rapidity and severity of Arctic warming (and by extension the globe).
    *It is many years ahead of what modelers were predicting just a few short years ago.
    *It potentially is the start of accelerated Arctic warming (runaway warming) due the loss of the albedo effect and activation of positive feedback loops (like permafrost thawing).
    *It opens the Arctic up to shipping, exploration, drilling and other forms of environmentally-questionable activity.

The report describes how Canadian scientist David Barber (Research Chair in Arctic System Science at the University of Manitoba) went searching for multi-year pack ice and found very little. “We are almost out of multiyear sea ice in the northern hemisphere,” he said in a recent presentation to the Canadian Parliament.

Reuters says that Barber spoke shortly after returning from an expedition that sought (and largely failed to find) a huge multiyear ice pack that should have been in the Beaufort Sea off the Canadian coastal town of Tuktoyaktuk.

This type of ice can be tens of metres thick and to date has been the barrier closing the fabled Northwest Passage:

Vast sheets of impenetrable multiyear ice, which can reach up to 80 meters (260 feet) thick, have for centuries blocked the path of ships seeking a quick short cut through the fabled Northwest Passage from the Atlantic to the Pacific. They also ruled out the idea of sailing across the top of the world.

Barber also said that the Arctic is now,  from a practical perspective,  almost seasonally ice-free. The scale and rapidity of the changes astounded Barber. “I’ve never seen anything like this in my 30 years of working in the high Arctic … it was very dramatic,” he said.

An increasing number of experts feel the North Pole will be ice free in summer by 2030 at the latest, for the first time in a million years.

The Arctic is an early indicator of what we can expect at the global scale as we move through the next few decades … So we should be paying attention to this very carefully, according to Barber

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Sea Level Rise to Be Higher & Faster Than Predicted by IPCC

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Recent research suggests that global warming-related sea level rise will be faster and greater than previously forecast. The poles are experiencing disproportionate warming and are undergoing accelerated melting. The amount of this melt will largely determine the degree of sea-level rise over coming centuries.

Polar Ice Is Melting Faster Than Predicted

Polar Ice Is Melting Faster Than Predicted

Melting is proceeding at an unprecedented pace that already exceeds the worst-case scenario in the 2007 IPCC report, and there is a growing scientific consensus that the IPCC wildly underestimated the rapidity and extent of glacial melting.

Over the coming centuries anthropogenic warming will be the main driver of sea-level rise, even if emissions decreased and atmospheric levels of CO2 stabilised at 450ppm. If we burn all remaining fossil fuel stores then sea level will be over 10 metres higher than it is today.

While the single biggest contributor to sea-level rise during the twentieth century was the melting of non-polar glaciers (such as those in the Himalayas and Andes), polar ice is predicted to rapidly overtake it. Thermal expansion of the oceans will also play a role but will pale into insignificance compared to the amount of water currently locked up in Greenland and Antarctica (which will raise sea level by 70 metres if it all melts).

Rising Sea Levels Are Due To Global Warming-Induced Climate CHange

Rising Sea Levels Are Due To Global Warming-Induced Climate Change

There are three main mechanisms contributing to the accelerating loss of polar ice.

Glacial lubrication by meltwater (where melting freshwater infiltrates through cracks in the glacier, reaching the bedrock and acting as a lubricant that accelerates glacial flow) is one mechanism. Initially thought to be the most important mechanism, it is probably not the primary factor that will lead to accelerated sea level rise.

A second mechanism is the break-up of floating ice shelves (like the Antarctic’s Larsen B shelf). While not increasing sea level directly (because they are already floating), they appear to act as a “cork” for the glacier behind them. Once they disappear, glacial flow accelerates significantly – This was observed at Larsen B where immediate glacial acceleration (of eight times normal speed) followed its demise.

The third (and probably most important) mechanism of ice loss has only just been discovered – the melting of Antarctic ice by the upwelling of warmer water from several hundred metres below the surface of the sea. This is occurring in increasingly greater amounts due to global warming. A warming pole has changed the pattern of wind flow around Antarctica, in turn changing sea currents and directing warm water towards vulnerable ice shelves.

This process is already happening to some ice shelves (notably the ice shelf holding back the massive Pine Island glacier) and could cause a sea-level rise of 3.3 metres over the next few hundred years.

Antarcticas Ice Is Disappearing

Antarctica's Ice Is Disappearing

Summary: Ice at the poles is melting much faster than predicted, and the majority of sea level experts are expecting at least a metre of sea-level rise by 2100.

Paul Roth is a health professional concerned about human-caused global warming and climate change. He is the founder of Climate Change Health, a blog dedicated to documenting climate change and its effects on human health.

Article Source: http://EzineArticles.com/?expert=Paul_Andrew_Roth
http://EzineArticles.com/?Sea-Level-Rise-to-Be-Higher-and-Faster-Than-Predicted-by-IPCC&id=2663108

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Smoke From Tundra Fires In Russia And Alaska

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NASA Earth Observatory: Intense fires burning in the boreal forests of Russia, Alaska and Canada darkened Northern skies with smoke in July 2009. Large fires were burning in both Russia and Alaska in late July, and this image tracks the smoke from those fires by illustrating the concentration of carbon monoxide in the atmosphere.

Smoke from Fires in Russia and Alaska

Smoke from Fires in Russia and Alaska

CO Concentrations

CO Concentrations

Tundra fires are important for several reasons:

  • About a third of the world’s soil-based carbon is locked-up in high-latitude tundra and boreal forest ecosystems.
  • Burning tundra releases CO2 and destroys stored carbon (in organic matter) – one study estimates that 50 years of accumulated plant matter was lost after one severe fire.
  • Severely burned tundra emits twice as much carbon as undamaged tundra normally stores away, for up to a year after burning.
  • It also absorbs around 70 per cent more solar radiation, warming faster (due to blackening and loss of vegetative cover) – this causes thawing of the underlying permafrost (up to 10 centimetres deep).
  • Thawing permafrost undergoes anaerobic decomposition and releases methane (a greenhouse gas 25 times more potent than CO2).
  • This creates a positive feedback loop – burning and its later effects release carbon and melt permafrost. This causes more warming and makes further fires more likely.
  • Tundra fires will become more frequent in future because higher temperatures and increasing dryness increase the amount of vegetation available to burn (by prompting a shift from tundra comprised mainly of small herbs and grasses to one dominated by larger shrubs).

*****

The image above was made with data collected by the Measurements of Pollution in the Troposphere (MOPITT) sensor on NASA’s Terra satellite between July 20 and July 26, 2009. Spots of red show where carbon monoxide concentrations were high, while orange areas point to moderate concentrations. Gray regions indicate places where no measurements were made, probably because of persistent clouds. The highest concentrations of carbon monoxide are centered over large fire complexes in Russia. Fires in Alaska were also pumping carbon monoxide into the atmosphere.

Carbon monoxide is a component of smoke that can be tracked long after the smoke has dispersed enough to no longer be visible. Carbon monoxide helps reveal where smoke’s other invisible fine particles and polluting gases end up. These invisible particles and gases, including carbon monoxide, are ingredients in the production of ground-level ozone, a harmful pollutant.

This article based on these two New Scientist articles:

Alaskas biggest tundra fire sparks climate warning.

Global warming may raise tundra wildfire risk.

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