Sea ice extent in the Bering Sea (Arctic) continues its decline. "Warm" and strong southerly winds have contributed to this anomalous retreat of ice into the Bering Strait. 2018 is the clear outlier in the satellite era (each thin line = 1979-2017, @NSIDC data) pic.twitter.com/kzEV6yEFmp— Zack Labe (@ZLabe) February 24, 2018
Showing posts with label Arctic. Show all posts
Showing posts with label Arctic. Show all posts
25 February 2018
What is happening in the Arctic is now beyond words, so here are the pictures
In the depths of the northern winter, and with 24-hour darkness at the North Pole, an extraordinary climate warming event is happening. And for many scientists it is now beyond words. So here from Zack Labe (@ZLabe) are some images which tell the story of the recording-smashing warming and sea-ice melting occurring right now high in the Arctic.
24 July 2017
A failure of imagination on climate risks
By Ian Dunlop and David Spratt
Climate change is an existential risk that could abruptly end human civilisation because of a catastrophic “failure of imagination” by global leaders to understand and act on the science and evidence before them.
At the London School of Economics in 2008, Queen Elizabeth questioned: “Why did no one foresee the timing, extent and severity of the Global Financial Crisis?” The British Academy answered a year later: “A psychology of denial gripped the financial and corporate world… [it was] the failure of the collective imagination of many bright people… to understand the risks to the system as a whole”.
A “failure of imagination” has also been identified as one of the reasons for the breakdown in US intelligence around the 9/11 attacks in 2001.
A similar failure is occurring with climate change today.
This is an extract from Disaster Alley: Climate change, conflict and risk published recently by Breakthrough.
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| Download the report |
At the London School of Economics in 2008, Queen Elizabeth questioned: “Why did no one foresee the timing, extent and severity of the Global Financial Crisis?” The British Academy answered a year later: “A psychology of denial gripped the financial and corporate world… [it was] the failure of the collective imagination of many bright people… to understand the risks to the system as a whole”.
A “failure of imagination” has also been identified as one of the reasons for the breakdown in US intelligence around the 9/11 attacks in 2001.
A similar failure is occurring with climate change today.
03 May 2016
Arctic sea ice is falling off a cliff and it may not survive the summer
Note: Thanks to robertscribbler.com for this excellent post on the eye-popping circumstances of Arctic sea-ice this melt season.
These are the kinds of climate-wrecking phase changes in the Arctic people have been worrying about since sea ice extent, area, and volume achieved gut-wrenching plunges during 2007 and 2012. Plunges that were far faster than sea ice melt rates predicted by model runs and by the then scientific consensus on how the Arctic Ocean ice would respond to human-forced warming this Century. For back during the first decade of the the 21st Century the mainstream scientific view was that Arctic sea ice would be about in the range that it is today by around 2070 or 2080. And that we wouldn’t be contemplating the possibility of zero or near zero sea ice until the end of this Century.
08 June 2014
Carbon budgets, climate sensitivity and the myth of "burnable carbon"
by David Spratt
In my previous post explaining why there is no carbon budget left for burning fossil fuels for a 2-degree Celsius (°C) target, I explained that these carbon budget calculations are expressed in probabilities of not exceeding the target. This reflects a number of uncertainties in understanding, including climate sensitivity, ocean heat uptake inertia, the influences of non-carbon dioxide forcing agents, and because results vary somewhat among model ensembles.
Of these, climate sensitivity is the biggest issue, because of the possibilities that climate change might proceed more rapidly than currently estimated because of reinforcing feedbacks, thresholds or tipping points in the climate system, or less rapidly because of dampening feedbacks.
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| Breakthrough National Climate Restoration Forum 21-22 June, Melbourne |
Of these, climate sensitivity is the biggest issue, because of the possibilities that climate change might proceed more rapidly than currently estimated because of reinforcing feedbacks, thresholds or tipping points in the climate system, or less rapidly because of dampening feedbacks.
23 February 2014
Arctic sea-ice loss adds 25% to carbon dioxide warming over last 30 years
First posted at robertscribler
What’s the difference between a majestic layer of white sea ice and an ominous dark blue open ocean?
For the Arctic, it means about a 30 to 50 per cent loss in reflectivity (or albedo). And when seasonal sea-ice states are between 30 and 80 per cent below 1979 measures (depending on the method used to gauge remaining sea ice and relative time of year), that means very, very concerning additional heating impacts to an already dangerous human-caused warming.
How concerning, however, remained somewhat unclear until recently.
In the past, idealized climate simulations and physical model runs had produced about a two per cent overall loss in Arctic albedo based on observed sea ice losses. This decline, though minor sounding, was enough, on its own, to add a little more than a 10 per cent amplifying feedback to the already powerful human atmospheric carbon dioxide (CO2) forcing during recent years. Such an addition was already cause for serious concern and with sea ice totals continuing to fall rapidly, speculation abounded that just this single mechanism could severely tip the scales toward a more rapid warming.
What’s the difference between a majestic layer of white sea ice and an ominous dark blue open ocean?
For the Arctic, it means about a 30 to 50 per cent loss in reflectivity (or albedo). And when seasonal sea-ice states are between 30 and 80 per cent below 1979 measures (depending on the method used to gauge remaining sea ice and relative time of year), that means very, very concerning additional heating impacts to an already dangerous human-caused warming.
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| A dark and mostly ice-free Arctic Ocean beneath a tempestuous swirl of clouds on September 1, 2012, a time when sea ice coverage had declined to an area roughly equal to the land mass of Greenland. Image source: Lance-Modis/NASA AQUA. |
In the past, idealized climate simulations and physical model runs had produced about a two per cent overall loss in Arctic albedo based on observed sea ice losses. This decline, though minor sounding, was enough, on its own, to add a little more than a 10 per cent amplifying feedback to the already powerful human atmospheric carbon dioxide (CO2) forcing during recent years. Such an addition was already cause for serious concern and with sea ice totals continuing to fall rapidly, speculation abounded that just this single mechanism could severely tip the scales toward a more rapid warming.
29 January 2014
With Arctic freezer door open, frigid air drains into USA and Eurasia, with Arctic unusually mild
by David Spratt
It's a cliche that a picture tells a story better than a thousand words, and it's really true in the case of this extraordinary map of weather modelling of northern hemisphere temperature anomalies (variations from the expected values based on climate records) for 29 January 2014:
It's a cliche that a picture tells a story better than a thousand words, and it's really true in the case of this extraordinary map of weather modelling of northern hemisphere temperature anomalies (variations from the expected values based on climate records) for 29 January 2014:
17 October 2013
Confused about the new IPCC's carbon budget?
So am I.
When the IPCC's new report on the physical basis of climate change was released in late September, media attention focused on a conclusion from the Summary for Policymakers that the world had emitted just over half of the allowable emissions if global warming is to be kept to 2 degrees Celsius (2°C) of warming.
Unfortunately, because many people think if you have a budget you should spend every last dollar, the "carbon budget" message could be interpreted as saying there is plenty of budget left to spend. The respected climate researcher Ken Caldeira told Climate Progress that the carbon budget concept is dangerous for two reasons:
There are no such things as an “allowable carbon dioxide (CO2) emissions.” There are only “damaging CO2 emissions” or “dangerous CO2 emissions.” Every CO2 emission causes additional damage and creates additional risk. Causing additional damage and creating additional risk with our CO2 emissions should not be allowed.
If you look at how our politicians operate, if you tell them you have a budget of XYZ, they will spend XYZ. Politicians will reason: “If we’re not over budget, what’s to stop us to spending? Let the guys down the road deal with it when the budget has been exceeded.” The CO2 emissions budget framing is a recipe for delaying concrete action now.
28 September 2013
IPCC summary report at a glance, in their own words
via Climate News Network
Summary for Policymakers of the Working Group I contribution to the Fifth Assessment Report
A note from the Climate News Network editors: we have prepared this very abbreviated version of the first instalment of the IPCC's Fifth Assessment Report (AR5) to serve as an objective guide to some of the headline issues it covers. It is in no sense an evaluation of what the Summary says: the wording is that of the IPCC authors themselves, except for a few cases where we have added headings. The AR5 uses a different basis as input to models from that used in its 2007 predecessor, AR4: instead of emissions scenarios, it speaks of RCPs, representative concentration pathways. So it is not possible everywhere to make a direct comparison between AR4 and AR5, though the text does so in some cases, and at the end we provide a very short list of the two reports' conclusions on several key issues. The language of science can be complex. What follows is the IPCC scientists' language. In the following days and weeks we will be reporting in more detail on some of their findings.
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| Observed changes in average surface temperature 1901-2012 |
A note from the Climate News Network editors: we have prepared this very abbreviated version of the first instalment of the IPCC's Fifth Assessment Report (AR5) to serve as an objective guide to some of the headline issues it covers. It is in no sense an evaluation of what the Summary says: the wording is that of the IPCC authors themselves, except for a few cases where we have added headings. The AR5 uses a different basis as input to models from that used in its 2007 predecessor, AR4: instead of emissions scenarios, it speaks of RCPs, representative concentration pathways. So it is not possible everywhere to make a direct comparison between AR4 and AR5, though the text does so in some cases, and at the end we provide a very short list of the two reports' conclusions on several key issues. The language of science can be complex. What follows is the IPCC scientists' language. In the following days and weeks we will be reporting in more detail on some of their findings.
24 September 2013
Is climate change already dangerous? (4): Tipping points and climate modelling
by David Spratt
Fourth in a series
A tipping point may be understood as a step change, or passing of a critical threshold, in a major earth-climate system component, where a small perturbation (a small push or change) unleashes a bigger change in the component. Potsdam Institute Director, Prof. Hans Joachim Schellnhuber, says that tipping points “identify the most vulnerable components (tipping elements) of the Earth System, the critical warming thresholds where the respective Earth System elements flip into a qualitatively new state”. These elements include ecosystems, major ocean and atmospheric circulation patterns, the polar ice sheets, and the land- and ocean-based carbon stores.
This process is often tied to positive feedbacks, where a change in a component leads to other changes that eventually “feed back” onto the original change to amplify it. The classic case in global warming (or, in reverse, cooling) is the ice-albedo feedback, where decreases (increases) in the ice cover area change surface reflectivity (albedo), trapping more (less) heat and producing further ice loss (gain).
Fourth in a series
A tipping point may be understood as a step change, or passing of a critical threshold, in a major earth-climate system component, where a small perturbation (a small push or change) unleashes a bigger change in the component. Potsdam Institute Director, Prof. Hans Joachim Schellnhuber, says that tipping points “identify the most vulnerable components (tipping elements) of the Earth System, the critical warming thresholds where the respective Earth System elements flip into a qualitatively new state”. These elements include ecosystems, major ocean and atmospheric circulation patterns, the polar ice sheets, and the land- and ocean-based carbon stores.This process is often tied to positive feedbacks, where a change in a component leads to other changes that eventually “feed back” onto the original change to amplify it. The classic case in global warming (or, in reverse, cooling) is the ice-albedo feedback, where decreases (increases) in the ice cover area change surface reflectivity (albedo), trapping more (less) heat and producing further ice loss (gain).
19 September 2013
Is climate change already dangerous (2): The Arctic
by David Spratt
Second in a series
On 16 September 2012, Arctic sea-ice reached its minimum extent for the 2012 northern summer of 3.41 million square kilometres, the lowest seasonal minimum extent in the satellite record since 1979, and just half of the average area for the 1979–2000 period. There was a loss of 11.83 million square kilometres of ice from the maximum extent on 20 March 2012. This was the largest summer ice extent loss in the satellite record, more than one million square kilometres greater than in any previous year.
Two-thirds of the loss of sea-ice extent has happened in the 12 years since 2000, and the process appears to be accelerating. From 1979 to 1983 in the Arctic, the sea ice summer minimum covered an average of just over 51 per cent of the ocean. It fell to just 24 per cent of the Arctic ocean surface in 2012.
Second in a series
Arctic sea ice
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| Download full report |
Two-thirds of the loss of sea-ice extent has happened in the 12 years since 2000, and the process appears to be accelerating. From 1979 to 1983 in the Arctic, the sea ice summer minimum covered an average of just over 51 per cent of the ocean. It fell to just 24 per cent of the Arctic ocean surface in 2012.
30 July 2013
Record heat hits rapidly melting Arctic as boreal forest burns at an unprecedented rate
by David Spratt
This image from North Pole Environmental Observatory's live cam has gone viral. The meltwater lake started forming July 13, following two weeks of warm weather in the high Arctic.
It's one of many arresting images and disturbing reports tumbling out of a rapidly melting Arctic this northern summer as researchers warn that the region’s mighty boreal forests have been burning at rates unprecedented in the past 10,000 years, and that Greenland is at risk of more rapid disintegration, pushing a quicker sea level rise.
This image from North Pole Environmental Observatory's live cam has gone viral. The meltwater lake started forming July 13, following two weeks of warm weather in the high Arctic.
11 July 2013
Arctic melt hits food security in bitter taste of life on a hotter planet
by David Spratt, first published in RenewEconomy
iIn
the UK and Ireland, wet summer and autumn followed by a cold winter and spring have hit wheat yields, potato production and cattle feed,
a foretaste of how climate change can affect food security, even in the
developed economies.
And the culprit in this drama is rapid Arctic melting, which has destabilised the Jet Stream and brought extreme weather – unusual cold, heavy snowfall, record rain and hot spells — to much of northern Europe and North America, and record heat to the Arctic. Following Superstorm Sandy’s battering of the US north-east coast in 2012, flooding in June across central Europe was the worst in 400 years.
Rapid Arctic melting – sea-ice volume in September 2012 was down by four-fifths compared to the summer average 30 years ago – has helped change the Jet Stream, the river of high altitude air that works to separates Arctic weather from that of northern Europe, Russia and Canada, and which governs much northern hemisphere weather.
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| Arctic melt has pushed the
Jet Stream into a more meandering, S-shape pattern, dragging down and stalling cold and wet conditions over Europe |
And the culprit in this drama is rapid Arctic melting, which has destabilised the Jet Stream and brought extreme weather – unusual cold, heavy snowfall, record rain and hot spells — to much of northern Europe and North America, and record heat to the Arctic. Following Superstorm Sandy’s battering of the US north-east coast in 2012, flooding in June across central Europe was the worst in 400 years.
Rapid Arctic melting – sea-ice volume in September 2012 was down by four-fifths compared to the summer average 30 years ago – has helped change the Jet Stream, the river of high altitude air that works to separates Arctic weather from that of northern Europe, Russia and Canada, and which governs much northern hemisphere weather.
25 October 2012
After the Arctic big melt: (1) A hotter planet
by David Spratt
The Arctic is a place of seasonal climate extremes, and it will become more extreme as the planet warms. “In the most dramatic reconfiguration of the map of the world since the end of the last Ice Age”, wrote John Gibbons recently in the Irish Times, “the Arctic ice cap is now committed to accelerated collapse”. There are global consequences.
In the first of a series, we look at how Arctic melting, in a self-perpetuating positive feedback, is leading to more global warming and a hotter future.
Day and night
For almost six months a year in winter, it is dark 24-hours-a-day at the North Pole as the Earth’s northern axis tips away from the sun. The sun sets around 25 September each year and does appear over the horizon again until 17 March, when it then stays in sight all day, every day, for the next six months.
Almost 2600 kilometres further south, around the Arctic Circle, there is sunlight 24-hours a day for a month around the summer solstice, but only two hours a day of sun at the December winter solstice.
The Arctic is a place of seasonal climate extremes, and it will become more extreme as the planet warms. “In the most dramatic reconfiguration of the map of the world since the end of the last Ice Age”, wrote John Gibbons recently in the Irish Times, “the Arctic ice cap is now committed to accelerated collapse”. There are global consequences.
In the first of a series, we look at how Arctic melting, in a self-perpetuating positive feedback, is leading to more global warming and a hotter future.
Day and night
For almost six months a year in winter, it is dark 24-hours-a-day at the North Pole as the Earth’s northern axis tips away from the sun. The sun sets around 25 September each year and does appear over the horizon again until 17 March, when it then stays in sight all day, every day, for the next six months.
Almost 2600 kilometres further south, around the Arctic Circle, there is sunlight 24-hours a day for a month around the summer solstice, but only two hours a day of sun at the December winter solstice.
20 September 2012
Arctic warning: As the system changes, we must adjust our science
Update 20 September:
EXTENT: Satellite data shows Arctic melt sea-ice extent probably reached the minimum for the year at around 3.4 million square kilometres on Monday 17 September, 18 per cent less than the previous record in 2007 of 4.2 m.sq.kms. The JAXA daily raw data is here and the NSIDC date is here. This extent is now well less than half of the average extent of the 1980s.
VOLUME: The sea-ice volume is now down to just one-fifth of what it was in 1979. Latest PIOMAS volume from September 3, 2012 is 3407 cubic kilometers of ice remaining in the Arctic. Contrasted with the 16,855 of 1979, that is just about 20 per cent. Extent has dropped further since 3 September, so minimum volume this melt season will be about 5–10 per cent less than the early-September figure.
ICE-FREE ARCTIC: Debate rages within the scientific community. Previously we covered Big call: Cambridge prof. predicts Arctic summer sea ice “all gone by 2015”. On Monday the Guardian reported "Arctic expert predicts final collapse of sea ice within four years", in which Prof. Peter Wadhams of Cambridge said: "I have been predicting [the collapse of sea ice in summer months] for many years. The main cause is simply global warming: as the climate has warmed there has been less ice growth during the winter and more ice melt during the summer… in the end the summer melt overtook the winter growth such that the entire ice sheet melts or breaks up during the summer months. This collapse, I predicted would occur in 2015-16 at which time the summer Arctic (August to September) would become ice-free. The final collapse towards that state is now happening and will probably be complete by those dates. As the sea ice retreats in summer the ocean warms up (to 7C in 2011) and this warms the seabed too. The continental shelves of the Arctic are composed of offshore permafrost, frozen sediment left over from the last ice age. As the water warms the permafrost melts and releases huge quantities of trapped methane, a very powerful greenhouse gas so this will give a big boost to global warming." Unforntunately, the eviednce is on his side.
Post of 13 September:
By David Spratt,
published in ReNewEconomy on 12 September 2012
and in Climate Progress on 13 September 2012
The Arctic sea-ice big melt of 2012 “has taken us by surprise and we must adjust our understanding of the system and we must adjust our science and we must adjust our feelings for the nature around us”, according to Kim Holmen, Norwegian Polar Institute (NPI) international director.
From Svalbard (halfway between mainland Norway and Greenland), the BBC’s David Shukman reported on 7 September that Holmen had described the current melt rate “a greater change than we could even imagine 20 years ago, even 10 years ago”.
As detailed last week, the thin crust of sea-ice which floats on the north polar sea is now only half of the average minimum summer extent of the 1980, and just one-quarter of the volume twenty years ago.
EXTENT: Satellite data shows Arctic melt sea-ice extent probably reached the minimum for the year at around 3.4 million square kilometres on Monday 17 September, 18 per cent less than the previous record in 2007 of 4.2 m.sq.kms. The JAXA daily raw data is here and the NSIDC date is here. This extent is now well less than half of the average extent of the 1980s.
VOLUME: The sea-ice volume is now down to just one-fifth of what it was in 1979. Latest PIOMAS volume from September 3, 2012 is 3407 cubic kilometers of ice remaining in the Arctic. Contrasted with the 16,855 of 1979, that is just about 20 per cent. Extent has dropped further since 3 September, so minimum volume this melt season will be about 5–10 per cent less than the early-September figure.
ICE-FREE ARCTIC: Debate rages within the scientific community. Previously we covered Big call: Cambridge prof. predicts Arctic summer sea ice “all gone by 2015”. On Monday the Guardian reported "Arctic expert predicts final collapse of sea ice within four years", in which Prof. Peter Wadhams of Cambridge said: "I have been predicting [the collapse of sea ice in summer months] for many years. The main cause is simply global warming: as the climate has warmed there has been less ice growth during the winter and more ice melt during the summer… in the end the summer melt overtook the winter growth such that the entire ice sheet melts or breaks up during the summer months. This collapse, I predicted would occur in 2015-16 at which time the summer Arctic (August to September) would become ice-free. The final collapse towards that state is now happening and will probably be complete by those dates. As the sea ice retreats in summer the ocean warms up (to 7C in 2011) and this warms the seabed too. The continental shelves of the Arctic are composed of offshore permafrost, frozen sediment left over from the last ice age. As the water warms the permafrost melts and releases huge quantities of trapped methane, a very powerful greenhouse gas so this will give a big boost to global warming." Unforntunately, the eviednce is on his side.
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Northern Polar Institute Research Director Kim Holmen, left,
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By David Spratt,
published in ReNewEconomy on 12 September 2012
and in Climate Progress on 13 September 2012
The Arctic sea-ice big melt of 2012 “has taken us by surprise and we must adjust our understanding of the system and we must adjust our science and we must adjust our feelings for the nature around us”, according to Kim Holmen, Norwegian Polar Institute (NPI) international director.
From Svalbard (halfway between mainland Norway and Greenland), the BBC’s David Shukman reported on 7 September that Holmen had described the current melt rate “a greater change than we could even imagine 20 years ago, even 10 years ago”.
As detailed last week, the thin crust of sea-ice which floats on the north polar sea is now only half of the average minimum summer extent of the 1980, and just one-quarter of the volume twenty years ago.
How British government's climate forecasting MET Office gets the Arctic wrong
Introductory note: It is now very likely that the Arctic will be sea-ice-free within a decade, with enormous consequences. Not only has the 2007 record minimum low been smashed, but the new record low 2012 sea-ice extent (3.4 million square kilometres) is less than half the figure three decades ago. And the volume of ice is now down to just one-fifth of the figure three decades ago. In 1979 the summer volume was 16,855 cubic kilometres, on 3 September this year it was just 3,407 cubic kilometres. 80 per cent of the ice has already been lost.
The IPCC 2007 got the Arctic sea-ice wrong in projecting an Arctic still containing summer sea-ice by 2100. Now, Arctic specialists relying on new, regional climate models such as Prof. Peter Wadhams of Cambridge are making the big call of a summer ice-free Arctic as early as 2015. By contrast, those relying for Arctic forecasts on global general circulation models (GCMs) used for the 2007 IPCC report are sticking to a 2030-2040 projection, but lament that “We just don’t know exactly why this (sea-ice loss) is moving so fast”. The predictions of those who rely too much on the GCM models seem strangely removed from the reality on the ground and even a common sense view of the evidence, as this analysis from Arctic News shows. Underestimating the speed and likely future rate of change in the climate system has deadly consequences. – David
UK MET Office keeps downplaying significance of events in the Arctic
by Sam Carana, Arctic NewsOne of the most respected datasets on Arctic sea-ice volume is PIOMAS, the Pan-Arctic Ice Ocean Modeling and Assimilation System developed at the Polar Science Center, Applied Physics Laboratory, University of Washington. The graph below shows PIOMAS data for annual minimum Arctic sea ice volume (black dots) with an exponential trend added (in red).
10 September 2012
On thin ice: Time-frame to save the Arctic is melting away
By David Spratt, first published by ReNew Economy on 5 September 2012
Something extraordinary is happening when graphs of melting Arctic sea-ice have their vertical axis redrawn because the data are falling off the chart.
But that’s what has occurred in the last 10 days, since the extent of floating Arctic sea-ice broke the satellite-era minimum record on 24 August. On that date it was 4.2 million square kilometres, according to data from the Japan Aerospace Exploration Agency.
Since then, an additional half a million square kilometres of sea-ice has melted. The extent on 4 September was just half of the average minimum extent of the 1980s. At the current rate of loss, with one to three weeks left in the northern melt season, the minimum may well shrink below 3.5 million square kilometres. This is an astounding story.
Something extraordinary is happening when graphs of melting Arctic sea-ice have their vertical axis redrawn because the data are falling off the chart.
But that’s what has occurred in the last 10 days, since the extent of floating Arctic sea-ice broke the satellite-era minimum record on 24 August. On that date it was 4.2 million square kilometres, according to data from the Japan Aerospace Exploration Agency.
Since then, an additional half a million square kilometres of sea-ice has melted. The extent on 4 September was just half of the average minimum extent of the 1980s. At the current rate of loss, with one to three weeks left in the northern melt season, the minimum may well shrink below 3.5 million square kilometres. This is an astounding story.
27 August 2012
Arctic sea-ice melt record more than broken, it’s being smashed
by David Spratt, first posted 25 August 2012
According to IARC/JAXA satellite data at Arctic Sea-ice Monitor from the Japan Aerospace Exploration Agency, the sea-ice extent of 24 August 2012 of 4,209,219 square kilometres broke the previous record in the satellite era of 4,254,531 square kilometres set on 24 August 2007. Back then the were scientific gasps that the sea ice was melting “100 years ahead of schedule”.
UPDATE 27 AUGUST: Sunday's data confirms that the previous sea-ice extent minimum of 24 September 2007 was broken last Friday, 24 August 2012. What is also stunning are sea-ice daily extent figures averaging ice loss of more than 100,000 square kilometres per day for the last four days. This suggest melt is accelerating very late in the melt season in a pattern that has never before been observed. The Arctic this year is heading into new territory and it looks like 2012 may in retrospect be seen as the year when a new melt regime took hold.Climate change impacts are frequently happening more quickly and at lower levels of global warming than scientists expected, even a decade or two ago. And this week the Arctic has provided a dramatic and deeply disturbing example.
The ice extent is about to drop below 4 million square kilometres for the first time in the satellite record, and the Arctic has shed almost half a million square kilometres of sea-ice in last five days! With three weeks of the melt season still to go, it's not hard to see extent dropping another half a million square kilometres (or more!) to 3.5 million square kilometres. (In previous big melt years of 2007 and 2011, around half a million square kilometres was lost after 26 August.)
This is starting to make the second graph (below) looking reasonable, and those scientists and models which have been suggesting an sea-ice-free summer Arctic within a decade to be on the money.
The commentary by Climate Commissioner Prof. Will Steffen in today's newspapers that ''We can expect to see an ice-free Arctic at about the middle of this century'' looks out of touch with the most recent data, and exhibits IMHO a scientific reticence which does a disservice to the urgent public debate we need on implications of the Arctic melt for Australian climate policy (and sea-level rises from Greenland!). Positive feedbacks now have a grip on Arctic sea-ice and the descent appears to be exponential, not linear. Looking at the PIOMASS date on sae ice volume (fifth chart here), its hard to know what Prof. Steffen has based his assertion upon.
Perhaps the enormity of the present situation is best summed up by sea-ice blogger Neven: "Basically, I'm at a loss for words, and not just because my jaw has dropped and won't go back up as long as I'm looking at the graphs. I'm also at a loss - and I have already said it a couple of times this year - because I just don't know what to expect any longer. I had a very steep learning curve in the past two years. We all did. But it feels as if everything I've learned has become obsolete. "
According to IARC/JAXA satellite data at Arctic Sea-ice Monitor from the Japan Aerospace Exploration Agency, the sea-ice extent of 24 August 2012 of 4,209,219 square kilometres broke the previous record in the satellite era of 4,254,531 square kilometres set on 24 August 2007. Back then the were scientific gasps that the sea ice was melting “100 years ahead of schedule”.
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| JAXA Arctic sea ice extent to 24 August 2012. Updates: http://www.ijis.iarc.uaf.edu/en/home/seaice_extent.htm |
20 August 2012
Arctic heads for record melt, but do we want to know?
Update to: Dramatic lessons from the Arctic big melt of 2012: It's already too hot, as Greenland melt record is smashedby David Spratt, first published at RenewEconomy, 21 August 2012
Related post: US Media Turn A Blind Eye To Record Greenland Ice Melt
Two extraordinary events at the end of last week say a lot about the state of the climate change conversation in Australia.
The first was data from US Arctic researcher Prof. Marco Tedesco showing that melting over the Greenland ice sheet had shattered the seasonal record on 8 August, a full four weeks before the close of the melting season (following image). The melting season lasts until the second week of September each northern summer, so this result is stunning: "With more yet to come in August, this year's overall melting will fall way above the old records. That's a goliath year -- the greatest melt since satellite recording began in 1979," said Tedesco.
Dramatic lessons from the Arctic big melt of 2012: It's already too hot, as Greenland melt record is smashed
Related post: Arctic heads for record melt, but do we want to know?
UPDATE 21 August: RECORD SEA-ICE MELT: The Arctic big melt is charging along and a number of data sets today show that 2012 has broken the 2007/2011 record for minimum sea-ice extent / area. These include data sets from Arctic ROOS and Cryosphere Today. This closeup from Neven of the Cryosphere Today data is very clear:
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| Cryosphere Today sea ice area August 2005-2012 |
Cryosphere Today data set shows:
- 2012, day 230, 2.87743 million square kilometers
- 2011, day 253, 2.90474 million square kilometers (previous record low)
16 July 2012
The wet side of Greenland
An Arctic Sea Ice blog crosspost
When writing The dark side of Greenland, a recent blog post on decreasing reflectivity of the Greenland ice sheet, with images comparing the southwest of Greenland with satellite images from previous years, I of course realized that when that ice sheet becomes less reflective, it will soak up more solar energy and thus melt faster. But the practical aspect of this theory never really dawned on me, until I saw this video:
More videos here and here.
When writing The dark side of Greenland, a recent blog post on decreasing reflectivity of the Greenland ice sheet, with images comparing the southwest of Greenland with satellite images from previous years, I of course realized that when that ice sheet becomes less reflective, it will soak up more solar energy and thus melt faster. But the practical aspect of this theory never really dawned on me, until I saw this video:
More videos here and here.
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