Arctic Sea Ice Extent, Area, and Volume

[SnoSki14]

I suspect as with the leap in record highs over the previous records that we'll eventually see a leap in sea ice decline that will rival or exceed the 2012 anomalous drop. 

Probably not this year but it's only a matter of time.

[ORH_wxman]

Given we're now past 7/1, it is time for the annual forecast.

Quick update on standings:

2020: -430k

2019: -380k

2018: +390k

2017: +70k

2016: -180k

2015: +190k

2014: +320k

2013: +390k

2012: -590k

2011: -140k

2010: -310k

2009: +710k

2008: +280k

2007: -330k

 

 

You can see last year's forecast here:

 

And here is last year's verification:

 

As for 2021.....below is what the final area would be if we followed the path of every other year from here on out. An example is that if we followed the path of 2012 from here on out and lost another 4.3 million sqkm of ice like that year did post-7/1, then we would finish at 2.7 million sq km. The reason the forecasts are pretty accurate is that area loss post-7/1 is pretty stable over time going back to 1979. There has been a bias toward a little bit higher in the post-2007 world, but it is much smaller than the differences we see prior to July 1st (i.e., most of the area loss can be explained by what happens prior to 7/1.)

 

 

 

Two things stick out on the graph....one, is that any minimum above 4.00 million sq km is basically impossible no matter which path we follow. Nevermind that we haven't had an area min above 4.0 million sq km since 2006 anyway, but there isn't even a realistic shot at one this year like perhaps was plausible in years like 2014.

Secondly, the chance at a new record minimum is basically impossible too. The two largest melt years post-7/1 were 1989 and 2016. You can see following both of their paths still only produces a min around 2.5 million sq km....well above the record-low 2.23 million sq km minimum in 2012.

 

Given that information, I will use the post-2007 average as my baseline. I might even skew a little on the high side of that unlike last year because the forecast is quite stormy over the arctic basin for the foreseeable future. The EPS have a pretty strong vortex over the pole through mid-July which is wasting what's left of prime insolation season up there.

 

Taking a post-2007 average result post-7/1 purely at face value would yield a minimum of 2.9 sq km in 2021. I'll skew just a touch higher than that based on the forecast and current distribution of the ice. So for an area minimum, I'll forecast 3.0 million sqkm +/- 300k. That would place 2021 around 8th lowest.

Sea ice extent is a bit more fickle since compaction plays a larger part unlike area. But I'll go 4.3 million sq km on NSIDC extent +/- 500k. I have a larger range on the extent min since it has a much higher standard deviation than area.

[madwx]

I can always know when sea ice has a slow loss period because I see weatherdude88 post on all the various arctic sea ice forums.   It's like clockwork waiting for this guy to pop out of his cave.

[LibertyBell]

2 minutes ago, madwx said:

I can always know when sea ice has a slow loss period because I see weatherdude88 post on all the various arctic sea ice forums.   It's like clockwork waiting for this guy to pop out of his cave.

lol he weenie'd Will's post just because Will made a good forecast of having over >4 million sq mile minimum being very unlikely, I mean it hasn't happened since 2006, so we have history "on our side"

 

[LibertyBell]

12 minutes ago, Weatherdude88 said:

I never have predicted, nor am I predicting the 2021 NSIDC sea ice area minimum will be greater than 4 million square kilometers. It is clear you have little knowledge of sea ice melting seasons, considering you think metrics and minimums are measure in miles .

Do not put words in my mouth. Stop the FUD! 

lmao awww poor baby, is 88 your IQ?  sure seems like it. if even that high.  

 

sorry, we're not in Europe, I'll use miles.  You can convert them back and forth, it's easy even for someone like you

also you're not going to last very long on here with that attitude of yours.  The person you weenie'd is actually a moderator and a trained meteorologist.

 

 

 

 

[LibertyBell]

Just now, Orangeburgwx said:

Point is, this thread is for the arctic sea ice and you brought up heat outside the Arctic Circle... And insulting these guys who put in time and effort doing the research, even my min (3.908) is under 4m km². I live here in the states, and even I use km² when it comes to sea ice because it tells a far better picture with extent and concentration so living outside Europe has nothing to do with it

Sent from my LGL322DL using Tapatalk
 

He was the one who was insulting someone else  who made a very good point about old standards not applying and then he responded with talking about an "isolated" event which it very clearly is not (and which we've extensively talked about in another thread.)  "These" guys is just one person who poked his little head in where it didn't belong.  I fully understand the conversion, I do it in my head (5/8 or 0625 miles in one km).  I'm not sure how much one understands about climate if one actually believes that anything occurs in "isolation" everything is part of much greater system and feedback mechanisms.  There is no such thing as "isolation".

 

[Orangeburgwx]

He was the one who was insulting someone else  who made a very good point about old standards not applying and then he responded with talking about an "isolated" event which it very clearly is not (and which we've extensively talked about in another thread.)  "These" guys is just one person who poked his little head in where it didn't belong.  I fully understand the conversion, I do it in my head (5/8 or 0625 miles in one km).  I'm not sure how much one understands about climate if one actually believes that anything occurs in "isolation" everything is part of much greater system and feedback mechanisms.  There is no such thing as "isolation".
 

That's the thing about climate, everything is linked... Jet stream, ocean currents, everything...

Sent from my LGL322DL using Tapatalk

[LibertyBell]

7 minutes ago, Weatherdude88 said:

I live in Texas. NSIDC National Snow and Ice Data Center is headquartered in Boulder, Colorado. This is the organization gathering and crunching the numbers from satellites to get the data above.  

When you go to a university for a STEM related degree, you are taught and learn why all peer reviewed literature and scientific measurements use the Metric instead of the Imperial system.

Some of the reasons are:

1. Metric is a rational number after a metric unit conversion

2. Prefixes carry the same weight for all base units

3. The overwhelming vast majority of countries use the metric system.

In fact, I though they taught this in Middle School these days.

I know all about the metric system and I do the conversion in my head, so that doesn't really matter.  Anyone with a basic education should be able to do it in their heads, it's not a big concern.  In computer systems we use hexadecimal, so it's pretty easy to talk back and forth between binary, decimal and hexadecimal.  None is better than any other as they are all like different languages.

More concerning is that you thought the heat in the western part of the continent was in "isolation".  If you know anything about how the planet works you should know that absolutely NOTHING occurs in isolation- that it's all part of one larger feedback mechanism.  And it isn't the only historic such outbreak that's occurred in recent years either.  It's part of a global trend.  And Etudiant's point about not using prior history to predict the future because we're in an entirely uncharted territory now is a very good and salient one.

 

[LibertyBell]

6 minutes ago, Weatherdude88 said:

Let me help you understand.

Every year there are weather event that effect different regions of the earth. When looking at record warm temperatures, you need to factor in the urban heat island effect (this is a discussion for another time).

Each year I could cherry pick and make a case for some weather event somewhere (isolated), will cause the arctic to set a new record minimum. If you understand how the arctic energy balance and Enthalpy of Fusion work, a weather event at lower latitudes being a catalyst for record sea ice melt is scientific fiction.

Look at the amount of reduce solar insolation over the high arctic due to the PV. Calculate the energy difference in watts / meter squared VS. the excess energy from the Pacific North West heat wave.

In the other thread (which I suggest you read) we were talking about both heat and drought and the parts of the world we were talking about have nothing to do with urban heat island (Siberia, Australia- where urban areas are confined to the immediate coast, etc.)

And I dont believe he implied that a weather event at lower latitudes would cause record sea ice melt.  His argument was that we're in a new era now and past history is not a good way to predict future outcomes.  Something that most generally agree with.

Sure, extreme weather occurs every year, but it's the magnitude of the extremes which is changing (also refer to the other thread where we discuss this.)

 

[LibertyBell]

18 hours ago, etudiant said:

Given the excursions we've just had on the West coast, I'd not be overly confident in historic trends. Clearly things can and do change on a dime

See this post here...hes just talking about being wary of applying historic trends to predict outcomes.  Nothing about a cause and effect between anomalous heatwaves and arctic sea ice.

 

[LibertyBell]

9 minutes ago, Weatherdude88 said:

Check your reading comprehension and stop embarrassing yourself.

It is clear from various sea ice metrics that the northern hemisphere cryosphere is looking more robust by the day.

This goes against your above statement. Historical trends are the best metric to predict interseason trends. This argument is made every year to no avail.

I would advise you to study the arctic energy budget and the specific heat capacity of water.

You still don't understand!  He didn't say there is a connection between one and the other!  He just said that past history isn't the best predictor of outcome!  To no avail? And yet we have a general trend towards a sea-less arctic regardless of these intermediate and short-term "gains"  It won't be in the next few years, but you can bet that it will be the case by 2050.  To deny that would be going against the vast body of scientific evidence.  Do you deny that there has been a general decrease in coverage on the scale of a few decades?

You seem to be a climate denialist, and in the year 2021, that's pretty damn embarrassing.

 

 

[bluewave]

https://theconversation.com/why-arctic-melting-will-be-erratic-in-the-short-term-35969

Why Arctic melting will be erratic in the short term

Arctic sea ice melts each summer, reaching its minimum extent sometime in September, before refreezing through the winter. Over the past 35 years, the September sea ice extent has reduced by about 35% overall and this decline is projected to continue as global temperatures increase.

In 2007 and 2012 the summer ice extent was dramatically lower, causing some some media speculation that we would soon see a summer which was “ice-free” (meaning a year with less than 1 million km² of sea-ice). 

Most climate scientists were more cautious. The weather in 2007 and 2012 was warmer than usual and the winds were particularly favourable for melting sea ice. Although human influence on Arctic sea ice has been detected, there was no evidence that these weather patterns would continue each year. 

In contrast, 2013 and 2014 had more sea ice than 2012, causing other speculation that a recovery was underway. Is this claim warranted?

The figure below shows Arctic sea ice extent (the black line) has undergone a long-term decrease, with the dashed line representing a linear trend. But there have also been shorter periods of rapid melt, no change, and apparent increases in extent during this decline – represented below by coloured trend lines for some deliberately chosen eight year periods.

 

Satellite observations of September Arctic sea ice extent. Ed Hawkins/University of Reading

The most recent eight-year period, starting from the extreme low of 2007, shows an upward trend. This does not mean that the Arctic sea ice is recovering. As with global temperature, these erratic changes are what we expect to see.

Bouncing towards an ice-free summer

Imagine a ball bouncing down a bumpy hill. Gravity will ensure that the ball will move downwards. But if the ball hits a bump at a certain angle it might move horizontally or even upwards for a time, before resuming its inevitable downward trajectory. This bouncing ball is an analogy for the changing Arctic sea ice. 

The hill represents the long-term downward trend in Arctic sea ice due to increasing global temperatures and the bumps introduce changes from this smooth trajectory. These erratic bounces could be in either direction, causing an apparent acceleration or temporary reduction in melt rate. By only examining a small part of the trajectory you might conclude that the ball was moving against gravity. A longer term view would see it as a bounce.

There is no expectation that sea ice, or any other aspect of the climate, will change smoothly over time. The climate system simply does not work that way. Previous studies have suggestedthat natural climate variations (or “bounces”) play a key role in how sea ice evolves, and suggested that some of the rapid melt in the early 2000s was a temporary acceleration.
 

A new study I co-authored with a team of Canadian and American scientists, published in Nature Climate Change, highlights that the recent slower melt is a temporary, but not unexpected, deceleration. The complex climate models used to make projections of future climate also exhibit similar periods of little change and more rapid change in Arctic sea ice. The recent trends are well within the range of these expectations. We might even see a decade or more with little apparent change in sea ice.

The causes of these fluctuations in melt rate are still being explored. One suggestion is that slow variations in Atlantic sea surface temperatures are involved. More observations of the Arctic ocean, atmosphere and sea ice would help answer this question.

An ice-free future?

When will the Arctic be ice-free – or equivalently, when will the ball reach the bottom of the hill? The IPCC concluded it was likely that the Arctic would be reliably ice-free in September by 2050, assuming high future greenhouse gas emissions (where “reliably ice-free” means five consecutive years with less than 1 million km² of sea ice).

We expect the long-term decline in Arctic sea ice to continue as global temperatures rise. There will also be further bounces, both up and down. Individual years will be ice-free sometime in the 2020s, 2030s or 2040s, depending on both future greenhouse gas emissions and these natural fluctuations. 

Even when it reaches the bottom of the hill the ball will continue to bounce. Similarly, not every future year will be ice-free in summer. But if global temperatures continue to increase the bounces will become smaller and the ice-free periods will spread from late summer into autumn and early summer. 

Commercial Arctic shipping is already increasing to exploit shorter journey times from Europe to Asia, while oil, gas & mineral extraction possibilities are being explored and Arctic tourism is growing. Decisions about such activities need to assess both the risks and opportunities. The important role of natural sea ice fluctuations needs to be considered in such assessments.

[LibertyBell]

2 hours ago, Weatherdude88 said:

In this thread we are discussing the 2021 northern hemisphere sea ice melting season.

We are analyzing this melting season. You keep rambling, deflecting, and changing the subject.

The weather event in the Pacific Northwest, is not a catalyst for some reduction in the 2021 melting season.

Will's sea ice area predictions do well, since they are based on history and data. Recent history, is the best predictor of the result for this melting season. 

Saying otherwise is a fantasy.

Stop putting words in my mouth.

 

You're being a hypocrite and putting words in my mouth, friend.  When did I or anyone else ever say that the event in the PNW was a catalyst for anything?  We just said that going back far in history is a bad idea because the climate is different.  The NWS recognizes this and has altered their methods for calculating averages, to weigh the past ten years more than previous periods in history.  So, if you want to use the past 10 years for historic trends, then fine.  But using the 50s, 60s, 70s, etc., makes no sense, this was basically a different planet back then.  Yes, recent history, as in the past 10 years.....but not going much father back in history, because again, that was a different climate.  So I take it you agree, then.

[LibertyBell]

3 minutes ago, LibertyBell said:

You're being a hypocrite and putting words in my mouth, friend.  When did I or anyone else ever say that the event in the PNW was a catalyst for anything?  We just said that going back far in history is a bad idea because the climate is different.  The NWS recognizes this and has altered their methods for calculating averages, to weigh the past ten years more than previous periods in history.  So, if you want to use the past 10 years for historic trends, then fine.  But using the 50s, 60s, 70s, etc., makes no sense, this was basically a different planet back then.  Yes, recent history, as in the past 10 years.....but not going much father back in history, because again, that was a different climate.  So I take it you agree, then.

Actually using any data prior to 1990 is a bad idea, so use the past 30 years, with twice the weighed average applied to the last 10 years for a fuller picture.

[LibertyBell]

2 hours ago, bluewave said:

https://theconversation.com/why-arctic-melting-will-be-erratic-in-the-short-term-35969

Why Arctic melting will be erratic in the short term

Arctic sea ice melts each summer, reaching its minimum extent sometime in September, before refreezing through the winter. Over the past 35 years, the September sea ice extent has reduced by about 35% overall and this decline is projected to continue as global temperatures increase.

In 2007 and 2012 the summer ice extent was dramatically lower, causing some some media speculation that we would soon see a summer which was “ice-free” (meaning a year with less than 1 million km² of sea-ice). 

Most climate scientists were more cautious. The weather in 2007 and 2012 was warmer than usual and the winds were particularly favourable for melting sea ice. Although human influence on Arctic sea ice has been detected, there was no evidence that these weather patterns would continue each year. 

In contrast, 2013 and 2014 had more sea ice than 2012, causing other speculation that a recovery was underway. Is this claim warranted?

The figure below shows Arctic sea ice extent (the black line) has undergone a long-term decrease, with the dashed line representing a linear trend. But there have also been shorter periods of rapid melt, no change, and apparent increases in extent during this decline – represented below by coloured trend lines for some deliberately chosen eight year periods.

 

Satellite observations of September Arctic sea ice extent. Ed Hawkins/University of Reading

The most recent eight-year period, starting from the extreme low of 2007, shows an upward trend. This does not mean that the Arctic sea ice is recovering. As with global temperature, these erratic changes are what we expect to see.

Bouncing towards an ice-free summer

Imagine a ball bouncing down a bumpy hill. Gravity will ensure that the ball will move downwards. But if the ball hits a bump at a certain angle it might move horizontally or even upwards for a time, before resuming its inevitable downward trajectory. This bouncing ball is an analogy for the changing Arctic sea ice. 

The hill represents the long-term downward trend in Arctic sea ice due to increasing global temperatures and the bumps introduce changes from this smooth trajectory. These erratic bounces could be in either direction, causing an apparent acceleration or temporary reduction in melt rate. By only examining a small part of the trajectory you might conclude that the ball was moving against gravity. A longer term view would see it as a bounce.

There is no expectation that sea ice, or any other aspect of the climate, will change smoothly over time. The climate system simply does not work that way. Previous studies have suggestedthat natural climate variations (or “bounces”) play a key role in how sea ice evolves, and suggested that some of the rapid melt in the early 2000s was a temporary acceleration.
 

A new study I co-authored with a team of Canadian and American scientists, published in Nature Climate Change, highlights that the recent slower melt is a temporary, but not unexpected, deceleration. The complex climate models used to make projections of future climate also exhibit similar periods of little change and more rapid change in Arctic sea ice. The recent trends are well within the range of these expectations. We might even see a decade or more with little apparent change in sea ice.

The causes of these fluctuations in melt rate are still being explored. One suggestion is that slow variations in Atlantic sea surface temperatures are involved. More observations of the Arctic ocean, atmosphere and sea ice would help answer this question.

An ice-free future?

When will the Arctic be ice-free – or equivalently, when will the ball reach the bottom of the hill? The IPCC concluded it was likely that the Arctic would be reliably ice-free in September by 2050, assuming high future greenhouse gas emissions (where “reliably ice-free” means five consecutive years with less than 1 million km² of sea ice).

We expect the long-term decline in Arctic sea ice to continue as global temperatures rise. There will also be further bounces, both up and down. Individual years will be ice-free sometime in the 2020s, 2030s or 2040s, depending on both future greenhouse gas emissions and these natural fluctuations. 

Even when it reaches the bottom of the hill the ball will continue to bounce. Similarly, not every future year will be ice-free in summer. But if global temperatures continue to increase the bounces will become smaller and the ice-free periods will spread from late summer into autumn and early summer. 

Commercial Arctic shipping is already increasing to exploit shorter journey times from Europe to Asia, while oil, gas & mineral extraction possibilities are being explored and Arctic tourism is growing. Decisions about such activities need to assess both the risks and opportunities. The important role of natural sea ice fluctuations needs to be considered in such assessments.

Sounds like 2050 is a good estimate.

An ice-free future?

When will the Arctic be ice-free – or equivalently, when will the ball reach the bottom of the hill? The IPCC concluded it was likely that the Arctic would be reliably ice-free in September by 2050, assuming high future greenhouse gas emissions (where “reliably ice-free” means five consecutive years with less than 1 million km² of sea ice).

[LibertyBell]

5 minutes ago, Weatherdude88 said:

You have accurate satellite data of the Arctic from the 50's, 60's, and 70's (before 1979) .

 

Let me guess? It is in square miles 

 

This just made my day 

 

No one ever made an argument for using the oldest data for this seasons final sea ice metric predictions. This is why I brought up Will's NSIDC sea ice area analysis which is based of recent history, and not random weather events at lower latitudes. Additionally, the initial debate was about isolated weather events at lower latitudes, causing the recent historical trends to deviate with respect to the current melting season. This is science fiction.

I just gave an example of data from the past we shouldn't be using lmao.  I only included the 50s because I was going by thirty year periods, which is what the NWS uses to calculate averages of temperatures.  So let's just say nothing before 1990 should be used and not because of satellite data, but because we live in a different climate.  Being from Texas i expect you to be a brainwashed flatlander, and expect nothing more of you except denialism.

[ORH_wxman]

We need winter temps to warm more to get to reliably ice free summers. Right now we are kind of in a new equilibrium where most of the ice is first year ice but the winters are still cold enough to freeze the first year ice to near it's maximum thickness (around 2m). We've been flat on volume since 2010. The minimums are mostly dependent on weather...specifically May and June weather which iswhy we can forecast the area mins somewhat accurately at this point.

We saw some extremely warm winters in the 2014-2018 time frame, but the most recent 3 winters since 2019 have sort of reverted to the late 2000s baseline. We'll have to see if we see them spike back up.

[LibertyBell]

1 minute ago, ORH_wxman said:

We need winter temps to warm more to get to reliably ice free summers. Right now we are kind of in a new equilibrium where most of the ice is first year ice but the winters are still cold enough to freeze the first year ice to near it's maximum thickness (around 2m). We've been flat on volume since 2010. The minimums are mostly dependent on weather...specifically May and June weather which iswhy we can forecast the area mins somewhat accurately at this point.

We saw some extremely warm winters in the 2014-2018 time frame, but the most recent 3 winters since 2019 have sort of reverted to the late 2000s baseline. We'll have to see if we see them spike back up.

That makes sense (the new equilibrium) because new ice (first year ice) is the one which is most variable.  Did the historic heat in Siberia last year have any influence on that, Will?  There was a six month period in Siberia where the temps were +20 F above average and wildfires were happening there (and 100 degrees was recorded.)

[ORH_wxman]

1 minute ago, LibertyBell said:

That makes sense (the new equilibrium) because new ice (first year ice) is the one which is most variable.  Did the historic heat in Siberia last year have any influence on that, Will?  There was a six month period in Siberia where the temps were +20 F above average and wildfires were happening there (and 100 degrees was recorded.)

The warmth in Siberia probably will have the largest effect on the Laptev and East Siberian sea ice....because the snow cover there in northern Siberia melted out earlier this year and that helps push warmer air closer to the ocean.

IF we were having a warmer year on the other side of the arctic where the Beaufort and Chukchi are, then we might have had a chance at a new record, but those seas are lagging way behind on the melt this season which will prevent a new record unless something really crazy happens.

 

If we look at the average temps (listed below) in the arctic basin (north of 70N) in the Dec-Mar time frame, we see how warm it was for some of those seasons between 2014-2018 when we were really lagging on the refreezing in the Chukchi. But the last 3 winters have cooled back closer to the late 2000s baseline. The question is whether we spike back up quickly to the 2014-2018 levels or if it takes another decade or two to consistently get there again. The arctic can be notoriously volatile on temp swings.

2000  -18.706
2001  -19.469
2002  -18.780
2003  -19.126
2004  -19.802
2005  -17.880
2006  -17.321
2007  -18.124
2008  -18.628
2009  -18.553
2010  -17.506
2011  -17.678
2012  -17.581
2013  -18.566
2014  -16.554
2015  -18.181
2016  -15.655
2017  -17.128
2018  -16.510
2019  -17.756
2020  -18.734
2021  -18.239

[LibertyBell]

2 minutes ago, ORH_wxman said:

The warmth in Siberia probably will have the largest effect on the Laptev and East Siberian sea ice....because the snow cover there in northern Siberia melted out earlier this year and that helps push warmer air closer to the ocean.

IF we were having a warmer year on the other side of the arctic where the Beaufort and Chukchi are, then we might have had a chance at a new record, but those seas are lagging way behind on the melt this season which will prevent a new record unless something really crazy happens.

 

If we look at the average temps (listed below) in the arctic basin (north of 70N) in the Dec-Mar time frame, we see how warm it was for some of those seasons between 2014-2018 when we were really lagging on the refreezing in the Chukchi. But the last 3 winters have cooled back closer to the late 2000s baseline. The question is whether we spike back up quickly to the 2014-2018 levels or if it takes another decade or two to consistently get there again. The arctic can be notoriously volatile on temp swings.

2000  -18.706
2001  -19.469
2002  -18.780
2003  -19.126
2004  -19.802
2005  -17.880
2006  -17.321
2007  -18.124
2008  -18.628
2009  -18.553
2010  -17.506
2011  -17.678
2012  -17.581
2013  -18.566
2014  -16.554
2015  -18.181
2016  -15.655
2017  -17.128
2018  -16.510
2019  -17.756
2020  -18.734
2021  -18.239

I remember those 2014-18 years, Alaska was setting heat longevity records in those years, especially the last couple in that dataset.  Was it Anchorage that had a record streak of 80+ days?  5 I think.

[bluewave]

This new winter negative feedback may be another reason why the 2012 record has held on.

 

It is important to stress that in the above analysis we are discussing winter ice growth, not the end of winter thickness

 

https://www.nasa.gov/feature/goddard/2018/wintertime-arctic-sea-ice-growth-slows-long-term-decline-nasa

New NASA research has found that increases in the rate at which Arctic sea ice grows in the winter may have partially slowed down the decline of the Arctic sea ice cover.

 

As temperatures in the Arctic have warmed at double the pace of the rest of the planet, the expanse of frozen seawater that blankets the Arctic Ocean and neighboring seas has shrunk and thinned over the past three decades. The end-of-summer Arctic sea ice extent has almost halved since the early 1980s. A recent NASA study found that since 1958, the Arctic sea ice cover has lost on average around two-thirds of its thickness and now 70 percent of the sea ice cap is made of seasonal ice, or ice that forms and melts within a single year.

But at the same time that sea ice is vanishing quicker than it has ever been observed in the satellite record, it is also thickening at a faster rate during winter. This increase in growth rate might last for decades, a new study accepted for publication in Geophysical Research Letters found.

 

This does not mean that the ice cover is recovering, though. Just delaying its demise.

 

"This increase in the amount of sea ice growing in winter doesn’t overcome the large increase in melting we've observed in recent decades," said Alek Petty, a sea ice scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and lead author of the study. "Overall, thickness is decreasing. Arctic sea ice is still very much in decline across all seasons and is projected to continue its decline over the coming decades. "

 

Petty and his team used climate models and observations of sea ice thickness from the European Space Agency’s CryoSat-2 satellite to explore sea ice growth variability across the Arctic. The climate model results compared well both with CryoSat-2’s measurements and the results of another commonly used Arctic sea ice model, giving the authors confidence in the climate model’s ability to capture Arctic sea ice variability.

 

"The global climate model seems to do a good job of capturing the Arctic sea ice state and shows that most of the thickness change in the central Arctic is from thermodynamics, that is, ice formation and ice melt, although around the Arctic sea ice edge dynamics, which is ice transport, can play a bigger role," Petty said.

 

These model simulations showed that in the 1980s, when Arctic sea ice was on average 6.6 feet thick in October, about 3.3 extra feet of ice would form over the winter. That rate of growth has increased and may continue to do so for several more decades in some regions of the Arctic; in the coming decades, we could have an ice pack that would on average be only around 3.3 feet thick in October, but could experience up to 5 feet of ice growth over the winter.

 

It seems counterintuitive: how does a weakening ice cover manage to grow at a faster rate during the winter than it did when the Arctic was colder and the ice was thicker and stronger? 

 

"Our findings highlight some resilience of the Arctic sea ice cover," Petty said. "If we didn't have this negative feedback, the ice would be declining even faster than it currently is. Unfortunately, the positive feedback loop of summer ice melt and increased solar absorption associated with summer ice melting still appears to be dominant and continue to drive overall sea ice declines."

 

Nonetheless, the increased rate of sea ice thickening in winter has other implications. As ice forms at the ocean surface, it releases a lot of the salty and dense water from which it originated, which sinks and increases the mixing of waters in the upper ocean. The more ice formation that takes place, the more mixing we expect to see in the upper ocean. Increases in this ice formation and mixing during winter may help mitigate the strong freshening of the Arctic Ocean’s surface waters that has been observed in recent decades due to increased summer melt.

 

"This is altering the seasonal balance and the salinity distribution of the upper ocean in the Arctic; it's changing when we have fresh water, when we have salty water and how deep and seasonal that upper oceanic mixed layer is," Petty said. "And that's all going to mean that local micro-organisms and ecosystems have to adapt to these rapidly evolving conditions."

 

Petty’s projections found that, by the middle of the century, the strong increases in atmospheric and oceanic temperatures will outweigh the mechanism that allows ice to regrow faster, and the Arctic sea ice cover will decline further. The study predicted that the switch will happen once the sea ice is less than 1.6 feet thick at the beginning of winter, or its concentration –the percentage of an area that is covered in sea ice– is less than 50 percent.

"This negative feedback mechanism increasing ice growth is unlikely to be sufficient in preventing an ice-free Arctic this century," Petty and his colleagues concluded.

Petty’s study was carried out in collaboration with scientists from the National Center for Atmospheric Research in Boulder, Colorado, with additional funding provided by the National Science Foundation's Office of Polar Programs

For more information: 

 

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018GL079223

[LoboLeader1]

Antarctica hit record high temp in 2020

https://thehill.com/policy/equilibrium-sustainability/561463-antarctica-hit-record-high-temperature-in-2020-scientists

[bluewave]

1 hour ago, LoboLeader1 said:

Antarctica hit record high temp in 2020

https://thehill.com/policy/equilibrium-sustainability/561463-antarctica-hit-record-high-temperature-in-2020-scientists

Recent studies have identified +2 C of global warming as a critical threshold for the Arctic and Antarctic.

https://www.nature.com/articles/s41558-018-0127-8?WT.feed_name=subjects_climate-and-earth-system-modelling

Arctic sea ice has declined rapidly with increasing global temperatures. However, it is largely unknown how Arctic summer sea-ice impacts would vary under the 1.5 °C Paris target compared to scenarios with greater warming. Using the Community Earth System Model, I show that constraining warming to 1.5 °C rather than 2.0 °C reduces the probability of any summer ice-free conditions by 2100 from 100% to 30%. It also reduces the late-century probability of an ice cover below the 2012 record minimum from 98% to 55%. For warming above 2 °C, frequent ice-free conditions can be expected, potentially for several months per year. Although sea-ice loss is generally reversible for decreasing temperatures, sea ice will only recover to current conditions if atmospheric CO₂ is reduced below present-day concentrations. Due to model biases, these results provide a lower bound on summer sea-ice impacts, but clearly demonstrate the benefits of constraining warming to 1.5 °C.

https://theconversation.com/antarctica-is-headed-for-a-climate-tipping-point-by-2060-with-catastrophic-melting-if-carbon-emissions-arent-cut-quickly-160978
 

The new study shows that if emissions continue at their current pace, by about 2060 the Antarctic ice sheet will have crossed a critical threshold and committed the world to sea level rise that is not reversible on human timescales. Pulling carbon dioxide out of the air at that point won’t stop the ice loss, it shows, and by 2100, sea level could be rising more than 10 times faster than today. 

The tipping point

Antarctica has several protective ice shelves that fan out into the ocean ahead of the continent’s constantly flowing glaciers, slowing the land-based glaciers’ flow to the sea. But those shelves can thin and break up as warmer water moves in under them. 

As ice shelves break up, that can expose towering ice cliffs that may not be able to stand on their own. 

There are two potential instabilities at this point. Parts of the Antarctic ice sheet are grounded below sea level on bedrock that slopes inward toward the center of the continent, so warming ocean water can eat around their lower edges, destabilizing them and causing them to retreat downslope rapidly. Above the water, surface melting and rain can open fractures in the ice. 

When the ice cliffs get too tall to support themselves, they can collapse catastrophically, accelerating the rate of ice flow to the ocean.

The study used computer modeling based on the physics of ice sheets and found that above 2 C (3.6 F) of warming, Antarctica will see a sharp jump in ice loss, triggered by the rapid loss of ice through the massive Thwaites Glacier. This glacier drains an area the size of Florida or Britain and is the focus of intense study by U.S. and U.K. scientists. 

To put this in context, the planet is on track to exceed 2 C warming under countries’ current policies. 

Other projections don’t account for ice cliff instability and generally arrive at lower estimates for the rate of sea level rise. While much of the press coverage that followed the new paper’s release focused on differences between these two approaches, both reach the same fundamental conclusions: The magnitude of sea level rise can be drastically reduced by meeting the Paris Agreement targets, and physical instabilities in the Antarctic ice sheet can lead to rapid acceleration in sea level rise. 

The disaster doesn’t stop in 2100

The new study, led by Robert DeConto, David Pollard and Richard Alley, is one of the few that looks beyond this century. One of us is a co-author. 

It shows that if today’s high emissions continued unabated through 2100, sea level rise would explode, exceeding 2.3 inches (6 cm) per year by 2150. By 2300, sea level would be 10 times higher than it is expected to be if countries meet the Paris Agreement goals. A warmer and softer ice sheet and a warming ocean holding its heat for centuries all prevent refreezing of Antarctica’s protective ice shelves, leading to a very different world.

 

[LibertyBell]

On 7/4/2021 at 9:23 AM, bluewave said:

Recent studies have identified +2 C of global warming as a critical threshold for the Arctic and Antarctic.

https://www.nature.com/articles/s41558-018-0127-8?WT.feed_name=subjects_climate-and-earth-system-modelling

Arctic sea ice has declined rapidly with increasing global temperatures. However, it is largely unknown how Arctic summer sea-ice impacts would vary under the 1.5 °C Paris target compared to scenarios with greater warming. Using the Community Earth System Model, I show that constraining warming to 1.5 °C rather than 2.0 °C reduces the probability of any summer ice-free conditions by 2100 from 100% to 30%. It also reduces the late-century probability of an ice cover below the 2012 record minimum from 98% to 55%. For warming above 2 °C, frequent ice-free conditions can be expected, potentially for several months per year. Although sea-ice loss is generally reversible for decreasing temperatures, sea ice will only recover to current conditions if atmospheric CO₂ is reduced below present-day concentrations. Due to model biases, these results provide a lower bound on summer sea-ice impacts, but clearly demonstrate the benefits of constraining warming to 1.5 °C.

https://theconversation.com/antarctica-is-headed-for-a-climate-tipping-point-by-2060-with-catastrophic-melting-if-carbon-emissions-arent-cut-quickly-160978
 

The new study shows that if emissions continue at their current pace, by about 2060 the Antarctic ice sheet will have crossed a critical threshold and committed the world to sea level rise that is not reversible on human timescales. Pulling carbon dioxide out of the air at that point won’t stop the ice loss, it shows, and by 2100, sea level could be rising more than 10 times faster than today. 

The tipping point

Antarctica has several protective ice shelves that fan out into the ocean ahead of the continent’s constantly flowing glaciers, slowing the land-based glaciers’ flow to the sea. But those shelves can thin and break up as warmer water moves in under them. 

As ice shelves break up, that can expose towering ice cliffs that may not be able to stand on their own. 

There are two potential instabilities at this point. Parts of the Antarctic ice sheet are grounded below sea level on bedrock that slopes inward toward the center of the continent, so warming ocean water can eat around their lower edges, destabilizing them and causing them to retreat downslope rapidly. Above the water, surface melting and rain can open fractures in the ice. 

When the ice cliffs get too tall to support themselves, they can collapse catastrophically, accelerating the rate of ice flow to the ocean.

The study used computer modeling based on the physics of ice sheets and found that above 2 C (3.6 F) of warming, Antarctica will see a sharp jump in ice loss, triggered by the rapid loss of ice through the massive Thwaites Glacier. This glacier drains an area the size of Florida or Britain and is the focus of intense study by U.S. and U.K. scientists. 

To put this in context, the planet is on track to exceed 2 C warming under countries’ current policies. 

Other projections don’t account for ice cliff instability and generally arrive at lower estimates for the rate of sea level rise. While much of the press coverage that followed the new paper’s release focused on differences between these two approaches, both reach the same fundamental conclusions: The magnitude of sea level rise can be drastically reduced by meeting the Paris Agreement targets, and physical instabilities in the Antarctic ice sheet can lead to rapid acceleration in sea level rise. 

The disaster doesn’t stop in 2100

The new study, led by Robert DeConto, David Pollard and Richard Alley, is one of the few that looks beyond this century. One of us is a co-author. 

It shows that if today’s high emissions continued unabated through 2100, sea level rise would explode, exceeding 2.3 inches (6 cm) per year by 2150. By 2300, sea level would be 10 times higher than it is expected to be if countries meet the Paris Agreement goals. A warmer and softer ice sheet and a warming ocean holding its heat for centuries all prevent refreezing of Antarctica’s protective ice shelves, leading to a very different world.

 

So 2060 is D Day for the planet to free itself from the plague virus that is humanity eh?

 

Question....so it turns out that curbing emissions wont stop this existential threat from becoming reality by the time we reach the +2 C tipping point?

[csnavywx]

Might be faster if we don't figure out why CH4 seems to be taking off again over the last 10-15 yrs (and subsequently stop it). It rose 15 ppb last year and we might beat that this year. That's going to significantly bolster warming at those rates. I don't think any of AR5's scenarios -- aside from RCP 8.5 -- had it rising like this. (RCP 8.5 had 1923ppb for 2020 actual, and we were at 1880ish; no other scenario is as high as current until after 2040).

[forkyfork]

On 7/2/2021 at 11:24 AM, Weatherdude88 said:

Check your reading comprehension and stop embarrassing yourself.

It is clear from various sea ice metrics that the northern hemisphere cryosphere is looking more robust by the day.

 

[bluewave]

Very unusual to get such a low a mid-July extent with a strong reverse dipole.This used to be a cold regime that was great for sea ice retention. But the NSIDC noted how its been warmer than expected for a strong low pressure pattern. 

https://nsidc.org/arcticseaicenews/

Unusually strong low pressure (up to 10 hPa below average) near the North Pole dominated the average atmospheric circulation pattern for June

Air temperatures near strong low pressure areas over the Arctic Ocean have historically been associated with relatively cool conditions. However, June temperatures in the vicinity of the low-pressure pattern were near the long-term average.

 

[so_whats_happening]

The rapid retreat of snow over land has been a killer for ice even in retention years. So even as we see this year being a rather ok year its struggling hard with the heat having very little barrier from land to ice. The albedo is struggling right now and that is a huge issue.

The system is trying to figure out the new balance so im curious where it lands us. We may have an idea but we may not know the end result until its happening, such a shame.

[csnavywx]

23 hours ago, bluewave said:

Very unusual to get such a low a mid-July extent with a strong reverse dipole.This used to be a cold regime that was great for sea ice retention. But the NSIDC noted how its been warmer than expected for a strong low pressure pattern. 

https://nsidc.org/arcticseaicenews/

Unusually strong low pressure (up to 10 hPa below average) near the North Pole dominated the average atmospheric circulation pattern for June

Air temperatures near strong low pressure areas over the Arctic Ocean have historically been associated with relatively cool conditions. However, June temperatures in the vicinity of the low-pressure pattern were near the long-term average.

 

Combined with winter temps, that'll end up being the kill-shot in the long run (few decades). Easy to forget that diabatic processes only go so far during the summer. If you keep mixing in much-above normal airmasses into an otherwise favorable ice-retention pattern, the lower limit is raised and the window shifts towards melting, even in good patterns. We may yet stay in this "transitional plateau" for a while longer but the creeping risk of a rapid collapse will eventually catch up as winter freezing degree days drop below a critical threshold and summer T-min increases during low pressure regimes, narrowing the stable space upon which the current pack is balanced. My eye is on the mid-2030s for something like that.

[bluewave]

27 minutes ago, csnavywx said:

Combined with winter temps, that'll end up being the kill-shot in the long run (few decades). Easy to forget that diabatic processes only go so far during the summer. If you keep mixing in much-above normal airmasses into an otherwise favorable ice-retention pattern, the lower limit is raised and the window shifts towards melting, even in good patterns. We may yet stay in this "transitional plateau" for a while longer but the creeping risk of a rapid collapse will eventually catch up as winter freezing degree days drop below a critical threshold and summer T-min increases during low pressure regimes, narrowing the stable space upon which the current pack is balanced. My eye is on the mid-2030s for something like that.

The big story is how much lower the sea ice extent is on this date than in 2013. That was the last time we had Arctic pressures nearly as low as this season so far. But as I noted in an earlier post, this season is much warmer on several fronts than 2013. The average pressure is the lowest since before the big 2007 shift.

 

1991  995.748
1992  993.569
1993  997.705
1994  989.170
1995  993.511
1996  993.554
1997  997.323
1998  999.264
1999  989.996
2000  991.390
2001  994.393
2002  991.603
2003  995.133
2004  998.124
2005  998.190
2006  989.570
2007  998.159
2008  995.824
2009  998.525
2010  996.097
2011  998.625
2012  996.246
2013  990.278
2014  997.406
2015  993.244
2016  992.118
2017  992.755
2018  992.805
2019  997.164
2020  992.695
2021  988.088