Dramatic Slowdown in Melting of Arctic Sea Ice Surprises Scientists (theguardian.com) 68
The melting of sea ice in the Arctic has slowed dramatically in the past 20 years, scientists have reported, with no statistically significant decline in its extent since 2005. From a report: The finding is surprising, the researchers say, given that carbon emissions from fossil fuel burning have continued to rise and trap ever more heat over that time. They said natural variations in ocean currents that limit ice melting had probably balanced out the continuing rise in global temperatures. However, they said this was only a temporary reprieve and melting was highly likely to start again at about double the long-term rate at some point in the next five to 10 years.
The findings do not mean Arctic sea ice is rebounding. Sea ice area in September, when it reaches its annual minimum, has halved since 1979, when satellite measurements began. The climate crisis remains "unequivocally real," the scientists said, and the need for urgent action to avoid the worst impacts remains unchanged. The natural variation causing the slowdown is probably the multi-decadal fluctuations in currents in the Atlantic and Pacific oceans, which change the amount of warmed water flowing into the Arctic. The Arctic is still expected to see ice-free conditions later in the century, harming people and wildlife in the region and boosting global heating by exposing the dark, heat-absorbing ocean.
The findings do not mean Arctic sea ice is rebounding. Sea ice area in September, when it reaches its annual minimum, has halved since 1979, when satellite measurements began. The climate crisis remains "unequivocally real," the scientists said, and the need for urgent action to avoid the worst impacts remains unchanged. The natural variation causing the slowdown is probably the multi-decadal fluctuations in currents in the Atlantic and Pacific oceans, which change the amount of warmed water flowing into the Arctic. The Arctic is still expected to see ice-free conditions later in the century, harming people and wildlife in the region and boosting global heating by exposing the dark, heat-absorbing ocean.
nuclear winter (Score:2)
cold day in hell
Hmmm, not immediately obvious from the paper (Score:5, Interesting)
Where's Tamino when you need him?
I've not read the paper, just scanned it for keywords but my first glance doesn't fill me with confidence that the headline matches the results.
They say that there's a decline for the last two decades 2005-2024 and that that's statistically indistinguishable from zero. Fair enough. But it's clearly also statistically indistinguishable from a larger decline.
So it's not completely obvious to me that there's been a change in the rate of sea level decline, just that the earlier decades might have been a bit high and regression to the mean giving a smaller rate of decline than statistics says is happening.
Need some change point analysis to tell if there's anything significant happening and I couldn't see anything in the article that suggested that this had been done.
Re:Hmmm, not immediately obvious from the paper (Score:4, Informative)
Hold on there, grasshopper. check https://climate.nasa.gov/vital... [nasa.gov]. Since you cannot be arsed to even do the minimal in Google-Foo, I'll repeat some of that page here:
Arctic sea ice reaches its minimum extent (the area in which satellite sensors show individual pixels to be at least 15% covered in ice) each September. September Arctic sea ice is now shrinking at a rate of 12.2% per decade, compared to its average extent during the period from 1981 to 2010.
Re:Hmmm, not immediately obvious from the paper (Score:4, Informative)
Sorry, but I don't know what point you're trying to make. Your kind link to climate.nasa.gov doesn't tell me anything I didn't already know.
The headline says "Dramatic Slowdown in Melting of Arctic Sea Ice Surprises Scientists", but I cannot see anything in the paper that suggests that there's actually a statistically significant slow down at all nor that it has surprised scientists.
The title of the paper is:
Minimal Arctic Sea Ice Loss in the Last 20 Years, Consistent With Internal Climate Variability
In my skim of the paper I saw:
The trend of September Arctic sea ice extent for the most recent two decades 2005â"2024 is â'0.35 and â'0.29 million per decade according to the NSIDC and OSISAF sea ice indices respectively (Figures 1a and 1b). The key point, we emphasize, is that these trends are not statistically significantly different from zero at a 95% confidence level.
So, unless there's something in the paper that I've missed, I'm not convinced that they've established that there's a pause at all. And the title of their letter even implies it! At best they have established that there might be a pause and that the measured *decline* over the last two decades is due to natural variability.
We need change point analysis to establish if there's been a statistically significant change in the rate of sea ice melting over the last two decades compared to the previous 2 1/2
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In the middle of TFA, there is a graph that shows exactly what the headline reports. Sea ice decreased until 2010, and since then there is no clear trend.
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No it doesn't show that. Definitely not by eye.
You do NOT see a change in trend by drawing a line between points A to B and B to C and declare that implies there's no trend in sea ice decline over the last 20 years.
You have to show that there's no possible trend from A to C that is consistent with the trends from A to B and B to C. (You also can't have a discontinuity at B which is another thing that doing it by eye can mislead)
My by eye look suggests that there's no significant change in change over the sa
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I'm failing to see what you're seeing. As I quoted above:
In my skim of the paper I saw:
The trend of September Arctic sea ice extent for the most recent two decades 2005Ã"2024 is Ã'0.35 and Ã'0.29 million per decade according to the NSIDC and OSISAF sea ice indices respectively (Figures 1a and 1b). The key point, we emphasize, is that these trends are not statistically significantly different from zero at a 95% confidence level.
But in case you missed it, let me quote the entire paragraph:
The m
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dont bother trying to discuss - you can tell from the tone neither of the previous repliers what to help, they just want to be right.
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Clearly here they're looking at the 2005-2024 range. There's nothing fundamentally wrong with doing that
Yes, now you got it.
They are looking at a short term trend. There is nothing wrong with that. It's helpful to try to understand short term trends.
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I've always got it. But you still haven't got it.
Their null hypothesis is that there's no trend, and picking a very short timescale they discover they cannot reject it. Woopie doo. Pick a short enough time scale and that is always going to be true unless there's no random variability at all.
So we first need to pick a reasonable null hypothesis. One reasonable null hypothesis is that there's been no change in trend in the entire satellite record and we find we cannot reject that either. And in my books, a 45
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Ouch. Teach me to not proof read carefully.
Of course, that 15 years plus should be from 2020, not 2012, i.e. it will be significant if the 2012 record isn't approximately matched by unexceptional melt by about 2033-2036.
Re:Hmmm, not immediately obvious from the paper (Score:5, Insightful)
Their claim is just wrong. Look at the actual data [statista.com]. There were three years of anomalously low sea ice in 2005-2007. Aside from those three years, the trend is completely clear and hasn't changed at all. So of course you pick 2005 as your starting point if you want to claim it's stopped decreasing.
It's the same way denialists claimed for years that global warming had stopped by choosing 1998 as their starting point. It was an exceptionally warm year, so they cherry picked it as the starting point to claim the planet had stopped warming.
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I recall a conversation I had on global warming and I started with the temperature records since 1850, or somewhere around then. That immediately got the reaction on why I picked that date. I picked that date because that's when we first had good records on temperature in the USA. That also happens to be about the time human civilization was shifting from power derived from windmills, water wheels, and burning wood to using coal and petroleum. Natural gas would not come along until about a century later. I thought I had good enough reasons to start with 1850-ish, I had no intent to deceive or put my thumb on the scale, I just wanted to establish some agreement on the scale of the problem.
That is most inconvenient for a lot of doomers, but I find the 1850s to be a good starting point as well. https://www.woodfortrees.org/p... [woodfortrees.org]
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Well, that's EXACTLY what they're saying. That - since 2005ish, there hasn't been a trend.
If you disregard pre-2005 as they state, no, it really doesn't look like there's a trend either way.
And if that was the start of a flatline, that wouldn't be "anomalously low" would it? They are literally saying "hey this is weird considering the previous trend" like you are, but with a little less emotion.
As far as cherry picking, I'm not sure Global Warming-ists(?) are exactly spotless, fwiw.
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You clearly didn't look at the graph. Look at it and it will be obvious what I meant.
If you pick 2008 as your starting point, you see a clear trend. Same if you pick 2009, 2010, 2011... Same if you pick an earlier year, say 2000, or 2001, or 2002. Basically if you pick any year other than 2005-2007 as your starting point, you see a clear trend. Out of all possible years you could pick, there are a whole lot that show a clear trend and just a few that don't. That's what cherry picking means. Out of al
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The is from the GUARDIAN.
Not exactly a bastion of conservatism.
Have you gone so far left that you seriously believe the Guardian is shilling for the right now?
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Re: And remember, folks... (Score:2)
Aeroplane contrails, large seas of asphalt, pollution, we've been doing large scale geoengineering for over a 100 years now
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Aeroplane contrails, large seas of asphalt, pollution, we've been doing large scale geoengineering for over a 100 years now
Side-effects of actions done for other purposes doesn't fit the usual definition of "engineering."
If it does, you should put "adding carbon dioxide and methane to the atmosphere" to the list of "geoengineering."
Re: You mean, killing off stupid species? (Score:3)
AND eating them.
Yummy, yummy stupid species.
Re:It's almost as if the Climate... is Changing (Score:5, Insightful)
Sigh. That's not at all what they said. If there was any nefarious "agenda" at play "they" (whoever the fuck "they" are in the minds of climate change conspiracists) wouldn't even be publishing data like this since smoothed brain folk like you will take the shallowest of positions on the observation to refute the underlying science.
Re:It's almost as if the Climate... is Changing (Score:5, Insightful)
Wouldn't it be better to make it change at the natural rate instead of the man-made rate it is changing now?
Indeed (Score:3)
And it doesn't give a fuck about us. In the Cretacious it is believed the daytime temp rose to 60-70C in some places inland, totally inhospitable for any life alive today apart from some bacteria. If we don't reduce our emissions we're heading back to that but hey, you carry on being blase about a large proportion of the continents being uninhabitable.
Re:It's almost as if the Climate... is Changing (Score:4, Informative)
Earth has been doing its thing for billions of years. It will continue to do so.
That is not and has never been a point of contention.
The question is what Earth doing its thing, when the cycles of climate are perturbed by our activity, will do to us.
Re:It's almost as if the Climate... is Changing (Score:4, Informative)
You are 100% correct that the Earth will continue to, as you say, 'do it's thing.'
The problem is, 'it's thing' might include 'no longer being habitable by humans,' and that's going to be a bit of an inconvenience for us.
Whoa! Whoa! Whoa! (Score:2, Interesting)
no statistically significant decline in its extent since 2005.
For the entirety of that 20 year period I have be told, persistently and with increasing urgency and shrillness, the exact opposite of that line.
For 20 years it has been 'melting at alarming rates. Melt rates accelerating! Sea ice extent SHRINKING! All time lows. Northwest passage could be completely ice free by next year....'
So how does this come out of left field in 2025? And how am I reading it in the Guardian of all places?
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Yeah Al Gore promised us a hockey stick shaped curve dam it!
Re:Whoa! Whoa! Whoa! (Score:5, Insightful)
no statistically significant decline in its extent since 2005.
For the entirety of that 20 year period I have be told, persistently and with increasing urgency and shrillness, the exact opposite of that line.
Looking at the graph [nasa.gov], there's considerable variation from year to year, and it's not clear if the loss of ice has actually slowed down, or if it's just statistical variation.
It really depends on how long a time period you average over.
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Well, the reason why is because news reporters aren't required to learn calculus. That chart is not a chart of the extent of sea ice, its a chart of the rate of sea ice decline. The ice is still shrinking. The ice is still at all time lows.
Ice extent graph [Re:Whoa! Whoa! Whoa!] (Score:2)
Well, the reason why is because news reporters aren't required to learn calculus. That chart is not a chart of the extent of sea ice, its a chart of the rate of sea ice decline.
Not sure what you're looking at; this graph [nasa.gov] is a chart of the minimal (September) extent of Arctic sea ice in millions of square kilometers. The rate of decline is the slope of the curve
The ice is still shrinking. The ice is still at all time lows.
The last sentence here is accurate; ignoring the year-to-year random variation, the ice is still at all-time lows.
"halved since 1979" (Score:3)
... halved since 1979...
... which was after a decade of news articles about global cooling and the coming ice age.
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No idea, neither does anyone else or they wouldn't have been telling us for 20 years how dramatically ice coverage has been dropping when it hasn't, according to this data set.
I'll bet if you looked, you would see that most of those articles were based on data from before 2017.
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“It is good to explain to people that [the slowdown] is happening, else they are going to hear it from someone who is trying to use it in bad faith as a way to undermine our very solid understanding of what’s happening with climate change.”
They were thinking of people exactly like you when they wrote that bit.
Re: (Score:2, Flamebait)
Clearly you didn't read it. They explain away why they have been wrong for twenty years, didn't know what was happening and misrepresented it. Then they state that they have "a very solid understanding" of what's happening. Clearly they didn't. Then why were your predictions so wrong? Why should you have any credibility at all?
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Those articles don't actually contradict global warming. Just that they assume no man-made influence on climate. Too simplistic is all.
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There will be people that will claim this didn't happen, that there were no concerns of a coming ice age in the 1970s.
That is not the counterargument to the claim that there was a belief among scientists that global cooling would occur. It's true that some of the media sensationalized the idea of global cooling in the 1970s. It happened again in the late 80s or early 90s sometime, which I am too lazy to go look up right now because I hate to try to wade through the Google results. I know it was around there somewhere because I (vaguely) remember it.
The easily verifiable facts of the global cooling theory is that only a sma
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Ugh, what will it take to put this to rest? Yes, global cooling was taken seriously by a handful of scientists for a brief period in the 1970s, but it was never a dominant scientific consensus like global warming is today.
During the 1960s and 1970s, some scientists observed a cooling trend in global temperatures from the 1940s to the early 1970s. This was partly due to an increase in aerosol pollution, which can reflect sunlight and cause temporary cooling. As a result, a few scientific papers and popular
Sea ice vs. Total ice (Score:2)
Aren't the glaciers draining out to sea? That's a constant influx of near freezing and frozen water settling out. I would expect things to remain in balance until that feed stops. Then when the temperature isn't held down any more we would see the impacts assert themselves in earnest.
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Mountain glaciers are a pinprick compared to the ice sheet currently melting at an accelerating rate on greenland not to mention in antartica.
/. needs a new icon (Score:2)
but but but.... (Score:1, Troll)
But but but it was "settled science."
Consider the volume (Score:2)
Like the Great Barrier Reef (Score:1)
Only makes news when it's bleaching... The last few years it's regrown at a rate faster than ever but nobody pays attention to that.