Antarctic sea ice levels dive in 'five-sigma event'
abc.net.au
abc.net.au
It occurred to me to connect it to recent unusual weather, and I found that I wasn't the first, but I don't see anything about it in news about the "crisis".
To be clear, I hadn't the least idea of whether it should result in warming or cooling, but the experts seem to be saying that an unprecedented amount of water vapor - which is a greenhouse gas - should be stuck high in the atmosphere and result in substantial additional global warming on a decade scale.
Via JPL [1]:
“In contrast, the Tonga volcano didn’t inject large amounts of aerosols into the stratosphere, and the huge amounts of water vapor from the eruption may have a small, temporary warming effect, since water vapor traps heat.”
[1] https://www.jpl.nasa.gov/news/tonga-eruption-blasted-unprece...
I think that the linked Research Letter is what I was referring to in my previous comment. I do not see anything implying I misinterpreted.
Are you suggesting that the quoted comment by the JPL author refutes or weakens my takeaway - that (1) this volcano unlike others should warm the planet, (2) it probably is having an effect already, and (3) it will probably last for several years?
Notice this, a little higher on the page:
"The excess water vapor injected by the Tonga volcano, on the other hand, could remain in the stratosphere for several years."
And of course, you can click through to the source.
"∼10% of the stratospheric burden"
That's a hell of a lot.
(2) no, unlikely to be having any effect yet
(3) maybe noticably at ground level for five years .. perhaps measurably (with sensitive instruments looking at the right things) at the tropopause and above for a bit longer.
In context "∼10% of the stratospheric burden" means that all in one hit the stratosphere got about 10% of the maximum water load it can carry (before physics makes any extra fall away).
As I understand it the stratosphere was running a bit under "normal" water load, so this rates as a top up and a bit of a push over 'normal' - the main thing that longer term models will look at is how this plays out the longer term rise and fall of water being pushed up into and sucked back out of the stratosphere through tropical storms and other such actions.
The (2) "no, not yet" is due to more lag than you might expect - it only happened 18 months ago and we are still lagging on the expected heating due to occur due to increased thermal insulation from CO2 released into the troposhere five years ago.
The key phrase from both the JPL presser release and source paper is:
The effect would dissipate when the extra water vapor cycles out of the stratosphere and would not be enough to noticeably exacerbate climate change effects.
Or not .. but that won't surface for another few years yet in anothr research paper.
>we are still lagging on the expected heating due to occur due to increased thermal insulation from CO2 released into the troposhere five years ago
I thought it's being widely reported - this year - that we seem ahead of the warming trend, breaking all sorts of records, etc.
As is mentioned in almost every article about climate change ad nauseum, global temperature increases measured in degrees are small but involve huge amounts of energy, and typically there is said to be a linkage to massive disruptions and suffering.
So saying this temporary source of warming is very small and unnoticeable seems rather equivocal. You can say it, but what is it meant to communicate?
Small and unnoticeable on your thermometer is literally true of the primary trend from CO2, but if you go around belaboring that, you sound like a denier.
A fully laden iron ore carrier 1 km in length with 100's of thousands of tonnes of mass can drift slowly toward your ore wharf and take an hour to first touch it.
The destruction of that jetty can be over in 20 minutes.
There's a lag time of 60 minutes on an event that lasts 20 minutes.
> I thought it's being widely reported - this year - that we seem ahead of the warming trend, breaking all sorts of records, etc.
Right now the global average tempreture is higher than it's been in recorded history.
This is caused by greater insulation in the atmosphere trapping heat that is normally reflected outwards in the thermal band - that insulation is greater CO2.
Here's the thing; were we to magically stop ALL CO2 emissions right now today and hold steady .. the global average tempreture would still continue to rise for many many years (smoothed over thhe usual decadal oscillations) until an equilibrium was reached .. that's the lag time.
You may be familiar with a similar lag on a cold night when you throw an extra blanket or six on the bed and you're not instantly warm .. it takes some time for your body heat to warm up the area under the blanket.
A good starting palce for all this is the heat equations - heat flows like a fluid, it takes time to travel through mediums such as metal bars, it takes to to radiate heat away, etc.
This event:
"For those of you who are interested in statistics, this is a five-sigma event. So it's five standard deviations beyond the mean. Which means that if nothing had changed, we'd expect to see a winter like this about once every 7.5 million years.
This is either:
* A very very very unusual outlier event, OR
* a clear sign that something is going on that is causing polar ocean and atmosphere to warm
( current models point toward the second case -- ie they're looking pretty accurate )
We say this is a 5-sigma event, but that's based on observations of the mean since 1979.
When you then try to extrapolate out from that and say "we expect to see this once every 7.5 million years," you have entered into a state of deep bullshit.
If the thirty year median satelite data 1981 - 2010 is the "normal state",
Then this years ice extent is more than five standard deviations (in one direction) from the mean of observed data,
and we'd expect such an event to happen once in every 7.5 million "samples".
However badly phrased the journalistic reporting of a researchr speaking casually gets there's not actual underlying intent that anything is being extrapolated forward or backward in time.
Simply the observation that most antartic sea ice extant data is tightly clumped and that this year (amd last year) represent either a very unusual event or a marked departure from "normal".
This may help visualise the data better:
https://nsidc.org/arcticseaicenews/charctic-interactive-sea-...
( click the antartic button to switch poles; the default is to grey the thrirty year normal data band and to only show last year and this year, other choices can be made by selection on the data table )