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Klondike Kat

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Re: Global Surface Air Temperatures
« Reply #1850 on: September 01, 2018, 05:56:48 PM »
I tend to agree with Wolfpack.  El Nino years tend to bring more oceanic heat to the surface, particularly at higher latitudes.  This lead to greater heat loss to the atmosphere, and eventually space.  The global average then will fall, until more heat can build up.  His plot tells it all.

gerontocrat

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Re: Global Surface Air Temperatures
« Reply #1851 on: September 12, 2018, 07:37:16 PM »
Some time ago I downloaded some GISS data on temperature change at different latitudes. So at last I've got around to looking at it. See Graph below.

The above average rise in the Arctic was not a surprise - but the Antarctic is a surprise - at least to me..
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Klondike Kat

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Re: Global Surface Air Temperatures
« Reply #1852 on: September 13, 2018, 01:44:28 PM »
Some time ago I downloaded some GISS data on temperature change at different latitudes. So at last I've got around to looking at it. See Graph below.

The above average rise in the Arctic was not a surprise - but the Antarctic is a surprise - at least to me..

It almost looks like the Antarctic is doing the opposite of the Arctic.  Any thoughts?

magnamentis

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Re: Global Surface Air Temperatures
« Reply #1853 on: September 13, 2018, 09:38:29 PM »

It almost looks like the Antarctic is doing the opposite of the Arctic.  Any thoughts?

most of that area in the antarctic is covering land and most of the same are in the arctic is covering oceans.

further the antarctic is surrounded by water only and the arctic is surrounded mostly by land, those are basically totally opposing conditions, not to forget that most of that area in the antarctic is at a certain altitude above sea-level which exposes big parts to very different weather and wind patterns.
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wili

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Re: Global Surface Air Temperatures
« Reply #1854 on: September 13, 2018, 09:46:09 PM »
In other words, they're basically polar opposites!  ;D
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wolfpack513

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Re: Global Surface Air Temperatures
« Reply #1855 on: September 19, 2018, 06:44:06 AM »
August GISS-LOTI came in at +0.77°C.  The super Niño ended in May of 2016 and the running 12-month mean has just now made it back down to the 30-year trend.  Global surface anomalies could take off any time now considering if +ENSO holds through this winter.

Sleepy

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Re: Global Surface Air Temperatures
« Reply #1856 on: September 20, 2018, 08:41:08 AM »
Article picking up on Rohde & Rahmstorf's tweets.
The five warmest months of August on our planet since record-keeping began? 2014 to 2018.
https://mashable.com/article/global-warming-august-2018-climate-change/
Omnia mirari, etiam tritissima.

Shared Humanity

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Re: Global Surface Air Temperatures
« Reply #1857 on: September 21, 2018, 02:38:16 AM »
August GISS-LOTI came in at +0.77°C.  The super Niño ended in May of 2016 and the running 12-month mean has just now made it back down to the 30-year trend.  Global surface anomalies could take off any time now considering if +ENSO holds through this winter.

In 5 years, they'll be talking about the hiatus in global warming.

wolfpack513

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Re: Global Surface Air Temperatures
« Reply #1858 on: September 21, 2018, 07:46:41 AM »
I don't disagree with you, deniers love to cherry pick.  Until the 30+ year trend starts to flatten I don't want to hear anything.  Check out the acceleration when you overlay 30, 60 & 90 year linear trends. 

Trends
90-year: 0.10 C per decade
60-year: 0.15 C per decade
30-year: 0.19 C per decade
« Last Edit: September 21, 2018, 07:51:50 AM by wolfpack513 »

oren

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Re: Global Surface Air Temperatures
« Reply #1859 on: September 21, 2018, 11:35:19 AM »
I think actual global warming began 45-50 years ago, after a lot of masking aerosols were removed from the atmosphere, and it's been pretty linear since then, with perhaps some recent acceleration. This never stopped deniers though.

mitch

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Re: Global Surface Air Temperatures
« Reply #1860 on: September 21, 2018, 05:59:26 PM »
Just wait until the 2018-2019 ENSO shows up. Right now there's another warm kelvin wave sweeping from W to E in the equatorial Pacific. Odds are 65-70% for el Niño in Dec-Jan-Feb this year.

Hautbois

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Re: Global Surface Air Temperatures
« Reply #1861 on: October 17, 2018, 07:47:28 PM »
Just to let you know I've started a blog which kicks off with a scoreboard of bets between 'warmists' and 'coolists' about global warming. Funnily enough the coolists don't seem to be doing very well.

Anyway, all are welcome to have a look, add comments etc

ohbwaa.blogspot.com .

Ned W

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Re: Global Surface Air Temperatures
« Reply #1862 on: October 17, 2018, 09:20:18 PM »
I think actual global warming began 45-50 years ago, after a lot of masking aerosols were removed from the atmosphere, and it's been pretty linear since then, with perhaps some recent acceleration. This never stopped deniers though.
I like the following approach, which I saw at David Appell's blog:

[1] People usually show "global warming as a function of time" with temperature on the Y axis and time (year AD) on the X axis.

[2] But global warming isn't caused by time.  It's caused by CO2 (and other gases). 

[3] More specifically, temperature is supposed to increase in proportion to the number of doublings of CO2 concentration (that is the definition of climate sensitivity).

[4] Therefore, it makes sense to evaluate temperature as a function of the number of doublings of CO2 concentration.

Here it is, for 1850-2017 (using temperatures from Berkeley Earth and Cowtan & Way):


And here it is for the past 50 years:


The past 50 years are certainly less noisy (and slightly steeper) but actual global warming appears to be reasonably linear going all the way back to the start of the temperature record in 1850, in direct proportion to the logarithmic increase in CO2.  Exactly as expected.

Obviously there are other forcings that play a role, too.  But it's remarkable how clear the dependence on CO2 is, and how linear it is over 167 years!

Maybe the post-1960s acceleration (compare the slopes 1850-present vs 1967-present) is due to the reduction in aerosol masking that Oren mentions.

Disclaimer: 
As mentioned above, I stole this from David Appell's blog.

Sources:
CO2 1979-present:  https://www.esrl.noaa.gov/gmd/aggi/aggi.html
CO2 up to 1979:  http://www.pik-potsdam.de/~mmalte/rcps/
Cowtan & Way:  http://www-users.york.ac.uk/~kdc3/papers/coverage2013/series.html
Berkeley Earth:  http://berkeleyearth.lbl.gov/auto/Global/Land_and_Ocean_summary.txt

Ned W

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Re: Global Surface Air Temperatures
« Reply #1863 on: October 17, 2018, 09:36:04 PM »
Just to let you know I've started a blog which kicks off with a scoreboard of bets between 'warmists' and 'coolists' about global warming. Funnily enough the coolists don't seem to be doing very well.

Anyway, all are welcome to have a look, add comments etc

ohbwaa.blogspot.com .

This is great.  Thanks for doing it.  I'm looking forward to reading the posts as you move through all the bets.

Annan and Hargreaves seem remarkably calm about being cheated out of US$10,000.  I suppose they've concluded there's nothing they can really do about it, aside from publicizing the dishonesty of their opponents in the bet.  This is brilliant:

Quote
I had hoped they would value their professional reputations as worth rather more to themselves than the sums of money involved. On the other hand a certain amount of intellectual dishonesty seems necessary in order to maintain the denialist mindset. Of course it could be argued that it's unfair to tar all denialists with the same brush, maybe I was just unlucky to come across the only two charlatans and the rest of the bunch are fine upstanding citizens who just happen to suffer from genuine misunderstandings. Who wants to bet on that?

I do wonder how much, if any, money will actually be donated to charity when Pierre Gosselin and his gang lose their bet.  Gosselin used to post sporadically about the bet, but stopped when it became obvious they were going to lose.

wolfpack513

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Re: Global Surface Air Temperatures
« Reply #1864 on: October 18, 2018, 01:29:33 AM »
September came in at +0.75 C on GISS-LOTI.   The current 30-year trend is twice that of 1958-1988.  Here's overlapping 30-years trends. 

wdmn

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Re: Global Surface Air Temperatures
« Reply #1865 on: October 18, 2018, 03:46:44 AM »
James Hansen just posted this graph a couple of days ago. Idea being that when you connect La Niña minima you get a decadal trend (for the last decade) of 0.38C.

Ned W

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Re: Global Surface Air Temperatures
« Reply #1866 on: October 18, 2018, 01:00:03 PM »
James Hansen just posted this graph a couple of days ago. Idea being that when you connect La Niña minima you get a decadal trend (for the last decade) of 0.38C.

There was talk about that in the comments at Tamino's recently.  I'm not the only person who was disappointed to see Hansen doing that.  It's the kind of cheesy amateurish thing that you'd normally see elsewhere.  Like, I remember some denialist connecting the 1998 El Nino and 2010 El Ninos in HADCRUT and saying "see, no warming".

Hansen can do better than that. 

Edit to add: Welcome to ASIF, wdmn.  Sorry about the grumpy response to your first post here...
« Last Edit: October 18, 2018, 01:06:40 PM by Ned W »

wdmn

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Re: Global Surface Air Temperatures
« Reply #1867 on: October 18, 2018, 02:10:53 PM »
Thanks, and no need to apologize Ned... that's why I posted it; to get opinions on its legitimacy. Hansen defended his move by saying La Niña minima have less variability than El Niño maxima. Between the El Niño maxima and the longer term La Niña minima fits on the graph do you think it's fair to say we're at 0.24C/decade now?


kassy

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Re: Global Surface Air Temperatures
« Reply #1868 on: October 18, 2018, 02:24:29 PM »
I think it is a good way to illustrate the point that temperature increase is accelerating. This is real and we know why - increased greenhouse gasses and ice albedo loss.

This is quite different then the denialists drawing arbitrary lines that fit the data but not the real world.


Ned W

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Re: Global Surface Air Temperatures
« Reply #1869 on: October 18, 2018, 03:30:49 PM »
As much as I respect Hansen, I mostly agree with Tamino on this.  There is not any convincing evidence for recent acceleration. 

Here's Tamino's analysis, after adjusting NASA GISTEMP for solar, volcanic, and ENSO:


He finds a single breakpoint in the mid-1970s, and writes this:

Quote from: Tamino
I’ve analyzed the adjusted data, just as I have the “as is” data, to look for any significant sign of deviation from the piecewise-linear trend (in particular, anything else we can say with confidence since about 1975). It’s not there.

https://tamino.wordpress.com/2018/10/09/the-global-warming-signal/

He calculates a trend of around 0.18 C/decade since 1970.

Here's my take on Tamino's adjusted data (monthly, not annual):


The thick orange line is a 30-year LOESS model.  It is almost perfectly linear in recent decades.  The slope since 2010 is 0.20 C/decade.  The slope since 2000 is also 0.20 C/decade. 

The thinner red line is a 10-year LOESS model.  It fluctuates more, but I think most of that is due to not fully correcting for ENSO and other internal variability.  The slope since 2010 is 0.30 C/decade (faster!) but the slope since 2000 is the same as for the 30-year LOESS (0.20 C/decade).

I think people who claim that the faster warming from ~2011 to ~2016 is "acceleration!" are deluding themselves in exactly the same way that the deniers deluded themselves about "hiatus!" in the previous decade.  It's a very short-term trend and it's not significant.

If the earth warms fast enough to force another breakpoint in Tamino's piecewise linear model, or to cause an upswing in my 30-year LOESS model, then I'll believe it.  For now, though, I'd say the underlying warming rate is somewhere around 0.20 C/decade.


Archimid

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« Last Edit: October 18, 2018, 04:37:17 PM by Archimid »
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Ned W

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Re: Global Surface Air Temperatures
« Reply #1871 on: October 18, 2018, 03:49:02 PM »
I think it is a good way to illustrate the point that temperature increase is accelerating. This is real and we know why - increased greenhouse gasses and ice albedo loss.

Greenhouse gases are "increasing" but the radiative forcing from those gases is not "accelerating":


From NOAA AGGI

Pretty much linear.

It's because, while concentrations are in fact accelerating, forcing per unit concentration decreases, and the two effects happen to cancel out almost perfectly.  (CO2 forcing is proportional to the log of concentration, and CH4 forcing is proportional to the square root of concentration).

Extremely nice animation tracking CO2, global temperatures and solar cycles

https://g.redditmedia.com/pPzUOtnlwKAIiqxqTJEAysl5qHINzR39RJa9hiBenzE.gif

Sounds nice, but for some reason it's not showing for me.   :-\

Archimid

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Re: Global Surface Air Temperatures
« Reply #1872 on: October 18, 2018, 04:37:35 PM »
Try again.
I am an energy reservoir seemingly intent on lowering entropy for self preservation.

wdmn

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Re: Global Surface Air Temperatures
« Reply #1873 on: October 18, 2018, 05:11:29 PM »
My understanding is that those asserting there has been an acceleration are explaining it as a result of positive feedback from the loss of arctic albedo. Certainly that is the position that Dr. Wadhams takes.

Ned W

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Re: Global Surface Air Temperatures
« Reply #1874 on: October 18, 2018, 05:19:06 PM »
Try again.

Thanks.  The new link works for me.  That's very well done.  I think I've mentioned that I dislike animations, but this one is rather good.

I can't get enough of watching the last 30 years, when temperature and CO2 are moving in lockstep while solar goes in exactly the opposite direction.  It nicely demolishes the (stupid) denialist claim that "it's the sun!".

AbruptSLR

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Re: Global Surface Air Temperatures
« Reply #1875 on: October 18, 2018, 06:16:26 PM »
..
Greenhouse gases are "increasing" but the radiative forcing from those gases is not "accelerating":

Of course aerosols feed directly into (negative) radiative forcing, so as we clear-up our air quality this would increase future total radiative forcing.
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wdmn

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Re: Global Surface Air Temperatures
« Reply #1876 on: October 20, 2018, 07:18:52 AM »
Hansen doubles down on his claim of La Niña minima implying acceleration in warming:

"Acceleration is predicted by climate models for continued high fossil fuel emissions as a result of amplifying climate feedbacks and is a cause for concern. We expect global temperature to rise in the next few months and confirm that the global warming rate has accelerated."

http://www.columbia.edu/~jeh1/mailings/2018/20181019_FromXianWithLove.pdf


Sleepy

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Re: Global Surface Air Temperatures
« Reply #1877 on: October 20, 2018, 07:53:37 AM »
Of course.
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sark

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Re: Global Surface Air Temperatures
« Reply #1878 on: October 20, 2018, 08:29:05 AM »
Good lord.  the GFS 10 day rockets up in the latter half to +0.9C global, relative to 1979-2000 with arctic zone anomalies up to +5.8C

James Hansen always seems to go out on a limb and then pluck a golden fruit
I am not a scientist

AbruptSLR

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Re: Global Surface Air Temperatures
« Reply #1879 on: October 20, 2018, 09:16:37 AM »
Good lord.  the GFS 10 day rockets up in the latter half to +0.9C global, relative to 1979-2000 with arctic zone anomalies up to +5.8C

James Hansen always seems to go out on a limb and then pluck a golden fruit

Up, Up and Away:
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wdmn

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Re: Global Surface Air Temperatures
« Reply #1880 on: October 22, 2018, 07:13:35 PM »
Doesn't this graph of Arctic seasonal anomalies also suggest that acceleration has been occurring? Or am I misreading it.

P.S. NCEP vs GFS anomaly outlook is continuing up, up and away....

crandles

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Re: Global Surface Air Temperatures
« Reply #1881 on: October 22, 2018, 11:00:57 PM »
Hansen doubles down on his claim of La Niña minima implying acceleration in warming:

"Acceleration is predicted by climate models for continued high fossil fuel emissions as a result of amplifying climate feedbacks and is a cause for concern. We expect global temperature to rise in the next few months and confirm that the global warming rate has accelerated."

http://www.columbia.edu/~jeh1/mailings/2018/20181019_FromXianWithLove.pdf

I am not sure he has 'doubled down'

Quote
La Nina minima probably provide a better estimate, and they provide a more recent rate. As the figure shows, the most recent two La Ninas imply a warming rate of 0.38°C per decade, at least double the longer term rate! Acceleration is predicted by climate models for continued high
fossil fuel emissions as a result of amplifying climate feedbacks and is a cause for concern.

This is only saying using La Ninas minima is 'probably' better than using El Nino peaks. This doesn't mean the 'double the longer term rate' is a reliable measure and it seems quite possible to believe that a better methodology would remove the ENSO signal then look for acceleration in the remainder.

Doesn't this graph of Arctic seasonal anomalies also suggest that acceleration has been occurring? Or am I misreading it.

P.S. NCEP vs GFS anomaly outlook is continuing up, up and away....

10 day average - that is surely weather not climate.

Arctic graph looks more like point change in rate (which is acceleration) rather than ongoing acceleration. However, I think this can be explained by extra heat from albedo difference from ice to water stored in ocean then released in fall. If we see a gompertz shaped curve in the ice extent and volume graphs, then perhaps this explains the point acceleration look of the graph rather than ongoing acceleration.

Quote
Acceleration is predicted as a result of amplifying climate feedbacks

Not sure I understand this part. I would expect acceleration as a result of high heat capacity of oceans causing inertia so not all of effects are felt til later. Is he referring to carbon uptakes reducing in effect changing the airborne fraction?

wdmn

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Re: Global Surface Air Temperatures
« Reply #1882 on: Today at 03:54:38 AM »
I am not sure he has 'doubled down'

Forgive my colloquialism. I simply meant that he repeated it in a second post on his website, which suggests he's quite confident that it has some merit (which I recognize does not mean that it does).

10 day average - that is surely weather not climate.


I meant that as a reply to AbruptSLR.

Arctic graph looks more like point change in rate (which is acceleration) rather than ongoing acceleration. However, I think this can be explained by extra heat from albedo difference from ice to water stored in ocean then released in fall. If we see a gompertz shaped curve in the ice extent and volume graphs, then perhaps this explains the point acceleration look of the graph rather than ongoing acceleration.

Quote
Acceleration is predicted as a result of amplifying climate feedbacks

Not sure I understand this part. I would expect acceleration as a result of high heat capacity of oceans causing inertia so not all of effects are felt til later. Is he referring to carbon uptakes reducing in effect changing the airborne fraction?

I assumed he was referring to oceans but also to increased warming from decline in albedo due to loss of summer sea ice. I thought this was widely accepted as an amplifying (or positive) feedback? I don't quite understand your explanation for the arctic graph. The annual data looks like there could be an acceleration kicking in around 2013, which is in keeping with Hansen's graph. Again, I understand it's a rough approximation, but what I don't understand is that there would be surprise if there were acceleration, that it would be evident in the arctic, or that it would be due to the loss of arctic sea ice... Granted I'm a newb.



crandles

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Re: Global Surface Air Temperatures
« Reply #1883 on: Today at 02:35:59 PM »
Forgive my colloquialism. I simply meant that he repeated it in a second post on his website, which suggests he's quite confident that it has some merit (which I recognize does not mean that it does).

No worries. I meant at least in part that the repetition seemed part of some timing issue with an improved version.

I assumed he was referring to oceans but also to increased warming from decline in albedo due to loss of summer sea ice. I thought this was widely accepted as an amplifying (or positive) feedback? I don't quite understand your explanation for the arctic graph. The annual data looks like there could be an acceleration kicking in around 2013, which is in keeping with Hansen's graph. Again, I understand it's a rough approximation, but what I don't understand is that there would be surprise if there were acceleration, that it would be evident in the arctic, or that it would be due to the loss of arctic sea ice... Granted I'm a newb.

Yes albedo feedback is widely accepted as positive feedback. It causes faster rate of rise but do you see acceleration with 'continued high fossil fuel emissions'?

A really fast feedback like water vapour feedback increases the rate immediately so with "continued high fossil fuel emissions" you wouldn't expect to see acceleration.

Albedo feedback from sea ice and land snow cover isn't quite so fast so maybe some acceleration but seems to me to be likely small enough to be lost in the noise. Glacier and ice sheet retreat are pretty slow feedbacks and I don't think we would expect continued high fossil fuel emissions to continue long enough at accelerating rates to keep the radiative forcing constant in order to see such acceleration.

Airborne fraction changes from failing carbon sinks also seems pretty slow and again I don't  think we would expect continued high fossil fuel emissions to continue long enough.

So I am still confused about precisely what he is saying about feedbacks.

I am suggesting that the arctic graph looks like it could be fitted with two straight lines which I tried to describe as a point acceleration. Ongoing acceleration would look more like a smooth curve like:


My explanation for the curves would be high ocean heat capacity causing inertia not climate feedbacks.

A slow curve is not much different from the straight line Hansen notes that we have observed so far, when you only look at a small portion of it. So I get that Hansen is saying that just because what we have observed so far looks like a straight line, this doesn't mean we shouldn't expect the acceleration to emerge. (It is just his explanation for the acceleration that seems dubious to me.)

Edit: Perhaps he is thinking about methane emissions from permafrost and methane clathrate burbs as feedbacks from temperature rises. Ocean heat capacity inertia seems more solid explanation to me for the moment.
« Last Edit: Today at 02:59:57 PM by crandles »

AbruptSLR

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Re: Global Surface Air Temperatures
« Reply #1884 on: Today at 05:04:17 PM »
As climate change is about more that just GMSTA, I provide the linked state of the climate report by Zeke Hausfather:

Title: "State of the climate: New record ocean heat content and a growing El Niño"

https://www.carbonbrief.org/state-of-the-climate-new-record-ocean-heat-content-and-growing-a-el-nino

Extract: "Ocean heat content (OHC) set a new record in the first half of 2018, with more warmth in the oceans than at any time since OHC records began in 1940."
« Last Edit: Today at 05:37:33 PM by AbruptSLR »
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson