Global Surface Air Temperatures

[The Walrus]

if temps were .24 degrees cooler than we thought ..... then it follows that the temp rise is .24 greater than we thought ......for the same increase in GHG"s  ....... hence sensitivity is greater


Or did i miss something ?  ......always happy to be shown the error of my ways !!

Sensitivity is calculated by starting a model in an equilibrium state, which is got by running it for 100 years or so to check that nothing substantial is changing. Then CO2 is instantly increased by four times, and the model is run for another 100 years or so to see how much the temperature increases. Half that increase is the sensitivity.

If the starting equilibrium is not a realistic climate, then there's a problem with the model in general, and fixing it might move the sensitivity up a bit, up a lot, or even down a bit. There's plenty of reasons to think it might be higher, and this points vaguely in that direction too, but its far from conclusive.

The equilibrium state is key.  We know temperatures fluctuated significantly over the previous millennia, while CO2 levels remained fairly constant.

[Renerpho]

if temps were .24 degrees cooler than we thought ..... then it follows that the temp rise is .24 greater than we thought ......for the same increase in GHG"s  ....... hence sensitivity is greater


Or did i miss something ?  ......always happy to be shown the error of my ways !!

Sensitivity is calculated by starting a model in an equilibrium state, which is got by running it for 100 years or so to check that nothing substantial is changing. Then CO2 is instantly increased by four times, and the model is run for another 100 years or so to see how much the temperature increases. Half that increase is the sensitivity.

If the starting equilibrium is not a realistic climate, then there's a problem with the model in general, and fixing it might move the sensitivity up a bit, up a lot, or even down a bit. There's plenty of reasons to think it might be higher, and this points vaguely in that direction too, but its far from conclusive.

The equilibrium state is key.  We know temperatures fluctuated significantly over the previous millennia, while CO2 levels remained fairly constant.

What do you mean? If you're talking about the local variations, commonly referred to as the "little ice age" and the "medieval warm period", those were not global, but mostly limited to the northern hemisphere (especially Europe). The global temperature average was quite stable over the past 2,000 years, varying by no more than about +/- 0.3°C over that period (much less than what we've seen since 1850). Quote: "Global average temperatures show that the Medieval Warm Period was not a planet-wide phenomenon, and that the Little Ice Age was not a distinct planet-wide time period but rather the end of a long temperature decline that preceded recent global warming." (See here for source information.)



This can be extended further, to the very end of the last ice age (source):



Global temperatures were in equilibrium (small/slow variations notwithstanding) for thousands of years before the current warming began. Even the temperature increase at the end of the last ice age, 17,000 to 10,000 years ago, while much larger absolutely, was also much slower than what we see today. Global temperatures are increasing at a rate of about 0.3°C per decade right now, faster than at any point during the last warming period.

[Renerpho]

Global temperatures are increasing at a rate of about 0.3°C per decade right now, faster than at any point during the last warming period.

And this is in line with the fact that CO₂ now is rising much faster than it did during the last deglaciation:

[The Walrus]

if temps were .24 degrees cooler than we thought ..... then it follows that the temp rise is .24 greater than we thought ......for the same increase in GHG"s  ....... hence sensitivity is greater


Or did i miss something ?  ......always happy to be shown the error of my ways !!

Sensitivity is calculated by starting a model in an equilibrium state, which is got by running it for 100 years or so to check that nothing substantial is changing. Then CO2 is instantly increased by four times, and the model is run for another 100 years or so to see how much the temperature increases. Half that increase is the sensitivity.

If the starting equilibrium is not a realistic climate, then there's a problem with the model in general, and fixing it might move the sensitivity up a bit, up a lot, or even down a bit. There's plenty of reasons to think it might be higher, and this points vaguely in that direction too, but its far from conclusive.

The equilibrium state is key.  We know temperatures fluctuated significantly over the previous millennia, while CO2 levels remained fairly constant.

What do you mean? If you're talking about the local variations, commonly referred to as the "little ice age" and the "medieval warm period", those were not global, but mostly limited to the northern hemisphere (especially Europe). The global temperature average was quite stable over the past 2,000 years, varying by no more than about +/- 0.3°C over that period (much less than what we've seen since 1850). Quote: "Global average temperatures show that the Medieval Warm Period was not a planet-wide phenomenon, and that the Little Ice Age was not a distinct planet-wide time period but rather the end of a long temperature decline that preceded recent global warming." (See here for source information.)

Global temperatures were in equilibrium (small/slow variations notwithstanding) for thousands of years before the current warming began. Even the temperature increase at the end of the last ice age, 17,000 to 10,000 years ago, while much larger absolutely, was also much slower than what we see today. Global temperatures are increasing at a rate of about 0.3°C per decade right now, faster than at any point during the last warming period.

I mean exactly what I said.  Even if the mwp and lia were confined to the northern hemisphere, that is still half of the globe.  Surely, that would have some impact!  In recent warming, the northern hemisphere is outpacing the southern.  Shall we dismiss that as an aberration also?

I prefer data from scientific sources, rather than wikipedia, and acknowledge that there is an uncertainty in proxy data, and choosing the one dataset that best represents your viewpoint, is not the best practice.  As can be seen from the graph, the choice of timeframe for preindustrial temperatures can make a large difference, and may include natural causes.

"Please understand that there is not one single correct reconstruction. Most of these reconstructions show a clear Medieval Warm Period and a clear Little Ice Age. Presently, we are interested in the reconstructions prior to about 1950."

http://www.atmo.arizona.edu/students/courselinks/spring17/atmo336s2/lectures/sec5/controversy_spring20.html

"There is a great deal of difficulty and uncertainty in trying to reconstruct global average temperature changes based on proxy data. One thing we can say with some certainty is that global average temperatures have fluctuated all throughout Earth's history, including the last 2000 years. Prior to 1900, we can safely say that the changes were not caused by anthropogenic additions of greenhouse gases, but were natural fluctuations."

[John_the_Younger]

Prior to 1900, we can safely say that the changes were not caused by anthropogenic additions of greenhouse gases, but were natural fluctuations.

I recall reading that some scientists discern human-induced greenhouse gas emissions from up to about 10,000 years ago - especially via rice cultivation and forest fire promulgation.  I understand that these human-caused emissions more-or-less countered Milankovitch cycles-caused cooling until 150+/- years ago whence they took off.

A quick search for one: Ruddiman (2003) saying 8,000 years:

THE ANTHROPOGENIC GREENHOUSE ERA BEGAN THOUSANDS OF YEARS AGO
WILLIAM F. RUDDIMAN
Department of Environmental Sciences, University of Virginia, Charlottesville, VA 22904, U.S.A. E-mail: wfr5c@virginia.edu
Abstract. The anthropogenic era is generally thought to have begun 150 to 200 years ago, when the industrial revolution began producing CO2 and CH4 at rates sufficient to alter their compositions in the atmosphere. A different hypothesis is posed here: anthropogenic emissions of these gases first altered atmospheric concentrations thousands of years ago. This hypothesis is based on three arguments. (1) Cyclic variations in CO2 and CH4 driven by Earth-orbital changes during the last 350,000 years predict decreases throughout the Holocene, but the CO2 trend began an anomalous increase 8000 years ago, and the CH4 trend did so 5000 years ago. (2) Published explanations for these mid- to late-Holocene gas increases based on natural forcing can be rejected based on paleocli- matic evidence. (3) A wide array of archeological, cultural, historical and geologic evidence points to viable explanations tied to anthropogenic changes resulting from early agriculture in Eurasia, including the start of forest clearance by 8000 years ago and of rice irrigation by 5000 years ago. In recent millennia, the estimated warming caused by these early gas emissions reached a global-mean value of ∼0.8◦C and roughly 2◦C at high latitudes, large enough to have stopped a glaciation of northeastern Canada predicted by two kinds of climatic models. CO2 oscillations of ∼10 ppm in the last 1000 years are too large to be explained by external (solar-volcanic) forcing, but they can be explained by outbreaks of bubonic plague that caused historically documented farm abandonment in western Eurasia. Forest regrowth on abandoned farms sequestered enough carbon to account for the observed CO2 decreases. Plague-driven CO2 changes were also a significant causal factor in temperature changes during the Little Ice Age (1300–1900 AD).

[kiwichick16]

another graph  showing temps and CO2 in sych

https://theconversation.com/the-three-minute-story-of-800-000-years-of-climate-change-with-a-sting-in-the-tail-73368

[kiwichick16]

looking at that graph , you can see the rise in CO2 levels about 125,000 years ago , of approx 100ppm CO2 ........and temps rose 6-7 degrees C

[Rodius]

What is funny about people who use the little ice age as proof that global temp vary a lot is they produce graphs that disprove their idea.

For example... http://www.atmo.arizona.edu/students/courselinks/spring17/atmo336s2/lectures/sec5/controversy_spring20.html

It shows a global drop during the little ice age on a global level of about -0.4 C
It also shows a graph of temps in Greenland... not sure how that relates to global temps but it does show a more varied, regional, temp variation.

But the author seems to think that a wider variation in temps in Greenland somehow proves the the same is true on a global scale... which it isn't but that is what cherry picked data is all about.

[kassy]

NASA Confirms: Every Month For Last Year Was Hottest on Record

It's not always easy to understand the current climate crisis in terms of simple, straightforward facts – not with so many variables at play – but here's a worrying stat for you: every single month of the last 12 has set a new global temperature record for that month.

NASA has confirmed that May 2024 followed April, March, February, and January in hitting new highs in terms of average global temperatures. Before that, June through December 2023 had done exactly the same.

A streak like this has never been seen before for as long as records have been kept, and it's an indication of the rapid warming that our planet is now experiencing. What's even more sobering is that there's worse to come.

...

Last November, the global average temperature was more than 2 °C hotter than pre-industrial levels for the first time, while the US just recorded its warmest ever winter.

Despite the evidence that our planet's climate is shifting drastically, humanity is pumping out more greenhouse gas emissions than at any point in history. We're hurtling towards a climate cliff edge and showing no signs of slowing down.

https://www.sciencealert.com/nasa-confirms-every-month-for-last-year-was-hottest-on-record

[gerontocrat]

https://climatereanalyzer.org/clim/t2_daily/?dm_id=world

SATs to 12 June (15 June for world from copernicus "pulse") Post 1 of 3

World for most days in 2024 still at daily record highs

Tropics for most days in 2024 still at daily record highs. In the last few days flirting with 2023 SSTs.

[gerontocrat]

https://climatereanalyzer.org/clim/t2_daily/?dm_id=world

SATs to 12 June (15 June for world from copernicus "pulse") Post 2 of 3

Arctic No records here

AntarcticA unusally high spike end may beginning of June. Apart from that normal high variability. No records so far.

[gerontocrat]

https://climatereanalyzer.org/clim/t2_daily/?dm_id=world

SATs to 12 June (15 June for world from copernicus "pulse") Post 3 of 3

Average temperatures year to date - World & Tropics 1 degree C above the 1979-2000 mean

Even with less than half the year gone in 2024, both the Tropics and World show a high number of days at recotd high SATs, a big contrast with the Arctic and Antarctic.

[gerontocrat]

https://climatereanalyzer.org/clim/t2_daily/?dm_id=world  to 25th June 2024
https://pulse.climate.copernicus.eu/ to 30th June 2024

It looks like World SATs will be another record high monthly average for June (just), as will be SATs in the Tropics.

Not so for the Arctic, and the Antarctic somewhat chilly.

Maybe July brings a different story

[gerontocrat]

https://climatereanalyzer.org/clim/t2_daily/?dm_id=world  to 25th June 2024
https://pulse.climate.copernicus.eu/ to 30th June 2024

Some more graphs

[vox_mundi]

Copernicus: June 2024 Marks 12th Month of Global Temperature Reaching 1.5°C Above Pre-Industrial
https://climate.copernicus.eu/copernicus-june-2024-marks-12th-month-global-temperature-reaching-15degc-above-pre-industrial



June 2024 was warmer globally than any previous June in the data record, with an average ERA5 surface air temperature of 16.66°C, 0.67°C above the 1991-2020 average for June and 0.14°C above the previous high set in June 2023. 

This is the thirteenth month in a row that is the warmest in the ERA5 data record for the respective month of the year. While unusual, a similar streak of monthly global temperature records happened previously in 2015/2016.

According to ERA5 data, the month was 1.50°C above the estimated June average for 1850-1900, the designated pre-industrial reference period, making it the twelfth consecutive month to reach or break the 1.5°C threshold.

The global-average temperature for the past 12 months (July 2023 – June 2024) is the highest on record, at 0.76°C above the 1991-2020 average and 1.64°C above the 1850-1900 pre-industrial average.



The average European temperature for June 2024 was 1.57°C above the 1991-2020 average for June, making the month the joint-second warmest June on record for Europe. 

Outside Europe, temperatures were most above average over eastern Canada, the western United States and Mexico, Brazil, northern Siberia, the Middle East, northern Africa and western Antarctica. 

The sea surface temperature (SST) averaged for June 2024 over 60°S–60°N was 20.85°C, the highest value on record for the month. 

This is the fifteenth month in a row that the SST has been the warmest in the ERA5 data record for the respective month of the year. 



-----------------------------------------------------------

[gerontocrat]

SATS to 10th July (July 15 for World SATs)

It looks likely that World SATs will be 2nd highest in the satellite record in July.

[kiwichick16]

global air temps look like they are close to last year


https://climatereanalyzer.org/clim/t2_daily/?dm_id=world

[gerontocrat]

global air temps look like they are close to last year

https://climatereanalyzer.org/clim/t2_daily/?dm_id=world

https://pulse.climate.copernicus.eu/ has more up-to-date data.

In the last 3 to 4 days world SATS back at record levels

[John_the_Younger]

Is that a new 'absolute' peak temperature?

[Rodius]

Is that a new 'absolute' peak temperature?

Still to be confirmed but, yeah, it is

[Renerpho]

Is that a new 'absolute' peak temperature?

Still to be confirmed but, yeah, it is

It's not the highest anomaly ever, but since global temperatures peak in July (due to the distribution of Earth's land masses), this is the time of the year when "absolute" temperature records are set.

[kiwichick16]

at least sea temps trending back towards normal

https://pulse.climate.copernicus.eu/

[gerontocrat]

SATs to 27th July + World SATs to 31 July

I do not think World or Tropic SATs made a record high July average - nearly but not quite.

Nevertheless if that 2023 data was absent, we would all be going "wow" about the 2024 data.

[gerontocrat]

SATs to 27th July + World SATs to 31 July

The Antarctic is interesting at the moment, a mixture of extreme +ve & -ve temperature anomalies, with the majority of the high temps on the continent.

[gerontocrat]

SATs to 12th August 2024, World to 16th August

It is possible that August 2024 World average will be another record high month.

Arctic SATs North of 66.5 (i.e. mainly the High Arctic) are now consistently below record levels though still quite high.

Antarctic SATs South of 66.5 (i.e. mainly the Antarctic Continent) are declining rapidly from record highs. There are still large areas of well below average temperatures especially over the Ross and Weddell Sea regions.

In the Tropics SATs are well below 2023 record levels, but still very high.

[gerontocrat]

SATs to 12th August 2024, World to 16th August Some more graphs

The variation from the 1979-2000 year to date averages shows that this year (and for the years after 2016) the Arctic (North of 66.5) is not showing rapid warming.

This is in contrast to the World and Tropics data.

The trend in Antarctic SATs is difficult to establish from the graph.

[Sublime_Rime]

Despite the mild La Nina conditions unfolding (albeit less than expected) GSATs are getting into territory we haven't seen since the height of El Nino last fall to winter. Its looking like 2024 will not only be above 1.5C on average, but significantly so, possibly above 1.6C if this continues.

Note: The plot below, courtesy of Karsten Haustein, is relative to 1980-2010 average, which I think is roughly 0.7C above pre-industrial

[John_the_Younger]

Its looking like 2024 will not only be above 1.5C on average, but significantly so, possibly above 1.6C if this continues.

Does anybody produce a 365-day running average of Global Surface Air Temperatures?  If "1.5C" really means "1.5C averaged over a year", then such a graph is required.  (If it's "1.5C averaged over 5 years", then that graph is needed.)

[Rodius]

Its looking like 2024 will not only be above 1.5C on average, but significantly so, possibly above 1.6C if this continues.

Does anybody produce a 365-day running average of Global Surface Air Temperatures?  If "1.5C" really means "1.5C averaged over a year", then such a graph is required.  (If it's "1.5C averaged over 5 years", then that graph is needed.)

I keep track of it but not with graphs and using data from https://climatereanalyzer.org/clim/t2_daily/?dm_id=world

We first hit +1.5 C (compared to 1850 to 1900 of 13.6 C) or 15.10 C in mid-April 2024.

It peaked at +1.54 (15.14 C) in June 2024

Currently sitting on +1.53 and seems to be dropping but it doesn't seem all that interested in doing it as it is supposed to.

To give a comparison, this is the temp year ending
2023: 14.98 C
2022: 14.72 C
2021: 14.70 C
2020: 14.83 C

In 2014 it was 14.48 C

This year is the first time +1.5 C has been hit.... last year maxed at +1.38 C

[Sublime_Rime]

Its looking like 2024 will not only be above 1.5C on average, but significantly so, possibly above 1.6C if this continues.

Does anybody produce a 365-day running average of Global Surface Air Temperatures?  If "1.5C" really means "1.5C averaged over a year", then such a graph is required.  (If it's "1.5C averaged over 5 years", then that graph is needed.)

Indeed my assertion was based on the efforts of others to make such 365-day average graphs, such as Eliot Jacobson, whose last one published online was for up to Oct. 15th (see attached). It was trending down, though still above 1.6. I'd guess that trend is now, at least temporarily, reversing.

[Rodius]

Its looking like 2024 will not only be above 1.5C on average, but significantly so, possibly above 1.6C if this continues.

Does anybody produce a 365-day running average of Global Surface Air Temperatures?  If "1.5C" really means "1.5C averaged over a year", then such a graph is required.  (If it's "1.5C averaged over 5 years", then that graph is needed.)

Indeed my assertion was based on the efforts of others to make such 365-day average graphs, such as Eliot Jacobson, whose last one published online was for up to Oct. 15th (see attached). It was trending down, though still above 1.6. I'd guess that trend is now, at least temporarily, reversing.

The anomaly needs to be compared to something... the 1.6 C anomaly is almost meaningless unless you give the temp range and time period it is compared to.

Actual temp is easier.

What we know is global temps are at all-time highs and 2023/24 had the added bonus of an El Nino event that is now over.

So, with El Nino gone the temp will reduce to a neutral level (no El Nino/ La Nina). That is not a reversal, not even close to it.

To get a better comparison, compare the current temps to previous El Nino events.

Chances are, the coming 12 months will see the temps go back below 15 C.
Depending on which period you compare it to will determine what the anomaly is.

Since I compare to 1850 to 1900 (when the temps were 13.6 C) to today, +1.5 C is where we are now.
I am not sure where the +1.6 C is coming from.

Either way, calling the current reduction a reversal is incorrect, it isn't reversing, it is a return to neutral and that neutral level is still increasing.

[Sublime_Rime]

Personally, I think as long as you are clear about which baseline used and are using it from the same dataset, then using an anomaly is much clearer than referring to the actual global average temp.


The plot from above was made using ERA5 data and a 1850-1900 baseline. Surpassing 1.6C this year has been clearly documented by others using this very popular and widely used dataset.

https://climate.copernicus.eu/surface-air-temperature-august-2024#:~:text=global%20temperature%20datasets.-,The%20last%2012%20months%20%2D%20September%202023%20to%20August%202024,/16%20and%202019/20.

I agree that GSAT is likely to go down in the next 3-6 months, but what i was pointing out earlier isn't that the downtrend is not as rapid as one would expect with the current transition from El Nino, even for mild La Nina. We're right neck and neck with where 2023 was for this time of year, as El Nino was reaching its full effect: https://climatereanalyzer.org/clim/t2_daily/?dm_id=world

[kassy]

We mostly use the anomaly.

ML CO2 is staying stubbornly high too. It will be interesting to see how much it will go down in 6 months time.

[gerontocrat]

https://climatereanalyzer.org/clim/t2_daily/?dm_id=world

A closer look at SATs. (post 1 of 3)

World SATs are back at record levels for the date, which given we are at the tail end of year 2 of the 2023-24 El Nino with rthe ENSO cycle firmly in neutral for some time. (ENSO 3.4 component at around -0.25C) - graph 1.

The SAT anomaly (compared with the 1991-2020 average is +1C - graph 2 - which also suggests that the rate of increase in this century may have increased a bit.

Tropics SATs, (graph 3) after being below 2023 levels for the last 6 weeks or so, are back close to record levels at +0.7C above the 1991-2020 average.

click images to enlarge

[gerontocrat]

https://climatereanalyzer.org/clim/t2_daily/?dm_id=world

A closer look at SATs. (post 2 of 3)

Arctic SATs remain high. (graph 1). The anomaly graph (graph 2) is interesting as it clealy shows that the rapid increase in Arctic SSTs is largely contained in the winter months, the year 2016 being the most spectacular demonstration of this.

Antarctic SATs are currently at record levels (3rd graph). The anomaly graph (4th Graph) shows that it is hard to see trends due to the wild daily variations in SATs and the anomaly. As the data is for latitudes south of 66.5 most of the area is the Antarctic land mass.

click images to enlarge

[gerontocrat]

https://climatereanalyzer.org/clim/t2_daily/?dm_id=world

A closer look at SATs. (post 3 of 3)

Just a couple of graphs because....

[Sublime_Rime]

Thanks for the analysis Gero!

GSAT average for October just came out at 1.65C above pre-industrial in the Copernicus ERA5 dataset, very odd considering the ENSO cycle. This pushes us to 1.59C for year to date (data and graph courtesy of Dr. Eliot Jacobson).

[Renerpho]

Does anybody produce a 365-day running average of Global Surface Air Temperatures?

Copernicus has a 12-month running average, using the 1850-1900 baseline. Their latest plot ends with September 2024. It has first surpassed 1.5°C in January 2024, and has peaked at 1.64°C in June. Its record high before this was 1.34°C in September 2016.
Subtract 0.88°C to convert that to a 1991-2020 baseline (the current Climate Normal).

https://climate.copernicus.eu/surface-air-temperature-september-2024

[Renerpho]

Today's Featured Picture on Wikipedia.
https://en.wikipedia.org/wiki/Main_Page

[kiwichick16]

new study of CO2 trapped in Antarctic ice suggests we are at 1.49 above per industrial levels

https://www.abc.net.au/news/science/2024-11-12/climate-change-warming-limit-close-antarctic-ice-reveals/104585566