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Cont: Global warming discussion V

aleCcowaN said:
AGW brings higher global average temperature but also higher variability. There are regions of the planet that aren't warming at an important rate. Also, the higher variability makes both high and low temperatures to reach extreme records. They key is that record-breaking highs fourfold record-breaking lows, as it is consistent with higher variability in a context of average temperature going higher and higher.

That said. There's the problem that so far this analysis doesn't take into account variations in the very same weather stations that give those old and new records. Bad placement, bad maintenance, etc can bring anomalous values. That is currently extremely rare in the First World, but not in 1913.

I don't have the faintest idea which old record are you talking about, but if it is an extremely high temperature in an extremely dry place like a desert then that temperature heavily depends on solar irradiation. And that hasn't basically change since 1913.
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It's what pops up when you google "What's the hottest ever temperature?"

"134.1 °F
According to the World Meteorological Organization's (WMO), the highest temperature ever recorded was 56.7 °C (134.1 °F) on 10 July 1913 in Furnace Creek (Greenland Ranch), California, USA. According to the WMO this temperature may have been the result of "a sandstorm that occurred at the time."

I assumed that was correct. Your explanation makes sense. I wondered whether it was a freak weather phenomenon that caused the high temperature.
 
«On 13 September 1922, a high temperature of 58.0 °C (136.4 °F) was recorded in Al-ʿAzīzīyah. This was long considered the highest temperature ever measured on Earth.[2][3][4]
However, that reading was controversial:[5][6][7]

  1. The weather station was first in 'Aziziya town, but, in 1919, it was moved to a hilltop fort, where the weather station was set up on black tarmac, which would have absorbed more sunlight and made the air there artificially hotter, explaining a period of very hot readings there from 1919 to 1928.
  2. Shortly before the record reading on 13 September 1922, the weather station's usual maximum thermometer had been damaged and then replaced by an uncalibrated, ordinary maximum-minimum thermometer such as often used in greenhouses.
  3. On 11 September 1922, the usual record keeper was replaced by an inexperienced observer, who was untrained in the use of the thermometer and the record log. This is known by the change in handwriting on the log sheets and by the high and low temperatures being recorded in the wrong columns. The thermometer used sliding colored cylinders to record maximum and minimum temperatures, and these cylinders were about 7 to 8 degrees Celsius long on the thermometer scale. The WMO now believes that the inexperienced observer was reading from the wrong end of the high-temperature cylinder inside the thermometer, getting a reading which was 7 to 8 degrees too high.
  4. On 13 September 2012, the World Meteorological Organization announced that the WMO Commission of Climatology World Archive of Weather and Climate Extremes had found that the record was invalid. Its world record for hottest temperature is now 56.7 °C (134.1 °F), recorded on 10 July 1913 at Greenland Ranch in Death Valley, California in the United States.[8]»
 
Quote from article: "In Broken Hill, 935km (580 miles) west of Sydney, groups of emus have been seen "running laps of the main street, eating gardens and gate crashing football matches", ABC News reports.

Ms Singleton, who works for the Rescue and Rehabilitation of Australian Native Animals, said: "We've had 14 on a sporting oval. They've been out there for weeks - the locals in that area are giving them food and water."

https://www.bbc.co.uk/news/world-australia-45239791?SThisFB

:(
 
Global warming can make extreme weather worse. Now scientists can say by how much.

snippet:

Otto is one of the leading scientists in the rapidly evolving field of extreme events attribution. The discipline is being driven by an increasing focus among academics, by better data collection worldwide and by open-source computer models that allow researchers ready access to complex climate simulations, particularly of what Earth’s temperatures likely would have looked like without the profusion of carbon dioxide and other greenhouse gases over the last century.

Many of the researchers in the field are determined to ensure that experts, not amateurs, drive the discussion of unusual weather. “If the answer is not given by scientists, it will be given by politicians or someone with an agenda,” Otto said. “We want to make sure there is scientific evidence in this debate.”
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Deleted - didn't read down as far as Lomiller's follow up. Tamino has been saying this all along.
 
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Greta Thunberg's challenge/message:


https://www.youtube.com/watch?v=HzeekxtyFOY


I expected that perhaps this would have appeared somewhere in these forums but that doesn't appear to be the case. Therefore, even though this discussion appears to have "died", I'm adding the link for those that might be interested and haven't yet seen it.
 
End of Year, Greetings!

I hope a merry holiday season has been had by all!

A new year approaches, and I wish good tidings, health, and wealth for all!


Time is tight for the next week or so, but I look forward to catching up with myself and you all in a brighter, more hopeful new year.
 
This might have us all "looking for shelter on a cloudless day!"

Earth could warm by 14°C as growing emissions destroy crucial clouds - https://www.newscientist.com/articl...-as-growing-emissions-destroy-crucial-clouds/

If we keep burning fossil fuels with reckless abandon, we could trigger a cloud feedback effect that will add 8°C on top of all the warming up to that point. That means the world could warm by more than 14°C above the pre-industrial level.

Needless to say, this would be cataclysmic. For instance, large parts of the tropics would become too hot for warm-blooded animals, including us, to survive.

The good news is that if countries step up their efforts to cut emissions we should avoid finding out if this idea is correct. “I don’t think we will get anywhere close to it,” says Tapio Schneider at the California Institute of Technology, Pasadena, who led the research...
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New Scientist is too much like OMNI, a bit too sensationalist for my daily reading. but there is the NatGeo paper
"Possible climate transitions from breakup of stratocumulus decks under greenhouse warming"
Tapio Schneider, Colleen M. Kaul & Kyle G. Pressel
Nature Geoscience volume 12, pages164–168 (2019)

Abstract
Stratocumulus clouds cover 20% of the low-latitude oceans and are especially prevalent in the subtropics. They cool the Earth by shading large portions of its surface from sunlight. However, as their dynamical scales are too small to be resolvable in global climate models, predictions of their response to greenhouse warming have remained uncertain. Here we report how stratocumulus decks respond to greenhouse warming in large-eddy simulations that explicitly resolve cloud dynamics in a representative subtropical region. In the simulations, stratocumulus decks become unstable and break up into scattered clouds when CO2 levels rise above 1,200 ppm. In addition to the warming from rising CO2 levels, this instability triggers a surface warming of about 8 K globally and 10 K in the subtropics. Once the stratocumulus decks have broken up, they only re-form once CO2 concentrations drop substantially below the level at which the instability first occurred. Climate transitions that arise from this instability may have contributed importantly to hothouse climates and abrupt climate changes in the geological past. Such transitions to a much warmer climate may also occur in the future if CO2 levels continue to rise.
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Depending upon the circumstances 1200ppm, is not near comfortably high enough to avoid reaching within the next 100 years, particularly if we stick to an accelerating definition of BAU.
 
Well, yesterday the UK had its first Winter temperature above 20 Celsius in several places.
 
macdoc said:
Yes was a wonderful Winter Solstice for all us pagans :thumbsup:
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(sorry to leave you hanging there!) it was fine for all the rural and provincial heathens hereabouts as well, even those of us who are at least nominally mainstream in our religious inclinations. ;)
 
Mr Clingford said:
Well, yesterday the UK had its first Winter temperature above 20 Celsius in several places.
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We've officially ended the California drought with a fire-hosing set of successive storm events over the last couple of months (big rains a few months after big fires is not a good combination). These even managed to refill some reservoirs (too bad we don't have more of these set up to catch these types of events and use the water to help recharge the ground water systems). I'm hearing about signs that we are looking at another El Nino firing up this spring, The west Coast of the US seems to have a lot more stormy weather in the transitional period ahead of El Nino events, but I'm wondering how much of this is biased anecdotal perception.
 
Also the biggest swing in temperature each day for winter, the UK doesn't normally experience 20C temperature swings from between day and night. It's brought forward the blossom and the bulb flowering, which is probably not good either.
 
Arctic ocean likely to be free of summer sea ice by 2050.

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018GL081393

Previous results suggested a date abound 2050 +/- 20 years. The new result finds that much of this variation is associated with the Interdecadal Pacific Oscillation. A positive phase is associated with less artic sea ice, a negative phase is associated with more and we appear to be entering a positive phase which points to an ice free arctic prior to 2050.


We found that a natural cycle called the Interdecadal Pacific Oscillation, or IPO for short, is particularly important. Arctic sea‐ice loss is faster when the IPO is moving from its cold to warm phase and slower when the IPO is moving from its warm to cold phase. This is because variations in the IPO cause changes in atmospheric wind patterns, which alter the amount of heat that is transported into the Arctic. Observations show that the IPO started to shift from its cold to warm phase in the past few years. If this shift continues, our results suggest that there is an increased chance of accelerated sea‐ice loss over the coming decades.
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Belz... said:
Now that starts being close to a runaway warming scenario.
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Nah, not if you are talking Venus type runaway, but it will definitely pump things into and above PETM conditions. High enough and long enough to dramatically alter almost all of the planet's biomes, not to mention the plant and animal life that makes up these biomes. It will be too fast for flora and fauna to adapt or evolve to meet such challenges. The only biomes left largely unchanged will be some of the relatively isolated extreme environments. I keep hoping we aren't stupid enough to actually let things go that far,...and then I read the news.
 
I reckon if I look back a thread or two on this subject, I'd find a load of people telling me that CO2 emissions were flat or falling.

Subsequent to the GFC, that was true, but seeing it as a trend has proven spectacularly wrong.

Two years in a row, emissions have increased, with 2018 showing an increase very much in line with global GDP. https://www.theguardian.com/environ...-up-by-third-as-greenhouse-gas-emissions-rise

Given the continuing rise and Trump's anti-AGW policies being enacted, I reckon you can lock in about 3 degrees, never mind the 2 in the Paris Accord.

I think this fight is just about over - buy high ground, sit back and watch.
 
The Atheist said:
I reckon if I look back a thread or two on this subject, I'd find a load of people telling me that CO2 emissions were flat or falling.
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That imaginary "load of people" will tell you that globally CO2 emissions continued to increase with the main sources being the USA, China and India. The EU though has decreased CO2 emissions since 1990. This is well known.
Global Carbon Budget 2018

Note that CO2 emissions vary, e.g. due to economic forces, so looking at a couple of years is not useful. You need to look at periods that smooth out economic cycles. Picking out last 2 years ignores the plateau from 2014-16.
 
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