Has the Global Temperature Trend Turned to Cooling?

Cold is coming.
The Geological Record of Climate Change and Why Today’s Increase in Atmospheric CO2 Is the Result of Global Warming, Not the Cause
David Shelley*
The climate is changing, and the geological record of climate change clearly shows that (a) we live in an unusually cold climate, (b) recent warming is neither dangerous or unusual,…

*David Shelley gained his PhD from Bristol University and then lectured in geology for nearly 40 years at the University of Canterbury, Christchurch, NZ. He was Dean of Postgraduate Studies for 6 years. He is the author of 62 research papers and two textbooks, one on mineralogy, the other on igneous and metamorphic petrology.

 

Data collection continues, despite technical challenges.
UAH v6.1 Global Temperature Update for October, 2024: +0.73 deg. C After Truncation of the NOAA-19 Satellite Record
November 2nd, 2024
The Version 6.1 global average lower tropospheric temperature (LT) anomaly for October, 2024 was +0.73 deg. C departure from the 1991-2020 mean, down from the September, 2024 anomaly of +0.80 deg. C.


The new (Version 6.1) global area-averaged temperature trend (January 1979 through October 2024) is now +0.15 deg/ C/decade (+0.21 C/decade over land, +0.13 C/decade over oceans).

The previous (version 6.0) trends through September 2024 were +0.16 C/decade (global), +0.21 C/decade (land) and +0.14 C/decade (ocean).

The following provides background for the change leading to the new version (v6.1) of the UAH dataset. . . .

• The older NOAA-19 satellite has now drifted too far through the diurnal cycle for our drift correction methodology to provide useful adjustments. Therefore, we have decided to truncate the NOAA-19 data processing starting in 2021. This leaves Metop-B as the only satellite in the UAH dataset since that date. This truncation is consistent with those made to previous satellites after orbital drift began to impact temperature measurements.

• This change reduces recent record global warmth only a little, bringing our calculated global temperatures more in line with the RSS and NOAA satellite datasets over the last 2-3 years.

• Despite the reduction in recent temperatures, the 1979-2024 trend is reduced by only 0.01 deg/ C/decade, from +0.16 C/decade to +0.15 C per decade. Recent warmth during 2023-2024 remains record-setting for the satellite era, with each month since October 2023 setting a record for that calendar month. . . .

 

At least there are no urban heat island effects up there.

 

It's getting colder in Greenland.
New Study: Greenland Cooled by -0.11°C From 2000-2019 – Including All Ice Free And Ice Covered Areas
By Kenneth Richard on 19. November 2024

Any 21st century ice melt across Greenland cannot be due to an accelerated warming trend, as the island as a whole has been cooling since the 1990s.
New research analyzes two decades of Greenland land surface temperature (LST) data. Contrary to the popular narrative of a significant warming trend, Greenland has instead cooled from 2000-2019 at a rate of -0.055°C per decade.

Southern Greenland also cooled from 1958-2001, suggesting the region has been cooling for over 60 years.

Any recent ice melt in Greenland thus cannot be due to surface warming, as LSTs have undergone a cooling trend in both ice free and ice covered areas.



Image Source: Pongsiri et al., 2024

 

Yes. The real climate danger is the next cooling cycle and the lack of reliable power generation capacity.

 

It never stopped cooling in Antarctica.
‘Global’ Warming? Little Ice Age Cooling And Sea Ice Expansion Is Still Ongoing Across Antarctica Today
By Kenneth Richard on 22. November 2024

New research indicates there has been no reduction in sea ice in Antarctica’s Robertson Bay (Ross Sea) during the last century. Instead, the frigid Little Ice Age and its expanded sea ice conditions continue unabated through the 20th and 21st centuries.
Between ~8000 and 3500 years before present the Antarctic ice sheet experienced several millennia of retreat and the sea ice extent surrounding the continent decreased throughout the Middle Holocene. For the next few millennia after that, or from about 3500 to 1500 years ago, the ice sheet and sea ice extent advanced to near modern levels.

“The East and West Antarctic ice sheets underwent rapid periods of retreat in the Ross Embayment, the continent’s largest ice drainage basin, between 8 and 3.5 calkyr BP. Recent work shows that retreat was followed by a period of readvance and the ice sheets reached their modern configurations during the late Holocene.”

During the Medieval Warm Period, or from approximately 1500 to 700 years before present, variations in F. curta diatom, a proxy for sea ice extent, indicate Antarctic sea ice retreated again to its much lower (<40%) Middle Holocene levels.

“…during the period between 1.5 and 0.7 calkyr BP…lower F. curta abundance in Robertson Bay (<40%) is characteristic of a reduction in spring sea ice concentration and a longer summer open water season.”

Then, after the Medieval Warm Period ended, Antarctica’s Little Ice Age (LIA) cooling began. The ice sheet grew and sea ice advanced to the highest levels of the last 7000 years (~60%).

The relative abundance of F. curta over the last 700 years indicate these icy LIA conditions have persisted to the present day. Sea ice has been increasing (with no declining long-term trend) since the late 1970s, which is consistent with significant (>1°C) cooling trends in this region during recent decades.

“…an increase in the seasonal duration of sea ice between 0.7 calkyr BP [~700 years ago] and the present [is] consistent with ice core temperature reconstructions of cooling atmospheric temperatures.”



Image Source: Truax et al., 2024

 

The Antarctic temperature has not increased as well despite the increase in atmospheric CO2 from 280 ppm to 420 ppm in the last 150 years. Gosh, the models predicted warming. What happened? Mr. B correctly pointed out the very low H2O vapor content of the Antarctic atmosphere but again no warming (possibly a slight cooling trend).

 

More cooling in the data.

Greenland Surface Temperatures Fall for 20 Years in Fresh Blow to Climate Alarm Narrative
Chris Morrison
Nowhere is this lack of scientific inquiry more evident than at the two Poles of the Earth. Antarctica has barely warmed during 70 years of detailed observations, while the situation…

 

Yes, but it's not all that puzzling because there are so many confounding factors, the data are so noisy, and the CO2 signal is so small. That said, if there was going to be a significant CO2 signal, it should have been easier to spot in the Antarctic because the geography is so much simpler than in the Arctic.

 

And the Antarctic temperature has been the same for the last ~ 150 years despite CO2 increasing from 280 to 420 ppm. As you pointed out there is practically zero H2O in the atmosphere so no contribution there but despite model predictions of temperature increase there is none. Also no urban heat islands down there.

 

Bingo. When you extract all the instrument data that are contaminated by urban heating, land use changes, night-time energy use, etc., the "unprecedented rapid warming" turns into a nothing burger.

 

Heading downhill.
UAH v6.1 Global Temperature Update for November, 2024: +0.64 deg. C
December 3rd, 2024
Metop-C Satellite Added to Our Processing

With this update, we have added Metop-C to our processing, so along with Metop-B we are back to having two satellites in the processing stream. The Metop-C data record begins in July of 2019. Like Metop-B, Metop-C was designed to use fuel to maintain its orbital altitude and inclination, so (until fuel reserves are depleted) there is no diurnal drift adjustment needed. Metop-B is beginning to show some drift in the last year or so, but it’s too little at this point to worry about any diurnal drift correction.

The Version 6.1 global average lower tropospheric temperature (LT) anomaly for November, 2024 was +0.64 deg. C departure from the 1991-2020 mean, down from the October, 2024 anomaly of +0.75 deg. C.


The Version 6.1 global area-averaged temperature trend (January 1979 through November 2024) remains at +0.15 deg/ C/decade (+0.21 C/decade over land, +0.13 C/decade over oceans).

 

Deleted.

 

That's where my money would be, if there was an average global surface temperature market like the election market. With El Nino likely to turn into a couple of years of La Nina, the water vapor from the Tonga submarine volcano slowly condensing out of the stratosphere, and solar activity having backed off to a level below the six strong cycles of the 20th century (though still above predicted levels and recent weak cycles like 16, 20 and 24), I wouldn't be surprised to see lower troposphere temperatures half a degree C below the 2024 peak level by late 2026. Indeed, 2024's record high temperature could well hold for decades if the sun goes quiet, as many astrophysicists expect. CO2 will continue to be nearly irrelevant -- so how low would temperatures have to go before the alarmists would find a willingness to consider the possibility that their CO2 climate narrative is busted?

 

An interesting question.

 

Antarctica is ahead of the curve.
Another New Study Reports A Lack Of A Long-Term Warming Trend Across Antarctica
Another New Study Reports A Lack Of A Long-Term Warming Trend Across Antarctica
By Kenneth Richard on 5. December 2024

Even though atmospheric CO2 rose from 337 ppm in 1979 to 420 ppm in 2022, there is no evidence of a warming trend across Antarctica during this period.
According to a new study, Antarctica’s station data indicate a pronounced cooling trend by over -1°C (-0.53°C per decade) from 1979-1999. The cooling trend thereafter slowed to a pause (-0.004°C per decade) from 1999-2022.

“Reanalysis” data reveal a less pronounced -0.43°C per decade cooling trend from 1979-1999, but a reversal to a +0.29°C per decade warming trend from 1999-2022.

Both the station data and the reanalyzed data affirm an overall long-term (43 years) cooling trend across Antarctica since 1979.



Image Source: Choi et al., 2024

 

It looks like 2024 was the warmest year of the satellite temperature era, but the trend now is down hill.
2024 Sets New Record for Warmest Year In Satellite Era (Since 1979)

The Version 6.1 global average lower tropospheric temperature (LT) anomaly for December, 2024 was +0.62 deg. C departure from the 1991-2020 mean, down slightly from the November, 2024 anomaly of +0.64 deg.


The Version 6.1 global area-averaged temperature trend (January 1979 through December 2024) remains at +0.15 deg/ C/decade (+0.22 C/decade over land, +0.13 C/decade over oceans).

As seen in the following ranking of the years from warmest to coolest, 2024 was by far the warmest in the 46-year satellite record averaging 0.77 deg. C above the 30-year mean, while the 2nd warmest year (2023) was +0.43 deg. C above the 30-year mean. [Note: These yearly average anomalies weight the individual monthly anomalies by the number of days in each month.]