Home/BlogThe Version 6.1 global average lower tropospheric temperature (LT) anomaly for April, 2025 was +0.61 deg. C departure from the 1991-2020 mean, up a little from the March, 2025 anomaly of +0.57 deg. C.
The Version 6.1 global area-averaged linear temperature trend (January 1979 through April 2025) remains at +0.15 deg/ C/decade (+0.22 C/decade over land, +0.13 C/decade over oceans).
The following table lists various regional Version 6.1 LT departures from the 30-year (1991-2020) average for the last 16 months (record highs are in red).
| YEAR | MO | GLOBE | NHEM. | SHEM. | TROPIC | USA48 | ARCTIC | AUST |
| 2024 | Jan | +0.80 | +1.02 | +0.58 | +1.20 | -0.19 | +0.40 | +1.12 |
| 2024 | Feb | +0.88 | +0.95 | +0.81 | +1.17 | +1.31 | +0.86 | +1.16 |
| 2024 | Mar | +0.88 | +0.96 | +0.80 | +1.26 | +0.22 | +1.05 | +1.34 |
| 2024 | Apr | +0.94 | +1.12 | +0.76 | +1.15 | +0.86 | +0.88 | +0.54 |
| 2024 | May | +0.78 | +0.77 | +0.78 | +1.20 | +0.05 | +0.20 | +0.53 |
| 2024 | June | +0.69 | +0.78 | +0.60 | +0.85 | +1.37 | +0.64 | +0.91 |
| 2024 | July | +0.74 | +0.86 | +0.61 | +0.97 | +0.44 | +0.56 | -0.07 |
| 2024 | Aug | +0.76 | +0.82 | +0.69 | +0.74 | +0.40 | +0.88 | +1.75 |
| 2024 | Sep | +0.81 | +1.04 | +0.58 | +0.82 | +1.31 | +1.48 | +0.98 |
| 2024 | Oct | +0.75 | +0.89 | +0.60 | +0.63 | +1.90 | +0.81 | +1.09 |
| 2024 | Nov | +0.64 | +0.87 | +0.41 | +0.53 | +1.12 | +0.79 | +1.00 |
| 2024 | Dec | +0.62 | +0.76 | +0.48 | +0.52 | +1.42 | +1.12 | +1.54 |
| 2025 | Jan | +0.45 | +0.70 | +0.21 | +0.24 | -1.06 | +0.74 | +0.48 |
| 2025 | Feb | +0.50 | +0.55 | +0.45 | +0.26 | +1.04 | +2.10 | +0.87 |
| 2025 | Mar | +0.57 | +0.74 | +0.41 | +0.40 | +1.24 | +1.23 | +1.20 |
| 2025 | Apr | +0.61 | +0.77 | +0.46 | +0.37 | +0.82 | +0.85 | +1.21 |
The full UAH Global Temperature Report, along with the LT global gridpoint anomaly image for April, 2025, and a more detailed analysis by John Christy, should be available within the next several days here.
The monthly anomalies for various regions for the four deep layers we monitor from satellites will be available in the next several days at the following locations:
Note the 10-year and 30-year moving averages over at https://datagraver.com/climate-data-set-uah/
They represent the important takeaway from the data. The short-term ‘noise’ is quite irrelevant from a CLIMATE perspective.
yet, without the monthly measurements, we would not have long-term averages. Kind of like living in a tiny town with 555 voters… would you say, “my vote doesn’t count anyway”?
Yes, I’m familiar with averages. Obviously we need measurements to calculate averages and I linked to a site that explicitly lists the UAH data as the input to the calculation of the averages.
The point I was making was that it is important to see the ‘forest’ (climate change) rather than the the ‘trees’ (monthly temperature fluctuations). I get the impression that many people commenting here don’t see the forest for all the trees, so to speak.
The current long term (think decades) global warming is around twenty times faster than the most rapid warming we’re aware of in Earth’s past, like the PETM and the deglacializations.
Ah, but without monthly numbers, people couldn’t get worked up into a froth about them on the regular, providing them with an opportunity to form communities and to ‘other’ their political opponents, providing a sense of belonging and superiority.
The 10-year averaging is rather interesting. The 30-year average is not much better that just taking the first year and the last year and drawing a line. There is no way to make any real sense out of 45 years of accurate data satellites, if the goal is to compare that to previous surface data. For example, there was the mini-warming in the 1930s and 1940s, and the genuine pause from about 1960 to 1990. There is no way to know what the satellite data might have shown if it was available.
The 10-year averaging is rather interesting. The 30-year average is not much better that just taking the first year and the last year and drawing a line. There is no way to make any real sense out of 45 years of accurate data from satellites, if the goal is to compare that to previous surface data. For example, there was the mini-warming in the 1930s and 1940s, and the genuine pause from about 1960 to 1990. There is no way to know what the satellite data might have shown if it was available in those years.
Equal 3rd warmest April. Tied with 2016, and close to 1998. Easily the warmest non El Nino year.
Year Anomaly
1 2024 0.94
2 1998 0.62
3 2016 0.61
4 2025 0.61
5 2019 0.32
6 2020 0.26
7 2022 0.26
8 2005 0.20
9 2010 0.20
10 2017 0.18
My projection for 2025 increases slightly to 0.48 +/- 0.15C. This makes it more likely that 2025 will be warmer than 2023. I have is at about 75% that 2025 being the second warmest year. But again, given the unusual patters we are seeing at the moment, that should be taken with a large pinch of salt.
A similar month wrt ENSO history would be April, 2017, which was a whopping 0.43 lower.
It’s surpring that at this point in 2023 April was 0.5C colder.
Equal 3rd warmest April and warmest non-El Nino year. The ten warmest Aprils are now:
Year Anomaly
1 2024 0.94
2 1998 0.62
3 2016 0.61
4 2025 0.61
5 2019 0.32
6 2020 0.26
7 2022 0.26
8 2005 0.20
9 2010 0.20
10 2017 0.18
(Sorry if this is a repeated comment. I’ve posted twice before but neither showed up. I’m now trying a different browser.)
This is the equal 3rd warmest April. Tied with 2016. It is the warmest non-El Nino April.
Year Anomaly
1 2024 0.94
2 1998 0.62
3 2016 0.61
4 2025 0.61
5 2019 0.32
6 2020 0.26
7 2022 0.26
8 2005 0.20
9 2010 0.20
10 2017 0.18
The recent slight UAH increase is from tropical warming since January.
https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/figure02.gif
Of more interest is the faster NH trend than any other region.
https://i.postimg.cc/Y9tfd3H8/UAH-LT-Regional-Trends.jpg
“Of more interest is the faster NH trend than any other region.”
It is well-known that land surface warms faster than ocean surface. And it’s also well-known that the northern hemisphere has much more land than the southern hemisphere, so it’s hardly surprising that it warms faster.
S. George Philander
An accurate map is “reality”. Believing CO2 can warm the planet is a “belief”.
Beliefs ain’t reality.
The atmospheric greenhouse effect was discovered in the 19th century. Without it, Earth would be around 30 degrees C colder than it is. I suggest you read up on Fourier, Foote, Tyndall and Arrhenius.
Sorry Gadden, but it was more like “imagined”.
Imagination ain’t science.
If you can’t show how CO2 can warm Earth’s 288K surface, then you’re just mired in false beliefs.
It’s basic physics. See for example any atmospheric science textbook.
1. Earth receives sunlight such that it is not at absolute zero temperature.
2. Earth radiates infrared radiation (thanks to it’s nonzero temperature) towards space.
3. Greenhouse gas molecules in the air absorb some of the outgoing infrared radiation and then deliver that energy to the air, making the air warmer than it OTHERWISE would have been. (Without the greenhouse gases, the infrared radiation (and thus the energy contained therein) would go straight to space in a fraction of a second.)
Gadden,
Show us your evidence that this happening. Also, show your evidence that the Earth is a black body and that the emissivity is 0.95.
Gadden,
I don’t thing the Atmospheric Green House Effect has ever been discovered. It has been hypothesized. Can you provide some evidence that CO2 causes 59F of warming? Can you provide some evidence the Earth behaves as a black body? Can you provide some evidence that the Earth’s Emissivity is 1.
S. George Philander.
As the C02 effect on temperature is linear , where is the waterfall? much ado about nothing .
The radiative forcing from carbon dioxide is close to logarithmic; it’s definitely not linear.
This isn’t really in dispute. It also doesn’t mean on its own that any particular concentration is either good or bad.
as the C02 effect on temperature is linear and hydrocarbons are finite,where is the waterfall? Its nonsense unless a warmer more productive planet scares you.
The assertion that “the CO₂ effect on temperature is linear” is scientifically incorrect, misleading, and betrays a fundamental misunderstanding of radiative physics and atmospheric thermodynamics.
If you can’t address the scientific question, there is no hope of you answering the political question.
Ian Brown and stephen p anderson should discuss the finer points of how increases in CO2 concentration having either a linear effect as Ian posits, or absolutely no effect, as stephen suggests.
The Monckton Pause extends to 22 months starting in 2023/06. The average of this pause is 0.70 C. The previous Monckton Pause started in 2014/06 and lasted 107 months and had an average of 0.21 C. That makes this pause 0.49 C higher than the previous one.
My prediction for 2025 from the March update was 0.43 +/- 0.16 C.
My prediction for 2025 including the April update is now 0.47 +/- 0.14 C.
It hasn’t cooled down much because TSI is still very high in 2025.
https://i.postimg.cc/SKwgLJGr/CERES-TSI-Composite.jpg
Many people like to think they’ve falsified solar activity forcing.
This time I am going to continue where I left off in last month’s blog, as bdgwx thought I was wrong about TSI, and since I was too busy in April with ice storm clean-up and dealing with poor internet to spend time on it, I think today would be a good day to respond to those comments and give you another update.
The sun has emitted 27.1782 W/m2 more solar irradiance in solar cycle #25 than in cycle #24 by the 64th month (March), updated from 26.3W through February. This total was derived by subtracting the NASA CERES TSI Composite monthly TSI for solar cycle #24 from cycle #25, and then summing the differences, as can be seen below:
https://i.postimg.cc/0N7sq7BL/Tale-of-2-Cycles.jpg
Here’s what bdgwx said last month in response to my comment:
“That is patently false.
The average TSI over 63 months starting from the beginning of SC25 from 2019/12 to 2025/02 is 1362.24 W.m-2.
The average TSI over 63 months starting from the beginning of SC24 from 2008/01 to 2013/03 is 1361.73 W.m-2.
That is a difference of 1362.24 – 1361.73 = 0.51 W.m-2. That isn’t even remotely close to your claimed 26.3 W.m-2.”
I thank bdgwx for the opportunity to demonstrate how easy it was for him to misrepresent this and still yet feel victorious, wrongly.
There are so many mistakes here so it will take some time, I’m sorry.
1. bdgwx didn’t use the same data set I used. There were two instruments that measured TSI during SC#24 & #25, SORCE and TSIS, both available from the LASP server. SORCE covered SC#24, and TSIS has covered SC#25. Their data were offset during the overlap period. This offset is handled by LASP and NASA in the NASA CERES composite.
bdgwx used the individual TSI data sets instead of the TSI composite.
2. bdgwx did not use the correct starting month for SC#24, which was 2008/12, not 2008/01.
3. bdgwx didn’t multiply his 0.51 by the 63 months duration to get the gross total excess TSI of SC#25 over SC#24!!! His number results in 32.13, not 26.3, because his start time for SC#24 was wrong so his average was wrong and then he didn’t use the composite TSI like I did so the difference in cycles is wrong too.
That’s 3 strikes and you’re out!
Let’s see what else bdgwx said. “BW said: This result is then divided by the canonical 4 to get 1.25 W/m^2/yr in average solar climate forcing over each of the last 5.25 years.
Again, this is patently false.
The actual radiative force is 0.51 W.m-2 * (1 – 0.3) / 4 = 0.09 W.m-2. That isn’t even remotely close to your claimed 1.25 W.m-2.
1. I didn’t say ‘radiative forcing’. We want use the form I used since it can be directly compared to other proposed forcings such as from CO2, which is similarly expressed.
2. bdgwx used the wrong calculated value of 0.51 to begin with.
3. bdgwx used the 0.3 value for albedo. Why? I said in my original comment bdgwx responded to last month that the albedo was lower during that period as it typically is during the start of a solar cycle, lower albedo being a function of eastern tropical Pacific ocean La Nina cooling, which leverages the available rising TSI. Furthermore I had said TSI contributed about 36% of the ASR, after the albedo effect, not 100% as he apparently intended to imply.
That’s 3 more strikes and you’re out again bdgwx!
What did I say?
Many people like to think they’ve falsified solar activity forcing.
“bdgwx didn’t multiply his 0.51 by the 63 months duration to get the gross total excess TSI”.
Oh dear. If you multiply with the number of months, the unit is no longer W/m^2. It’s like saying that a car, driving at 50 mph for 63 months will accumulate a gross total speed of 3,150 mph.
Very good Gadden. People don’t understand radiative physics, especially “radiative flux”
Flux does not simply add, like energy does. People confuse the two. The more people, like you, that recognize the mistakes, the more others can learn.
Good job.
I standby what I said. You are wrong. That is unequivocal and indisputable. Your response here contains an egregious math mistake. 0.51 W.m-2 * 63 months does NOT equal 32.1 W.m-2. What it equals is 32.1 Wmonths.m-2. That is Wmonths.m-2; not W.m-2. Those are two completely different things. Fix your math and resubmit for review.
You’re right. BobW’s number ends up in joules/m2.
(0.51 W/m2)*(63 months) = 1.3 megajoules/m2
That’s energy delivery, not power delivery, over 5+ years. That’s not much. That’s about one 100 W light bulb running for 3 hours. 3 hours out of 5+ years.
We have more mystery. Is it really going down, or is it leveling off. Once again, next month will be interesting.
Compelling evidence that CO2 does not cause climate change is double. 1. Paleo and recent CO2 data show no correlation (without substantial proportionality change) between CO2 and T at CO2>300 ppmv. 2. Average global water vapor has been increasing about 1.4 % per decade which is more than twice as fast as possible from just planet warming. The measured increase in WV can account for all of the climate change attributable to humanity
Compelling evidence that CO2 does not cause climate change is double. 1. Paleo and resent CO2 data show no correlation (without substantial proportionality change) between CO2 and T at CO2>300 ppmv. 2. Average global water vapor has been increasing about 1.4 % per dekade which is more than twice as fast as possible from just planet warming. The measured increase in WV can account for all of the climate change attributable to humanity
I have a theory that the double posts (including mine) are a result of the site updating very slowly so it appears that the comment did not get posted. This is different than 403 Forbidden.