The best context for understanding decadal temperature changes comes from the world’s sea surface temperatures (SST), for several reasons:

• The ocean covers 71% of the globe and drives average temperatures;
• SSTs have a constant water content, (unlike air temperatures), so give a better reading of heat content variations;
• A major El Nino was the dominant climate feature in recent years.

HadSST is generally regarded as the best of the global SST data sets, and so the temperature story here comes from that source. Previously I used HadSST3 for these reports, but Hadley Centre has made HadSST4 the priority, and v.3 will no longer be updated.  HadSST4 is the same as v.3, except that the older data from ship water intake was re-estimated to be generally lower temperatures than shown in v.3.  The effect is that v.4 has lower average anomalies for the baseline period 1961-1990, thereby showing higher current anomalies than v.3. This analysis concerns more recent time periods and depends on very similar differentials as those from v.3 despite higher absolute anomaly values in v.4.  More on what distinguishes HadSST3 and 4 from other SST products at the end. The user guide for the current version HadSST4.1.1.0 is here.   The charts and analysis below is produced from the current data.

The Current Context

The chart below shows SST monthly anomalies as reported in HadSST4 starting in 2015 through May 2025. A global cooling pattern is seen clearly in the Tropics since its peak in 2016, joined by NH and SH cycling downward since 2016, followed by rising temperatures in 2023 and 2024.

Note that in 2015-2016 the Tropics and SH peaked in between two summer NH spikes.  That pattern repeated in 2019-2020 with a lesser Tropics peak and SH bump, but with higher NH spikes. By end of 2020, cooler SSTs in all regions took the Global anomaly well below the mean for this period.  A small warming was driven by NH summer peaks in 2021-22, but offset by cooling in SH and the tropics, By January 2023 the global anomaly was again below the mean.

Then in 2023-24 came an event resembling 2015-16 with a Tropical spike and two NH spikes alongside, all higher than 2015-16. There was also a coinciding rise in SH, and the Global anomaly was pulled up to 1.1°C last year, ~0.3° higher than the 2015 peak.  Then NH started down autumn 2023, followed by Tropics and SH descending 2024 to the present. After 12 months of cooling in SH and the Tropics, the Global anomaly came back down, led by NH cooling the last 8 months from its 1.3C peak in August, down to 0.8C in March and April.  Remarkably, April 2025 SST anomalies in all regions and globally are the coolest since March 2023.  May shows little change in the Global anomaly, with a SH decline offsetting an upward bump in NH.

Comment:

The climatists have seized on this unusual warming as proof their Zero Carbon agenda is needed, without addressing how impossible it would be for CO2 warming the air to raise ocean temperatures.  It is the ocean that warms the air, not the other way around.  Recently Steven Koonin had this to say about the phonomenon confirmed in the graph above:

El Nino is a phenomenon in the climate system that happens once every four or five years.  Heat builds up in the equatorial Pacific to the west of Indonesia and so on.  Then when enough of it builds up it surges across the Pacific and changes the currents and the winds.  As it surges toward South America it was discovered and named in the 19th century  It iswell understood at this point that the phenomenon has nothing to do with CO2.

Now people talk about changes in that phenomena as a result of CO2 but it’s there in the climate system already and when it happens it influences weather all over the world.   We feel it when it gets rainier in Southern California for example.  So for the last 3 years we have been in the opposite of an El Nino, a La Nina, part of the reason people think the West Coast has been in drought.

It has now shifted in the last months to an El Nino condition that warms the globe and is thought to contribute to this Spike we have seen. But there are other contributions as well.  One of the most surprising ones is that back in January of 2022 an enormous underwater volcano went off in Tonga and it put up a lot of water vapor into the upper atmosphere. It increased the upper atmosphere of water vapor by about 10 percent, and that’s a warming effect, and it may be that is contributing to why the spike is so high.

A longer view of SSTs

The graph below  is noisy, but the density is needed to see the seasonal patterns in the oceanic fluctuations.  Previous posts focused on the rise and fall of the last El Nino starting in 2015.  This post adds a longer view, encompassing the significant 1998 El Nino and since.  The color schemes are retained for Global, Tropics, NH and SH anomalies.  Despite the longer time frame, I have kept the monthly data (rather than yearly averages) because of interesting shifts between January and July.

The graph above is noisy, but the density is needed to see the seasonal patterns in the oceanic fluctuations.  Previous posts focused on the rise and fall of the last El Nino starting in 2015.  This post adds a longer view, encompassing the significant 1998 El Nino and since.  The color schemes are retained for Global, Tropics, NH and SH anomalies.  Despite the longer time frame, I have kept the monthly data (rather than yearly averages) because of interesting shifts between January and July. 1995 is a reasonable (ENSO neutral) starting point prior to the first El Nino.

The sharp Tropical rise peaking in 1998 is dominant in the record, starting Jan. ’97 to pull up SSTs uniformly before returning to the same level Jan. ’99. There were strong cool periods before and after the 1998 El Nino event. Then SSTs in all regions returned to the mean in 2001-2.

SSTS fluctuate around the mean until 2007, when another, smaller ENSO event occurs. There is cooling 2007-8,  a lower peak warming in 2009-10, following by cooling in 2011-12.  Again SSTs are average 2013-14.

Now a different pattern appears.  The Tropics cooled sharply to Jan 11, then rise steadily for 4 years to Jan 15, at which point the most recent major El Nino takes off.  But this time in contrast to ’97-’99, the Northern Hemisphere produces peaks every summer pulling up the Global average.  In fact, these NH peaks appear every July starting in 2003, growing stronger to produce 3 massive highs in 2014, 15 and 16.  NH July 2017 was only slightly lower, and a fifth NH peak still lower in Sept. 2018.

The highest summer NH peaks came in 2019 and 2020, only this time the Tropics and SH were offsetting rather adding to the warming. (Note: these are high anomalies on top of the highest absolute temps in the NH.)  Since 2014 SH has played a moderating role, offsetting the NH warming pulses. After September 2020 temps dropped off down until February 2021.  In 2021-22 there were again summer NH spikes, but in 2022 moderated first by cooling Tropics and SH SSTs, then in October to January 2023 by deeper cooling in NH and Tropics.

Then in 2023 the Tropics flipped from below to well above average, while NH produced a summer peak extending into September higher than any previous year.  Despite El Nino driving the Tropics January 2024 anomaly higher than 1998 and 2016 peaks, following months cooled in all regions, and the Tropics continued cooling in April, May and June along with SH dropping.  After July and August NH warming again pulled the global anomaly higher, September through January 2025 resumed cooling in all regions, continuing February through April 2025, with little change in May.

What to make of all this? The patterns suggest that in addition to El Ninos in the Pacific driving the Tropic SSTs, something else is going on in the NH.  The obvious culprit is the North Atlantic, since I have seen this sort of pulsing before.  After reading some papers by David Dilley, I confirmed his observation of Atlantic pulses into the Arctic every 8 to 10 years.

Contemporary AMO Observations

Through January 2023 I depended on the Kaplan AMO Index (not smoothed, not detrended) for N. Atlantic observations. But it is no longer being updated, and NOAA says they don’t know its future.  So I find that ERSSTv5 AMO dataset has current data.  It differs from Kaplan, which reported average absolute temps measured in N. Atlantic.  “ERSST5 AMO  follows Trenberth and Shea (2006) proposal to use the NA region EQ-60°N, 0°-80°W and subtract the global rise of SST 60°S-60°N to obtain a measure of the internal variability, arguing that the effect of external forcing on the North Atlantic should be similar to the effect on the other oceans.”  So the values represent SST anomaly differences between the N. Atlantic and the Global ocean.

The chart above confirms what Kaplan also showed.  As August is the hottest month for the N. Atlantic, its variability, high and low, drives the annual results for this basin.  Note also the peaks in 2010, lows after 2014, and a rise in 2021. Then in 2023 the peak was holding at 1.4C before declining.  An annual chart below is informative:

Note the difference between blue/green years, beige/brown, and purple/red years.  2010, 2021, 2022 all peaked strongly in August or September.  1998 and 2007 were mildly warm.  2016 and 2018 were matching or cooler than the global average.  2023 started out slightly warm, then rose steadily to an  extraordinary peak in July.  August to October were only slightly lower, but by December cooled by ~0.4C.

Then in 2024 the AMO anomaly started higher than any previous year, then leveled off for two months declining slightly into April.  Remarkably, May showed an upward leap putting this on a higher track than 2023, and rising slightly higher in June.  In July, August and September 2024 the anomaly declined, and despite a small rise in October, ended close to where it began.  Note 2025 started much lower than the previous year and is headed sharply downward, well below the previous two years, now in May aligning with 2010.

The pattern suggests the ocean may be demonstrating a stairstep pattern like that we have also seen in HadCRUT4.

The purple line is the average anomaly 1980-1996 inclusive, value 0.17.  The orange line the average 1980-2024, value 0.38, also for the period 1997-2012. The red line is 2013-2024, value 0.67. As noted above, these rising stages are driven by the combined warming in the Tropics and NH, including both Pacific and Atlantic basins.

Curiosity:  Solar Coincidence?

The news about our current solar cycle 25 is that the solar activity is hitting peak numbers now and higher  than expected 1-2 years in the future.  As livescience put it:  Solar maximum could hit us harder and sooner than we thought. How dangerous will the sun’s chaotic peak be?  Some charts from spaceweatherlive look familar to these sea surface temperature charts.

Summary

The oceans are driving the warming this century.  SSTs took a step up with the 1998 El Nino and have stayed there with help from the North Atlantic, and more recently the Pacific northern “Blob.”  The ocean surfaces are releasing a lot of energy, warming the air, but eventually will have a cooling effect.  The decline after 1937 was rapid by comparison, so one wonders: How long can the oceans keep this up? And is the sun adding forcing to this process?

Footnote: Why Rely on HadSST4

HadSST is distinguished from other SST products because HadCRU (Hadley Climatic Research Unit) does not engage in SST interpolation, i.e. infilling estimated anomalies into grid cells lacking sufficient sampling in a given month. From reading the documentation and from queries to Met Office, this is their procedure.

HadSST4 imports data from gridcells containing ocean, excluding land cells. From past records, they have calculated daily and monthly average readings for each grid cell for the period 1961 to 1990. Those temperatures form the baseline from which anomalies are calculated.

In a given month, each gridcell with sufficient sampling is averaged for the month and then the baseline value for that cell and that month is subtracted, resulting in the monthly anomaly for that cell. All cells with monthly anomalies are averaged to produce global, hemispheric and tropical anomalies for the month, based on the cells in those locations. For example, Tropics averages include ocean grid cells lying between latitudes 20N and 20S.

Gridcells lacking sufficient sampling that month are left out of the averaging, and the uncertainty from such missing data is estimated. IMO that is more reasonable than inventing data to infill. And it seems that the Global Drifter Array displayed in the top image is providing more uniform coverage of the oceans than in the past.

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June 19, 2025 at 07:55AM

By Paul Homewood

 

We’re all going to die!

 

Amber heat health alerts are in place across the whole of England with temperatures likely to exceed 30C for the first time this year.

The alerts, which will last until 09:00 BST on Monday, come as an expected heatwave approaches much of the country.

The UK Health Security Agency (UKHSA) said increased pressures on health and social care services were likely, including increased demand.

Temperatures will widely be between 27C and 30C on Thursday across east Wales, the Midlands, and East and South East England with a few locations around Greater London and the home counties reaching 31C.

https://www.bbc.co.uk/news/articles/cm2z4rmyl0yo

Meanwhile back in the real world, summer remains the season when deaths tolls are at their lowest:

https://www.ons.gov.uk/peoplepopulationandcommunity/birthsdeathsandmarriages/deaths/datasets/monthlyfiguresondeathsregisteredbyareaofusualresidence

I can’t recall the UKHSA issuing magenta alerts for mild weather in April!

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June 19, 2025 at 07:46AM

52.22277 -4.08031 Met Office CIMO Assessed Class 4 Temperature records from 31/5/2018 – current operational status uncertain.

Corgam is a manual reporting weather station to the north east of Lampeter in mid west Wales which was only installed in 2018 and its current operating status is peculiarly uncertain. The reasons for its installation and subsequent operational history are somewhat odd and seem to represent a very casual approach to Meteorology by the Met Office itself.

Firstly this low grade assessed Class 4 site is under 3.5 miles from the long standing automatic Swyddffynnon weather station operational from 1955. This very sparsely populated area of south west Wales already had numerous long term sites as demonstrated by this map showing only automated sites. The site above Tregaron showing “17” is Swyddffynnon with both the high quality Trawsgoed just north of it and Gogerddan just outside Aberystwyth. Corgam is just to the south west of Swyddffynnon.

The Met Office produces a list of all its CIMO assessed weather stations here with Corgam clearly shown as one of its “Climate Stations” intended to be representative of the wider area climatic conditions.

This webpage specifically states the following purposes of manual reporting “Climate Stations” as below

“The map shows the current network of automatic (synoptic) and manual (climate) stations covering the UK.

UK weather stations report a mixture of snapshot hourly observations of the weather known as synoptic observations, and daily summaries of the weather known as climate observations.

For instance, hourly temperature is a synoptic observation, but daily maximum and minimum temperature are climate observations; cloud is synoptic but sunshine is climate. Climate observations are made at 0900UTC, with some stations making further climate observations at 2100UTC.  In summer these correspond to 1000BST and 2200BST respectively.

Observations from around 260 UK automatic (synoptic) stations are collected in real time; climate data from these stations also comes in straight after readings are taken. Climate observations from around 140 co-operating observers at manual climate stations are also received in slower time.

All climate stations record daily maximum and minimum air temperature and rainfall amount, recorded over the period 0900-0900UTC (1000-1000BST in summer).”

I feel that is an extremely specific definition of the purposes of a “Climate Reporting” weather station, so how does that sit with this detailed description of the site.

Pause for thought………..the Met Office is basing its reports on “Climate Change” ( noted to the second decimal place of a degree) based on data from a site described as “This station provides data for an agricultural business.” So presumably that is “Near enough for Jazz” as far as the Met Office is concerned? I have no wish to in any way disparage the, no doubt, meteorologically interested amateur running this site, however, the British public are being led to believe in the high quality of the Met Office station as detailed here.

https://www.metoffice.gov.uk/binaries/content/assets/metofficegovuk/pdf/research/library-and-archive/library/publications/factsheets/factsheet_17-observations_over_land_2023.pdf

Just one example:-

“Wind
Wind over the land surface should ideally be measured at a height of 10 m above ground level at the top
of a mast or some other supporting structure that has small impact on the local flow of air. Wind is the
horizontal movement of air and is specified by its speed and direction. “

Okay how does that square up to the reality of –

“Wind gauge is mounted on a 2 metre pole above ridge of farm building which is itself approx. 6 metres high.“

THIS IS COMPLETELY UNACCEPTABLE ON THE PART OF THE MET OFFICE .

The function of a climate weather station is to take timely and accurate readings. Clearly any wind recordings, if taken, are junk. The site itself is generously assessed by the Met Office as Class 4, frankly ,without wasting too much time, it really is not. The Ordnance survey sheet shows a significant sloping gradient, the screen is subject to shade and the whole site is a working farm with no enclosure at all to the screen.

Moving onto reading regularity does not indicate recording temperatures was a priority. The site started 1/6/2018 and of the 214 days readings failed to provide both tmax and/or tmin on 10 occasions meaning 10 days where no daily average was possible to derive. 2019 there were only 321 complete days, 2020 – 340 complete days, 2021 just 249 days , 2022 just 284 days. In 2023 all readings abruptly stopped on 1/10/2023 having only managed 260 readings to that point. Whether or not the site is still officially reporting is open to question though it has not been deleted from the listings noted above. This lack of readings does not, however, restrict the Met office from deriving “annual daily means” from sites as demonstrated by the absurdity of deriving an annual daily mean from Mickleham (and others) from tiny fractions of annual readings.

A slightly ironic aspect of my research into individual sites is that I occasionally discover the site owner’s identities such as at Whitechurch. In the case of Corgam I unintentionally stumbled across the owner/observer on “X” (formerly twitter). I have no wish to identify them or criticise their efforts but it certainly seemed that, whilst they held an interest in meteorology for their occupational advantage, it was not an over-riding interest of theirs for their unsuitable data to be used in the construction of a national historic temperature record. The Met Office is solely to blame for the inclusion of this unacceptable climate reporting station.

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June 19, 2025 at 06:29AM

via Watts Up With That?

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June 19, 2025 at 04:04AM