Archives par mot-clé : Global Temperature

CET 30-Year Averages

by P. Homewood, Sept 7, 2021 in NotaLotofPeopleKnowThat

The World Meteorological Organisation is clear about defining climate average:


It is disappointing then that the Met Office still continues to use the 1981-2010 period as its base. By doing this, of course, it exaggerates temperature increases in the UK.

If we look at the Central England Temperature mean temperatures, for example, we see that both winter and spring this year were colder than average, whilst summer was only 0.3C warmer:



New Study: 2000-Year Precipitation Reconstructions Expose Climate Models Still Of Junk Grade

by Atwood et al., Aug 18, 2021 in NoTricksZone

A new study by Atwood et al (2021) published in the journal of Paleoceanography and Paleoclimatology found there’s “poor agreement” between precipitation reconstructions and model simulations over the past 2000 years. This means future projections made by current models are unreliable. 


Models and reconstructions don’t agree

These comprehensive reconstructions show that from 800 to 1000 CE there was a pronounced drying event relative from the eastern Pacific and parts of Mesoamerica.

Also the period “1400–1700 CE is marked by pronounced hydroclimate changes across the tropics, including dry and/or isotopically enriched conditions in South and East Asia, wet and/or isotopically depleted conditions in the central Andes and southern Amazon in South America, and fresher and/or isotopically depleted conditions in the Maritime Continent.”

The study’s abstract also notes how there’s a glaring disagreement between the simulations done by models and what the reconstructions show: “We find notable dissimilarities between the regional hydroclimate changes and global-scale and hemispheric-scale temperature reconstructions, indicating that more work needs to be done to understand the mechanisms of the widespread tropical hydroclimate changes during the LIA.”

The New Pause lengthens again

by C. Monckton of Brenchley, Aug 3 2021 in WUWT

The New Pause has lengthened by another two months. Even though the brief la Niña that began in late 2020 has now ended, on the UAH dataset there has been no global warming for 6 years 6 months till July 2021. As always, the Pause is calculated as the longest period ending in the present that shows no warming trend, taken as the least-squares linear-regression trend on the UAH satellite monthly global mean surface temperature anomalies for the lower troposphere:


Global Warming Stalls Again – Back To Levels Seen 20 Years Ago

by P. Gosselin & Kirye, July 6, 2021 in ClimateChangeDispatch

Before we begin, Dr. Roy Spencer just published that Version 6 of the University of Alabama-Huntsville satellite-based global average lower tropospheric temperature (LT) anomaly for June 2021 was -0.01 deg. C, down from the May 2021 value of +0.08 deg. C.

As Dr. Spencer’s chart above shows, temperatures are back within the range seen 20 years ago. The hiatus in global temperature rise appears to have resumed.

June cooling in Tokyo


Source: JMA

Read more at No Tricks Zone

El Niño and the lengthening New Pause: now 6 years 10 months

by C. Monckton of Brenchley, July 3, 2021 in WUWT

The latest UAH temperature anomalies show that the New Pause has lengthened by another two months to 6 years 10 months. As usual, the Pause is defined as the longest period, up to the most recent month for which data are available, during which the linear-regression trend on the monthly global mean lower-troposphere temperature anomalies shows no increase.


Pauses have no predictive purpose. Just because there has been no global warming for more than seven years (HadCRUT4) or almost seven years (UAH), that does not mean there will be no global warming in future.

see also:  Global Warming Stalls Again – Back To Levels Seen 20 Years Ago! And: No Warming In Tokyo This Century

UAH Global Temperature Update for June 2021: -0.01 deg. C

by Roy Spencer, July 3, 2021 in WUWT

The Version 6.0 global average lower tropospheric temperature (LT) anomaly for June, 2021 was -0.01 deg. C, down from the May, 2021 value of +0.08 deg. C.

REMINDER: We have changed the 30-year averaging period from which we compute anomalies to 1991-2020, from the old period 1981-2010. This change does not affect the temperature trends.

The linear warming trend since January, 1979 remains at +0.14 C/decade (+0.12 C/decade over the global-averaged oceans, and +0.18 C/decade over global-averaged land).


UAH Global Temperature Update for May 2021: +0.08 deg. C

by R. Spencer, June 1st, 2021 in GlobalWarming

The Version 6.0 global average lower tropospheric temperature (LT) anomaly for May, 2021 was +0.08 deg. C, up from the April, 2021 value of -0.05 deg. C.

REMINDER: We have changed the 30-year averaging period from which we compute anomalies to 1991-2020, from the old period 1981-2010. This change does not affect the temperature trends.

The linear warming trend since January, 1979 remains at +0.14 C/decade (+0.12 C/decade over the global-averaged oceans, and +0.18 C/decade over global-averaged land).

Greta Hasn’t Seen April Warming In Her Life. Global Surface Temperatures Plummet 0.75°C Since 2016

by P. Gosselin, May 14, 2021 in NoTricksZone

The April, 2021, mean temperature data collected by the Japan Meteorological Agency (JMA) has been tabulated and are ready to be added to our monthly plots.

Today we look at the April mean temperature trends for stations which the JMA has sufficient data and which are located in northern countries. Global warming is thought to be first visible at the far northern and Arctic regions.

German Professor: Climate Model Deviation From Observations “Striking”…”Politically Significant”

by P. Gosselin, May 8, 2021 in NoTricksZone

At Die kalte Sonne, Prof. Fritz Vahrenholt – one of the founders of Germany’s modern environmental movement – presents his monthly summary, which includes a look at global temperature and how the models are doing.

The global mean temperature deviation of satellite-based measurements from the mean of the 1991 – 2020 period was -0.05 degrees Celsius in April 2021. Nevertheless, German courts have ruled that something has got to be done about the warming planet!

Global temperature curve in April 2021

The cool La Niña situation over the recent months is still having an effect. According to the U.S. National Oceanic and Atmospheric Administration (NOAA), there is an 80% probability that La Niña will end between May and July. However, the agency expects a new La Niña to begin again in the fall.

The average temperature increase has been 0.14 degrees Celsius per decade. The model calculations, on which the IPCC’s recommendations are based, come up with a temperature increase that is twice as high for the same period (see chart below, source: R. Spencer 2021).

This striking deviation from the real temperature development is politically significant, because model forecasts are the basis for far-reaching decisions, such as constitutional court rulings.”

UAH Global Temperature Update for February 2021: +0.20 deg. C

by Roy Spencer, March. 3rd, 2021 in Global Warming

The Version 6.0 global average lower tropospheric temperature (LT) anomaly for February, 2021 was +0.20 deg. C, up from the January, 2021 value of +0.12 deg. C.

REMINDER: We have changed the 30-year averaging period from which we compute anomalies to 1991-2020, from the old period 1981-2010. This change does not affect the temperature trends.

The linear warming trend since January, 1979 remains at +0.14 C/decade (+0.12 C/decade over the global-averaged oceans, and +0.18 C/decade over global-averaged land).

Various regional LT departures from the 30-year (1991-2020) average for the last 14 months are:

…Temperature Records…

by Donn Dears, March 2, 2021

There has been an unending stream of media reports about how the last few years have been the warmest on record.

They gloss over that they are only referring to the last 150 years, because temperatures have been higher than today on several occasions over the past 10,000 years, a period between glaciations know as the Holocene.

Recently, a presentation by Tony Heller caught my attention, in which he had facts, coupled with evidence, that shed light on the media’s hypocrisy. 

What follows uses some of the materials from Mr. Heller’s presentation, coupled with additional information. (Relevant links are itemized below.)

The first chart is Figure 3, from Dr. Roy Spencer’s evaluation of the heat island effect.

It shows that the urban heat island effect has skewed reported temperatures higher than where population density is low. Areas with low population density are representative of the vast majority of land surface areas.


Today’s temperatures are not the highest, or second highest, on record: Not for the past one-hundred-fifty years, or for the past 10,0000 years.




Real Climate Science:

UK National Temperature record at Cambridge Botanic Garden –An examination of the data.

by C. Rotter, Feb 13, 2021 in WUWT

Guest Post by Tony Brown

Section 1 Introduction

A visit to the Botanical gardens in Cambridge was made by the author of this paper on August 7th 2020 between 10.15AM to 12.25pm.  The purpose was to look at the site of the Stevenson screen there,  following the establishment at this location of the highest ever recorded UK instrumental  temperature, confirmed by the Met Office as 38.7 C ( 101.6 Fahrenheit ) taken at the gardens on 25 July 2019, and to determine the possible effects on this record caused by urbanisation.  From the botanic garden web site we note:

 “Analysis of the Garden’s weather records show that over the last 100 years our average temperature has risen by 1.2 Celsius and the hottest day, highest monthly and yearly average have all occurred within the last 20 years. The highest ever temperature recorded at the Garden before this new record was 36.9 C, recorded on 10 August, 2003.”  * See; “Section 5; Temperature trends.”

Cambridge University Botanic Garden records highest ever UK temperature – Cambridge Botanic Garden

Some context is provided by firstly examining the past and present urbanisation of the gardens, the location of the Stevenson screen and there then follows an examination of various temperature recordings locally to determine what affect if any the urbanisation may have had.

The visit  was  made during one of the hottest spells of the 2020 summer and  in similar conditions to the record, in as much it had been hot in the days running up to the record with  prolonged sunshine and light winds and these were mirrored on the day of the visit. The preceding day, August 6th 2020 was partially cloudy and very warm at 27C, close by at Cambridge Airport.

CMIP6 and AR6, a preview

by Andy May, Feb 11, 2021 in WUWT

The new IPCC report, abbreviated “AR6,” is due to come out between April 2021 (the Physical Science Basis) and June of 2022 (the Synthesis Report). I’ve purchased some very strong hip waders to prepare for the events. For those who don’t already know, sturdy hip waders are required when wading into sewage. I’ve also taken a quick look at the CMIP6 model output that has been posted to the KNMI Climate Explorer to date. I thought I’d share some of what I found.

Does “global warming” mean it’s warming everywhere?

by C. Kennedy, Oct 29, 2020 in

No, “global warming” means Earth’s averageannual air temperature is rising, but not necessarily in every single location during all seasons across the globe.  It’s like your grades. If one semester you get all Bs and Cs, and the next you get all As and Cs, your grade point average rises, even though you didn’t improve in every class.

That’s the way it is with Earth’s near-surface temperature as atmospheric greenhouse gas levels climb. Temperature trends across the entire globe aren’t uniform because of the diverse geography on our planet—oceans versus continents, lowlands versus mountains, forests versus deserts versus ice sheets—as well as natural climate variability. When you’re zoomed in on a particular place, you may not be able to see the overall trend.

It is only when scientists calculate the average of temperature changes from every place on Earth over the course of a year to produce a single number, and then look at how that number has changed over time that a very clear, global warming trend emerges. In other words, it’s only when we “zoom out” to the planet-wide scale that the trend is obvious: despite a few, rare areas experiencing an overall cooling trend, the vast majority of places across the globe are warming.



The reason a “zoomed out” view makes the long-term trend so clear is that Earth’s annual average temperatures from year to year are found to be very stable when nothing is forcing it to change. Today, though, every decade since 1960 has been warmer than the last, and the last three decades each have been the warmest on record. Relative to geologic time, the warming that has occurred—1.8°F (1°C) over a span of about 120 years—is an unusually large temperature change in a relatively short span of time.

La fin du réchauffement… Pas du changement climatique!

by B. Van Vliet-Lanoë, Jan 1, 2021 in ScienceClimatEnergie

Un hiver froid s’annonce : le premier d’une série qui devrait durer au moins jusqu’en 2053 (Youssef et al., 2009 ; Zharkova et al.  2015 ; Van Vliet, 2019), période où les médias nous assènent une disparition de la banquise estivale, des ours polaires et des phoques ! Ceci est favorisé par l’activité solaire réduite depuis et le minimum solaire actuel (Fig.1). Le cycle solaire suivant (n°25) devrait aussi être faible. Nous y sommes entrés sans un Minimum d’activité aussi profond que celui Dalton (1790-1830) qui a présidé à la « Bérézina ».


Fig. 1: Intensité des cycles solaires depuis 1975 et la prédiction du cycle 25 (calculés avec le nombre de taches solaires  2018 * ANRPFD ).  B) évolution de l’extension en km2 des banquises arctique et antarctique depuis 1978 par rapport à la déviation standard 1981-2010 (NSDIC).

UAH Global Temperature Update for December 2020: +0.27 deg. C

by R. Spencer, Jan 2, 2020 in WUWT

The Version 6.0 global average lower tropospheric temperature (LT) anomaly for December, 2020 was +0.27 deg. C, down substantially from the November, 2020 value of +0.53 deg. C.For comparison, the CDAS global surface temperature anomaly for the last 30 days at was +0.31 deg. C.

2020 ended as the 2nd warmest year in the 42-year satellite tropospheric temperature record at +0.49 deg. C, behind the 2016 value of +0.53 deg. C.

Cooling in December was largest over land, with 1-month drop of 0.60 deg. C, which is the 6th largest drop out of 504 months. This is likely the result of the La Nina now in progress.

The linear warming trend since January, 1979 remains at +0.14 C/decade (+0.12 C/decade over the global-averaged oceans, and +0.18 C/decade over global-averaged land).


The full UAH Global Temperature Report, along with the LT global gridpoint anomaly image for December, 2020 should be available within the next few days here.

The global and regional monthly anomalies for the various atmospheric layers we monitor should be available in the next few days at the following locations:

Lower Troposphere:
Lower Stratosphere:

Greenland Fall Temperatures Unchanged. Proxy Data Show No Warming At 8 Of 9 Antarctic Peninsula Sites Since 1830!

by Kyrie, Dec 29, 2020 in NoTricksZone

Before looking at Antarctica Peninsula, we first take a look at Greenland, which also is considered by the global warming alarmists to be part of the most threatening tipping points. If the ice on Greenland ever melted, like they warn it will, sea levels globally would rise some 6 meters. (Never mind this scenario would take many centuries).

Today we look at the November and autumn trends in Greenland. First we look at November mean temperatures for which the Japan meteorological Agency (JMA) has sufficient data to compute a trend going back to 1999.


Four of the 6 stations examined show cooling or no warming trend.

But that’s only for one month, and so doesn’t really tell us a whole lot. So next we look at autumn mean temperatures for these six stations. If autumn is warming then we no that is not ideal for the overall ice formation season.

HadCRUT5 Adjusts Temperatures Upwards Again

by P. Homewood, Dec 16, 2020 in NotaLotofPeopleKnowThat

The Morice paper claims the extra warming has come from an improved representation of Arctic warming and a better understanding of evolving biases in sea‐surface temperature measurements from ships.

In fact it is not scientific to average together Arctic temperatures with the rest of the planet, as it is comparing apples with oranges. It all has to do with latent heat and water vapour, as Tony Heller brilliantly explained:

Sea surface skin temperature

by A. May, Dec 9, 2020 in WUWT

In previous posts, see here and here, I’ve tried to show that because the oceans cover 71% of Earth and they contain 99% of the thermal energy stored on the Earth’s surface, they dominate the speed and magnitude of climate changes. In all my posts the Earth’s surface is defined as everything from the ocean floor to the top of the atmosphere. The details of the calculation of ocean and atmospheric heat content is detailed in this spreadsheet. The ocean’s huge heat capacity prevents large temperature swings and dampens and delays those that do occur.

Attempting to show the direction, speed, and magnitude of climate change by measuring and averaging atmospheric surface temperatures is pointless, in my opinion. The record we have of atmospheric and ocean surface temperatures is too short and far too inaccurate to provide us with useful trends on a climatic (30 years +) time scale. Further, these records are sporadic measurements in a chaotic surface zone that has large temperature swings. In Montana, United States, for example, recent minimum/maximum temperatures have been as low as -70°F (-57°C) and as high as 117°F (47°C). These enormous swings make measuring year-to-year global average differences of 0.1°C exceedingly difficult. Yet, this is the precision demanded if we are to properly characterize a climate that is only warming at a rate of roughly 1.4°C/century, which is 0.014°C per year and 0.14°C/decade.

CO2 Coalition: “The Global Mean Temperature Anomaly Record How it works and why it is misleading”

by D. Middleton,  Dec 8, 2020 in WUWT

Our friends at the CO2 Coalition have published another excellent report.

This white paper by Richard Lindzen and John Christy explores the global mean temperature anomaly record. Their focus isn’t on whether it’s right or wrong; it’s on its significance relative to natural variability and its inherently low signal-to-noise ratio. Here’s the executive summary:


4 DEC, 2020
The Global Mean Temperature Anomaly Record
How it works and why it is misleading

by Richard S. Lindzen and John R. Christy

The CO2 Coalition is honored to present this Climate Issues in Depth paper by two of America’s most respected and prolific atmospheric physicists, MIT professor emeritus Richard Lindzen, who is a longtime member of the Coalition, and University of Alabama in Huntsville professor John Christy.

Professor Lindzen has published over 200 scientific articles and books over a five-decade career. He has held professorships at the University of Chicago, Harvard University and MIT. He is a fellow and award recipient of the American Meteorological Society and the American Geophysical Union. He is also a member of the National Academy of Science and was a lead author of the UN IPCC’s third assessment report’s scientific volume. His research has highlighted the scientific uncertainties about the impact of carbon dioxide emissions on temperature and climate more generally.

Professor Christy, the director of the Earth System Science Center at The University of Alabama in Huntsville, began studying global climate issues in 1987. He has been Alabama’s State Climatologist since 2000 and a fellow of the American Meteorological Society since 2002. He and CO2 Coalition member Dr. Roy W. Spencer developed and have maintained one of the key global temperature data sets relied on by scientists and government bodies, using microwave data observed in the troposphere from satellites since 1979. For this achievement, they were awarded NASA’s Medal for Exceptional Scientific Achievement.

The purpose of this paper is to explain how the data set that is referred to by policy-makers and the media as the global surface temperature record is actually obtained, and where it fits into the popular narrative associated with climate alarm.

Executive Summary
At the center of most discussions of global warming is the record of the global mean surface temperature anomaly—often somewhat misleadingly referred to as the global mean temperature record. This paper addresses two aspects of this record. First, we note that this record is only one link in a fairly long chain of inference leading to the claimed need for worldwide reduction in CO2 emissions. Second, we explore the implications of the way the record is constructed and presented, and show why the record is misleading.

This is because the record is often treated as a kind of single, direct instrumental measurement. However, as the late Stan Grotch of the Laurence Livermore Laboratory pointed out 30 years ago, it is really the average of widely scattered station data, where the actual data points are almost evenly spread between large positive and negative values.

The average is simply the small difference of these positive and negative excursions, with the usual problem associated with small differences of large numbers: at least thus far, the one-degree Celsius increase in the global mean since 1900 is swamped by the normal variations at individual stations, and so bears little relation to what is actually going on at a particular one.

The U.S. National Temperature Index, is it based on data? Or corrections?

by Andy May, Nov 24, 2020 in WUWT

The United States has a very dense population of weather stations, data from them is collected and processed by NOAA/NCEI to compute the National Temperature Index. The index is an average temperature for the nation and used to show if the U.S. is warming. The data is stored by NOAA/NCEI in their GHCN or “Global Historical Climatology Network” database. GHCN-Daily contains the quality-controlled raw data, which is subsequently corrected and then used to populate GHCN-Monthly, a database of monthly averages, both raw and final. I downloaded version 4.0.1 of the GHCN-Monthly database on October 10, 2020. At that time, it had 27,519 stations globally and 12,514 (45%) of them were in the United States, including Alaska and Hawaii. Of the 12,514 U.S. stations, 11,969 of them are in “CONUS,” the conterminous lower 48 states. The current station coverage is shown in Figure 1.

Figure 1. The GHCN weather station coverage in the United States is very good, except for northern Alaska. There are two stations in the western Pacific that are not shown.

igure 4. The orange line is the uncorrected monthly mean temperature, which is “qcu” in NOAA terminology. The blue line is corrected, or NOAA’s “qcf.”

New Study Finds A Robust Link Between European Temperatures And Solar Activity Via AMO/NAO Modulation

by K. Richard, Oct 22, 2020 in NoTricksZone

European winter temperature variability is “dominated” by the North Atlantic Oscillation (NAO), which is, in turn, modulated by solar activity.

Even proponents of anthropogenic global warming (AGW) agree natural processes (AMO, NAO, ENSO, solar forcing, volcanism) drive temperature variability. But they insist the rising temperature trend is human-caused.

So if we don’t have a regional upward trend, is the non-warming natural or anthropogenic?

Lüdecke et al., 2020 find temperatures across Europe have been oscillating, not rising in linear fashion, for the last century. The timings of the temperature undulations correspond quite closely to natural ocean cycles (the NAO and AMO). The authors detail a non-linear and indirect solar activity impact on these ocean cycles, and ultimately to the European climate.

Why lockdown had little to no effect on global temperatures

by A.N. Archer & J.Weber, Oct 22, 2020 in Phys.Org

Countries across the world took unprecedented action in the first few months of 2020 to control the spread of COVID-19. At its peak, one-third of the world’s population was in lockdown. Around the world, car travel fell by 50%, the number of flights plummeted by 75% and industrial activity fell by around 35%.

With so many cars parked, airplanes grounded and factories closed, global carbon dioxide (CO₂) emissions fell by around 17% compared with the same period in 2019. But greenhouse gases such as CO₂ weren’t the only emissions to fall, and not all pollution heats the planet. Some of the industrial activities that shut down—particularly heavy industry, including steel and cement making—also produced aerosols, which are that linger in the atmosphere for weeks and reflect heat from the Sun.

Previous studies have suggested that if a lot of these industrial processes were to suddenly shut down, it would lead to short-term warming because the atmosphere would lose the reflective effect of aerosols. But as the lockdown cleared skies, temperatures didn’t rocket.

In new research, we show that lockdown had a negligible effect on global temperatures. So what really happened?