Archives par mot-clé : Warming

better to know...?, climate-debate

Don’t Be Alarmed About Unusually Warm Temperatures

by A. Epstein, Appt 13, 2024 in ClimateChangeDispatch

Myth: Recent, unusually warm temperatures show that fossil fuels are making our climate more and more dangerous.

Truth: Even with recent temperatures, which are a temporary anomaly, not the new normal, cold is a bigger problem than heat and fossil fuels keep us safer from both. [emphasis, links added]

Leading outlets are portraying the recent streak of warmer-than-expected months as ominous and deadly, and offering anti-fossil-fuel policies as a solution.

In reality, cold is a far bigger problem than heat—and anti-fossil-fuel policies will make us more endangered by both.

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climate-debate

Warming Earth Has Changed U.S. Hardiness Zones

by  K. Hansen, March 4, 2024 in WUWT

Several times I have had readers at WUWT ask in comments:  “If the climate is changing, why haven’t the planting zone maps changed?”

Well, they have and they do.  The U.S. Department of Agriculture issues a new U.S.D.A. “Plant Hardiness Zone Map” periodically.  A new version of the map was just released on Nov. 15, 2023.  I became aware of it because my wife is an avid gardener and follows our local agricultural County Cooperative Extension news.

When she followed the link to the new Plant Hardiness map and checked our very local area, she was surprised to see that it had “warmed” here by 5°F.   Here is the bit of the page she was looking at:

She was a bit perplexed by this news, as we have been having not “hot” years but cooler years recently. It took me a minute to sort through it to see that the drop down was not clear on what temperature change they were talking about.  That temperature change elevated us one half a zone from zone 5b to zone 6a.

 

 

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climate-debate

NOAA Study: Atmosphere Warming At Half The Rate Predicted By Climate Models

by R. MCKitrick, Apr 13, 2023 in ClimateChangeDispatch

An important new study on climate change came out recently. I’m not talking about the Intergovernmental Panel on Climate Change (IPCC) Synthesis Report with its nonsensical headline, “Urgent climate action can secure a liveable future for all.”

No, that’s just meaningless sloganeering proving yet again how far the IPCC has departed from its original mission of providing objective scientific assessments. [emphasis, links added]

I’m referring instead to a new paper in the Journal of Geophysical Research-Atmospheres by a group of scientists at the U.S. National Oceanic and Atmospheric Administration (NOAA) headed by Cheng-Zhi Zou, which presents a new satellite-derived temperature record for the global troposphere (the atmospheric layer from one kilometer up to about 10 km altitude).

The troposphere climate record has been heavily debated for two reasons. First, it’s where climate models say the effect of warming due to greenhouse gases (GHGs) will be the strongest, especially in the mid-troposphere.

And since that layer is not affected by urbanization or other changes to the land surface, it’s a good place to observe a clean signal of the effect of GHGs.

Since the 1990s the records from both weather satellites and weather balloons have shown that climate models predict too much warming.

In a 2020 paper, John Christy of the University of Alabama-Huntsville (UAH) and I examined the outputs of the 38 newest climate models and compared their global tropospheric warming rates from 1979 to 2014 against observations from satellites and weather balloons.

All 38 exhibited too much warming, and in most cases, the differences were statistically significant. We argued that this points to a structural error in climate models where they respond too strongly to GHGs.

But, and this is the second point of controversy, there have also been challenges to the observational record.

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better to know...?, climate-debate

History and Human Biology Argue for Warmth, not Cold

by V. Jayaraj, Apr 6, 2023 in CO2Coalition

To those who have been misled to believe that a warming planet is dangerous, prepare to have a myth shattered: Data from hundreds of scientific journals across major publishing platforms and policy reports from major governments say cold is responsible for more deaths than hot weather worldwide.

Nonetheless, many people find it hard to believe this fact because of the decades-long propaganda and hysteria surrounding global warming. Here is why we should be thankful that our world is warming.

Human Body is Made for Warm Weather

Humans evolved in warm environments. The body is better equipped to handle heat than cold as it can regulate temperature through sweating and other mechanisms. However, in cold weather, our bodies must work harder to maintain a normal temperature, which can lead to a variety of health problems.

Anecdotes of heart attacks induced by shoveling snow are common in northern climes. When exposed to cold temperatures, the body’s blood vessels constrict to conserve heat, which can increase blood pressure and strain the heart.

The relative dryness of cold air is irritating to airways, causing inflammation and making breathing more difficult, particularly for those with preexisting respiratory conditions like asthma or chronic obstructive pulmonary disease (COPD).

So, it is no wonder that civilizations flourished when temperatures were higher, especially when home heating was primitive or nonexistent.

Lessons from Norse Farming in Greenland

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climate-debate

Greenland Temperatures Rose 1°C In 1994 … Since Then They Have Been ‘Relatively Constant’

by K. Richard, Feb 27, 2023 in NoTricksZone

A warming event that spans only one year, with decades of stable temperatures before and after, would not appear to align with rapidly rising human CO2 emissions or a gradually rising atmospheric CO2 concentration.

From 1958 to 2020, as CO2 rose from 320 ppm to 410 ppm, Greenland had a warming period of 1°C that lasted one year – 1994. Over the next 26 years (1994-2020) and spanning the years 1958 to 1993, there have been “relatively constant” temperatures across Greenland (Zhang et al., 2022).

These temperature trends appear to align much better with phases of the North Atlantic Oscillation (NAO), Greenland blocking indexes (GBI), and volcanism better than they do with any anthropogenic causal agents.

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climate-debate

Why Is Antarctica’s Climate Considered ‘Global’ But Arctic Siberia’s Is Not?

by K. Richard, Jan 26, 2023 in NoTricksZone

Independent analyses from multiple independent sources indicate Arctic Siberia was 3 to 5°C warmer than today during the peak of the last glacial, or when CO2 levels were below 200 ppm.

Measurements from Antarctica’s ice sheet are almost invariably used to characterize both the global-scale atmospheric CO2 levels and climate for the last 10s to 100s of thousands of years.

But it is rather odd that Antarctica’s climate is considered globally representative (i.e., “global warming”) since there has been no warming here for the last seven decades.

Further, ice samples from Antarctica have CO2 values that range between 900 and 2900 ppm (Matsuo and Miyake, 1966) for the modern period (i.e., the 1960s). These values are far outside the range of the accepted modern global atmospheric values (~300 to 400 ppm).

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climate-debate

In Search Of A (Near) Perfect CO2 Global Warming Analogy

by R. Barmby, Jan 23; 2023 in ClimateChangeDispatch

Most people have a firm opinion on whether human emissions of carbon dioxide (CO2) are causing unnatural global warming, and hold that opinion without understanding how the molecule physically absorbs and then releases heat energy.

Understanding that mechanism reveals why today’s significant global CO2 emissions are insignificant to future global warming.

Analogies are a great way to explain science, and I’m going to share the worst and best analogies for how carbon dioxide acts as a greenhouse gas. I will also share why the warming effect of CO2 is limited.

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Why Today’s Carbon Dioxide Emissions Are Insignificant To Global Warming

As more CO2 molecules are added as potential absorbers for the fixed amount of the specific band of infrared radiation, there is less chance that any CO2 molecule will be hit. If the additional CO2 molecules do not absorb infrared radiation, they cannot contribute to global warming.

The ever-reducing CO2 contribution to global warming looks like this graph, which, ironically, is based on the IPCC’s formula (from Inconvenient Facts by Gregory Wrightstone):

On the graph above, consider that the pre-industrial (circa 1875) atmospheric CO2 level was about 280 parts per million (ppm), and today it is about 420 ppm—an increase of 140 ppm.

As a rough approximation, the three bars labeled 350, 400, and 450 ppm represent this past increase in CO2, and the sum of the global warming temperature increases associated with those three bars is about 0.7°C.

The next four bars (500, 550, 600, and 650 ppm) represent a future CO2 increase of 200 ppm, which at today’s rate of 2.5 ppm increase each year would take from now to about 2100.

The global warming associated with those four bars is only 0.65°C. The graph shows it keeps taking more CO2 to achieve a smaller amount of global warming.

I chose bars 350 through 650 ppm to highlight that the IPCC’s formula predicts that global warming from current CO2 emissions held flat (1.35°C) would still beat the IPCC’s target of 1.5°C of human-caused global warming from preindustrial times to the year 2100.

The above graph suggests global warming from increasing CO2 never stops, but we know from ancient climates that even 12 times today’s CO2 concentrations did not cause runaway global warming.

Drs. Happer, Koonin, and Lindzen submitted to the U.S. (Northern California) District Court in 2021 that minor changes in cloud cover and convection currents can have a bigger effect on the Earth’s surface temperature than major increases in CO2.

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climate-debate

New Study: Observational Data Affirm 95% Of Post-1970s Warming Is Not Linked To CO2 Increases

by K. Richard, Dec 8, 2022 in NoTricksZone

Of the warming trends in Poland and greater Europe, “only about 4–5% are explained by an increase in CO2 concentration.”  –  Marsz et al., 2022 

Internal changes to the thermal structure of the ocean transmit decadal-scale changes in the atmospheric circulation and consequent surface air temperature via its modulating impact on the variation in the amount and intensity of solar radiation (sunshine duration, or SD) reaching the Earth’s surface.

This is not only observed for Poland and/or Europe as detailed in a new study, but the causal structuring of cloud cover changes driving the variations in solar radiation reaching the surface and modulating climate can be applied throughout the globe ( Wang et al., 2002, Wielicki et al., 2002, Loeb et al., 2021, Herman et al., 2013, Poprovsky, 2019, Dübal and Vahrenholt, 2021, Swift, 2018, Stephens et al., 2022).

Therefore, “the main cause of the change in the state of the climate may be the action of the internal variability of the ocean–atmosphere system” (Marsz et al., 2022).

unclassified

CMIP6 GCM ensemble members versus global surface temperatures

by N. Scafetta, Sep 18, 2022 in Springer

Abstract

The Coupled Model Intercomparison Project (phase 6) (CMIP6) global circulation models (GCMs) predict equilibrium climate sensitivity (ECS) values ranging between 1.8 and 5.7 ∘∘C. To narrow this range, we group 38 GCMs into low, medium and high ECS subgroups and test their accuracy and precision in hindcasting the mean global surface warming observed from 1980–1990 to 2011–2021 in the ERA5-T2m, HadCRUT5, GISTEMP v4, and NOAAGlobTemp v5 global surface temperature records. We also compare the GCM hindcasts to the satellite-based UAH-MSU v6 lower troposphere global temperature record. We use 143 GCM ensemble averaged simulations under four slightly different forcing conditions, 688 GCM member simulations, and Monte Carlo modeling of the internal variability of the GCMs under three different model accuracy requirements. We found that the medium and high-ECS GCMs run too hot up to over 95% and 97% of cases, respectively. The low ECS GCM group agrees best with the warming values obtained from the surface temperature records, ranging between 0.52 and 0.58 ∘∘C. However, when comparing the observed and GCM hindcasted warming on land and ocean regions, the surface-based temperature records appear to exhibit a significant warming bias. Furthermore, if the satellite-based UAH-MSU-lt record is accurate, actual surface warming from 1980 to 2021 may have been around 0.40 ∘∘C (or less), that is up to about 30% less than what is reported by the surface-based temperature records. The latter situation implies that even the low-ECS models would have produced excessive warming from 1980 to 2021. These results suggest that the actual ECS may be relatively low, i.e. lower than 3 ∘∘C or even less than 2 ∘∘C if the 1980–2021 global surface temperature records contain spurious warming, as some alternative studies have already suggested. Therefore, the projected global climate warming over the next few decades could be moderate and probably not particularly alarming.

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better to know...?, climate-debate

Activist Scientists Have Now Officially Changed A -0.5°C Global Cooling Trend Into A Warming Trend

by K. Richard, Aug 15, 2022 in NotricksZone

Back in the days when data manipulation was still strictly forbidden, scientists reported the globe cooled significantly for decades even as CO₂ concentrations increased.

The global cooling amplitude was -0.5°C from 1960-1965, and 1976 was reported to be the coldest year of any year measured since 1958 (Angell and Korshover, 1978).

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Today these recorded 1960-1965 and 1958-1963 cooling trends have been fully erased and replaced with a slight warming or pause.

better to know...?

Scientists: The Global Warming Since 1985 Cannot Be Attributed To CO2 Forcing

by K. Richard, Aug 8, 2022 in NoTricksZone

Cloud modulation of shortwave radiation and greenhouse effect forcing has largely been the determining factor in the global warming of the last 45 years. Not CO2.

CO2 forcing and its effect on surface temperatures is detailed in analyses of changes in clear-sky radiation only because all-sky radiation effects that include clouds (and the real-world atmosphere has clouds) overshadow the CO2 impact (Feldman et al., 2015, Harries et al., 2001).

Late 20th Century Climate Forcing

Per satellite observations, from 1985 to 1998 the “background clear-sky OLR [outgoing longwave radiation] was essentially unchanged” (Wang et al., 2002). In other words, any variations in OLR attributed to changes in greenhouse gas concentrations were not detectable.

In contrast, cloud vertical distributions explained 40% of increased tropical outgoing longwave radiation (OLR) and 60% could be explained by the emissivity of clouds, which means OLR changes were “most likely due entirely to changes in tropical cloud characteristics” and “cannot be attributed to increases in greenhouse gas concentrations.”

Furthermore, there was a decrease in reflected shortwave radiation (RSR) of -2.4 W/m² per decade observed from 1985 to 1999, which means there was a +3.6 W/m² increase in solar radiation absorbed by the Earth system during these 14 years. This can easily explain the warming during this period.

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climate and geology

Tonga Eruption Blasted Unprecedented Amount of Water Into Stratosphere

by C. Rotter, Aug 3, 2022 in WUWT

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This looping video shows an umbrella cloud generated by the underwater eruption of the Hunga Tonga-Hunga Ha’apai volcano on Jan. 15, 2022. The GOES-17 satellite captured the series of images that also show crescent-shaped shock waves and lightning strikes.
Credit: NASA Earth Observatory image by Joshua Stevens using GOES imagery courtesy of NOAA and NESDIS

The huge amount of water vapor hurled into the atmosphere, as detected by NASA’s Microwave Limb Sounder, could end up temporarily warming Earth’s surface.

When the Hunga Tonga-Hunga Ha’apai volcano erupted on Jan. 15, it sent a tsunami racing around the world and set off a sonic boom that circled the globe twice. The underwater eruption in the South Pacific Ocean also blasted an enormous plume of water vapor into Earth’s stratosphere – enough to fill more than 58,000 Olympic-size swimming pools. The sheer amount of water vapor could be enough to temporarily affect Earth’s global average temperature.

“We’ve never seen anything like it,” said Luis Millán, an atmospheric scientist at NASA’s Jet Propulsion Laboratory in Southern California. He led a new study examining the amount of water vapor that the Tonga volcano injected into the stratosphere, the layer of the atmosphere between about 8 and 33 miles (12 and 53 kilometers) above Earth’s surface.

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climate-debate

Why the Sun, Not CO2, Heats the Oceans Revisiting the Debate: Does Greenhouse Back-radiation Warm the Oceans?

by J. Steele, Aug 1, 2022 in WUWT

About a decade ago there was a heated and unresolved debate on whether infrared back radiation from greenhouse gases is heating the oceans. Because infrared penetrates less than a millimeter into the ocean’s surface, many skeptics argued it is impossible to blame rising CO2 for ocean warming. However, several prominent skeptic scientists, people who I have great respect for, also weighed in arguing it was silly and useless to argue infrared heat can’t warm the ocean.

After analyzing the physics detailed in this video, I’m convinced it is solar energy that drives the observed ocean heating, and any infrared ocean heating is insignificant at best. If this analysis holds, it is another significant strike against the prevailing CO2 driven global warming theory

To ensure lay people are brought up to speed, here’s a quick summary of where consensus climate science stands today.

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climate and geology

A Tropical Plant’s Warmth Threshold Affirms Mid-Holocene Temps Were ‘7.7°C Higher Than Today’

by K. Richard, July 25, 2022 in NoTricksZone

A warmth-demanding plant can provide us with solid evidence of a much warmer than today Mid-Holocene climate.

Growth of the tropical aquatic plant ceases when air temperatures fall below 10°C.

A new study says that from about 8000 to 5000 years ago it was warm enough in winter that could grow at the 40°N latitude in northern China. Today its warmth threshold growth limit is ~34°N.

Scientists can therefore deduce the Mid-Holocene winter temperatures needed to have been “7.7°C higher than today” at that time.

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climate-debate

Radiosonde Temps Show Northern Hemisphere, Tropical Warming Has Mostly Paused Since 1998

by K. Richard, May 22, 2022 in NoTricksZone

A new study indicates nearly all the Northern Hemisphere and Tropical warming in the last 40 years occurred by the late 1990s.

CO2 has risen by about 50 ppm since 1998 (367 to 418 ppm).

Interestingly, upper-air measurements of temperature from balloon-borne sensor radiosonde data, shown below in the image from a new study (Madonna et al., 2022), suggest there was more warming from the early 1980s to late 1990s – when CO2 only rose about 25 ppm (341 to 367 ppm) – than there has been this century.

Radiosonde measurements appear to depict mostly flat temperatures trends since 1998 in both the Northern Hemisphere (25°N to 70°N) and tropics (25°S to 25°N).

 

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Image Source: Madonna et al., 2022

 

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biology+acidification

Doomsday Climate Studies Turn Out To Be Overblown Nonsense

by Washington Are Beacon Staff, Feb 17, 2022  in The WashigntonFreeBeacon

For over a decade, scientists have warned that the acidification of ocean water could decimate fish populations. Acidification changed fish behavior, several studies found, making them less likely to evade predators.

As carbon emissions pushed pH levels higher and higher, climate advocates sounded an apocalyptic tone. Fewer fish would mean fewer fisheries, which would imperil the livelihoods of millions of fishermen across the globe. It could also mean fewer medicines, many of which are derived from marine life.

 

According to a new paper in a top-ranked biology journal, these concerns are vastly overblown.

The paper, published in PLOS Biology on Feb. 3, reviewed 91 studies of the effect of ocean acidification on fish behavior. It found that better-quality studies tended to find smaller effects on fish behavior—and that the studies with the most dramatic results tended to have low sample size, making them less statistically reliable.

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climate-debate

The Arctic Ocean began warming decades earlier than previously thought, new research shows

by P. Homewood, Nov 27, 2021 in NotaLotofPeopleKnowThat

A new study throws doubt on the theory that Arctic warming is man made.

The Arctic Ocean has been warming since the onset of the 20th century, decades earlier than instrument observations would suggest, according to new research.

The study, published Wednesday in the journal Science Advances, found that the expansion of warm Atlantic Ocean water flowing into the Arctic, a phenomenon known as “Atlantification,” has caused Arctic water temperature in the region studied to increase by around 2 degrees Celsius since 1900.

Francesco Muschitiello, an author on the study and assistant professor of geography at the University of Cambridge, said the findings were worrisome because the early warming suggests there might be a flaw in the models scientists use to predict how the climate will change.

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climate-debate

Physicists: Climate Model Error Overestimates CO2 Impact On Global Temps By Factor Of 5

by K. Richard, Nov 22, 2021 in NoTricksZone

A new study suggests CO2 molecules have little consequential impact affecting outgoing radiation, and that climate models attribute global temperature effects to CO2 that are fundamentally erroneous.

Russian physicists (Smirnov and Zhilyaev, 2021) have published a peer-reviewed paper in the Advances in Fundamental Physics Special Issue for the journal Foundations.

They assesses the role of CO2 molecules in the standard atmosphere and assert “we have a contradiction with the results of climatological models in the analysis of the Earth’s greenhouse effect.”

Key points from the paper include the following:

1. Climate model calculations of CO2’s impact on global temperatures are in error by a factor of 5 as a result of “ignoring, in climatological models, the Kirchhoff law” which says radiators are “simultaneously the absorbers.”

2. Change in the concentration of an optically active atmospheric component (like CO2) “would not lead to change in the outgoing radiative flux.”

3. CO2 molecules “are not the main radiator of the atmosphere.” Water vapor molecules are, and thus they “may be responsible for the observed heating of the Earth.”

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climate-debate

The anatomy of past abrupt warmings recorded in Greenland ice

by C. Rotter, Apr 19, 2021 in WUWT/Nature

New paper at Nature Communications

Abstract

Data availability and temporal resolution make it challenging to unravel the anatomy (duration and temporal phasing) of the Last Glacial abrupt climate changes. Here, we address these limitations by investigating the anatomy of abrupt changes using sub-decadal-scale records from Greenland ice cores. We highlight the absence of a systematic pattern in the anatomy of abrupt changes as recorded in different ice parameters. This diversity in the sequence of changes seen in ice-core data is also observed in climate parameters derived from numerical simulations which exhibit self-sustained abrupt variability arising from internal atmosphere-ice-ocean interactions. Our analysis of two ice cores shows that the diversity of abrupt warming transitions represents variability inherent to the climate system and not archive-specific noise. Our results hint that during these abrupt events, it may not be possible to infer statistically-robust leads and lags between the different components of the climate system because of their tight coupling.

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climate-debate

Committed warming and the pattern effect

by Nic Lewis, Jan 19, 2021 in ClilmateEtc.

Key points

  • The pattern effect is the dependence of outgoing radiation to space on the spatial pattern of surface warming.
  • A pattern effect, relative to that in equilibrium, can be caused both by evolution over time in the climate system’s response to forcing and by its internal variability.
  • The paper fails to distinguish between a historical period pattern effect that is forced, which will unwind very slowly, and one that is caused by internal variability, which can quickly unwind, causing rapid warming.
  • The forced pattern effect is very small in CAM5.3
  • The pattern effect found in the paper is greatly affected by being estimated during the hiatus.
  • The estimated post-hiatus unforced historical pattern effect is non-negligible in CAM5.3 when using the AMIP2 sea surface temperature dataset, as in the paper, but negligible when using the UK Met Office HadISST1 dataset.
  • The historical pattern effect is not robust; it varies hugely between models and SST datasets.
  • The paper’s claims about greater committed warming directly reflect its estimate of the size of the historical pattern effect.

Introduction

A new paper “Greater committed warming after accounting for the pattern effect” led by Chen Zhou  (Zhou et al.[1]) has recently been published in Nature Climate Change. Here is the accompanying press release.

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climate-debate

New Study: East Antarctica Was Up To 6°C Warmer Than Today During The Medieval Warm Period

by K. Richard, Oct 15, 2020 in NoTricksZone

As recently as 2000 to 1000 years ago, spanning the Roman to Medieval Warm Periods, East Antarctica was 5-6°C warmer than it is today. The consequent ice melt resulted in >60 meters higher water levels in East Antarctica’s lakes.

East Antarctica has been rapidly cooling in recent decades, with magnitudes reaching -0.7°C to -2.0°C per decade since the mid-1980s (Obryk et al., 2020).

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A new study (Myers et al., 2020) reports that until about 15,000 years ago and throughout the Last Glacial Maximum, East Antarctica was 4-9°C colder than it is today.

Antarctica then abruptly warmed 15°C within centuries. From 12,000 to 6,000 years before present, East Antarctica was about 5°C warmer than it is today.

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climate-debate

New confirmation that climate models overstate atmospheric warming

by Dr. Judith Curry, August 27, 2020 in WUWT

Reposted from Dr. Judith Curry’s Climate Etc.

Posted on August 25, 2020

by Ross McKitrick

Two new peer-reviewed papers from independent teams confirm that climate models overstate atmospheric warming and the problem has gotten worse over time, not better.

The papers are Mitchell et al. (2020) “The vertical profile of recent tropical temperature trends: Persistent model biases in the context of internal variability” Environmental Research Letters, and McKitrick and Christy (2020) “Pervasive warming bias in CMIP6 tropospheric layers” Earth and Space Science. John and I didn’t know about the Mitchell team’s work until after their paper came out, and they likewise didn’t know about ours.

Mitchell et al. look at the surface, troposphere and stratosphere over the tropics (20N to 20S). John and I look at the tropical and global lower- and mid- troposphere. Both papers test large samples of the latest generation (“Coupled Model Intercomparison Project version 6” or CMIP6) climate models, i.e. the ones being used for the next IPCC report, and compare model outputs to post-1979 observations. John and I were able to examine 38 models while Mitchell et al. looked at 48 models. The sheer number makes one wonder why so many are needed, if the science is settled. Both papers looked at “hindcasts,” which are reconstructions of recent historical temperatures in response to observed greenhouse gas emissions and other changes (e.g. aerosols and solar forcing). Across the two papers it emerges that the models overshoot historical warming from the near-surface through the upper troposphere, in the tropics and globally.

Mitchell et al. 2020

Mitchell et al. had, in an earlier study, examined whether the problem is that the models amplify surface warming too much as you go up in altitude, or whether they get the vertical amplification right but start with too much surface warming. The short answer is both.

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climate-debate

CLAIM: 100 degrees in Siberia? 5 ways the extreme Arctic heat wave follows a disturbing pattern

by C. Rotter, June 28, 2020 in WUWT

This essay from director of NSIDC, Mark Serreze, is provided for reference. You may remember Serreze who once said “the Arctic is screaming” while botching and then backpedaling on claims of “ice free summers” on the near horizon for the Arctic that never happened. Give it all the consideration it is due. For some perspective, see my article on a previous 100 degree event above the Arctic circle over 100 years ago. By the way, with 24 hours daylight above the Arctic circle, and near 24 hour daylight in Siberia this time of year, (the first day of summer aka  the summer solstice) is it any surprise it would get warm?

This Arctic heat wave has been unusually long-lived. The darkest reds on this map of the Arctic are areas that were more than 14 degrees Fahrenheit warmer in the spring of 2020 compared to the recent 15-year average. Joshua Stevens/NASA Earth Observatory
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climate-debate

CMIP6 Climate Models Show 50% More Warming Than Observations Since 1979

by Roy W. Spencer, June 26, 2020 in ClimateChangeDispatch

Those who defend climate model predictions often produce plots of observed surface temperature compared to the models which show very good agreement.

Setting aside the debate over the continuing adjustments to the surface temperature record which produce ever-increasing warming trends, let’s look at how the most recent (CMIP6) models are doing compared to the latest version of the observations (however good those are).

First, I’d like to explain how some authors get such good agreement between the models and observations. Here are the two “techniques” they use that most annoy me.

  1. They look at long periods of time, say the last 100+ years. This improves the apparent agreement because most of that period was before there was substantial forcing of the climate system by increasing CO2.
  2. They plot anomalies about a common reference period but do not show trend lines. Or, if they show trend lines, they do not start them at the same point at the beginning of the record. When you do this, the discrepancy between models and observations is split in half, with the discrepancy in the latter half of the record having the opposite sign of the discrepancy in the early part of the record. They say, “See? The observed temperatures in the last few decades nearly match the models!”

In the following plot (which will be included in a report I am doing for the Global Warming Policy Foundation) I avoid both of those problems.

During the period of strongest greenhouse gas forcing (since 1979), the latest CMIP6 models reveal 50% more net surface warming from 1979 up to April 2020 (+1.08 deg. C) than do the observations (+0.72 deg. C).

 

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