by A. Watts, Sep 28, 2020 in WUWT
From the GWPF and the better late than never department: (the paper was published in late 2019 but seems pretty solid, using Oxygen18 isotope analysis) – Anthony
A new analysis of global air temperature by researchers from Tongji University in Shanghai has cast light on the much debated recent hiatus in global temperature.
Writing in the Journal of Earth Science the Chinese scientists say there was a rapid rise in global mean surface air temperature after the late 1970s but that this stalled and there was a relative stagnation and even slight cooling that lasted for about 15 years (1998–2012). They add that even though the slowdown was acknowledged by the Intergovernmental Panel on Climate Change Fifth Assessment Report (IPCC AR5) and termed as a hiatus (IPCC, 2013) there was a debate in the scientific community about whether there was a hiatus in global warming or not.
The researchers believe that the debate about the global warming hiatus poses a substantial challenge to our understanding of the global climate response to anthropogenic greenhouse gas emissions and natural variability. They say that the disagreements about the recent global warming hiatus mainly arise from different sources, among which differences across observational SAT datasets may be a key contributor to the contradictory conclusions. So they use an alternative set of data.
They use the ratio of two oxygen isotopes in precipitation, oxygen 16 and 18, which is a proxy for the temperature of precipitation and surface temperature. They are particularly interested in what they term a “robust correlation” between precipitation oxygen ratios and surface temperature over mid- and high-latitude regions. Twelve stations were selected of which ten are located in Europe, and the remaining two in Antarctica and North America, respectively. Using the data they constructed a composite isotope index spanning 1970–2016 by combining twelve precipitation oxygen isotope records collected over mid and high-latitude continents. With it they evaluate the recent global warming hiatus.
Continuer la lecture de Study: Global Warming Hiatus (aka “The Pause”) Was Real
by Dr A. Ollila, March 16, 2020 in ClimateChange Dispatch
During the years 2000-2014, the global temperature hardly increased, and that period has been called the temperature pause or hiatus.
The debate among the climate community has resulted in more than 200 research studies in some cases with opposite results about the reasons.
This amount of papers can be compared to the research studies of Earth’s energy balance and the greenhouse effect. I have found about 10 publications for both subjects.
During the years 2000-2014, the emissions of carbon dioxide were 126 gigatons carbon (GtC) being 31% of the total emission after 1750, but the greenhouse (GH) gases were not able to increase the temperature.
According to the IPCC, the temperature increase should have been 0.4°C from 2000 to 2014 (Ref. 1).
It looks like that the pause ended to the super El Nino 2015-2016 because the temperature has been thereafter about 0.2 °C above-the-pause average.
Research study about the pause and the ENSO
The impulse for my research study came from a story figure on WUWT that showed shortwave (SW) radiation variations during the pause.
A curve showed increased values around El Nino 2015-16 and thereafter. I decided to find out what could be the impact of this finding on the temperatures.
In Fig. 1, I have depicted the total solar irradiance (TSI), SW radiation and LW radiation from 2000 onward. This data is available from the CERES databank maintained by NASA.
Fig.1. TSI, SW radiation and LW radiation trends normalized to the altitude of 20 kilometers.
by K. Richard, October 17 2019, in NoTricksZone
Mainstream climate science claims CO2 molecules “slow down the rate of heat-loss from the surface” like a blanket does. And yet the rate at which a CO2 molecule retains or slows down heat loss is, at most, a negligible 0.0001 of a second. A CO2 concentration of 300 ppm versus 400 ppm will therefore have no detectable impact.
SkepticalScience, a blog spearheaded by climate science “consensus” advocate John Cook, is widely considered the explanatory guidebook for the anthropogenic global warming movement.
The blog claims CO2 molecules, with a representation of 4 parts in 10,000 in the atmosphere (400 parts per million, or ppm), collectively function like a blanket does in slowing down the rate at which the human body cools.
Image Source: Nahle, 2011b
by Institute of Atmospheric Physics, Chinese Academy of Sciences, October 10, 2019 in WUWT
As a result of industrialization, the carbon dioxide in the Earth’s atmosphere has increased continuously over the past 100 years, which is considered as the main reason behind global warming. However, the observational global mean atmospheric temperature leveled off over the first decade of the 21st century, in contrast to the rapid warming during the late 20th century. This phenomenon, known as the “atmospheric warming slowdown” or “global warming hiatus”, has attracted great attention worldwide owing to its ostensible contradiction of the human-induced global warming theory.
The changes in ocean heat content might have a tight relationship with the atmospheric warming slowdown. Dr Changyu Li, Prof. Jianping Huang and their colleagues, a group of researchers from the Key Laboratory for Semi-Arid Climate Change of the Ministry of Education, College of Atmospheric Sciences, Lanzhou University, have had their findings published in Advances of Atmospheric Sciences.
In their paper, they explore the energy redistribution between the atmosphere and ocean at different latitudes and depths by using observational data as well as simulations of a coupled atmosphere-ocean box model.
by Paul Matthews, June 30, 2019 in ClimateScepticism
The history of climate scientists adjusting data to try to make recent warming look greater than it really is goes back quite a long way – it’s a regular topic at Paul Homewood’s blogfor example. But climate scientists continue to do it, giving the sceptics plenty of ammunition. Here are three recent blog posts discussing how climate scientists continue to adjust data to exaggerate warming.
At Pierre Gosselin’s blog there’s a guest post by Kirje from Japan, on NASA GISS temperature adjustments. In the latest GISS version, V4, the supposedly “unadjusted” data sets are different from the unadjusted data in the previous version V3.
Tony Heller has a graph of the 2000, 2017 and 2019 version of NASA GISTEMP, showing that Gavin Schmidt and his team have managed to crank up warming, particularly in the era of the inconvenient pause. You can also see this effect in fig 2 and fig 4 of the GISS history page.
Here in the UK, the HadCRUT4 team are doing the same thing. Clive Best asks Whatever happened to the Global Warming Hiatus? The answer is that they have demolished it with a sequence of adjustments to the data. HadCRUT3, as published in 2014, shows a clear pause, with no warming from about 2001-2013, but the latest new improved data set HadCRUT4.6 cranks recent temperatures upwards. Clive thought that night be due to including different measurement stations, but checked and found that was not the case. The numbers have simply been adjusted.
Here the red diamond is the raw data, the green diamond is HadSST3, and the new HadSST4 is shown as the black line, with grey shading representing uncertainty. In the early years of the 20th century, there was global warming that doesn’t fit with the carbon-dioxide-controlled theory of climate scientists, so that is adjusted downwards. But look at the trend over the pause era, since 2000. The raw data shows literally no trend at all. HadSST3 adjusted the trend upwards to create warming, and HadSST4 adjusts things upwards again, roughly doubling the previous adjustment. And this is in an era when the data quality should be excellent, thanks to the introduction of the ARGO float system.
by Vijay Jayaraj, May 16,2019 in WUWT
A new temperature reconstruction, using proxy temperature measurements from locations in central Asia, has revealed that there has been no warming in the past 432 years.
The Global Warming “Hiatus” or Pause
The word “hiatus” became popular in recent years after the discovery of a pause or hiatus in global warming. There has been a lack of warming in the atmosphere since 1999, despite the predictions of computer climate models.
by P. Gosselin, April 2, 2019 in NoTricksZone
A number of scientists from the alarmist camp like to insist that there had never been such a hiatus. The latest paper contradicts that claim.
The new study states that many published analyses show that lightning activity is responsive to temperature on time scales ranging from the diurnal to the decadal and that the hiatus in global warming earlier this century can be seen in several global datasets.
Scientists found that the statistically flat behavior of the global lightning record from the NASA Lightning Imaging Sensor over the same decadal period is consistent with this hiatus in global warming.
What follows is the paper’s abstract:
Multiple records of global temperature contain periods of decadal length with flat or declining temperature trend, often termed a ‘hiatus’. Towards assessing the physical reality of two such periods (1940–1972 and 1998–2014), lightning data are examined. Lightning activity is of particular interest because on many different time scales it has been shown to be non-linearly dependent on temperature. During the earlier hiatus, declining trends in regional thunder days have been documented. During the more recent hiatus, lightning observations from the Lightning Imaging Sensor in space show no trend in flash rate. Surface-based, radiosonde-based and satellite-based estimates of global temperature have all been examined to support the veracity of the hiatus in global warming over the time interval of the satellite-based lightning record. Future measurements are needed to capture the total global lightning activity on a continuous basis.”
by K. Richard, March 28, 2019 in NoTricksZone
An unheralded but significant 2016 scientific paper – “A Hiatus of the Greenhouse Effect” – is now publicly available.
Scientists have found the greenhouse effect’s (GHE) influence on planetary temperatures went on “hiatus” during 1992-2014.
The estimated GHE radiative influence for these 22 years was a slightly negative -0.04 Wm-2 per year.
The reason why the GHE influence went on hiatus in recent decades is that (a) decadal-scale changes in cloud cover exert dominant radiative control in longwave forcing (GHE) efficacy, and (b) the shortwave effects of cloud cover changes override the radiative longwave effects, meaning that a decrease in cloud cover will allow more direct shortwave radiation to be absorbed by the Earth system, eliciting a net positive imbalance in the energy budget.
by P. Gosselin , February 19, 2019 in NoTricksZone
Readers should note that among climate modelers volcanoes and atmospheric aerosols have been a favorite way of fudging climate models to explain away inconvenient cooling periods that weren’t supposed to happen in a system that is supposed to be dominated by trace gas CO2.
Extratropical volcanoes influence climate more than assumed
Study shows surprisingly strong cooling after volcanic eruptions in mid and high latitudes
by Christopher Monckton of Brenchley, January 10, 2019 in WUWT
The prolonged el Niño of 2016-2017, not followed by a la Niña, has put paid to the great Pause of 18 years 9 months in global warming that gave us all such entertainment while it lasted. However, as this annual review of global temperature change will show, the credibility gap between predicted and observed warming remains wide, even after some increasingly desperate and more or less openly prejudiced ever-upward revisions of recent temperatures and ever-downward depressions in the temperatures of the early 20th century in most datasets with the effect of increasing the apparent rate of global warming. For the Pause continues to exert its influence by keeping down the long-run rate of global warming.
by David Whitehouse, December 20, 2018 in GWPF
Using simple statistics it looked at and dismissed over 200 peer-reviewed papers that analysed the pause and concluded it was a real phenomenon. How did they, and the IPCC, get it all so wrong?
Source: Clive Best
Nobody who keeps an eye on climate research will be at all surprised by this “new” paper. Its conclusions were well aired in April 2018 at a meeting of the European Geophysical Union.
The authors must have been rather frustrated at the time as the paper describing their work had been submitted to the journal Environmental Research Letters over a year earlier, in February 2017 in fact, still had not been published. This was remedied a few days ago when it was finally published — one year and nine months after its submission!
by M. Ding et al., August 27, 2018 in CO2Science
The results of their analysis revealed that warming in this high Arctic site had proceeded at four times the global mean rate calculated in other data sets. However, Ding et al. note that over the last decade (2005-2014), “the warming rate in Ny-Ålesund slowed to 0.03 ± 1.85°C per decade,” which is essentially indicative of no-trend in the data. Lead-lag analysis further revealed that “Ny-Ålesund and global temperature variations were remarkably consistent, with a lag time of 8-9 years.” Consequently, the researchers say that “the ‘warming hiatus’ many scientists [have] studied also appears in Ny-Ålesund, it just started later than [that observed in] other areas.”
by Sun X. et al., 2018 in CO2Science
Sun, X., Ren, G., Ren, Y., Fang, Y., Liu, Y., Xue, X. and Zhang, P. 2018. A remarkable climate warming hiatus over northeast China since 1998. Theoretical and Applied Climatology 133: 579-594.
A prominent feature of all climate model projections is their prediction that temperatures should be rising in response to ever-increasing concentrations of greenhouse gases. However, for the past two decades global surface air temperatures have not warmed to the degree predicted by the models, which lack of warming has been a conundrum to the climate alarmist movement.
by Anthony Watts, July 18, 2018 in WUWT
In response to a study from the University of Washington posted on WUWT (and elsewhere) today about a shift in the AMOC and a very clear statement about it not collapsing (as posited for collapse by many), including Michael Mann, Dr. Judith Curry gave this response to the Daily Caller’s Mike Bastasch: …
by Grégoire Canlorbe, June 18, 2018 in WUWT
Richard Siegmund Lindzen is an American atmospheric physicist known for his work in the dynamics of the atmosphere, atmospheric tides, and ozone photochemistry. He has published more than 200 scientific papers and books. From 1983 until his retirement in 2013, he was Alfred P. Sloan Professor of Meteorology at the Massachusetts Institute of Technology. He was a lead author of Chapter 7, “Physical Climate Processes and Feedbacks,” of the Intergovernmental Panel on Climate Change’s Third Assessment Report on climate change. He has criticized the scientific consensus about climate change and what he has called “climate alarmism.”
by Anthony Watts, June 10, 2018 i
On June 8th, the California Department of Forestry and Fire Protection (Cal Fire) made its first official announcement via press release that 12 big Northern California wildfires in October 2017 were caused by problems associated with electric utility power lines.
The October 2017 Fire Siege involved more than 170 fires and burned at least 245,000 acres in Northern California. About 11,000 firefighters from 17 states and Australia helped battle the blazes. They concluded that 12 Wildfires in Mendocino, Humboldt, Butte, Sonoma, Lake, and Napa Counties were caused by Pacific Gas & Electric (PG&E) “power and distribution lines, conductors and the failure of power poles.”
The words “global warming” and “climate change” were conspicuously absent from the announcement even…
by Anthony Watts, June 7, 2018 in WUWT
More excuses for “the pause”.
A team of researchers from the U.K. Met Office, Sweden and Australia has found that three periods of global warming slowdown since 1891 were likely due to natural causes rather than disruptions to the factors causing global warming. In their paper published on the open access site Science Advances, the group describes their study of global mean surface temperatures (GMST) since the late 19th century and what they found.
In this new paper, the researchers looked at GMST as registered by multiple sources around the globe over the past 127 years, noting the slow march of temperature increases. More specifically, they noted the three previously identified slowdowns in GMST increases—the time periods from 1896 to 1910, from 1941 to 1975, and then from 1998 to 2013. They then looked at factors that could have contributed to these slowdowns and found natural causes for each. (…)
by Ron Clutz, May 16, 2018 in ScienceMatters
Thanks to GWPF for publishing posthumously Bill Gray’s understanding of global warming/climate change. The paper was compiled at his request, completed and now available as Flaws in applying greenhouse warming to Climate Variability This post provides some excerpts in italics with my bolds and some headers. Readers will learn much from the entire document (title above is link to pdf).
The Fundamental Correction
The critical argument that is made by many in the global climate modeling (GCM) community is that an increase in CO2 warming leads to an increase in atmospheric water vapor, resulting in more warming from the absorption of outgoing infrared radiation (IR) by the water vapor (…)
Figure 14: Global surface temperature change since 1880. The dotted blue and dotted red lines illustrate how much error one would have made by extrapolating a multi-decadal cooling or warming trend beyond a typical 25-35 year period. Note the recent 1975-2000 warming trend has not continued, and the global temperature remained relatively constant until 2014.
by K. Richard, May 10, 2018 in NoTricksZone
During 2017, there were 150 graphs from 122 scientific papers published in peer-reviewed journals indicating modern temperatures are not unprecedented, unusual, or hockey-stick-shaped — nor do they fall outside the range of natural variability. We are a little over 4 months into the new publication year and already 81 graphs from 62 scientific papers undermine claims that modern era warming is climatically unusual.
by Ron Clutz, May 8, 2018 in ScienceMatters
Years ago, Dr. Roger Pielke Sr. explained why sea surface temperatures (SST) were the best indicator of heat content gained or lost from earth’s climate system. Enthalpy is the thermodynamic term for total heat content in a system, and humidity differences in air parcels affect enthalpy. Measuring water temperature directly avoids distorted impressions from air measurements. In addition, ocean covers 71% of the planet surface and thus dominates surface temperature estimates.
More recently, Dr. Ole Humlum reported from his research that air temperatures lag 2-3 months behind changes in SST. He also observed that changes in CO2 atmospheric concentrations lag behind SST by 11-12 months. This latter point is addressed in a previous post Who to Blame for Rising CO2?
by K. Richard, April 19, 2018 in NoTricksZone
The Arctic region was the largest contributor to the positive slope in global temperatures in recent decades.
Consequently, the anomalously rapid warming in the Arctic region (that occurred prior to 2005) has been weighted more heavily in recent adjustments to instrumental temperature data (Cowtan and Way, 2013; Karl et al., 2015) so as to erase the 1998-2015 hiatus and instead produce a warming trend.
Meanwhile, other scientists have been busy determining that only about 50% of the warming and sea ice losses for the Arctic region are anthropogenic, or connected to the rise in CO2 concentrations.
The rest of the warming and ice declines can be attributed to unforced natural variability.
by Uzbek, 2 avril 2018 in ClimatoRéalistes
La Global Warming Policy Foundation (GWPF) a publié son rapport sur l’état du climat pour 2017. Etabli par Ole Humlum, Professeur émérite à l’Université d’Oslo, ce rapport est un examen complet du climat mondial.
En voici les 10 principales conclusions :
1. Il est probable que 2017 ait été une des années les plus chaudes depuis le début des mesures instrumentales en 1850, moins chaude cependant que 2016.
2. À la fin de l’année 2017, la température moyenne à la surface de la planète avait retrouvé les niveaux antérieurs à l’épisode El Niño. Cela montre que la hausse récente des températures mondiales a été causée principalement par ce phénomène océanographique dans le Pacifique. Cela suggère aussi que le « hiatus » se poursuivra dans les années à venir.
by P. Homewood, April 5, 2018 in NotaLotofPeopleKnowThat
Hadcrut now have numbers out for February, giving an anomaly of 0.523C, measured against the 1961-90 baseline, slightly down on January’s 0.556C.
This means that the last six months have been below 0.59C.
It is clear that temperatures are settling down at a similar level to the period between 2002 and 2007, following the record El Nino of 2015/16. Bear in mind as well that the degree of accuracy, according to the Hadley Centre, is about +/-0.1C. As such, it cannot be said that there has been any statistically measurable warming since 2001, or indeed previously.
It is possible temperatures may drop further in coming months, with weak La Nina conditions established, although these are predicted to disappear by the summer.