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Climate models don't "predict." They project what will happen given a set of initial conditions and may include several scenarios. If a certain scenario didnt happen, it does not mean the prediction was wrong. It means the conditions for that particular scenario didnt happen. The scenarios are often grouped as most likely and worst case etc.All studies shows models have underestimated the realities.Part of the problem here stems from people either misunderstanding or deliberately misrepresenting how predictive models work. Many people have the unrealistic expectation that the observed data need to be a near perfect match for the prediction line, but that’s not actually how things work.Some are still "under the mistaken impression that concern about global warming is based on climate models, which in reality play little role in our understanding -- our understanding is based mainly on how the Earth responded to changes of boundary conditions in the past and on how it is responding to on-going changes."- Dr. James HansenSome people argue that climate models are unreliable if they don't make perfect short-term predictions. However, a number of unpredictable influences such as ocean and solar cycles have short-term influences on climate. Over the long term, these effects average out, which is why climate models do so well at long-term predictions.It’s basic physics which follows the same principles as other laws of nature.CLIMATE PROJECTIONS HAVE BEEN VERY ACCURATE:We’ll check the models, but first:Latest 2020:Climate models published between 1970 and 2007 provided accurate forecasts of subsequently observed global surface warming. This finding shows the value of using global observations to vet climate models as the planet warms.The first climate models to numerically describe an evolving and interacting atmosphere, ocean and land surface on a grid covering the entire Earth date back to the 1970s (for example, refs 1–3). Since then, the planet’s surface has warmed, in large part because of increased emissions of greenhouse gases. Writing in Geophysical Research Letters, Hausfather et al.4 retrospectively assessed the forecasting skill of climate models published between 1970 and 2007. Their results show that the physics in these early models was accurate in predicting subsequently observed global surface warming.Early climate models successfully predicted global warmingThe First Climate Model Turns 50, And Predicted Global Warming Almost PerfectlyEven 50-year-old climate models correctly predicted global warmingThe Worst-Case Scenario for Global Warming Tracks Closely With Actual EmissionsStudy Confirms Climate Models are Getting Future Warming Projections RightStudy Confirms Climate Models are Getting Future Warming Projections Right – Climate Change: Vital Signs of the PlanetModels that were used in the IPCC 4th Assessment Report can be evaluated by comparing their approximately 20-year predictions with what actually happened. In this figure, the multi-model ensemble and the average of all the models are plotted alongside the NASA Goddard Institute for Space Studies (GISS) Surface Temperature Index (GISTEMP). Climate drivers were known for the ‘hindcast’ period (before 2000) and forecast for the period beyond. The temperatures are plotted with respect to a 1980-1999 baseline. Credit: Gavin SchmidtUpdate day 2020!Nov 2019:"According to the research published today, almost every peer-reviewed climate model of human-caused global temperature rise dating back to 1970 lines up with the warming we see today.“Taken together,” he added, “these climate models have always been quantitatively accurate.”How good have climate models been at truly predicting the future?Hausfather et al 2019Evaluating the performance of past climate model projectionsCONTENTCLIMATE MODELS HAVE BEEN VERY ACCURATEIPCC MODELSTHE HISTORY OF CLIMATE MODELSBONUSES - INCLUDING DEBUNKING OF MODEL MYTHSThe reason why long term climate predictions ARE possible, and 2–3 days weather predictions are NOT possible, is very logical:A number of unpredictable influences such as ocean and solar cycles have short-term influences on climate. Over the long term, these effects average out, which is why climate models do so well at long-term predictions.It’s basic physics which follows the same principles as other laws of nature.“The physics we use to understand the earth’s climate system is the same physics that explains how stoves, fridges, airplanes and more work. And most people don’t really have a problem with the physics of non-linear fluid dynamics and radiative transfer that have been well understood for decades, even centuries.” (Climate scientist Katharine Hayhoe.)Just check out world known and verified Quora account climate scientist Katharine Hayhoe:Katharine Hayhoe's answer to What climate models do you believe to be the most accurate? In other words, what scenario do you think will most likely play out in the near future and far future? How do you communicate this to the public?Now, let’s check the models:" the close match between projected and observed warming since 1970 suggests that estimates of future warming may prove similarly accurate."Here are some actual predictions from Global Climate Models all of which have proven correct. Im even linking to the paper directly so you can go and read for yourself.- That the Earth would warm, and about how fast, and about how much(Arrhenius 1896, Callendar 1938, Plass 1956, Sawyer 1972,Broecker 1975; validated by Crowley 2000, Philipona et al 2004,Evans and Puckrin 2006, Lean and Rind 2008, Mann et al. 2008, etc)- That nighttime temperatures would increase more than daytime temperatures(Arrhenius 1896; validated by Dai et al. 1999, Sherwood et al. 2005, etc)- That winter temperatures would increase more than summer temperatures(Arrhenius 1896, Manabe and Stouffer 1980, Rind et al 1989; validated by Balling et al 1999, Volodin and Galin 1999, Crozier2003, etc)- Polar amplification (that temperatures increase more as you move toward the poles)(Arrhenius 1896, Manabe and Stouffer 1980; validated by Polyakov et al 2001, Holland and Bitz 2003, etc)- That the Arctic would warm faster than the Antarctic(Arrhenius 1896, Manabe and Stouffer 1980; validated by Doran et al 2002, Comiso 2003, Turner et al 2007, etc)- That the Earth’s troposphere would warm and the stratosphere would cool(Manabe and Wetherald 1967, Manabe and Stouffer 1980; validated by Ramaswamy et al. 1996, 2006, De F. Forster et al 1999, Langematz et al 2003, Vinnikov and Grody 2003, Fu et al 2004, Thompson and Solomon 2005, etc)- The near constancy of relative humidity on global average(Manabe and Wetherall 1967; validated by Minschwaner and Dessler 2004, Soden et al 2005, Gettelman and Fu 2008, etc)- Scientists made a retrodiction (a model prediction based on established physics) for Last Glacial Maximum sea surface temperatures which was inconsistent with the paleo evidence for those times; better paleo evidence showed the models were right(Rind and Peteet 1985; validated by Farreral et al 1999, Melanda et al 2005, etc)- The clear sky super greenhouse effect from increased water vapor in the tropics(Vonder Haar 1986; validated by Lubin 1994, etc)- That coastal upwelling of ocean water would increase(Bakun 1990; validated by Goes et al 2005, McGregor et al 2007, etc)- The magnitude (0.3 C) and duration (two years) of the cooling from the Mt. Pinatubo eruption(Hansen et al 1992; validated by Hansen et al 1996, Soden et al 2002, etc)- The amount of water vapor feedback due to ENSO(Lau et al 1996; validated by Soden 2000, Dessler and Wong 2009, etc)- The rising of the tropopause and the effective radiating altitude(Thuburn and Craig 1997, Kushner et al 2001; validated by Santer et al 2003, Seidel and Randel 2006, etc)- The response of southern ocean winds to the ozone hole(Fyfe et al 1999, Kushner et al 2001, Sexton 2001; validated by Thompson and Solomon 2002, etc)- The expansion of the Hadley cells(Quan et al 2002; validated by Fu et al 2006, Hu and Fu 2007, etc)- They predicted a trend significantly different in amount and different in nature from UAH satellite temperatures, and then a bug was found in the satellite data which showed that surface temperatures were more accurate and reliable than UAH temperature data.(Christy et al 2003; validated by Santer et al 2003, Mears and Wentz 2005, Santer et al 2005, Sherwood et al 2005, etc)- The poleward movement of storm tracks(Trenberth and Stepaniak 2003; validated by Yin 2005, etc)NASA scientist Gavin Schmidt:“In this new study, NASA scientists analyzed the GISTEMP data to see if past predictions of rising temperatures were accurate. They needed to know that any uncertainty within their data was correctly accounted for. The goal was to make sure that the models they use are robust enough to rely on in the future. The answer: Yes they are. Within 1/20th a degree Celsius. Kudos.”Here's How Scarily Accurate NASA's Long-Term Climate Predictions Have Been So FarReality check december 2018:"Twenty years ago in Nature we concluded that recent warming was unprecedented in at least six centuries"https://www.nature.com/articles/33859This year in Nature, scientists concluded it's unprecedented in at least eleven millenniahttps://www.nature.com/articles/nature25464SUMMARY:Global climate models aren’t given nearly enough credit for their accurate global temperature change projections. As the 2014 IPCC report showed, observed global surface temperature changes have been within the range of climate model simulations.Now a new study shows that the models were even more accurate than previously thought. In previous evaluations like the one done by the IPCC, climate model simulations of global surface air temperature were compared to global surface temperature observational records like HadCRUT4. However, over the oceans, HadCRUT4 uses sea surface temperatures rather than air temperatures.Climate models are even more accurate than you thought | Dana NuccitelliWere the predictions we made about climate change 20 years ago accurate? Here's a lookLiterature that suggests the models are on track after all. And while that may be worrisome for the planet, it’s good news for the scientists working to understand its future. Climate models are even more accurate than you thought The difference between modeled and observed global surface temperature changes is 38% smaller than previously thought. Global climate models aren’t given nearly enough credit for their accurate global temperature change projections.As the 2014 IPCC report showed, observed global surface temperature changes have been within the range of climate model simulations.Worrisome first quarter of 2017 climate trends » Yale Climate ConnectionsClimate Models - OSS FoundationSlow climate mode reconciles historical and model-based estimates of climate sensitivityRobust comparison of climate models with observations using blended land air and ocean sea surface temperatureshttps://www.researchgate.net/pub...Factcheck: Climate models have not 'exaggerated' global warmingBonus:CMIP6: the next generation of climate models explained | Carbon Brief2. IPCC PREDICTIONS:The IPCC predictions have been accurate, but conservative. They have in fact underestimated the warming.“Comparisons to the most recent data consistently finds that climate change is occurring more rapidly and intensely than indicated by IPCCpredictions.”“Brysse et al. (2012) suggests that the IPCC and climate scientists in general tend to be too conservative in their predictions because they are "erring on the side of least drama" (ESLD). However, they point out that an underprediction is just as wrong as an overprediction. Climate scientists may be introducing bias into their predictions for fear of being called "alarmist," but this conservative bias may leave us unprepared for the magnitude of future climate change.”Science is conservative by nature and climate science even more.“one thing is certain: Several fundamental projections found in U.N. Intergovernmental Panel on Climate Change reports have consistently underestimated real-world observations, potentially leaving world governments in doubt as to how to guide climate policy.”The IPCC, for instance, failed to anticipate China's economic growth, or resistance by the United States and other nations to curbing greenhouse gases.“We really haven't explored a world in which the emissions growth rate is as rapid as we have actually seen happen,” Fields said.IPCC Predictions: Then Versus NowClimate Science Predictions Prove Too ConservativeClimate change prediction: Erring on the side of least drama?https://skepticalscience.com/ipc...Let’s look at the realities:IPCC models fits well when put on end of other predictions. But ,as mentioned, a bit conservative:Assessment of the first consensus prediction on climate changeComparing CMIP5 & observationsRobust comparison of climate models with observations using blended land air and ocean sea surface temperaturesA global perspective on CMIP5 climate model biasesAssessment of the first consensus prediction on climate changehttps://skepticalscience.com/ipc...IPCC PREDICTIONS HAVE DONE WELL AND MUCH BETTER THAN CONTRARIANS PREDICTIONS:BONUS: CONFUSING SHORT TERM MODELS WITH LONG TERM CMIP MODELS.Some people argue that climate models are unreliable if they don't make perfect short-term predictions. However, a number of unpredictable influences such as ocean and solar cycles have short-term influences on climate. Over the long term, these effects average out, which is why climate models do so well at long-term predictions.IPCC explains this difference here:IPCC confirms that short term internal climate variability, in any given 15-year period is hard to predict."For the period from 1998 to 2012, 111 of the 114 available climate-model simulations show a surface warming trend larger than the observations"Then they confirms their CMIP5 models are accurate and explains recent 15-year period short term predictions, showing a surface warming trend larger than the observations, was because of El Ninò:"There is hence very high confidence that the CMIP5 models show long-term GMST trends consistent with observations, despite the disagreement over the most recent 15-year period. Due to internal climate variability, in any given 15-year period the observed GMST trend sometimes lies near one end of a model ensemble, an effect that is pronounced in Box TS.3, Figure 1a, b as GMST was influenced by a very strong El Niño event in 1998."https://www.ipcc.ch/pdf/assessme...Risbey et al (2014) found that climate models actually generate good estimates of recent and past trends provided they also took into account natural variability, particularly the key El Nino-La Nina phases in the Pacific.“You’re always going to get periods when the warming slows down or speeds up relative to the mean rate because we have these strong natural cycles,” Dr Risbey said.In roughly 30-year cycles, the Pacific alternates between periods of more frequent El Ninos - when the ocean gives back heat to the atmosphere - to La Ninas, when it acts as a massive heat sink, setting in train relatively cool periods for surface temperatures.By selecting climate models in phase with natural variability, the research found that climate models have provided good estimates of 15-year trends, including for recent periods and for Pacific spatial trend patterns.By selecting climate models in phase with natural variability, the research found that climate models have provided good estimates of 15-year trends, including for recent periods and for Pacific spatial trend patterns.Well-estimated global surface warming in climate projections selected for ENSO phase3. LETS TAKE A LOOK AT THE HISTORY OF CLIMATE MODELS:“The researchers compared annual average surface temperatures across the globe to the surface temperatures predicted in 17 forecasts. Those predictions were drawn from 14 separate computer models released between 1970 and 2001. In some cases, the studies and their computer codes were so old that the team had to extract data published in papers, using special software to gauge the exact numbers represented by points on a printed graph.Most of the models accurately predicted recent global surface temperatures, which have risen approximately 0.9°C since 1970. For 10 forecasts, there was no statistically significant difference between their output and historic observations, the team reports today in Geophysical Research Letters”Even 50-year-old climate models correctly predicted global warmingThe First Climate Model Turns 50, And Predicted Global Warming Almost PerfectlyModeling the Earth's climate is one of the most daunting, complicated tasks out there. If only we were more like the Moon, things would be easy. The Moon has no atmosphere, no oceans, no icecaps, no seasons, and no complicated flora and fauna to get in the way of simple radiative physics. No wonder it's so challenging to model! In fact, if you google "climate models wrong", eight of the first ten results showcase failure. But headlines are never as reliable as going to the scientific source itself, and the ultimate source, in this case, is the first accurate climate model ever: by Syukuro Manabe and Richard T. Wetherald. 50 years after their groundbreaking 1967 paper, the science can be robustly evaluated, and they got almost everything exactly right.The effects and dangers of human made climate change was well known and understood by the US military and the president already in the 1960s.Fifty four years ago: The White House knew all about climate changeOn November 5, 1965, President Lyndon B. Johnson’s White House released “Restoring the Quality of our Environment”, a report that described the impacts of climate change, and foretold dramatic Antarctic ice sheet loss, sea level rise, and ocean acidification.That 1965 White House report stated:“Carbon dioxide is being added to the earth’s atmosphere by the burning of coal, oil, and natural gas at the rate of 6 billion tons a year. By the year 2000 there will be about 25 percent more CO2 in our atmosphere than present.”[…] “This will modify the heat balance of the atmosphere to such an extent that marked changes in climate, not controllable through local or even national efforts, could occur.On the 50th anniversary of the White House report, CO2 concentrations in the atmosphere are indeed at 399 ppm: 25 percent over 1965 levels, exactly as predicted 50 years ago.http://ourchildrenstrust.org/sit...Scientists warned the President about global warming 50 years ago today | Dana NuccitelliEven oil company Exxon knew everything in the 70’s:Exxon Knew about Climate Change Almost 40 Years AgoExxon predicted in 1982 exactly how high global carbon emissions would be todayAccording to a graph displaying the “growth of atmospheric CO2 and average global temperature increase” over time, the company expected that, by 2020, carbon dioxide in the atmosphere would reach roughly 400 to 420 ppm. This month’s measurement of 415 ppm is right within the expected curve Exxon projected under its “21st Century Study-High Growth scenario.”IN 1982, EXXON SCIENTIST PROJECTED CARBON DIOXIDE CONCENTRATIONS IN THE ATMOSPHERE. (CREDIT: EXXON VIA INSIDE CLIMATE NEWS)Not only did Exxon predict the rise in emissions, it also understood how severe the consequences would be.“At the high end, some scientists suggest there could be considerable adverse impact including the flooding of some coastal land masses as a result of a rise in sea level due to melting of the Antarctic ice sheet,” it continued, stating this would only take place centuries after temperatures warmed by 3 degrees Celsius.”Watch to see Exxon scientist show how accurate their prediction was:https://insideclimatenews.org/sites/default/files/documents/1982%20Exxon%20Primer%20on%20CO2%20Greenhouse%20Effect.pdfComparing what climate scientists said in the early 80s with today:Comparing what climate scientists said in the early 80s with today:Listening to James Hansen on Climate Change, Thirty Years Ago and Now30 years ago global warming became front-page news – and both Republicans and Democrats took it seriously40 years ago, scientists predicted climate change. And hey, they were rightThe 1984 Climate Change DocumentaryThe 1984 Climate Change DocumentaryClimate models have been correct for literally 40 yearsEven 50-year-old climate models correctly predicted global warmingBONUS 1:Latest:Humans Have Caused the Most Dramatic Climate Change in 3 Million Years1. By including dropping CO2 levels and the removal of the sediment overburden atop the bedrock underneath the ice sheets and glaciers (the ice scoured the sediments down & into the bedrock itself), scientists were able to successfully reproduce the observed climate as found in the various proxy records over that same time interval2. The mid-Pleistocene transition from 40,000 year glacial phases to 100,000 year phases was successfully replicated using the new forcing values3. The Earth's climate system has a strong response to even small variations in CO2 (3 C climate sensitivity in the model)4. CO2 levels during that interval have never been as high as they are today (~410 ppm)5. A continuance of Business As Usual Emissions Pathways, as at present, would push our climate beyond the bounds of climate experienced over the Quaternary Period (the period covered by this study).First successful model simulation of the past 3 million years of climate changeHumans Have Caused the Most Dramatic Climate Change in 3 Million YearsMid-Pleistocene transition in glacial cycles explained by declining CO2 and regolith removalBONUS 2:“The physics we use to understand the earth’s climate system is the same physics that explains how stoves, fridges, airplanes and more work. And most people don’t really have a problem with the physics of non-linear fluid dynamics and radiative transfer that have been well understood for decades, even centuries.” (Climate scientist Katharine Hayhoe.)Q&A: How do climate models work?https://www.carbonbrief.org/qa-h...There is an excellent description of climate models evaluation in the following IPCC report:http://www.ipcc.ch/pdf/assessmen...If anything else, I suggest you read page 600-601 that address how reliable current models are.The last paragraph states:"In summary, confidence in models comes from their physical basis, and their skill in representing observed climate and past climate changes. Models have proven to be extremely important tools for simulating and understanding climate, and there is considerable confidence that they are able to provide credible quantitative estimates of future climate change, particularly at larger scales. Models continue to have significant limitations, such as in their representation of clouds, which lead to uncer- tainties in the magnitude and timing, as well as regional details, of predicted climate change. Nevertheless, over several decades of model development, they have consistently provided a robust and unambiguous picture of significant climate warming in re-sponse to increasing greenhouse gases."BONUS 3:DENIERS ATTACK ON CLIMATE MODELSROY SPENCERS BIG LIE AND CHEAT WAS BASED ON FALSELY CALIBRATED DATA“Climate scientists have been terrible at predicting temperatures.”This is a claim that's often made by climate skeptics: that predictions about the near-term future have been bad, so we shouldn't trust predictions about the longer-term future. But is that true? Have predictions historically been bad?Have predictions historically been bad?The evidence they cite is from Dr. Roy Spencer, who showed in 2013 that 95% of climate models over predict the temperature rises due to greenhouse gases. The chart showing that is below. Unfortunately, that chart itself is based on falsely calibrated data.Unfortunately, that chart itself is based on falsely calibrated data.“In 2014, the truth came out: Spencer’s UAH team had made a huge mistake in the calibration of their data. Instead of negligible upper-atmosphere warming, they found that the upper atmosphere had been warming at +0.14 degrees per decade, double the 1880-2014 rate of 0.07 degrees per decade. The other major satellite data set, RSS, also found a calibration error, meaning the Earth warmed 140% faster since 1998 than previous conclusions indicated. At the same time, the ground-based data from NOAA, NASA, the Hadley center and BEST all displayed agreement with one another. Once the 2014, 2015 and 2016 data are also included, the graph shows the scientific truth: the models are very much in line with what we observe.”The correctly adjusted chart:JOHN CHRISTYS LYING non-peer reviewed GRAPH:DEBUNK:In addition to various statistical sizes, Christy uses different physical measures in comparison when comparing temperatures at the surface with the temperature of 15 km of the atmosphere."Christy showed a graph of only mid-troposphere temperatures. The mid-troposphere is the atmospheric layer from about 25,000–50,000 feet, or about 8–15km in altitude. One might reasonably ask why Christy only showed data for such high altitudes. For perspective, the highest point on the Earth’s surface is on Mount Everest at 29,000 feet (8.8km), and the highest elevation city in the world is La Rinconada, Peru at 16,700 feet (5.1km). Humans live in the lower troposphere, not the mid-troposphere.However, climate models have done a good job matching the observed temperature change at the surface and in the lower troposphere, where humans live. We understand the workings of the Earth’s climate much better than Christy suggests, especially where it matters most to humans."Christy compared the average of 102 climate model simulations with temperature from satellite measurements (average of three different analyses) and weather balloons (average of two analyses). This is a flawed comparison because it compares a statistical parameter with a variable.Temperature from satellites are also model resultsIt is fair to compare the satellite record with model results to explore uncertainties, but the satellite data is not the ground truth and cannot be used to invalidate the models. The microwave sounding unit (MSU), the instrument used to measure the temperature, measures light in certain wavelength bands emitted by oxygen molecules. Satellite data are 5 timers less accurate than ground data.Different types of numbersThe upper left panel in Fig. 1 shows that Christy compared the average of 102 climate model simulations with temperature from satellite measurements (average of three different analyses) and weather balloons (average of two analyses). This is a flawed comparison because it compares a statistical parameter with a variable.A parameter, such as the mean (also referred to as the ‘average’) and the standard deviation, describe the statistical distribution of a given variable. However, such parameters are not equivalent to the variable they describe.The comparison between the average of model runs and observations is surprising, because it is clearly incorrect from elementary statistics (This is similar statistics-confusion as the flaw found in the Douglass et al. (2007)).http://www.realclimate.org/index...http://www.realclimate.org/index...Climate scientists, using current science, are successful in predicting temperatures.https://skepticalscience.com/graphics/ChristyChart500.gifhttps://skepticalscience.com/gra...https://skepticalscience.com/republicans-favorite-climate-chart-has-serious-problems.htmlCongress manufactures doubt and denial in climate change hearing | Dana NuccitelliDEBUNK#2Graph shows a comparison between the average of an ensemble of 102 model calculations and observations (average of 3 satellite measurements and 4 balloon measurements). They have clearly not understood that they compare different sizes, so that they can not dismiss model calculations based on such.The model calculations shown by Christy are derived from the Dutch data portal ClimateExplorer. However, model calculations of temperatures at different heights above the ground in this web portal can not be found, only the temperature near the ground. The satellite measurements and balloons, on the other hand, represent the average temperature in a volume that stretches from the ground to a height of about 15 km.In addition to various statistical sizes, Christy uses different physical measures in comparison when comparing temperatures at the surface with the temperature of 15 km of the atmosphere. Increased greenhouse effect causes the lower part of the atmosphere (troposphere, which goes up to about 10km) to get warmer while the above layers of the stratosphere become colder. Does anyone see the problem with this comparison?Not only that. The satellite measurements are also model calculations,. In fact, they base on similar models that show that CO2 provides global warming. Ironically, neither Spencer nor Christy have realized this fact. In addition, the satellite curve is sewn together by different satellites with short lifespan, and the measurements from the different satellites are scattered. It is not so easy to put them together to a reliable temperature curve. They have been corrected several times.In other words, the figure of Christy and Spencer reveals basic deficiencies in understanding both statistics and physics.https://www.theguardian.com/envi...BONUS 4:With the increased knowledge on climate sensitivity added , there is every reason to believe future climate models will be even better:A new study by Kate Marvel, Gavin Schmidt, Ron Miller, and Larissa Nazarenko at the NASA Goddard Institute for Space Studies appears to have found the answer. They drew upon previous research by Drew Shindell and Kummer & Dessler, who identified a flaw in studies taking the energy budget approach. Those studies had assumed that the Earth’s climate is equally sensitive to all forcings.In reality, as world-renowned climate scientist James Hansen noted in a 1997 paper, some forcings are more efficient at causing the Earth’s surface temperature to change than others. Those in which the effects are focused in the northern hemisphere tend to be more efficient, for example. [...]The NASA study shows that the previous estimates were indeed biased low, and correcting for that bias brings them into agreement with estimates using other approaches. A number of independent studies using near-global satellite data find positive feedback and high climate sensitivity. [...] Climate sensitivity is a measure of how much our climate responds to an energy imbalance. The most common definition is the change in global temperature if the amount of atmospheric CO2 was doubled. If there were no feedbacks, climate sensitivity would be around 1°C. But we know there are a number of feedbacks, both positive and negative. So how do we determine the net feedback? An empirical solution is to observe how our climate responds to temperature change. We have satellite measurements of the radiation budget and surface measurements of temperature. Putting the two together should give us an indication of net feedback.Less than 2 °C warming by 2100 unlikely The likely range of global temperature increase is 2.0–4.9 °C, with median 3.2 °C and a 5% (1%) chance that it will be less than 2 °C (1.5 °C). Population growth is not a major contributing factor. Our model is not a ‘business as usual’ scenario, but rather is based on data which already show the effect of emission mitigation policies. Net positive feedback is confirmed by many different lines of evidence.Spread in model climate sensitivity traced to atmospheric convective mixingA Less Cloudy Future: The Role of Subtropical Subsidence in Climate SensitivityThe Impact of Global Warming on Marine Boundary Layer Clouds over the Eastern Pacific—A Regional Model StudyGreater future global warming inferred from Earth’s recent energy budget.Tan I, Storelvmo T, and Zelinka MD: Observational constraints on mixed-phase clouds imply higher climate sensitivity. Science 352(6282):224–27, 2016.Shaffer G, Huber M, Rondanelli R, and Pepke Pedersen JO: Deep-time evidence for climate sensitivity increase with warming. Geophysical Research Letters 43(12):6538–45, 2016.Armour KC: Energy budget constraints on climate sensitivity in light of inconstant climate feedbacks. Nature Climate Change 7(5):331–35, 2017The most likely value of ECS constrained by different lines of evidence is 3 °C, not lower than that.Knutti R, Rugenstein MA, and Hegerl GC: Beyond equilibrium climate sensitivity. Nature Geoscience 10:727–736, 2017.Greater future global warming inferred from Earth’s recent energy budgethttps://www.nature.com/articles/...All the models and evidence confirm a minimum warming close to 2°C for a doubling of atmospheric CO2 with a most likely value of 3°C and the potential to warm 4.5°C or even more. Even such a small rise would signal many damaging and highly disruptive changes to the environment. In this light, the arguments against reducing greenhouse gas emissions because of climate sensitivity are a form of gambling.Papers on climate sensitivity estimateshttps://agwobserver.wordpress.co...

The earth is cooling evident from recent winter weather in Sweden and Norway rebutting support for the thesis of man made global warming. The massive snowfall and winter weather with record colder temperatures gives credence to the view that snowfall will trigger the end of global warming fears. Sweden and Norway are becoming poster children of the end of global warming fears.Colder and snowy winters are evidence against global warming according to the UN IPCC when they predicted the end of snow.This IPCC prediction is common sense especially because snow has a special climate effect called the albedo that goes beyond the immediate cooler temperatures at the moment of falling. The snow albedo may cause weather changes in future years and decades particularly when the snow falls on glaciers. The albedo is that snow and ice reflects 85 to 90% of sunlight back into the atmosphere not reaching earth. If this cooling process was fully engaged how could there be any unprecedented warming? Answer there could not.for all to observe with the new climate reality from the alleged ‘activities of mankind’ primarily emissions of CO2. If there wasa not this major climate shift in warmer winter weather how could that be unprecedented warming? This is why when the snowfalls prediction is nearly 100% false and moderate winters are not surely this gives weight to the truth of null hypothesis i.e. “there is no climate/global warming.”Further, the assumption that there is ‘climate change’ or the Alice in Wonderland new meaning “man made global warming” lacks evidence over a time scale that fits the definition. The more scientific question is how does climate variability affect Sweden and Norway. When looking at weather data for a time scale of less the 100 years we will not see verifiable climate change. This is definitional revision is very relevant as the evidence over centuries shows no unusual global warming and a decline in temperatures.The world’s longest temperature record 1659 -2020 from England show climate stability and no unusual warming.Alarmist claim otherwise arguing the global warming has happened dramatically fast so the last 30 years is far enough. This argument is wrong on two accounts. First warming is not happening fast at all because temperature rise is in a pause and indeed recent evidence is temperatures are falling globally. The best evidence of this is the observable increase in record colder winter weather. Snow comes earlier in unusual places like Morocco and stay longer like the snowfall this year across the UN Northeast on Mothers day.GLOBAL TEMPERATURES SUFFER SECOND LARGEST TWO MONTH DROP IN RECORDED HISTORYMAY 6, 2020 CAP ALLONThe Temperature of the Global Lower Atmosphere plunged 0.38C through March and April, halving its February above baseline high of 0.76C to 0.38C — the second-largest two-month drop in the UAH temperature dataset.The largest two month drop remains the 0.69C observed back in 1987. And note how the global average temperature back in 1987 –before both the drop AND the inception of the global warming scare— is EXACTLY the same as it is now:Global Temperatures Suffer Second Largest Two Month Drop in Recorded History - ElectroverseSEARCH RESULTS FOR: SWEDENExtreme Weather GSMALL-TIME RECORD SNOWFALL BURIES PARTS OF SWEDEN — 3.25 M (10.7 FT) — DON’T TELL GRETA…MARCH 19, 2020 CAP ALLON0 COMMENTThe first flakes of the season in Kiruna fell back on Sept 30 and from then on have continued relentlessly, with accumulations now comfortably surpassing the region’s all-time snowfall record.Extreme Weather GSMSWEDEN SUFFERS ITS BIGGEST NOVEMBER SNOWSTORMS IN [AT LEAST] 40 YEARSNOVEMBER 13, 2019 CAP ALLON0 COMMENT…best not tell Greta.Extreme Weather GSMSEPTEMBER SNOW IN SWEDEN: “EARLIEST IN AT LEAST 20 YEARS”SEPTEMBER 18, 2019 CAP ALLON0 COMMENTIt isn’t usually until November, and the arrival of much cooler polar air, when Värmland sees snow totals like these…SEARCH RESULTS FOR: NORWAYExtreme Weather GSMNORWAY JUST SUFFERED ITS SNOWIEST WINTER SINCE 1958, AND “THERE ARE STILL ABSURD AMOUNTS OF SNOW IN THE MOUNTAINS RIGHT NOW”MAY 26, 2020 CAP ALLON0 COMMENTFurthermore, the month of May is continuing the snowy trend seeing “more than three times as much snow as usual in many places,” said Heidi Stranden, spokeswoman for NVE.Extreme Weather GSMNORWAY BREAKS SNOWFALL RECORDS: “I HAVE NEVER EXPERIENCED SO MUCH SNOW IN ONE DAY,” SAYS TROMSØ METEOROLOGISTAPRIL 7, 2020 CAP ALLON0 COMMENTIn addition, Total Snow Mass for Northern Hemisphere is now holding at a staggering 600+ Gigatons above the 1982-2012 average…Extreme Weather GSM“NO SPRING IN THE NORTH” — NORWAY BATTERED BY SNOWSTORM AFTER SNOWSTORM DURING “RECORD BREAKING” AND “EXCEPTIONAL” MARCHAPRIL 1, 2020 CAP ALLON0 COMMENTAn online road-map reveals the current state of chaos for northern Norwegian road users, as ALL passes along the coast fall like dominoes due to heavy snow & avalanches…Extreme Weather GSMMONSTER FEBRUARY SNOWFALL BURIES PARTS OF NORWAY — TOTALS SURPASS 2 METERS (7 FEET) IN MANY REGIONSFEBRUARY 20, 2020 CAP ALLON0 COMMENTThe largest Feb snow totals in 15+ years have blocked train tracks, trapped people in their cars, and buried homes–not that you’d know it if AGW-propaganda rags are all you read…Articles GSMELECTRICITY SURGES THROUGH THE SOIL OF NORWAYJANUARY 7, 2020 CAP ALLON1 COMMENTOur universe is electromagnetic, and earth’s magnetosphere is waning -fast- in line with historically low solar activity and an ongoing magnetic excursion/reversal — ‘space weather’ events that would have ordinarily passed by unnoticed are having an increasingly-bigger impact here on the ground…Extreme Weather GSMLAST MONTH WAS NORWAY’S COLDEST OCTOBER IN 10 YEARS (SINCE SOLAR MINIMUM OF CYCLE 23)Furthermore, 70cm (28 inches) of snow had accumulated in Tromsø by Nov 06 — the largest amount by this date since 1923 (solar minimum of cycle 15)…NOVEMBER 8, 2019 CAP ALLON0 COMMENTMore evidence of cooling comes from the fact Norway shows sea level decline over the past 100 years.Relative Sea Level Trend040-081 Narvik, NorwayEXPORT TO TEXT | EXPORT TO CSV | SAVE IMAGEThe relative sea level trend is -2.1 millimeters/year with a 95% confidenceinterval of +/- 0.41 mm/yr based on monthly mean sea level data from1928 to 2018 which is equivalent to a change of -0.69 feet in 100 years.The relative sea level trend is -2.1 mm/year with a 95% confidence interval of +/- 0.41 mm/year based on monthly mean sea level data from 1928 to 2018 which is equivalent to a change of -0.69 feet in 100 years.-2.1mm/year1928 - 2018NOAA Tides & CurrentsFour Studies Find ‘No Observable Sea-Level Effect’ From Man-Made Global WarmingBy Barbara Hollingsworth | September 14, 2016 | 11:39am EDT(Home | CNSNews) – Ten years after former Vice President Al Gore warned in his 2006 Oscar-winning film, An Inconvenient Truth, that if nothing was done to stop man-made global warming, melting Antarctic and Greenland ice sheets could raise sea levels by up to 20 feet, four peer-reviewed scientific studies found “no observable sea-level effect of anthropogenic global warming.”“It is widely assumed that sea levels have been rising in recent decades largely in response to anthropogenic global warming,” Kenneth Richard writes at NoTricksZone. “However, due to the inherently large contribution of natural oscillatory influences on sea level fluctuations, this assumption lacks substantiation….“Scientists who have recently attempted to detect an anthropogenic signal in regional sea level rise trends have had to admit that there is ‘no observable sea-level effect of anthropogenic global warming’,” Richard points out, listing four peer-reviewed studies published this year that have all come to the same conclusion.…..In a fourth paper published online in January in the Journal of Coastal Research, lead author Jens Morten Hansen of the Geological Survey of Denmark and Greenland and his co-authors studied sea level patterns from the eastern North Sea to the central Baltic Sea over a 160-year period (1849-2009).“Identification of oscillators and general trends over 160 years would be of great importance for distinguishing long-term, natural developments from possible, more recent anthropogenic sea-level changes,” the researchers note.“However, we found that a possible candidate for such anthropogenic development, i.e. the large sea-level rise after 1970, is completely contained by the found small residuals, long-term oscillators, and general trend. Thus, we found that there is (yet) no observable sea-level effect of anthropogenic global warming in the world's best recorded region.”In addition, the Earth’s coasts actually gained land over the past 30 years, according to another study published August 25 in Nature Climate Change.Researchers led by Gennadii Donchyts from the Deltares Research Institute in the Netherlands found that the Earth’s surface gained a total of 58,000 square kilometers (22,393 square miles) of land over the past 30 years, including 33,700 sq. km. (13,000 sq. mi.) in coastal areas.“We expected that the coast would start to retreat due to sea level rise, but the most surprising thing is that the coasts are growing all over the world,” study co-author Fedor Baart told the BBC.“We were able to create more land than sea level rising was taking.”Four Studies Find ‘No Observable Sea-Level Effect’ From Man-Made Global WarmingSurely the evidence from Sweden and Norway buttresses the fact the science of man made global warming is not settled. I have expanded on this reality in my answer to the following Quora question.James Matkin's answer to Why do we need more study before blaming humanity for climate change?Here is a brief analysis of why we need more study of ‘global warming’ -So, to answer the question as succinctly as I can, global warming as a consequence of human CO2 emission is a nonsense that is not supported by rigorous mathematical proof, nor by empirical evidence; in fact, exactly the opposite. All models based on this thesis have failed to deliver results that are even remotely like those being experienced. All of the dire predictions have not come true. Satellite data disproves the theory of temperature amplification as a result of CO2. The IPCC theory breaks the 2nd law of thermodynamics. So much for good science!! Just about everything to do with this movement, including its bogus 97% consensus, is fraudulent, ie, attempting to gain a benefit through deception.Kevin Loughrey, New South Wales

CLIMATE PREDICTIONS HAVE BEEN VERY ACCURATE:" the close match between projected and observed warming since 1970 suggests that estimates of future warming may prove similarly accurate."Latest nov 2019:"According to the research published today, almost every peer-reviewed climate model of human-caused global temperature rise dating back to 1970 lines up with the warming we see today.“In scientific terms, we'd say there's no bias,” the paper’s co-author Henri Drake, a PhD candidate at MIT, told me over the phone. “Once we accounted for the differences in CO2 emissions, 14 of the 17 models we analyzed were consistent with current observations.”“Taken together,” he added, “these climate models have always been quantitatively accurate.”Figure 2 from Hausfather et al (2019) showing the comparisons between model predictions and observations for a) the temperature trends (above) and b) the implied Transient Climate Response (TCR) which is the trend divided by the forcing and scaled to an equivalent 2xCO2 forcing.How good have climate models been at truly predicting the future?Hausfather et al 2019Evaluating the performance of past climate model projectionsCONTENTCLIMATE MODELS HAVE BEEN VERY ACCURATEIPCC MODELSTHE HISTORY OF CLIMATE MODELSBONUSES - INCLUDING DEBUNKING OF MODEL MYTHSThe reason why long term climate predictions ARE possible, and 2–3 days weather predictions are NOT possible, is very logical:A number of unpredictable influences such as ocean and solar cycles have short-term influences on climate. Over the long term, these effects average out, which is why climate models do so well at long-term predictions.It’s basic physics which follows the same principles as other laws of nature.“The physics we use to understand the earth’s climate system is the same physics that explains how stoves, fridges, airplanes and more work. And most people don’t really have a problem with the physics of non-linear fluid dynamics and radiative transfer that have been well understood for decades, even centuries.” (Climate scientist Katharine Hayhoe.)Just check out world known and verified Quora account climate scientist Katharine Hayhoe:Katharine Hayhoe's answer to What climate models do you believe to be the most accurate? In other words, what scenario do you think will most likely play out in the near future and far future? How do you communicate this to the public?Now, let’s check the models:Here are some actual predictions from Global Climate Models all of which have proven correct. Im even linking to the paper directly so you can go and read for yourself.- That the Earth would warm, and about how fast, and about how much(Arrhenius 1896, Callendar 1938, Plass 1956, Sawyer 1972, Broecker 1975; validated by Crowley 2000, Philipona et al 2004, Evans and Puckrin 2006, Lean and Rind 2008, Mann et al. 2008, etc)- That nighttime temperatures would increase more than daytime temperatures(Arrhenius 1896; validated by Dai et al. 1999, Sherwood et al. 2005, etc)- That winter temperatures would increase more than summer temperatures(Arrhenius 1896, Manabe and Stouffer 1980, Rind et al 1989; validated by Balling et al 1999, Volodin and Galin 1999, Crozier 2003, etc)- Polar amplification (that temperatures increase more as you move toward the poles)(Arrhenius 1896, Manabe and Stouffer 1980; validated by Polyakov et al 2001, Holland and Bitz 2003, etc)- That the Arctic would warm faster than the Antarctic(Arrhenius 1896, Manabe and Stouffer 1980; validated by Doran et al 2002, Comisa 2003, Turner et al 2007, etc)- That the Earth’s troposphere would warm and the stratosphere would cool(Manabe and Wetherald 1967, Manabe and Stouffer 1980; validated by Ramaswamy et al. 1996, 2006, De F. Forster et al 1999, Langematz et al 2003, Vinnikov and Grody 2003, Fu et al 2004, Thompson and Solomon 2005, etc)- The near constancy of relative humidity on global average(Manabe and Wetherall 1967; validated by Minschwaner and Dessler 2004, Soden et al 2005, Gettelman and Fu 2008, etc)- Scientists made a retrodiction (a model prediction based on established physics) for Last Glacial Maximum sea surface temperatures which was inconsistent with the paleo evidence for those times; better paleo evidence showed the models were right(Rind and Peteet 1985; validated by Farreral et al 1999, Melanda et al 2005, etc)- The clear sky super greenhouse effect from increased water vapor in the tropics(Vonder Haar 1986; validated by Lubin 1994, etc)- That coastal upwelling of ocean water would increase(Bakun 1990; validated by Goes et al 2005, McGregor et al 2007, etc)- The magnitude (0.3 C) and duration (two years) of the cooling from the Mt. Pinatubo eruption(Hansen et al 1992; validated by Hansen et al 1996, Soden et al 2002, etc)- The amount of water vapor feedback due to ENSO(Lau et al 1996; validated by Soden 2000, Dessler and Wong 2009, etc)- The rising of the tropopause and the effective radiating altitude(Thuburn and Craig 1997, Kushner et al 2001; validated by Santer et al 2003, Seidel and Randel 2006, etc)- The response of southern ocean winds to the ozone hole(Fyfe et al 1999, Kushner et al 2001, Sexton 2001; validated by Thompson and Solomon 2002, etc)- The expansion of the Hadley cells(Quan et al 2002; validated by Fu et al 2006, Hu and Fu 2007, etc)- They predicted a trend significantly different in amount and different in nature from UAH satellite temperatures, and then a bug was found in the satellite data which showed that surface temperatures were more accurate and reliable than UAH temperature data.(Christy et al 2003; validated by Santer et al 2003, Mears and Wentz 2005, Santer et al 2005, Sherwood et al 2005, etc)- The poleward movement of storm tracks(Trenberth and Stepaniak 2003; validated by Yin 2005, etc)Here's How Scarily Accurate NASA's Long-Term Climate Predictions Have Been So FarReality check december 2018:"Twenty years ago in Nature we concluded that recent warming was unprecedented in at least six centuries"https://www.nature.com/articles/33859This year in Nature, scientists concluded it's unprecedented in at least eleven millenniahttps://www.nature.com/articles/nature25464SUMMARY:Global climate models aren’t given nearly enough credit for their accurate global temperature change projections. As the 2014 IPCC report showed, observed global surface temperature changes have been within the range of climate model simulations.Now a new study shows that the models were even more accurate than previously thought. In previous evaluations like the one done by the IPCC, climate model simulations of global surface air temperature were compared to global surface temperature observational records like HadCRUT4. However, over the oceans, HadCRUT4 uses sea surface temperatures rather than air temperatures.Climate models are even more accurate than you thought | Dana NuccitelliWere the predictions we made about climate change 20 years ago accurate? Here's a lookLiterature that suggests the models are on track after all. And while that may be worrisome for the planet, it’s good news for the scientists working to understand its future. Climate models are even more accurate than you thought The difference between modeled and observed global surface temperature changes is 38% smaller than previously thought. Global climate models aren’t given nearly enough credit for their accurate global temperature change projections.As the 2014 IPCC report showed, observed global surface temperature changes have been within the range of climate model simulations.Worrisome first quarter of 2017 climate trends » Yale Climate ConnectionsClimate Models - OSS FoundationSlow climate mode reconciles historical and model-based estimates of climate sensitivityRobust comparison of climate models with observations using blended land air and ocean sea surface temperatureshttps://www.researchgate.net/pub...Factcheck: Climate models have not 'exaggerated' global warmingBonus:CMIP6: the next generation of climate models explained | Carbon Brief2. IPCC PREDICTIONS:The IPCC predictions have been accurate, but conservative. They have in fact underestimated the warming.“Comparisons to the most recent data consistently finds that climate change is occurring more rapidly and intensely than indicated by IPCCpredictions.”“Brysse et al. (2012) suggests that the IPCC and climate scientists in general tend to be too conservative in their predictions because they are "erring on the side of least drama" (ESLD). However, they point out that an underprediction is just as wrong as an overprediction. Climate scientists may be introducing bias into their predictions for fear of being called "alarmist," but this conservative bias may leave us unprepared for the magnitude of future climate change.”Science is conservative by nature and climate science even more.“one thing is certain: Several fundamental projections found in U.N. Intergovernmental Panel on Climate Change reports have consistently underestimated real-world observations, potentially leaving world governments in doubt as to how to guide climate policy.”The IPCC, for instance, failed to anticipate China's economic growth, or resistance by the United States and other nations to curbing greenhouse gases.“We really haven't explored a world in which the emissions growth rate is as rapid as we have actually seen happen,” Fields said.IPCC Predictions: Then Versus NowClimate Science Predictions Prove Too ConservativeClimate change prediction: Erring on the side of least drama?https://skepticalscience.com/ipc...Let’s look at the realities:IPCC models fits well when put on end of other predictions. But ,as mentioned, a bit conservative:Assessment of the first consensus prediction on climate changeComparing CMIP5 & observationsRobust comparison of climate models with observations using blended land air and ocean sea surface temperaturesA global perspective on CMIP5 climate model biasesAssessment of the first consensus prediction on climate changehttps://skepticalscience.com/ipc...IPCC PREDICTIONS HAVE DONE WELL AND MUCH BETTER THAN CONTRARIANS PREDICTIONS:Some people argue that climate models are unreliable if they don't make perfect short-term predictions. However, a number of unpredictable influences such as ocean and solar cycles have short-term influences on climate. Over the long term, these effects average out, which is why climate models do so well at long-term predictions.IPCC explains this difference here:IPCC confirms that short term internal climate variability, in any given 15-year period is hard to predict."For the period from 1998 to 2012, 111 of the 114 available climate-model simulations show a surface warming trend larger than the observations"Then they confirms their CMIP5 models are accurate and explains recent 15-year period short term predictions, showing a surface warming trend larger than the observations, was because of El Ninò:"There is hence very high confidence that the CMIP5 models show long-term GMST trends consistent with observations, despite the disagreement over the most recent 15-year period. Due to internal climate variability, in any given 15-year period the observed GMST trend sometimes lies near one end of a model ensemble, an effect that is pronounced in Box TS.3, Figure 1a, b as GMST was influenced by a very strong El Niño event in 1998."https://www.ipcc.ch/pdf/assessme...Risbey et al (2014) found that climate models actually generate good estimates of recent and past trends provided they also took into account natural variability, particularly the key El Nino-La Nina phases in the Pacific.“You’re always going to get periods when the warming slows down or speeds up relative to the mean rate because we have these strong natural cycles,” Dr Risbey said.In roughly 30-year cycles, the Pacific alternates between periods of more frequent El Ninos - when the ocean gives back heat to the atmosphere - to La Ninas, when it acts as a massive heat sink, setting in train relatively cool periods for surface temperatures.By selecting climate models in phase with natural variability, the research found that climate models have provided good estimates of 15-year trends, including for recent periods and for Pacific spatial trend patterns.By selecting climate models in phase with natural variability, the research found that climate models have provided good estimates of 15-year trends, including for recent periods and for Pacific spatial trend patterns.Well-estimated global surface warming in climate projections selected for ENSO phase3. LETS TAKE A LOOK AT THE HISTORY OF CLIMATE MODELS:“The researchers compared annual average surface temperatures across the globe to the surface temperatures predicted in 17 forecasts. Those predictions were drawn from 14 separate computer models released between 1970 and 2001. In some cases, the studies and their computer codes were so old that the team had to extract data published in papers, using special software to gauge the exact numbers represented by points on a printed graph.Most of the models accurately predicted recent global surface temperatures, which have risen approximately 0.9°C since 1970. For 10 forecasts, there was no statistically significant difference between their output and historic observations, the team reports today in Geophysical Research Letters”Even 50-year-old climate models correctly predicted global warmingThe First Climate Model Turns 50, And Predicted Global Warming Almost PerfectlyModeling the Earth's climate is one of the most daunting, complicated tasks out there. If only we were more like the Moon, things would be easy. The Moon has no atmosphere, no oceans, no icecaps, no seasons, and no complicated flora and fauna to get in the way of simple radiative physics. No wonder it's so challenging to model! In fact, if you google "climate models wrong", eight of the first ten results showcase failure. But headlines are never as reliable as going to the scientific source itself, and the ultimate source, in this case, is the first accurate climate model ever: by Syukuro Manabe and Richard T. Wetherald. 50 years after their groundbreaking 1967 paper, the science can be robustly evaluated, and they got almost everything exactly right.The effects and dangers of human made climate change was well known and understood by the US military and the president already in the 1960s.Fifty four years ago: The White House knew all about climate changeOn November 5, 1965, President Lyndon B. Johnson’s White House released “Restoring the Quality of our Environment”, a report that described the impacts of climate change, and foretold dramatic Antarctic ice sheet loss, sea level rise, and ocean acidification.That 1965 White House report stated:“Carbon dioxide is being added to the earth’s atmosphere by the burning of coal, oil, and natural gas at the rate of 6 billion tons a year. By the year 2000 there will be about 25 percent more CO2 in our atmosphere than present.”[…] “This will modify the heat balance of the atmosphere to such an extent that marked changes in climate, not controllable through local or even national efforts, could occur.On the 50th anniversary of the White House report, CO2 concentrations in the atmosphere are indeed at 399 ppm: 25 percent over 1965 levels, exactly as predicted 50 years ago.http://ourchildrenstrust.org/sit...Scientists warned the President about global warming 50 years ago today | Dana NuccitelliEven oil company Exxon knew everything in the 70’s:Exxon Knew about Climate Change Almost 40 Years AgoExxon predicted in 1982 exactly how high global carbon emissions would be todayAccording to a graph displaying the “growth of atmospheric CO2 and average global temperature increase” over time, the company expected that, by 2020, carbon dioxide in the atmosphere would reach roughly 400 to 420 ppm. This month’s measurement of 415 ppm is right within the expected curve Exxon projected under its “21st Century Study-High Growth scenario.”IN 1982, EXXON SCIENTIST PROJECTED CARBON DIOXIDE CONCENTRATIONS IN THE ATMOSPHERE. (CREDIT: EXXON VIA INSIDE CLIMATE NEWS)Not only did Exxon predict the rise in emissions, it also understood how severe the consequences would be.“At the high end, some scientists suggest there could be considerable adverse impact including the flooding of some coastal land masses as a result of a rise in sea level due to melting of the Antarctic ice sheet,” it continued, stating this would only take place centuries after temperatures warmed by 3 degrees Celsius.”https://insideclimatenews.org/si...Comparing what climate scientists said in the early 80s with today:Comparing what climate scientists said in the early 80s with today:Listening to James Hansen on Climate Change, Thirty Years Ago and Now30 years ago global warming became front-page news – and both Republicans and Democrats took it seriouslyThe 1984 Climate Change DocumentaryClimate models have been correct for literally 40 yearsEven 50-year-old climate models correctly predicted global warmingBONUS 1:Latest:Humans Have Caused the Most Dramatic Climate Change in 3 Million Years1. By including dropping CO2 levels and the removal of the sediment overburden atop the bedrock underneath the ice sheets and glaciers (the ice scoured the sediments down & into the bedrock itself), scientists were able to successfully reproduce the observed climate as found in the various proxy records over that same time interval2. The mid-Pleistocene transition from 40,000 year glacial phases to 100,000 year phases was successfully replicated using the new forcing values3. The Earth's climate system has a strong response to even small variations in CO2 (3 C climate sensitivity in the model)4. CO2 levels during that interval have never been as high as they are today (~410 ppm)5. A continuance of Business As Usual Emissions Pathways, as at present, would push our climate beyond the bounds of climate experienced over the Quaternary Period (the period covered by this study).First successful model simulation of the past 3 million years of climate changeHumans Have Caused the Most Dramatic Climate Change in 3 Million YearsMid-Pleistocene transition in glacial cycles explained by declining CO2 and regolith removalBONUS 2:Lets clear up a few common mistakes:Climate models don't "predict." They project what will happen given a set of initial conditions and may include several scenarios. If a certain scenario didnt happen, it does not mean the prediction was wrong. It means the conditions for that particular scenario didnt happen. The scenarios are often grouped as most likely and worst case etc.All studies shows models have underestimated the realities.Part of the problem here stems from people either misunderstanding or deliberately misrepresenting how predictive models work. Many people have the unrealistic expectation that the observed data need to be a near perfect match for the prediction line, but that’s not actually how things work.Some are still "under the mistaken impression that concern about global warming is based on climate models, which in reality play little role in our understanding -- our understanding is based mainly on how the Earth responded to changes of boundary conditions in the past and on how it is responding to on-going changes."- Dr. James HansenSome people argue that climate models are unreliable if they don't make perfect short-term predictions. However, a number of unpredictable influences such as ocean and solar cycles have short-term influences on climate. Over the long term, these effects average out, which is why climate models do so well at long-term predictions.It’s basic physics which follows the same principles as other laws of nature.“The physics we use to understand the earth’s climate system is the same physics that explains how stoves, fridges, airplanes and more work. And most people don’t really have a problem with the physics of non-linear fluid dynamics and radiative transfer that have been well understood for decades, even centuries.” (Climate scientist Katharine Hayhoe.)Q&A: How do climate models work?https://www.carbonbrief.org/qa-h...There is an excellent description of climate models evaluation in the following IPCC report:http://www.ipcc.ch/pdf/assessmen...If anything else, I suggest you read page 600-601 that address how reliable current models are.The last paragraph states:"In summary, confidence in models comes from their physical basis, and their skill in representing observed climate and past climate changes. Models have proven to be extremely important tools for simulating and understanding climate, and there is considerable confidence that they are able to provide credible quantitative estimates of future climate change, particularly at larger scales. Models continue to have significant limitations, such as in their representation of clouds, which lead to uncer- tainties in the magnitude and timing, as well as regional details, of predicted climate change. Nevertheless, over several decades of model development, they have consistently provided a robust and unambiguous picture of significant climate warming in re-sponse to increasing greenhouse gases."BONUS 3:DENIERS ATTACK ON CLIMATE MODELSROY SPENCERS BIG LIE AND CHEAT WAS BASED ON FALSELY CALIBRATED DATA“Climate scientists have been terrible at predicting temperatures.”This is a claim that's often made by climate skeptics: that predictions about the near-term future have been bad, so we shouldn't trust predictions about the longer-term future. But is that true? Have predictions historically been bad?The evidence they cite is from Dr. Roy Spencer, who showed in 2013 that 95% of climate models over predict the temperature rises due to greenhouse gases. The chart showing that is above. Unfortunately, that chart itself is based on falsely calibrated data.Have predictions historically been bad? The evidence they (deniers) cite is from Dr. Roy Spencer, who showed in 2013 that 95% of climate models over predict the temperature rises due to greenhouse gases.”Unfortunately, that chart itself is based on falsely calibrated data.“In 2014, the truth came out: Spencer’s UAH team had made a huge mistake in the calibration of their data. Instead of negligible upper-atmosphere warming, they found that the upper atmosphere had been warming at +0.14 degrees per decade, double the 1880-2014 rate of 0.07 degrees per decade. The other major satellite data set, RSS, also found a calibration error, meaning the Earth warmed 140% faster since 1998 than previous conclusions indicated. At the same time, the ground-based data from NOAA, NASA, the Hadley center and BEST all displayed agreement with one another. Once the 2014, 2015 and 2016 data are also included, the graph shows the scientific truth: the models are very much in line with what we observe.”The correctly adjusted chart:JOHN CHRISTYS LYING non-peer reviewed GRAPH:DEBUNKED:"Christy showed a graph of only mid-troposphere temperatures. The mid-troposphere is the atmospheric layer from about 25,000–50,000 feet, or about 8–15km in altitude. One might reasonably ask why Christy only showed data for such high altitudes. For perspective, the highest point on the Earth’s surface is on Mount Everest at 29,000 feet (8.8km), and the highest elevation city in the world is La Rinconada, Peru at 16,700 feet (5.1km). Humans live in the lower troposphere, not the mid-troposphere.However, climate models have done a good job matching the observed temperature change at the surface and in the lower troposphere, where humans live. We understand the workings of the Earth’s climate much better than Christy suggests, especially where it matters most to humans."In addition to various statistical sizes, Christy uses different physical measures in comparison when comparing temperatures at the surface with the temperature of 15 km of the atmosphere.Christy compared the average of 102 climate model simulations with temperature from satellite measurements (average of three different analyses) and weather balloons (average of two analyses). This is a flawed comparison because it compares a statistical parameter with a variable.Temperature from satellites are also model resultsIt is fair to compare the satellite record with model results to explore uncertainties, but the satellite data is not the ground truth and cannot be used to invalidate the models. The microwave sounding unit (MSU), the instrument used to measure the temperature, measures light in certain wavelength bands emitted by oxygen molecules. Satellite data are 5 timers less accurate than ground data.Different types of numbersThe upper left panel in Fig. 1 shows that Christy compared the average of 102 climate model simulations with temperature from satellite measurements (average of three different analyses) and weather balloons (average of two analyses). This is a flawed comparison because it compares a statistical parameter with a variable.A parameter, such as the mean (also referred to as the ‘average’) and the standard deviation, describe the statistical distribution of a given variable. However, such parameters are not equivalent to the variable they describe.The comparison between the average of model runs and observations is surprising, because it is clearly incorrect from elementary statistics (This is similar statistics-confusion as the flaw found in the Douglass et al. (2007)).http://www.realclimate.org/index...http://www.realclimate.org/index...Climate scientists, using current science, are successful in predicting temperatures.https://skepticalscience.com/gra...https://skepticalscience.com/gra...https://skepticalscience.com/rep...Congress manufactures doubt and denial in climate change hearing | Dana NuccitelliDEBUNK#2Graph shows a comparison between the average of an ensemble of 102 model calculations and observations (average of 3 satellite measurements and 4 balloon measurements). They have clearly not understood that they compare different sizes, so that they can not dismiss model calculations based on such.The model calculations shown by Christy are derived from the Dutch data portal ClimateExplorer. However, model calculations of temperatures at different heights above the ground in this web portal can not be found, only the temperature near the ground. The satellite measurements and balloons, on the other hand, represent the average temperature in a volume that stretches from the ground to a height of about 15 km.In addition to various statistical sizes, Christy uses different physical measures in comparison when comparing temperatures at the surface with the temperature of 15 km of the atmosphere. Increased greenhouse effect causes the lower part of the atmosphere (troposphere, which goes up to about 10km) to get warmer while the above layers of the stratosphere become colder. Does anyone see the problem with this comparison?Not only that. The satellite measurements are also model calculations,. In fact, they base on similar models that show that CO2 provides global warming. Ironically, neither Spencer nor Christy have realized this fact. In addition, the satellite curve is sewn together by different satellites with short lifespan, and the measurements from the different satellites are scattered. It is not so easy to put them together to a reliable temperature curve. They have been corrected several times.In other words, the figure of Christy and Spencer reveals basic deficiencies in understanding both statistics and physics.https://www.theguardian.com/envi...