Archives par mot-clé : Sensitivity

THE SUN ALLERGY OF CLIMATE RESEARCHERS

by  Ulli Kulke, June 29, 2018 in GWPF


Henrik Svensmark, head of solar research at Denmark’s Technical University in Copenhagen, is one of them. And he ventures far ahead in the climate debate, the research with perhaps the greatest significance of our time. His research is contested, of course. Nevertheless, Svensmark and his critics agree that the topic “sun” deserves more attention in climate research. The participants are particularly interested in the complex interplay between our central star and ionizing emissaries from the depths of the galaxy – “cosmic radiation”.

Svensmark says: “The climate is influenced more by changes in cosmic radiation than by carbon dioxide”. CO2 has an effect, of course, “but it is far less than most current climate models assume, and also less than the influence of cosmic radiation”. In his opinion, a doubling of the greenhouse gas in the atmosphere would cause an increase in global temperature of at most one degree, and not two degrees, as is now generally accepted.

In other words, the “climate sensitivity” of carbon dioxide is only half as high as assumed (…)

Ross McKitrick: All those warming-climate predictions suddenly have a big, new problem

by Ross McKitrick, June 20, 2018 in FinancialPost


One of the most important numbers in the world goes by the catchy title of Equilibrium Climate Sensitivity, or ECS. It is a measure of how much the climate responds to greenhouse gases. More formally, it is defined as the increase, in degrees Celsius, of average temperatures around the world, after doubling the amount of carbon dioxide in the atmosphere and allowing the atmosphere and the oceans to adjust fully to the change. The reason it’s important is that it is the ultimate justification for governmental policies to fight climate change.

The United Nations Intergovernmental Panel on Climate Change (IPCC) says ECS is likely between 1.5 and 4.5 degrees Celsius, but it can’t be more precise than that. Which is too bad, because an enormous amount of public policy depends on its value. People who study the impacts of global warming have found that if ECS is low — say, less than two — then the impacts of global warming on the economy will be mostly small and, in many places, mildly beneficial.

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Atomic Physicist: Human CO2 Emissions Have An Equilibrium Climate Sensitivity Of A ‘Not Important’ 0.02 K

by K. Richard, June 4, 2018 in NoTricksZone


Dr. Boris M. Smirnov, a prominent atomic physicist, has authored 20 physics textbooks during the last two decades.  His latest scientific paper suggests that the traditional “absorption band” model for calculating the effect of atmospheric CO2 during the radiative transfer process is flawed.  New calculations reveal that the climate’s sensitivity to a doubling of the CO2 concentration is just 0.4 K, and the human contribution to that value is a negligible 0.02 K.

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Is climate alarmist consensus about to shatter?

by A. Watts, May 2, 2008 in WUWT


A new study by climatologists Nicholas Lewis and Judith Curry concludes that Earth’s “equilibrium climate sensitivity” (ECS) to more atmospheric carbon dioxide is as much as 50% lower than climate alarmists have been claiming. That their paper was published in the Journal of Climate  suggests that the asserted “97% consensus” of climate experts may be eroding.

Or as Cornwall Alliance founder Cal Beisner puts it (paraphrasing Winston Churchill) it may not be the beginning of the end of climate alarmism. But it could be the end of the beginning of alarmism as the dominant, ever-victorious tenet of our times.

Indeed, say other noted climatologists, there are good reasons to think ECS and alarmist errors are even greater than 50 percent. For one thing, there is no persuasive reason to assume our planet’s climate system (…)

New Lewis & Curry Study Concludes Climate Sensitivity is Low

by Ph.D. Roy W. Spencer, Apritl 24, 2018 in Global Warming


Global warming “problem” cut by 50%

As readers here are aware, I don’t usually critique published climate papers unless they are especially important to the climate debate. Too many papers are either not that important, or not that convincing to me.

The holy grail of the climate debate is equilibrium climate sensitivity (ECS): just how much warming (and thus associated climate change) will occur in response to an eventual doubling of the CO2 concentration in the atmosphere?

Yesterday’s early online release of a new paper by Nicholas Lewis and Judith Curry (“The impact of recent forcing and ocean heat uptake data on estimates of climate sensitivity“, Journal of Climate) represents one of those seminal papers.

The impact of recent forcing and ocean heat uptake data on estimates of climate sensitivity

by J. Curry and N. Lewis, April 24, 2018 in ClimateAudit


There has been considerable scientific investigation of the magnitude of the warming of Earth’s climate by changes in atmospheric carbon dioxide (CO2) concentration. Two standard metrics summarize the sensitivity of global surface temperature to an externally imposed radiative forcing. Equilibrium climate sensitivity (ECS) represents the equilibrium change in surface temperature to a doubling of atmospheric CO2 concentration. Transient climate response (TCR), a shorter-term measure over 70 years, represents warming at the time CO2 concentration has doubled when it is increased by 1% a year.

(…)

See also here

Emergent constraints on climate sensitivity in global climate models, Part 3

by Nic Lewis, March 29, 2018 in ClimateAudit (Steve McIntyre)


The two strongest potentially credible constraints, and conclusions

In Part 1 of this article the nature and validity of emergent constraints[1] on equilibrium climate sensitivity (ECS) in GCMs were discussed, drawing mainly on the analysis and assessment of 19 such constraints in Caldwell et al. (2018),[2] who concluded that only four of them were credible. An extract of the rows of Table 1 of Part 1 detailing those four emergent constraints is given below.[3]

Climate scientist admits embarrassment over future climate uncertainty

by J. Cartwright, March 16, 2018 in A. Watts WUWT


WUWT readers may recall this chart which clearly illustrates just how uncertain climate science really is.

t seems that some climate academics are a bit embarrassed that they haven’t been able to pin down climate sensitivity. From EU Horizon Magazine

Climate sensitivity – reducing the uncertainty of uncertainty

by Jon Cartwright

A study published in January 2018 claims to halve the uncertainty around how much our planet’s temperature will change in response to rising carbon dioxide (CO2) levels, potentially giving governments more confidence to prepare for the future.

Marvel et al.’s new paper on estimating climate sensitivity from observations

by Nic Lewis, February 5, 2018 in ClimateAudit


Recently a new model-based paper on climate sensitivity was published by Kate Marvel, Gavin Schmidt (the head of NASA GISS) and others, titled ‘Internal variability and disequilibrium confound estimates of climate sensitivity from observations’. It appears to me that the novel part of its analysis is faulty, and that the part which isn’t faulty isn’t novel.

Emergent constraint on equilibrium climate sensitivity from global temperature variability

by P.M. Cox et al., January 18, 2018 in Nature


Equilibrium climate sensitivity (ECS) remains one of the most important unknowns in climate change science. ECS is defined as the global mean warming that would occur if the atmospheric carbon dioxide (CO2) concentration were instantly doubled and the climate were then brought to equilibrium with that new level of CO2.

(…)

This metric of variability can also be calculated from observational records of global warming3, which enables tighter constraints to be placed on ECS, reducing the probability of ECS being less than 1.5 degrees Celsius to less than 3 per cent, and the probability of ECS exceeding 4.5 degrees Celsius to less than 1 per cent.

Study: no acceleration in global warming, climate sensitivity to CO2 too high

by Anthony Watts, November 29, 2017 in WUWT


New research yields old result: Climate warming slow, steady. Observed value is half that of CMIP5 climate models.

The rate at which Earth’s atmosphere is warming has not significantly accelerated over the past 23 years, according to research at The University of Alabama in Huntsville (UAH).

If you take away the transient cooling in 1983 and 1992 caused by two major volcanic eruptions in the preceding years, the remaining underlying warming trend in the bottom eight kilometers (almost five miles) of the atmosphere was 0.096 C (about 0.17° Fahrenheit) per decade between January 1979 and June 2017.

That was unexpectedly close to the 0.09 C warming trend found when similar research was published in 1994 with only 15 years of data, said Dr. John Christy, director of UAH’s Earth System Science Center.

See also here

Israeli Astrophysicist rejects UN IPCC – Finds ‘the sun completely overturns the way we should see global warming’

by Dr. Shaviv, November 9, 2017 in ClimateDepot


(…)The body of evidence however clearly shows that the climate sensitivity is on the low side, about 1 to 1.5 degree increase per CO2 doubling. People in the climate community are scratching their heads trying to understand the so called hiatus in the warming. Where is the heat hiding? While in reality it simply points to a low sensitivity.

CO2 Contributed Only 0.12°C To Global Temps Since 1850

by Kenneth Richard, July 17, 2017


A Swiss scientist known to have published hundreds of scientific papers in physics journals has authored a new scholarly paper that casts serious doubts on the effectiveness of CO2 as a greenhouse gas influencing Earth’s temperatures.

This paper has been added to a growing volume of peer-reviewed scientific papers that seriously question estimates of a high climate sensitivity to significant increases in CO2 concentrations.