Archive for the ‘Clouds’ Category

Plants produce biogenic aerosols and provide a negative feedback to warming climate

April 30, 2013

Another study showing a negative feedback to a warming climate. Needless to say such a negative feeback finds no place in climate models. (The lead author points out that this previous statement is erroneus). Needless to say I doubt if such negative feedback is included in all climate models.

 Paasonen, P., et. al. 2013. Evidence for negative climate feedback: warming increases aerosol number concentrationsNature Geoscience doi: 10.1038/NGEO1800

The International Institute for Applied Systems Analysis (IIASA) reports:

© Veronika Markova |

As temperatures warm, plants release gases that help form clouds and cool the atmosphere, according to research from IIASA and the University of Helsinki. 

The new study, published in Nature Geoscience, identified a negative feedback loop in which higher temperatures lead to an increase in concentrations of natural aerosols that have a cooling effect on the atmosphere. “Plants, by reacting to changes in temperature, also moderate these changes,” says IIASA and University of Helsinki researcher Pauli Paasonen, who led the study. 

Scientists had known that some aerosols – particles that float in the atmosphere – cool the climate as they reflect sunlight and form cloud droplets, which reflect sunlight efficiently. Aerosol particles come from many sources, including human emissions. But the effect of so-called biogenic aerosol – particulate matter that originates from plants – had been less well understood. Plants release gases that, after atmospheric oxidation, tend to stick to aerosol particles, growing them into the larger-sized particles that reflect sunlight and also serve as the basis for cloud droplets. The new study showed that as temperatures warm and plants consequently release more of these gases, the concentrations of particles active in cloud formation increase. 

“Everyone knows the scent of the forest,” says Ari Asmi, University of Helsinki researcher who also worked on the study. “That scent is made up of these gases.” While previous research had predicted the feedback effect, until now nobody had been able to prove its existence except for case studies limited to single sites and short time periods. The new study showed that the effect occurs over the long-term in continental size scales. 

The effect of enhanced plant gas emissions on climate is small on a global scale – only countering approximately 1 percent of climate warming, the study suggested. “This does not save us from climate warming,” says Paasonen. However, he says, “Aerosol effects on climate are one of the main uncertainties in climate models. Understanding this mechanism could help us reduce those uncertainties and make the models better.”  

The study also showed that the effect was much larger on a regional scale, counteracting possibly up to 30% of warming in more rural, forested areas where anthropogenic emissions of aerosols were much lower in comparison to the natural aerosols. That means that especially in places like Finland, Siberia, and Canada this feedback loop may reduce warming substantially. ….. 

Criegee intermediates further unsettle climate science

April 26, 2013

Far from being a “settled” science, global warming in particular and “climate science” in general are looking decidedly shaky these days!

What is not in doubt is that clouds and their formation are of critical importance for our climate. But clouds can both “warm” and “cool”. They can attenuate the sun’s radiation that reaches the earth during the day and they can prevent the radiation of heat  from the earth into space during the night. They can absorb some of the sun’s radiation and transfer that heat into the atmosphere and radiate some of it back into space as well. The net effect of clouds is uncertain. Solar effects themselves can affect the formation of clouds (Svensmark’s theory) as has been confirmed recently by experiments at CERN. Current climate models speculate that carbon dioxide can affect the moisture levels and therefore increase clouds in the atmosphere. But no mechanisms are known and these assumptions are more fanciful than based on any evidence. Moreover the assumed enhanced warming due to the increased moisture (positive forcing) is even more fanciful since it is also not known as to whether any such extra moisture results and whether any exists as clouds. Computer models – in the absence of any known mechanisms for such forcing – merely assume some “net, resultant” level of the forcing which (of course) causes warming and can be attributed to carbon dioxide. These assumptions about the forcing due to carbon dioxide effectively presuppose the forcing and are little more than “fudge factors”.

But even the chemistry of and the chemical reactions in the upper atmosphere are uncertain. A new paper  provides new evidence of how Criegee intermediate molecules in the atmosphere could help in aerosol and cloud formation and contribute to cooling in the atmosphere.

A  Criegee intermediate is a carbonyl oxide with two free radical centres which act independently of each other. These molecules could help to break down sulfur dioxide and nitrogen dioxide in the atmosphere and their existence formation of Criegee biradicals was first postulated in the 1950s by Rudolf Criegee. 

Rudolf Criegee (1902-1975) was a German chemist. He studied in Tübingen, Greifswald, and Würzburg and received his doctorate at Würzburg in 1925. He proposed a reaction mechanism for ozonolysis in 1953. The Criegee intermediate and the Criegee rearrangement are named after him. In this context, his research on cyclic reactions and cyclic rearrangement-mechanisms led him, independently of the Nobel-Prize winning work of R.B.Woodward and R.Hoffmann (Woodward-Hoffmann rules), to the same conclusions as theirs, but he failed to publish his findings in time.

File:Carbonyl oxide (Criegee zwitterion).svg

Carbonyl oxide (Criegee zwitterion): wikipedia

The new paper is published in Science:

Direct Measurements of Conformer-Dependent Reactivity of the Criegee Intermediate CH3CHOOCraig A Taatjes et al, Science 12 April 2013: Vol. 340 no. 6129 pp. 177-180 DOI: 10.1126/science.1234689

Abstract: Although carbonyl oxides, “Criegee intermediates,” have long been implicated in tropospheric oxidation, there have been few direct measurements of their kinetics, and only for the simplest compound in the class, CH2OO. Here, we report production and reaction kinetics of the next larger Criegee intermediate, CH3CHOO. Moreover, we independently probed the two distinct CH3CHOO conformers, syn- and anti-, both of which react readily with SO2 and with NO2. We demonstrate that anti-CH3CHOO is substantially more reactive toward water and SO2 than is syn-CH3CHOO. Reaction with water may dominate tropospheric removal of Criegee intermediates and determine their atmospheric concentration. An upper limit is obtained for the reaction of syn-CH3CHOO with water, and the rate constant for reaction of anti-CH3CHOO with water is measured as 1.0 × 10−14 ± 0.4 × 10−14 centimeter3 second−1.

From the Manchester University Press Release:

Scientists have discovered further evidence for the existence of new molecules in the atmosphere that have the potential to off-set global warming by reacting with airborne pollutants.

Researchers from The University of Manchester, Bristol University, Southampton University and Sandia National Laboratories in California have detected the second simplest Criegee intermediate molecule – acetaldehyde oxide – and measured its reactivity.

Intermediates are molecules that are formed during a chemical reaction and react further to produce the final chemicals of the reaction. Criegee intermediates – carbonyl oxides – were first identifies by the team in January last year and shown to be powerful oxidisers, reacting with pollutants such as nitrogen dioxide and sulphur dioxide.

The authors, whose latest study is again published in the journal Science, believe Criegee intermediates have the potential to cool the planet by converting these pollutants into sulphate and nitrate compounds that will lead to aerosol and cloud formation.

Professor Carl Percival, who led the Manchester team in the University’s School of Earth, Atmospheric and Environmental Sciences, said: “We have carried out the first ever studies on the second simplest Criegee intermediate and were able to show that it also reacts extremely quickly with sulphur dioxide to produce sulphates under experimental conditions.

“We can therefore say that the reaction of these intermediates with sulphur dioxide will have a significant impact on sulphuric acid production in the atmosphere if they follow the pattern established by these two studies.

He continued: “One of the main questions from our first study was if this increased reactivity would be observed for other Criegee intermediates, so with these findings we now have additional evidence that Criegee intermediates are indeed powerful oxidisers of pollutants such as nitrogen dioxide and sulphur dioxide.

“What this study suggests is that the biosphere could have a significant impact on aerosol production and thus potentially climate cooling via the formation of Criegee intermediates. The next steps will be to carry out modelling studies to quantify the impact of Criegee intermediates on climate and to quantify the level of alkene present in various environments.”

The formation of Criegee intermediates or biradicals was first postulated by the German chemist Rudolf Criegee in the 1950s but, despite their importance, it had not been possible to study the chemicals in the laboratory. The detection of the molecules was made possible through a unique apparatus that uses light from a third-generation synchrotron facility at the Lawrence Berkeley National Laboratory.

The latest study has also revealed which of the two isomers of acetaldehyde oxide is the most reactive. Isomers are molecules that contain the same atoms but arranged in different combinations, while conformational isomerism refers to the way the atoms of a molecule are rotated around a single chemical bond.

“In this new paper we have been able to show that the reactivity depends on the conformer of acetaldehyde oxide in a dramatic way,” said Professor Percival. “The ‘anti’ conformer is much more reactive than the ‘syn’ conformer, which we believe more likely to be formed in the atmosphere. This enabled us to measure the rate coefficient for reaction with water for the first time; the removal, via reaction with water, is of vital importance if we want to understand the role of Criegee intermediates in the atmosphere.”

Sandia combustion chemist Craig Taatjes, the lead author on the paper, added: “Observing conformer-dependent reactivity represents the first direct experimental test of theoretical predictions. The work will be of tremendous importance in validating the theoretical methods that are needed to accurately predict the kinetics for reactions of Criegee intermediates that still cannot be measured directly.”


Criegee Intermediates Found to Have Big Impact On Troposphere

Offsetting Global Warming: Molecule in Earth’s Atmosphere Could ‘Cool the Planet’


Climate forcing: Missing water must be hiding in the deep ocean

April 19, 2013

Clive Best points out that NASA data shows quite clearly that water vapour in the atmosphere has been decreasing quite significantly especially since about 1998 while carbon dioxide has continued rising. All the wonderful climate models (settled science after all) take it for granted that increased water vapour in the atmosphere is a key forcing caused by increasing carbon dioxode.

I wonder where the water went?

Presumably hiding along with all the missing heat in the deep oceans!

And causing the sea level to increase no doubt.

The fact is that we can’t account for the lack of water in the atmosphere and it is a travesty that we can’t.

H2O decreasing while CO2 rises !

Posted on April 18, 2013 by Clive Best

Dire predictions of global warming all  rely on positive feedback from  water vapor. The argument goes that as surface temperatures rise so  more water will evaporate from the oceans thereby amplifying temperatures because H2O itself is a strong GHG.  Climate models all assume net amplification factors of between 1.5 and 6. But in the real world has the water content of the atmosphere actually been increasing as predicted?

NASA have just released their latest NVAP-M  survey of global  water content derived from satellite data and radio-sondes over the period from 1988 to 2009. This new data is explicitly intended for climate studies . So lets take a look at the comparison between actual NVAP-M atmospheric H2O levels and those of CO2 as measured at Mauna Loa. I have extracted all the daily measurement NVAP-M data and then calculated the global average. Figure 1 shows the running 30 day average of all the daily data recorde between 1988 and 2009 inclusive. The 365 day (yearly) running average is also shown. Plotted on the right hand scale are the Mauna Loa CO2 concentration data in red over the same period.

Fig1: Total precipitative H2O (running 30 day average) compared to Mauna Loa CO2 data in red. The central black curve is a running 365 day average.

Fig1: Total precipitative H2O (running 30 day average) compared to Mauna Loa CO2 data in red. The central black curve is a running 365 day average.

There is indeed some correlation in the data from 1988 until 1998, but thereafter the two trends diverge dramatically. Total atmospheric water content actually falls despite a relentless slow rise in CO2. This fall in atmospheric H2O also coincides with the observed and now widely accepted stalling of global temperatures over the last 16 years. All climate models (that I am aware of) predict exactly the opposite, so something is clearly amiss with theory. Is it not now time for “consensus” climate scientists perhaps to have a rethink ?

more to follow…

  1. My thanks to Ken Gregory for help with the  data. The conversion from NetCDF was a bit of a nightmare !
  2. NASA NVAP-M data is available here. Thanks to NASA Water Vapor Project-Measures (NVAP-M) team.

Anthony Watts in a comment does point out that sensor degradation or failure would need to be eliminated. (But I wonder why sensor integrity would not have been checked by NASA before the data was published as data)

Chaos of climate models only shows that “we don’t know what we don’t know”

April 17, 2013

I spent a large part of my early career in mathematical modelling (of combustion systems and of heat flow) and have a very clear idea of what models can do and what they can’t. Models after all are used primarily to simplify complex systems which are otherwise intractable. They are – always – severely limited by the assumptions and simplifying approximations that have to be introduced. Models are a powerful tool for investigation but are only as good as their most inaccurate assumption. But they are a tool primarily for investigation — and can be dangerous when used for decision making based on their imperfect predictions. The spectacular failures of mathematical models of the global economy are a case in point. It is worth noting that in spite of the great strides made in weather forecasting  for example – much of which is empirical – the simple statement that “tomorrows weather will be like today’s”  is as correct – statistically – as the most complex model running on some super-computer somewhere.

It has therefore always amazed me that so-called “scientists” would be so certain about their approximate models of climate systems – which are perhaps as complex, chaotic and “unknown” systems as any one could study. It has been a boon for politicians looking for new ways of raising revenue. It has been exploited by the alarmists since the alarmist predictions cannot be tested. The wide spread of results from climate models is rarely mentioned.

When reality does not match model forecasts it is time to back off and rethink the models and hopefully they will be better next time. And it is time to back track from all the political decisions made on the basis of patently incomplete and inaccurate models.

The simple reality about climate is that rather than being a “settled science”

  • we don’t know the impact of solar effects on climate
  • we don’t know the impact of clouds or even if they are net “warmers” or net “coolers”
  • we don’t know how much of the earth’s radiative energy balance is dependent upon carbon dioxide
  • we don’t know how much carbon dioxide is absorbed  by the oceans and living things
  • we don’t know the impact of aerosols and particles in the atmosphere
  • we don’t know the role of the oceans in transporting heat around the globe
  • we don’t know how much heat is stored in the oceans and how it varies
  • we don’t know the impact of solar effects on cloud formation
  • we don’t know what triggers ice ages, and
  • we don’t know what we don’t know.

This from Dr. Roy Spencer and the ridiculously wide spread of the model results and the obvious deviation of reality from model results are particularly striking:

Global Warming Slowdown: The View from Space

Since the slowdown in surface warming over the last 15 years has been a popular topic recently, I thought I would show results for the lower tropospheric temperature (LT) compared to climate models calculated over the same atmospheric layers the satellites sense.

Courtesy of John Christy, and based upon data from the KNMI Climate Explorer, below is a comparison of 44 climate models versus the UAH and RSS satellite observations for global lower tropospheric temperature variations, for the period 1979-2012 from the satellites, and for 1975 – 2025 for the models:



Clearly, there is increasing divergence over the years between the satellite observations (UAH, RSS) and the models. The reasons for the disagreement are not obvious, since there are at least a few possibilities:


The dark line in the above plot is the 44-model average, and it approximately represents what the IPCC uses for its official best estimate of projected warming. Obviously, there is a substantial disconnect between the models and observations for this statistic.

I find it disingenuous for those who claim that, because not ALL of individual the models disagree with the observations, the models are somehow vindicated. What those pundits fail to mention is that the few models which support weaker warming through 2012 are usually those with lower climate sensitivity.

So, if you are going to claim that the observations support some of the models, and least be honest and admit they support the models that are NOT consistent with the IPCC best estimates of warming.

More evidence that cloud cover – and not carbon dioxide – dominates climate

May 17, 2012

The Hockey Shtick reports on a recent paper by Aldert J. van Beelen and Aarnout J. van Delden of the Institute for Marine and Atmospheric Research Utrecht, Utrecht University, The Netherlands which shows that the hours of sunshine decreased somewhat from 1958-1983 and then increased sharply between 1985 and 2010 at a number of places. The authors postulate that the reduction of cloud cover since 1985 was possibly due to the cleaner air with reduced aerosols during this period.

It was not so long ago that the CERN CLOUD experiments showed that cosmic rays could indeed influence cloud formation providing support for Svensmark’s hypothesis that it is solar effects via cloud formation which dominates climate.

If we assume that the reduction in sunshine hours between 1958 and 1983 was due to man-made pollution and that this was reversed in the period after 1985, it still needs Svensmark’s solar effects or some other mechanism to explain the very sharp reduction in cloud cover and increase in sunshine hours  after 1985. It seems patently obvious from every day observations that cloud cover is far more important to weather and climate than any far-fetched notions of man-made carbon dioxide having any significant influence.

The Hockey Shtick: A paper recently published in the journal Weather finds that global summer average sunshine [solar short-wave radiation that reaches Earth’s surface] dimmed during the period 1958-1983 [prompting an ice age scare], but markedly increased from 1985-2010. The increase in summer average sunshine between those two periods is 6 Watts per square meter, which dwarfs the alleged effects of CO2 by more than 5 times. [Alleged CO2 effect from 1958-2010 was calculated using the IPCC formula 5.35*ln(389.78/315) = 1.14 Watts per square meter]. At one measurement site [De Bilt], summer sunshine increased from 1985-2010 by 15 Watts per square meter, more than 23 times the IPCC alleged forcing from CO2 during the same timeframe [5.35*ln(389.78/346.04) = 0.64 Watts per square meter].

The paper states the increase in sunshine reaching the Earth’s surface is due to a decrease in aerosols including clouds, which are influenced by both anthropogenic and natural factors, and possibly changes in solar activity.

from van Beelen and van Delden “Weather” Vol.67 No. 1, January 2012

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