Archive for the ‘Clouds’ Category

How will we know when the transition to a new glacial age has started?

September 13, 2014

Once glacial conditions have been established (and they will), they will be unmistakable. Ice sheets will have covered large parts of the northern hemisphere making large swathes uninhabitable. Sea levels would have dropped by about 100 m. Global mean temperature would be around 10-12 ºC rather than the 15 ºC in an interglacial.

Glacials and interglacials graphic http://anthro.palomar.edu/

Habitable and fertile land would have increased around the equator and in the tropics – but not as much as would be rendered uninhabitable by the ice sheets. Modern technology and recourse to energy would still allow some exploitation of resources under the ice sheets. Precipitation levels would reduce however (with so much of the water cycle being bound up in the ice sheets). Some of the equatorial regions would see a desertification. New resources would be available due to the 100 m drop in sea level. Population would probably be significantly lower than during an interglacial but what population could be sustained comfortably will be strongly dependent upon the availability of energy and the ease of energy conversion. River flows and hydropower will dry up. Fossil fuels and nuclear energy is what will make the difference.

Ice sheets graphic http://anthro.palomar.edu

But whenever it comes, it will not happen overnight. It would take not less than a few hundred years for the transition from interglacial to glacial conditions but it might take 1000 years or more.

interglacials

The next glacial will come …

But how will we know if the transition has started? What are the signs to look for? For example a few years of reduction of global precipitation may mean nothing if at the same time an increase of water locked up as ice is not also evident.

Probably the most potent feedback loops (forcings) for the transition to glacial conditions is the ice cover on the earth’s surface and the cloud cover in the upper reaches of our atmosphere. Both of these act directly on the sun’s energy being reflected away from the earth and will shift the earth to a different paradigm of solar energy input. There may be other parameters which cause incoming solar insolation to vary but how much the earth reflects away of whatever is coming in is controlled by the ice and the high clouds. We can consider the interglacial and glacial conditions to be semi-stable equilibrium conditions, each representative of a particular level of solar energy input to the earth system.

So the first real indicators will be the growth of ice cover and an increase in high clouds. All other prior indicators  must finally show up as ice cover or high cloud. Even global temperature (which is merely an averaged, composite, weighted artefact) is not of great relevance except when it shows up as ice or cloud. Note that ice cover at a lower latitude is of greater significance since it causes a greater reduction of received solar insolation than at the poles. For ice cover to be on an increasing path we will first see a reduction in the melt of the previous season’s ice – regularly. We should see this not only at both poles but also at lower latitudes on high ground. We will see warming factors being neutralised. We will see a decrease in precipitation but this will probably lag the reduction of ice cover and the reduction of sea level by many years. It might begin to show up first as a reduction of low rain clouds and increase of high clouds. We should see the sea level increase characteristic of an interglacial, level off and then begin to fall – slowly at first and then accelerating.

An impulse or trigger is needed to shift from one semi-stable equilibrium state to another. What that trigger – or those impulses –  might be is unknown. But I note that

  1. A cooling cycle of 30 + years may have begun and may well be a trigger for a transition.
  2. Expected global temperature increase due to the undoubted (but small) effect of carbon dioxide concentration in the atmosphere is not happening and will not any time soon.
  3. Expected increase of sea level (even if based on fallacious CO2 based climate models) is not happening and sea level rise seems to be decelerating.
  4. Antarctic ice cover is at its highest level ever and has been increasing over the last few years.
  5. Arctic ice has recovered from its decrease of a few years ago and is at the same level as about 2 decades ago.
  6. Some unusual sign of fresh glacier formation have been observed on Ben Nevis.
  7. Some Himalayan glaciers. and even Alpen glaciers have shown signs of growth or reduced rates of decrease.

Just indicators of course – and another 50 or so years should tell.

But one thing is clear. Our future depends upon the availability of energy – and that will be primarily fossil and nuclear (and fusion if that has been developed by then). The pointless (and futile) attempts to curtail exploration for and the use of fossil fuels will have to cease – and better they be abandoned sooner rather than later.

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Climate warming due to humans is highly uncertain says new paper in Science

February 2, 2014

The level of uncertainty in this supposedly “settled” science never fails to amaze. But I observe that it is beginning to be politically acceptable to talk about the uncertainties and even – as in this paper – to begin to question the significance of human activities on climate.

“Climate Effects of Aerosols-Cloud Interactions. Daniel Rosenfeld, Steven Sherwood, Robert Wood, Leo Donner. Science VOL 343, 24 JANUARY 2014

Abstract: Aerosols counteract part of the warming effects of greenhouse gases, mostly by increasing the amount of sunlight reflected back to space. However, the ways in which aerosols affect climate through their interaction with clouds are complex and incompletely captured by climate models. As a result, the radiative forcing (that is, the perturbation to Earth’s energy budget) caused by human activities is highly uncertain, making it difficult to predict the extent of global warming (12). Recent advances have led to a more detailed understanding of aerosol-cloud interactions and their effects on climate, but further progress is hampered by limited observational capabilities and coarse-resolution climate models.

The paper is behind a pay-wall but the accompanying press release begins “The warming effect of human-induced greenhouse gases is a given, but to what extent can we predict its future influence?”. I have no doubt that “greenhouse gases” in the atmosphere have a small warming effect but evidence is still lacking even for this simple statement because the carbon balance of the earth is still far from certain and the extent to which fossil fuel combustion contributes to the carbon dioxide concentration is still not certain. So while the warming effect of  greenhouse gases is established, its magnitude is not and the impact of humans on the concentration is also not yet certainly established. In fact, the primary contributors to the “greenhouse effect” are still water vapour and clouds but clouds also cause significant cooling by blocking insolation. Carbon dioxide by itself is almost of minor consequence and the weakness of climate models has always been that they make unjustified assumptions for the forcing effects of carbon dioxide. The pause in warming over the last 17-18 years and the slight decline in global temperatures for the last decade – while carbon dioxide concentrations have been steadily increasing – is a further indicator that the warming effect of carbon dioxide has been grossly exaggerated.

The Press Release goes on:

…… Indeed, one could say that the picture is a “cloudy” one, since the determination of the greenhouse gas effect involves multifaceted interactions with cloud cover.

To some extent, aerosols –- particles that float in the air caused by dust or pollution, including greenhouse gases – counteract part of the harming effects of climate warming by increasing the amount of sunlight reflected from clouds back into space. However, the ways in which these aerosols affect climate through their interaction with clouds are complex and incompletely captured by climate models, say the researchers. As a result, the radiative forcing (that is, the disturbance to the earth’s “energy budget” from the sun) caused by human activities is highly uncertain, making it difficult to predict the extent of global warming.

And while advances have led to a more detailed understanding of aerosol-cloud interactions and their effects on climate, further progress is hampered by limited observational capabilities and coarse climate models, says Prof. Daniel Rosenfeld of  the Fredy and Nadine Herrmann Institute of Earth Sciences at the Hebrew University of Jerusalem, author of the article in Science. ….. 

Their recent studies have revealed a much more complicated picture of aerosol-cloud interactions than considered previously. Depending on the meteorological circumstances, aerosols can have dramatic effects of either increasing or decreasing the cloud sun-deflecting effect, the researchers say. Furthermore, little is known about the unperturbed aerosol level that existed in the preindustrial era. This reference level is very important for estimating the radiative forcing from aerosols.

Also needing further clarification is the response of the cloud cover and organization to the loss of water by rainfall. Understanding of the formation of ice and its interactions with liquid droplets is even more limited, mainly due to poor ability to measure the ice-nucleating activity of aerosols and the subsequent ice-forming processes in clouds.

Needless to say they end up asking for more funds:

While it is unfortunate that further progress on understanding aerosol-cloud interactions and their effects on climate is limited by inadequate observational tools and models, achieving the required improvement in observations and simulations is within technological reach, the researchers emphasize, provided that the financial resources are invested. 

Another unverifiable doomsday model predicts 4°C rise by 2100

December 31, 2013

What must first be noted is that the lead author, Steve Sherwood,  is from the Climate Change Research Centre, University of New South Wales and is a colleague of Chris Turney – the global warming cheer-leader currently stuck in the Antarctic ice. The paper is largely unfounded speculation – no evidence or measurements in sight –  but speculation alarmist enough for Nature to publish it. The paper – according to the Nature Editor

offers an explanation for the long-standing uncertainty in predictions of global warming derived from climate models. Uncertainties in predicted climate sensitivity — the magnitude of global warming due to an external influence — range from 1.5° C to 5° C for a doubling of atmospheric CO2. It has been assumed that uncertainties in cloud simulations are at the root of the model disparities, and here Steven Sherwood et al. examine the output of 43 climate models and demonstrate that about half of the total uncertainty in climate sensitivity can be traced to the varying treatment of mixing between the lower and middle troposphere — and mostly in the tropics. When constrained by observations, the authors’ modelling suggests that climate sensitivity is likely to exceed 3° C rather than the currently estimated lower limit of 1.5° C, thereby constraining model projections towards more severe future warming.

Clouds are not well understood it seems but they are the answer!

The time-scale for their predictions – till 2100 is sufficiently far away that nothing can be confirmed or denied.

Presumably Sherwood was one of those advising the pilgrims trapped in the Antarctic.

Spread in model climate sensitivity traced to atmospheric convective mixing, Steven C. Sherwood, Sandrine Bony & Jean-Louis Dufresne, Nature 505, 37–42, doi:10.1038/nature12829

Abstract:Equilibrium climate sensitivity refers to the ultimate change in global mean temperature in response to a change in external forcing. Despite decades of research attempting to narrow uncertainties, equilibrium climate sensitivity estimates from climate models still span roughly 1.5 to 5 degrees Celsius for a doubling of atmospheric carbon dioxide concentration, precluding accurate projections of future climate. The spread arises largely from differences in the feedback from low clouds, for reasons not yet understood. Here we show that differences in the simulated strength of convective mixing between the lower and middle tropical troposphere explain about half of the variance in climate sensitivity estimated by 43 climate models. The apparent mechanism is that such mixing dehydrates the low-cloud layer at a rate that increases as the climate warms, and this rate of increase depends on the initial mixing strength, linking the mixing to cloud feedback. The mixing inferred from observations appears to be sufficiently strong to imply a climate sensitivity of more than 3 degrees for a doubling of carbon dioxide. This is significantly higher than the currently accepted lower bound of 1.5 degrees, thereby constraining model projections towards relatively severe future warming.

It all smacks of post-rationalisation.

Garbage In Garbage Out.

Clouds – Just water and a bit of dirt

October 17, 2013

Check these “60 insane cloud formations” at the Matador Network:

Lenticular cloud, Mt. Fuji, Japan

Lenticular cloud, Mt. Fuji, Japan

and this one leaving this world

Lenticular UFO in Patagonia image A Lamy

Lenticular UFO in Patagonia image A Lamy

IPCC still cooking it’s books to cover-up the inconvenient truths

September 27, 2013

The 95% probability/certainty of global warming being due to human activity is based on a show of hands and not on any evidence or statistical analysis of data. What it actually says is that 95% of all global warming believers, believe.

Late last night the IPCC delegates in Stockholm were still messing around preparing their 30 page political summary of their AR5 report to be released today.

The political summary of AR5 is primarily a CYA effort to protect the posteriors of the policy makers (mainly political figures, bureaucrats and activists) in the face of a long row of broken models and broken hypotheses. The IPCC has forgotten that natural variability is a euphemism for unknown mechanisms which cannot be calculated or predicted. It is going to be interesting to see just how the summary report will cover-up, deny or ignore the long string of inconvenient facts:

  • Global temperatures have not risen for 17-18 years while CO2 has kept on increasing. 
  • Global temperatures have been declining for the last 11 years. 
  • None of the IPCC’s computer models have predicted the warming hiatus or the cooling over the last decade.
  • Global wildfires are lower than normal. 
  • Rainfall patterns (and the Indian monsoon) continue within the bounds of known natural variability. 
  • Food and grain production is at an all-time high. 
  • Flood frequency and flood levels have not been at unprecedented levels. Just more people live in flood-plains today than before. 
  • CO2 in the atmosphere reached the magic level of 400 ppm (albeit for just a few hours) and nothing happened.
  • How much of the CO2 concentration increase is due to carbon dioxide from fossil fuel. combustion is unclear but fossil fuel emissions are only 5% of global carbon dioxide emissions. 
  • The absorption and release of carbon dioxide by the oceans is unknown and the error margin is greater than the total amount released by fossil fuels.
  • CO2 absorption mechanisms do not care where the CO2 being absorbed came from.
  • The sensitivity of global temperature to CO2 concentration has been grossly exaggerated by the computer models.
  • Carbon dioxide concentration is more likely to follow global temperature (due to subsequent changes in emission and absorption rates) than to lead it.
  • Sea ice levels are increasing at both poles with the Antarctic at record high levels.
  • Polar bear populations are thriving and increasing.
  • Sea levels are continuing to rise at just the historical levels due to the recovery from the last glacial and are not accelerating due to industrialisation or the use of fossil fuels.
  • Oceans are still strongly alkaline and any increase in acidity is within known natural variability.
  • Coral reefs have shown themselves to be self-healing when damaged and are not showing any signs of ocean acidification.
  • Climate models have grossly underestimated solar effects because the mechanisms are unknown.
  • Sunspot activity in SC24 is well down from SC 23 and is not unlike the period of the dalton minimum during SC5 and SC6.
  • Clouds and moisture in the atmosphere have a much bigger impact on global warming and cooling than CO2 in the atmosphere.
  • Cloud formation is linked to sunspot activity and cosmic rays.
  • Global warming and cooling follow solar effects via the oceans in long decadal cycles.
  • The number of hurricanes and tornadoes are at historically low levels.
  • Heat released from the earth’s interior by tectonic and volcanic activity is not known.
  • A Little Ice Age is more likely than further Global Warming and a global cooling cycle lasting 20-30 years may have begun.
  • This interglacial is due (within c. 1000 years) to come to an end.

There is more we don’t know that we don’t know about the climate than the IPCC would like to admit. And for policy makers, activists and bureaucrats who have followed misguided policies for the last 25 years it is no longer possible to admit that they have been making “certain” predictions in an ocean of uncertainty. They have replaced scientific objectivity by “consensus science” where the validity of a hypothesis is based on how many believe and not on evidence. The 95% probability/certainty of global warming being due to human activity being touted by the IPCC is based on a show of hands of believers, and not on any evidence or statistical analysis of data.

The sun, the clouds and the climate

September 5, 2013

The Svensmark theory is that variations in the Sun’s electromagnetic  behaviour leads to varaiations of the cosmic ray flux reaching earth which in turn impacts cloud formation on earth and that connects to global warming or cooling.  A more active sun leads to fewer cosmic rays which gives fewer clouds and more warming on earth.

Graphic from Jonova

The CLOUD experiments at CERN have shown that cosmic rays can in fact lead to cloud formation. Now Svensmark and his colleagues have published further evidence from the SKY2 experiments which confirm the connection.

H. Svensmark, Martin B. Enghoff and Jens Olaf Pepke Pedersen, Response of cloud condensation nuclei (>50 nm) to changes in ion-nucleation,   Physics Letters A 377 (2013) 2343–2347,

Full paper is available here: svensmark et al 2013

Abstract: In experiments where ultraviolet light produces aerosols from trace amounts of ozone, sulfur dioxide, and water vapor, the relative increase in aerosols produced by ionization by gamma sources is constant from nucleation to diameters larger than 50 nm, appropriate for cloud condensation nuclei. This result contradicts both ion-free control experiments and also theoretical models that predict a decline in the response at larger particle sizes. This unpredicted experimental finding points to a process not included in current theoretical models, possibly an ion-induced formation of sulfuric acid in small clusters.

The Technical University of Denmark has issued a Press Release:

Danish experiment suggests unexpected magic by cosmic rays in cloud formation

Researchers in the Technical University of Denmark (DTU) are hard on the trail of a previously unknown molecular process that helps commonplace clouds to form. Tests in a large and highly instrumented reaction chamber in Lyngby, called SKY2, demonstrate that an existing chemical theory is misleading.

Back in 1996 Danish physicists suggested that cosmic rays, energetic particles from space, are important in the formation of clouds. Since then, experiments in Copenhagen and elsewhere have demonstrated that cosmic rays actually help small clusters of molecules to form. But the cosmic-ray/cloud hypothesis seemed to run into a problem when numerical simulations of the prevailing chemical theory pointed to a failure of growth. 

Fortunately the chemical theory could also be tested experimentally, as was done with SKY2, the chamber of which holds 8 cubic metres of air and traces of other gases. One series of experiments confirmed the unfavourable prediction that the new clusters would fail to grow sufficiently to be influential for clouds. But another series of experiments, using ionizing rays, gave a very different result, as can be seen in the accompanying figure. 

The reactions going on in the air over our heads mostly involve commonplace molecules. During daylight hours, ultraviolet rays from the Sun encourage sulphur dioxide to react with ozone and water vapour to make sulphuric acid. The clusters of interest for cloud formation consist mainly of sulphuric acid and water molecules clumped together in very large numbers and they grow with the aid of other molecules.

Atmospheric chemists have assumed that when the clusters have gathered up the day’s yield, they stop growing, and only a small fraction can become large enough to be meteorologically relevant. Yet in the SKY2 experiment, with natural cosmic rays and gamma-rays keeping the air in the chamber ionized, no such interruption occurs. This result suggests that another chemical process seems to be supplying the extra molecules needed to keep the clusters growing. 

“The result boosts our theory that cosmic rays coming from the Galaxy are directly involved in the Earth’s weather and climate,” says Henrik Svensmark, lead author of the new report. “In experiments over many years, we have shown that ionizing rays help to form small molecular clusters. Critics have argued that the clusters cannot grow large enough to affect cloud formation significantly. But our current research, of which the reported SKY2 experiment forms just one part, contradicts their conventional view. Now we want to close in on the details of the unexpected chemistry occurring in the air, at the end of the long journey that brought the cosmic rays here from exploded stars.”

Simulating what could happen in the atmosphere, the DTU’s SKY2 experiment shows molecular clusters (red dots) failing to grow enough to provide significant numbers of “cloud condensation nuclei” (CCN) of more than 50 nanometres in diameter. This is what existing theories predict. But when the air in the chamber is exposed to ionizing rays that simulate the effect of cosmic rays, the clusters (blue dots) grow much more vigorously to the sizes suitable for helping water droplets to form and make clouds. (A nanometre is a millionth of a millimetre.)

Clean air legislation reinstated the global warming suppressed by industrial pollution

August 20, 2013

A fascinating post at WUWT:

The story so far;

  1. The earth was warming naturally after the Little Ice Age (1350 – 1850).
  2. Along came the industrial revolution. Dust and aerosol pollution covered large parts of the earth and blocked out the Sun. This caused a gradually increasing suppression of the global warming that was occurring as the industrialisation of the world proceeded. This suppression reached a maximum during the 1970’s.
  3. Then came clean air legislation around the world, cleaned up the atmosphere and the Earth basked in the sunlight again.

Global warming was rediscovered.

And now as the LIA temperature recovery is coming to a natural end, global temperatures will decrease again.

Well it is a settled science after all.

Shocker: Global warming may simply be an artifact of clean air laws

global-dimming-brightening

Figure 1 from Wild et al 2012 showing radiation balance differences due to aerosols (via WUWT)

 

Sea level dropped in 2010/11 but only because it rained in Australia!

August 19, 2013

Wonders will never cease! If we just make sure that more moisture is trapped in clouds and that it rains more over land we can prevent sea level rise and even cause sea level to fall

Sea level is rising to catastrophic levels because of global warming and that, of course, is due the our using fossil fuels – or so the global warming theology would have us believe. But sea levels dropped by 0.7mm in 2010/2011. But not to worry. The catastrophe theory remains intact. This was just due to it raining too much over land in Australia and the tropics that year.

A new paper but an old tired song:

John T. Fasullo, Carmen Boening, Felix W. Landerer and R. Steven Nerem, Australia’s unique influence on global sea level in 2010–2011, Geophysical Research Letters, DOI: 10.1002/grl.50834

AbstractIn 2011, a significant drop in global sea level occurred that was unprecedented in the altimeter era and concurrent with an exceptionally strong La Niña. This analysis examines multiple datasets in exploring the physical basis for the drop’s exceptional intensity and persistence. Australia’s hydrologic surface mass anomaly is shown to have been a dominant contributor to the 2011 global total and associated precipitation anomalies were among the highest on record. The persistence of Australia’s mass anomaly is attributed to the continent’s unique surface hydrology, which includes expansive arheic and endorheic basins that impede runoff to ocean. Based on Australia’s key role, attribution of sea level variability is addressed. The modulating influences of the Indian Ocean Dipole and Southern Annular Mode on La Niña teleconnections are found to be key drivers of anomalous precipitation in the continent’s interior and the associated surface mass, and sea level responses.

PhysOrg recites the dogma:

When enough raindrops fall over land instead of the ocean, they begin to add up. New research led by the National Center for Atmospheric Research (NCAR) shows that when three atmospheric patterns came together over the Indian and Pacific oceans, they drove so much precipitation over Australia in 2010 and 2011 that the world’s ocean levels dropped measurably. Unlike other continents, the soils and topography of Australia prevent almost all of its precipitation from running off into the ocean. 

The 2010-11 event temporarily halted a long-term trend of rising sea levels caused by higher temperatures and melting ice sheets. 

Now that the atmospheric patterns have snapped back and more rain is falling over tropical oceans, the seas are rising again. In fact, with Australia in a major drought, they are rising faster than before.

“It’s a beautiful illustration of how complicated our climate system is,” says NCAR scientist John Fasullo, the lead author of the study. “The smallest continent in the world can affect sea level worldwide. Its influence is so strong that it can temporarily overcome the background trend of rising sea levels that we see with climate change.”

….. As the climate warms, the world’s oceans have been rising in recent decades by just more than 3 millimeters (0.1 inches) annually. This is partly because the heat causes water to expand, and partly because runoff from retreating glaciers and ice sheets is making its way into the oceans.

But for an 18-month period beginning in 2010, the oceans mysteriously dropped by about 7 millimeters (about 0.3 inches), more than offsetting the annual rise.

Fasullo and his co-authors published research last year demonstrating that the reason had to do with the increased rainfall over tropical continents. They also showed that the drop coincided with the atmospheric oscillation known as La Niña, which cooled tropical surface waters in the eastern Pacific and suppressed rainfall there while enhancing it over portions of the tropical Pacific, Africa, South America, and Australia.

But an analysis of the historical record showed that past La Niña events only rarely accompanied such a pronounced drop in sea level. ….

When sea level rises it is due to global warming. But when it falls it is due to too much rain over Australia. Nothing to do with the standstill in global temperatures for the last 17 years of course!

As I posted a month or so ago

Sea levels in the past have been 10 m higher than today and 150 m lower than today.

Alarmism will have us believe that +5 cm ±15 cm in sea level that may actually happen by 2100 will threaten the very existence of humanity!

new paper from Nils-Axel Mörner.

SEA LEVEL CHANGES PAST RECORDS AND FUTURE EXPECTATIONS

……. The Earth’s rate of rotation records a mean acceleration from 1972 to 2012, contradicting all claims of a rapid global sea level rise, and instead suggests stable, to slightly falling, sea levels.Best estimates for future sea level changes up to the year 2100 are in the range of +5 cm ±15 cm

Satellite data clearly shows global cooling from 1984 – 2006

August 4, 2013

Brightness temperatures derived from the Meteosat data show a planetary trend of global cooling of upto  2K/decade since 1984.

One wonders why this data has not been publicised earlier.

In general, the Atlantic Ocean, Africa and Europe show a negative temperature trend, varying between zero and -2 K/decade.

Andries Rosema, Steven Foppes and Joost van der Woerd, Meteosat Derived Planetary Temperature Trend 1982-2006Energy & Environment, Volume 24, Number 3 – 4 / June 2013, 381-396, doi:10.1260/0958-305X.24.3-4.381

The paper is behind a paywall at the Journal but a pdf version is available (via climategate.nl): Rosema et al Meteosat data 1984-2006

From the author’s conclusions:

The amazing finding of the present study is that we do not observe global warming in the period 1982-2006, but significant cooling. …

The satellite data are from a reliable origin supported by the European meteorological community. Their accurate calibration has received due attention and efforts from Eumetsat. Our processing of these data has been simple and straight forward, involving only noon and midnight image composition, averaging and a filter to eliminate cloud effects. We have created similar planetary temperature change images for the unfiltered, 10, 20 and 30 day filtered data, clearly showing convergence towards the longer filters, indicating that cloud influences were effectively removed. 

Moreover, we do observe significant temperature increase at some locations which are due to human interventions, and which are quantitatively in line with the theoretically expected effects of these interventions. Therefore we believe the observed planetary temperature decrease for most of the hemisphere to be real.

The cloud filtered temperature change patterns, in figure 2c, indicate that the largest decrease occurs in the more cloudy regions of the hemisphere: the tropics and the temperate zones, while in the desert belt the temperature decrease is much smaller. This suggests that cloudiness changes could be the mechanism behind the observed global cooling since 1982: an increase in cloudiness would decrease global radiation and increase rainfall and evapotranspiration. Both effects tend to decrease the surface temperature.

While their conclusions about cloud cover as the determining mechanism are plausible – but as yet unproven – their general observations are quite significant:

In general, the Atlantic Ocean, Africa and Europe show a negative temperature trend, varying between zero and -2 K/decade. Remarkable, is a large area in southern Africa, mainly Zimbabwe and Mozambique, where the temperature decrease is even larger and in the range of -2 to -3 K. Also note the temperature decrease of Lake Chad and Lake Nasser, probably due to an increase in their surface areas. There are also some spots that show a substantial temperature increase, in particular in SE Iraq (figure 3a) and NW Tanzania (figure 3b).

They see a general reduction of temperature everywhere except in two small areas of Iraq and Tanzania:

  1. SE Iraq- An exceptional location which shows a strong temperature increase of some 5K in the period of 20 year. This increase took mainly place in the period 1993-1995 and reflects the draining of the marshes at the confluence of the Ephrata and Tigris under the regime of Sadam Hussein.
  2. NW Tanzania, south of Lake Victoria. There is a temperature increase of 1.3 K in 20 year. This location is in a strongly developing mining area. Decrease in vegetation cover and reduced  evapotranspiration may have caused this temperature increase.

ABSTRACT
24 year of Meteosat hourly thermal infrared data have been used to study planetary surface temperature change. Thermal infrared radiation in the 10.5-12.5mm spectral window is not affected by CO2 and only slightly by atmospheric water vapor. Satellite thermal infrared data have been converted to brightness temperatures as prescribed by Eumetsat. Hourly brightness temperature images were then composed to corresponding noon and midnight temperature data fields. The resulting data fields were cloud filtered using 10, 20 and 30 day maximum temperature substitution. Filtered data were subsequently averaged for two 10 yearly periods: 1986-1995 and 1996-2005. Finally the change in brightness temperature was determined by subtraction. In addition nine locations were selected and data series were extracted and studied for the period 1982-2006. Our observations point to a decrease in planetary temperature over almost the entire hemisphere, most likely due to an increase of cloudiness. Two small areas are found where a considerable temperature increase has occurred. They are explained in terms of major human interventions in the hydrological balance at the earth surface.

“Climate science” now hunting for cooling effects – and finds the brightness of clouds

May 6, 2013

How is it that – for a settled science – all these new “cooling” mechanisms are suddenly being found? Could it have something to do with trying to rescue climate models which have failed to predict the slowdown in global warming? “Climate science” is now hunting for previously unidentified cooling effects to explain the warming that has not happened.

This time it is the brightness of clouds! Apparently manmade pollution in the form of organics can enhance the formation of clouds which happen to be brighter from above and which reflect more of the suns radiation. Voilà! An as yet unidentified cooling effect.

But this conclusion comes not from measurements but from yet another model!

From the University of Machester (via Alpha Galileo):

Organic vapours affect clouds leading to previously unidentified climate cooling

University of Manchester scientists, writing in the journal Nature Geoscience, have shown that natural emissions and manmade pollutants can both have an unexpected cooling effect on the world’s climate by making clouds brighter.

Clouds are made of water droplets, condensed on to tiny particles suspended in the air. When the air is humid enough, the particles swell into cloud droplets. It has been known for some decades that the number of these particles and their size control how bright the clouds appear from the top, controlling the efficiency with which clouds scatter sunlight back into space. A major challenge for climate science is to understand and quantify these effects which have a major impact in polluted regions.

The tiny seed particles can either be natural (for example, sea spray or dust) or manmade pollutants (from vehicle exhausts or industrial activity). These particles often contain a large amount of organic material and these compounds are quite volatile, so in warm conditions exist as a vapour (in much the same way as a perfume is liquid but gives off an aroma when it evaporates on warm skin).

The researchers found that the effect acts in reverse in the atmosphere as volatile organic compounds from pollution or from the biosphere evaporate and give off characteristic aromas, such as the pine smells from forest, but under moist cooler conditions where clouds form, the molecules prefer to be liquid and make larger particles that are more effective seeds for cloud droplets.

“We discovered that organic compounds such as those formed from forest emissions or from vehicle exhaust, affect the number of droplets in a cloud and hence its brightness, so affecting climate,” said study author Professor Gordon McFiggans, from the University of Manchester’s School of Earth, Atmospheric and Environmental Sciences.

“We developed a model and made predictions of a substantially enhanced number of cloud droplets from an atmospherically reasonable amount of organic gases.

“More cloud droplets lead to brighter cloud when viewed from above, reflecting more incoming sunlight. We did some calculations of the effects on climate and found that the cooling effect on global climate of the increase in cloud seed effectiveness is at least as great as the previously found entire uncertainty in the effect of pollution on clouds.”

  • ‘Cloud droplet number enhanced by co-condensation of organic papers,’ by Gordon McFiggans et al, will be published in Nature Geoscience on Sunday 5 May 2013.

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