Climate Conversation Group

I am sent this snippet of correspondence that refers intriguingly to continuing research into the effect of clouds on the climate. No, I won’t say who’s speaking.

Your reference to clouds led me to the work of Prof Roger Davies, who holds the Buckley-Glavish chair in Climate Physics at Auckland U.

He is part of a global group triangulating cloud data from a dedicated satellite, and seems to be developing a view that clouds provide a natural thermostat function (which Richard Lindzen has previously speculated about).

This comes from a 2008 article “Watching the Clouds” in the science faculty magazine:

Over the past eight years of data, there has been little change in the clouds over much of the Earth. However two regions stand out as exceptions. Near the equator, where the high clouds that determine the greenhouse effect are especially numerous, the cloud cover has dropped in height, suggesting a lowering of their greenhouse effect, potentially to offset global warming.

In addition, the reflectivity of the Arctic has changed. In northern summer 2006, the reflectivity of the Arctic decreased significantly, due to less cloud cover and less ice in the area, both of which reflect sunlight. However, from the ground, only a moderate decrease in ice was seen compared to its normal summer melt. The following year, there was a significantly higher ice melt than predicted, despite the fact that satellite pictures were brighter than average, and much brighter than the previous summer, due to increased cloud.

But was the 2007 melt due to the darkness of 2006? Were the clouds of 2007 compensating for the low ice reflectivity to keep a balance? Right now, we don’t know enough to say.

Interesting, but Google shows up nothing recent. He generally seems to keep his head down.

/end snippet

See commentary on WUWT.

Nature has just published Cloud formation may be linked to cosmic rays, which acknowledges results from an experiment at CERN probing a connection between climate change and radiation bombarding the atmosphere.

[In comments, Alan Burke quickly diminishes the significance.]

In the meantime, Nigel Calder posts CERN experiment confirms cosmic ray action, nailing confirmation of such a “connection” to the scientific wall.

You can draw your own conclusions from the revealing graph he gives:

A graph they’d prefer you not to notice. Tucked away near the end of online supplementary material, and omitted from the printed CLOUD paper in Nature, it clearly shows how cosmic rays promote the formation of clusters of molecules (“particles”) that in the real atmosphere can grow and seed clouds. In an early-morning experimental run at CERN, starting at 03.45, ultraviolet light began making sulphuric acid molecules in the chamber, while a strong electric field cleansed the air of ions. It also tended to remove molecular clusters made in the neutral environment (n) but some of these accumulated at a low rate. As soon as the electric field was switched off at 04.33, natural cosmic rays (gcr) raining down through the roof of the experimental hall in Geneva helped to build clusters at a higher rate. How do we know they were contributing? Because when, at 04.58, CLOUD simulated stronger cosmic rays with a beam of charged pion particles (ch) from the accelerator, the rate of cluster production became faster still. The various colours are for clusters of different diameters (in nanometres) as recorded by various instruments. The largest (black) took longer to grow than the smallest (blue). This is Fig. S2c from supplementary online material for J. Kirkby et al., Nature, 476, 429-433, © Nature 2011. See original graphic.

Take your pick between Nature and Calder. Is the link alleged or confirmed? Is there a non-GHG-induced magnification of solar influence on cloud formation, and therefore global lower tropospheric temperature, or not?

This must give Nick Smith cause to review our ETS.

Stand back as the warmists rush the exits.

Spencer – finding unsuspected climate processes

In a dramatic recent article on his blog, Clouds Dominate CO₂ as a Climate Driver Since 2000, Roy Spencer sets out clear evidence for internally-forced changes in the climate system. An internal forcing is a feedback, as when a change in temperature causes some other change which itself also changes the temperature.

For example, when temperature rises, it may cause an increase in atmospheric water vapour; that water vapour may condense into clouds, which in turn, by reflecting the incoming sunlight back to space, may cause the temperature to drop.

Such a process might be termed a thermostat, a natural regulator, keeping the temperature within its natural bounds, much as it has done for half a billion years and more.

In our example, the forcing was a temperature increase and the feedback was a temperature decrease – a negative feedback, moving the temperature in the opposite direction from the forcing. A positive feedback would move the temperature in the same direction as the forcing.

To date, the IPCC assumes two vital things: that climate sensitivity is high and internal forcing (feedback) is positive.

I do not follow every detail that Dr Spencer describes, but, after challenging these two assumptions and showing them to be wrong, his conclusion pulls no punches.

This is a stunning piece of work. Have a look. I hope to say more later.

Who knew that the sun has increased its output by 30% since the far geological past, and yet the earth did not heat up as it did so? It’s called the Faint Early Sun Paradox and it was always a bit tricky to explain, until now…

The stability of the earth’s temperature over time has been a long-standing climatological puzzle. The globe has maintained a temperature of ± ~ 3% (including ice ages) for at least the last half a billion years during which we can estimate the temperature. During the Holocene, temperatures have not varied by ±1%. And during the ice ages, the temperature was generally similarly stable as well.

Willis Eschenbach has proposed a thermostat for the control of global temperature. His clear exposition of it has just appeared on Watts Up With That. Will it survive scrutiny? Read it through, have a think, let us know.

Richard Treadgold

Clouds are the issue in more than one facet of global warming. Apart from causing rain, clouds have two important effects: cooling and warming. Dr Roy Spencer, one of few scientists studying clouds, has said that a sustained change in cloud cover of just 1%, up or down, can cause a Medieval Warm Period or a Little Ice Age.

Cooling is achieved by reflecting back the heat from the sun; warming is done by keeping that heat in, like a blanket. I’m not an expert on clouds, but from my reading I’ve got the impression that low-level clouds usually cause cooling and high-level clouds usually keep the warmth in. I also think they might do both, at different times of the day.

For example, low clouds at night keep things warm — a clear sky means a cold night — while low clouds during the day reduce temperatures. We’ve all experienced the sudden cooling as a cloud moves across the sun on a hot day.

It’s a current and vexed question to discover just how these conflicting effects are influenced by increasing humidity, whether that acts to raise or to lower air temperatures and what the balance of the effects is around the world. As the global temperature rises (though I’m not suggesting that it is right now) more water evaporates. Where does the resulting water vapour go? What does it do? Are more clouds created, or fewer clouds? Do they warm or cool?

This post on Watts Up With That introduces and enhances a recent post on Climate Audit describing strong negative cloud feedbacks found by the Climate Process Team on Low-Latitude Cloud Feedbacks on Climate Sensitivity.

I especially like, as does Anthony Watts, the remarks of the first of Steve’s commenters, Willis Eschenbach:

Cloud positive feedback is one of the most foolish and anti-common sense claims of the models.

This is particularly true of cumulus and cumulonimbus, which increase with the temperature during the day, move huge amounts of energy from the surface aloft, reflect huge amounts of energy to space, and fade away and disappear at night.

I love the stunning picture of cumulonimbus on WUWT and the clarifying diagrams he gives to help us understand. Who can fail to notice that a cloud is not simply a cloud, but an ever-changing expression of shifting forces?

Richard Treadgold