Of Trees, Clouds, And Cosmic Rays
Recently, the journals Nature and Science reported on two experiments which revealed molecules released by trees can seed clouds. These findings run contrary to an assumption that sulphuric acid is required for a certain type of cloud formation. This further suggest that climate predictions may have underestimated the role that clouds had in shaping the preindustrial climate. And since sulphuric acid is considered an anthropogenic pollutant, this means man has a smaller role in climate change than previously assumed. Almost left unmentioned in the news reports of these results is the role cosmic rays play in the formation of cloud nuclei, an idea proposed years ago and treated with derision by the mainstream climate change cabal.
For more than two decades, clouds have been the largest source of uncertainty in understanding how manmade emissions affect the atmosphere. Climate scientists know it, climate modelers admit it, clouds and cloud formation have remained a mystery. You see, aside from releasing dreaded CO2 into the atmosphere, burning fossil fuels indirectly produces sulphuric acid, which is known to seed clouds. Because of this, climate scientists have assumed that since preindustrial times, there has been a large increase in cloud cover due to human activity.
With Earth's climate stubbornly refusing to warm as quickly as scientists predict, warmists are at pains to explain why climate sensitivity to CO2 is lower then they predict. Conveniently, more clouds have a supposed overall cooling effect by reflecting sunlight back into space. Rather than rethink their erroneous theory, climate alarmists have assumed that this overall cooling effect has partially masked the climate’s underlying sensitivity to rising carbon dioxide levels. Now comes the inconvenient news that most cloud formation is totally natural and that previous times were just as cloudy as today.
Reported in Nature News: “The latest experiments suggest that it may have been cloudier in pre-industrial times than previously thought. If this is so, then the masking effect, and in turn the warming effects of carbon dioxide, might have been overestimated, says Jasper Kirkby, a physicist at the CERN, Europe’s particle-physics laboratory near Geneva, Switzerland, who led one of the experiments.”
Everyone knows that clouds are made up of water, but water vapor doesn't just condense out of the atmosphere on its own. It needs other molecules or particles to condense onto, a process called nucleation. Until recently, scientists thought that only sulphuric acid vapor (H2SO4) could trigger this process. As a result, it was thought that preindustrial skies were not as cloudy than present day ones because they contained less of this pollutant.
In two Nature papers, “Ion-induced nucleation of pure biogenic particles” and “The role of low-volatility organic compounds in initial particle growth in the atmosphere,” Kirkby and his co-authors report that aerosols can form and grow to the size needed to seed a cloud from compounds emitted by trees — without any sulphuric acid and accelerated by simulated cosmic rays. In a third paper, “New particle formation in the free troposphere: A question of chemistry and timing ,” published in Science, a team that includes some of Kirkby’s co-authors reported a similar finding using a different experiment.
According to the Science and second Nature papers, molecules similar to α-pinene—an organic molecule that is emitted by fir trees—that could originate from vegetation can seed clouds without much sulphuric acid. Here is a description of the research findings from the Nature paper's abstract:
About half of present-day cloud condensation nuclei originate from atmospheric nucleation, frequently appearing as a burst of new particles near midday. Atmospheric observations show that the growth rate of new particles often accelerates when the diameter of the particles is between one and ten nanometres. In this critical size range, new particles are most likely to be lost by coagulation with pre-existing particles, thereby failing to form new cloud condensation nuclei that are typically 50 to 100 nanometres across. Sulfuric acid vapour is often involved in nucleation but is too scarce to explain most subsequent growth, leaving organic vapours as the most plausible alternative, at least in the planetary boundary layer. Although recent studies predict that low-volatility organic vapours contribute during initial growth, direct evidence has been lacking. The accelerating growth may result from increased photolytic production of condensable organic species in the afternoon, and the presence of a possible Kelvin (curvature) effect, which inhibits organic vapour condensation on the smallest particles (the nano-Köhler theory), has so far remained ambiguous. Here we present experiments performed in a large chamber under atmospheric conditions that investigate the role of organic vapours in the initial growth of nucleated organic particles in the absence of inorganic acids and bases such as sulfuric acid or ammonia and amines, respectively. Using data from the same set of experiments, it has been shown that organic vapours alone can drive nucleation. We focus on the growth of nucleated particles and find that the organic vapours that drive initial growth have extremely low volatilities (saturation concentration less than 10−4.5 micrograms per cubic metre). As the particles increase in size and the Kelvin barrier falls, subsequent growth is primarily due to more abundant organic vapours of slightly higher volatility (saturation concentrations of 10−4.5 to 10−0.5 micrograms per cubic metre). We present a particle growth model that quantitatively reproduces our measurements. Furthermore, we implement a parameterization of the first steps of growth in a global aerosol model and find that concentrations of atmospheric cloud concentration nuclei can change substantially in response, that is, by up to 50 per cent in comparison with previously assumed growth rate parameterizations.
Highlighted above is the key statement, “using data from the same set of experiments, it has been shown that organic vapours alone can drive nucleation.” In other words, no manmade H2SO4 is needed to drive cloud formation, plants can do it on their own. Using a different experiment, the researchers in Science, led by Federico Bianchi, reported the same basic result. This leads us to the other result reported by CERN.
Back over a decade ago, Henrik Svensmark hypothesized that cosmic rays might have a significant impact on cloud formation and hence on climate. In several papers, including “Cosmic rays and Earth's climate,” Svensmark and others pushed for an investigation of such a cosmic connection to Earth's climate. His efforts were greeted with great animosity by the climate change establishment (see “Attempt To Discredit Cosmic Ray-Climate Link Using Computer Model), but in the end he managed to convince CERN to run a long-term experiment to test his hypothesis—the CLOUD experiment. Both Nature papers resulted from the CLOUD experiment.
The idea that low solar activity might cause Earth's climate to cool may not sound far fetched, but the mechanism that is responsible for that cooling may seem counterintuitive—an increase in the number of cosmic rays striking Earth's atmosphere. For a century, scientists have known that charged particles from space constantly bombard Earth. Originating in distant stars and galaxies, these cosmic rays strike our planet's atmosphere, where they can ionize volatile compounds. This causes airborne droplets, or aerosols, to condense providing the nuclei around which clouds can form. It is the formation of lowlevel clouds that cools Earth, and that formation is controlled by cosmic rays. Ultimately, the cosmic rays are controlled by the Sun.
Here is what the researchers found after investigating the problem as captured in the paper's abstract:
Atmospheric aerosols and their effect on clouds are thought to be important for anthropogenic radiative forcing of the climate, yet remain poorly understood1. Globally, around half of cloud condensation nuclei originate from nucleation of atmospheric vapours. It is thought that sulfuric acid is essential to initiate most particle formation in the atmosphere and that ions have a relatively minor role. Some laboratory studies, however, have reported organic particle formation without the intentional addition of sulfuric acid, although contamination could not be excluded. Here we present evidence for the formation of aerosol particles from highly oxidized biogenic vapours in the absence of sulfuric acid in a large chamber under atmospheric conditions. The highly oxygenated molecules (HOMs) are produced by ozonolysis of α-pinene. We find that ions from Galactic cosmic rays increase the nucleation rate by one to two orders of magnitude compared with neutral nucleation. Our experimental findings are supported by quantum chemical calculations of the cluster binding energies of representative HOMs. Ion-induced nucleation of pure organic particles constitutes a potentially widespread source of aerosol particles in terrestrial environments with low sulfuric acid pollution.
So there you have it, a widely disparaged idea—that something other than human pollution could be causing cloud formation—has been shown to be quite plausible by actual scientific research. It turns out that human pollution is not necessary to create clouds, only trees and cosmic rays. It also means that climate alarmists will have to find another excuse why their climate sensitivity estimates are proving to be wrong.
This is what happens when scientists actually do science: design experiments, take empirical measurements, and interpret results. Instead of consensus driven dogma generated by computer models, ignorance is dispelled and science advances. Eventually the sham that is current mainstream climate science will be cast aside and real science will reassert itself, the charlatans and publicity seekers will move on to the next scam. Until then, keep looking for the gold among all the dross.
Be safe, stay skeptical and enjoy the interglacial.