A new study from Scripps at UC San Diego claims proof of greenhouse gas warming by means of changes to the clouds. The paper is behind a paywall, so the reasoning is not accessible, but the media releases will ensure wide repetition.
From the news release July 11, 2016 (here)
Clouds Are Moving Higher, Subtropical Dry Zones Expanding, According to Satellite Analysis
Scripps-led study confirms computerized climate simulations projecting effects of global warming
Inconsistent satellite imaging of clouds over the decades has been a hindrance to improving scientists’ understanding. Records of cloudiness from satellites originally designed to monitor weather are prone to spurious trends related to changes in satellite orbit, instrument calibration, degradation of sensors over time, and other factors.
When the researchers removed such artifacts from the record, the data exhibited large-scale patterns of cloud change between the 1980s and 2000s that are consistent with climate model predictions for that time period, including poleward retreat of mid-latitude storm tracks, expansion of subtropical dry zones, and increasing height of the highest cloud tops. These cloud changes enhance absorption of solar radiation by the earth and reduce emission of thermal radiation to space. This exacerbates global warming caused by increasing greenhouse gas concentrations.
The researchers drew from several independent corrected satellite records in their analysis. They concluded that the behavior of clouds they observed is consistent with a human-caused increase in greenhouse gas concentrations and a planet-wide recovery from two major volcanic eruptions, the 1982 El Chichón eruption in Mexico and the 1991 eruption of Mt. Pinatubo in the Philippines. Aerosols ejected from those eruptions had a net cooling effect on the planet for several years after they took place.
Barring another volcanic event of this sort, the scientists expect the cloud trends to continue in the future as the planet continues to warm due to increasing greenhouse gas concentrations. (My bolds)
Another Example of Lop-sided Myopia and Confirmation Bias
The report above violates basic physics, resulting in a gross distortion. Two points are critical. When it comes to clouds, the greenhouse gas that matters is H2O, not CO2. Any IR effects are 96% due to the presence of water vapor and the droplets in the clouds.
And even more importantly, as Dr. Salby illustrated (here), the net effect from clouds is cooling, not warming.
Net cloud forcing is then −15 W m−2. It represents radiative cooling of the Earth-atmosphere system. This is four times as great as the additional warming of the Earth’s surface that would be introduced by a doubling of CO2. Latent heat transfer to the atmosphere (Fig. 1.32) is 90 W m−2. It is an order of magnitude greater. Consequently, the direct radiative effect of increased CO2 would be overshadowed by even a small adjustment of convection (Sec. 8.7).
This is confirmed by other researchers, such as I. Koren, G. Dagan, and O. Altaratz. From aerosol-limited to invigoration of warm convective clouds. Science, 2014; 344 (6188) here.
They then looked at another source of data: that of the Clouds’ and Earth’s Radiant Energy System (CERES) satellite instruments which measure fluxes of reflected and emitted radiation from Earth to space, to help scientists understand how the climate varies over time. When analyzed together with the aerosol loading over the same area at the same time, the outcome, says Koren, was a “textbook demonstration of the invigoration effect” of added aerosols on clouds. In other words, the radiation data fit the unique signature of clouds that were growing higher and larger. Such clouds show a strong increase in cooling due to the reflected short waves, but that effect is partly cancelled out by the enhanced, trapped, long-wave radiation coming from underneath. (My bold)
More info on clouds is here:Climate Partly Cloudy
Once again, atmospheric physics is willfully distorted in order to get a headline and burnish credentials in support of man-made climate change. They promote a myopic and lop-sided picture to frighten a public mostly ill-equipped to see through their mumbo-jumbo.