Thursday, August 02, 2012

Hot Air, Climate and Models

This piece is reprinted in part from a piece by David Evans (former official in the Australian Department of Climate Change) in the Brisbane Times, August 2nd 2012. Those parts in italics I have added. Stephen, Please go to the Brisbane Times for the full piece...

In the theory of man-made climate change, two-thirds of the predicted warming comes from changes in humidity and clouds, and only one-third comes directly from the extra carbon dioxide (CO2) and other greenhouse gases. The theory assumes humidity and clouds amplify the warming directly due to CO2 by a factor of three: extra CO2 warms the ocean surface, causing more evaporation and extra humidity. Water vapour, or humidity, is the main greenhouse gas, so this causes even more surface warming.

Scientists can calculate how much warming results directly from an increase in CO2 levels. We know how much CO2 levels and temperature have risen since pre-industrial times, but the warming directly due to CO2 is only a third of the observed warming. The theory assumes no other major influence on temperature changed, so the effect of the CO2 must have been amplified threefold, presumably by changes in the atmosphere due to humidity and clouds. There is no observational evidence for this amplification, but it is nonetheless built into all the climate change models in use today. Sceptics point out that if the extra humidity simply forms extra clouds, then there would be no amplification. They also point out that there are other sources of warming – notably the sun – and that there are non-human forms of greenhouse gas emissions, such as volcano’s.

If the CO2 theory of global warming is right, the climate models should predict the climate fairly well. If the CO2 theory is wrong, because there is another, larger driver of the temperature, then the climate models will perform indifferently. According to the latest data from mankind's best and latest instruments, from impeccable sources, the climate models are doing very poorly. Indeed, some recent work suggests that they fail to predict climate at all well.

Ocean temperatures have only been measured properly since 2003 when the Argo program became operational. Some 3000 Argo buoys roam the oceans, measuring temperatures on each 10-day dive into the depths. Before Argo, we used sporadic sampling with buckets and diving darts along a few commercial shipping lanes. But these measurements have such massively high uncertainties as to be useless. Since Argo started, the ocean temperatures have been flat, no warming at all.

The assumed temperature amplification due to changes in humidity and clouds exhibits itself in all the models as prominent warming about 10 kilometers up over the tropics. We have been measuring the atmospheric warming pattern since the 1960s using weather balloons, released twice a day from 900 locations around the planet, many millions of them in total, and no such ''hot spot'' has been detected. This is direct observational proof that the amplification is missing.

The climate models predict that the outgoing radiation from the earth decreases in the weeks following a rise in the surface temperature, due to aggressive heat-trapping by extra humidity. But analysis of the outgoing radiation measured by NASA satellites for the last two decades shows the opposite occurs: the earth gives off more heat after the surface temperature rises. Again, this suggests that the amplification assumed in the models simply does not occur in reality.

No comments: