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Evaporative Cooling Limits Global Warming to Less Than 1-degree


At present the energy flows at the earth's surface keep it at a global average temperature of around 15°C.


The NASA schematic diagram below shows us that 48% of the solar energy that strikes planet earth is absorbed by and warms the surface.  The other 52% is reflected back into space or is absorbed in the atmosphere.



As the NASA diagram shows us the most important cooling process is evaporation, then 'net thermal radiation', with convection providing the balance.  The percentages in the diagram relate to the total solar energy that strikes planet earth being 100%.


The reason evaporative cooling is so powerful is that 70% of the earth's surface is covered by the oceans.  This is shown pretty dramatically on the Google Earth satellite image below.



When mankind adds carbon dioxide to the atmosphere the cooling 'net thermal radiation' (see NASA schematic above) is reduced and the earth's surface gets warmer.


When the earth's surface gets warmer it gives rise to a number of what are called feedbacks.  Some of these feedbacks are 'positive' in that they further warm the surface and some of these feedbacks are 'negative' in that they cool the surface.


When the earth's surface gets warmer this increases 'net thermal radiation' (see NASA schematic above) and cools the surface.


When the earth's surface gets warmer this warms the atmosphere and increases the amount of water vapour in the atmosphere.  Water vapour is a greenhouse gas, so this reduces the cooling 'net thermal radiation' and gives rise to the so called positive water vapour feedback.


When the surface, which is 70% water gets warmer we also get increased evaporation from all that warmer water, which increases evaporative cooling.


We find that for a doubling of carbon dioxide and a surface temperature increase of 0.6°C the 'net thermal radiation' that cools the surface would decrease by 1.2% from 17% to 15.8% and be balanced by an increase in evaporative cooling of 1.2% from 25% to 26.2%, with little change in convection.  (see Climate Facts & Calculations for details)


This shows us that if the amount of carbon dioxide in the atmosphere was to double, then the surface temperature would need to increase by around 0.6°C to restore the energy balance at the earth's surface.


This is considerably less than the 4°C to over 7°C claimed by the IPCC, which is something of a puzzle.


However, investigations reveal that the global climate models slow down the virtual global hydrological cycle, commonly known as the water cycle, and lengthen its period as the climate warms.  This greatly reduces evaporative cooling.


The schematic diagram below illustrates the water cycle process.




This artefact of the climate models has the effect of greatly reducing the increase in virtual evaporative cooling.  Because of this artefact a typical computer model has to amplify the increase in the surface temperature on its virtual earth by five to ten times from 0.6°C to around 4°C and higher, before the energy flows are once again in balance at the virtual surface.


However, the proposition that the water cycle slows down as the climate warms is scientifically counter intuitive.  Because of their training scientists expect that as more energy is fed in the water cycle will speed up.  Indeed we all expect that as more energy is fed in man made cyclical processes such as car engines will accelerate as will natural cyclical processes such as the water cycle.


Further, this unsubstantiated and scientifically counter intuitive proposition is contradicted by observational data collected by scientists.  In its May 2011 Report "The Critical Decade - Climate science, risks and responses" on page 21, Australia's Climate Commission tells us there is considerable evidence that the water cycle accelerates as the climate warms.


So, in the models that predict potentially dangerous global warming the virtual water cycle slows down as the climate warms, but in the real world it doesn't slow down, but accelerates.  (see Observation Based Science for details)


The analysis above shows that around 80% of predicted global warming is attributable to a scientifically counter intuitive and unsubstantiated proposition, which is contradicted by observational data.  This disproven proposition states that the water cycle slows down as the climate warms.


In his letter of August 2012 (see second dot point), The Hon Greg Combet, Australia's Minister for Climate Change and Energy Efficiency confirmed that as the climate warmed on the virtual planets, the global climate models previously underestimated the increase in virtual evaporative cooling by a factor of two.


Minister Combet's letter was equivocal on whether the severe structural flaws in the CSIRO's global climate models have been fixed, so that virtual evaporative cooling now increases by 8% for each 1-degree increase in the surface temperature.


Minister Combet's letter did not provide information as to the increase in surface temperature that the CSIRO's hopefully by now reconfigured global climate models predict for a mooted doubling of atmospheric carbon dioxide.


In September 2012 Mr Cummings wrote a letter requesting that Minister Combet provides the additional information referred to above.


Minister Combet's reply is awaited. 

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