By Andy May
The following is a quote from my book Climate Catastrophe! Science or Science Fiction?
“99.9 percent of the Earth’s surface heat capacity is in the oceans and less than 0.1 percent is in the atmosphere. Further, CO2 is only 0.04 percent of the atmosphere. It beggars belief that a trace gas (CO2), in an atmosphere that itself contains only a trace amount of the total thermal energy on the surface of the Earth, can control the climate of the Earth. This is not the tail wagging the dog, this is a flea on the tail of the dog wagging the dog.”
One would think that this is clear, but to some it clearly is not. A commenter on Amazon.com named “Stephen” thinks it is “Scientific gibberish” and explains as follows:
“Apparently, May believes that the way CO2 acts to heat the earth is by getting hot. Then, the CO2 transfers its heat to the rest of the earth. Since the heat capacity of the CO2 is negligible, the earth’s temperature cannot rise.
This represents a profound misunderstanding of how the greenhouse effect works. The amount of heat contained in the CO2 has nothing whatsoever to do with CO2‘s effect on temperature. CO2‘s effect is to prevent radiative heat transfer from the earth [sic] to space. That is, it keeps the heat in.
Here is a way to think about this. Imagine that you have a pot of hot water sitting on the counter. If the pot is open to the air, it will cool quickly. If the pot is covered, it will cool more slowly. It doesn’t matter if the cover is made out of Saran wrap, which has no heat capacity–it will still keep the water hot. This analogy isn’t perfect since the water may be losing heat mostly by convective heat transfer. But the point is that CO2 is acting by keeping the heat in; it doesn’t actually heat the earth.”
He obviously did not read the book and misses the significance of the large difference between the heat capacity of the oceans and the atmosphere. He also misses the significance of “… control the climate of the Earth.” OMG! I’ve been quoted out of context, that never happens! But, since Stephen does seem to understand a little of the science, I did respond. The version below is edited a bit for this post, the actual answer is on Amazon.com.
What does this quote mean?
As you will see when you read my book, the IPCC AR5 Physical Science Basis report (2013) states on page 667 that “CO2 is the main anthropogenic control knob on climate.” This is also in the title of a paper by Lacis, et al. (2010) cited in the IPCC report. Both works acknowledge that the infrared active CO2 alone does not have enough of an effect to cause problems. But, if the atmospheric CO2 concentration increases, due to burning fossil fuels, the IPCC authors claim the lower atmosphere will warm due to the resulting additional delay in the radiative transfer of thermal energy to space. This warming will cause the amount of water vapor to increase in the lower atmosphere. Water vapor is a much stronger “greenhouse gas” and this will cause the problem they espouse.
In addition, the same IPCC report states on page 7 that they present “clear and robust conclusions … that the science now shows with 95 percent certainty that human activity is the dominant cause of observed warming since the mid-20th century.” Of course, the human effect on climate has never been measured, so the “95%” confidence is based solely upon computer models and “expert” opinion.
There are several problems with these ideas. Most heat transfer in the lower atmosphere, where there is a lot of water vapor, occurs via convection. Water vapor (and water) have a high heat capacity and carry a lot of latent heat, they transport most of the thermal energy near the surface in the so-called atmospheric “boundary layer.” CO2 has a low heat capacity. It is infrared active and absorbs and emits IR radiation, with a small delay, whereas latent heat can be carried by water vapor for weeks before it condenses as rain and emits it as radiant energy. At high altitudes, where there is little water vapor, it is responsible for emitting most of the IR to space as thermal radiation. But, near the surface water vapor does most of the cooling.
The oceans are very cool, with an average temperature of about 4 degrees C. As stated in the quote, they contain 1,000 times the heat capacity of the atmosphere and provide a huge buffer that limits the Earth’s surface temperature. Most of the solar thermal energy that reaches the surface is absorbed by the oceans. The warmest part of the ocean is the surface of the tropical Pacific. Here evaporation limits the temperature to a maximum of 30 degrees C (86 degrees F) according to many sources, but Newell and Dopplick (1978, J. of Applied Meteorology, Vol. 18, page 822) and Newell, Navato and Hsiung (1978 in Pure Applied Geophysics, Vol 116, page 351) are the original sources. In isolated shallow seas, for example the Red Sea or the Caribbean, or close to land in unusual meteorological conditions, sea-surface temperatures may reach as much as 34 degrees. But, in the open ocean the limit is generally 30 degrees. This is the temperature where the thermal energy lost to evaporation is about the same as the energy received from the Sun.
This energy is transmitted all over the world, mostly by ocean currents, but also by wind. It is emitted to space, mostly by CO2, in net emitting areas like the poles and the Sahara, and from the upper atmosphere. Thunderstorms are a main mechanism for transporting thermal energy to the upper atmosphere where it is easily emitted to space. Thus, the point of the quote is that the atmosphere (and thus CO2, a trace gas in the atmosphere) cannot “control” the climate if oceans exist. The oceans are the main control. If they were to completely disappear somehow (unlikely) then CO2 may play a role in long-term climate. But, if they exist, the maximum ocean surface temperature is 30 degrees. Since the oceans cover 70% of the Earth’s surface, this limits the maximum surface temperature.
One last point, in the first quote I state that 99.9% of the heat capacity is in the oceans and 0.1% is in the atmosphere. I ignored the heat capacity of the land because temperature measurements on land are made in the air above the land. Normally at about 2 meters altitude.