The impact of hot soils on the climate

The last post on heat extremes in soils states (from the press release of the scientific publication):

When the temperature in the soil is higher than in the air, additional heat is released to the lower atmosphere – causing temperatures in the atmosphere to rise. “Soil temperature acts as a factor in the feedback loop between soil moisture and temperature and can thus intensify heat waves in certain regions”.

I find this sentence particularly interesting because I suspect that the explanation behind it is the effect of the Stefan-Boltzmann law, and thus the role that land destruction has on the climate.

Of course we know that when nature is destroyed there is an important switch between the production of latent energy (LE; energy bound in water vapor) and sensible heat (“hot air”). Nature produces a lot of LE that can rise vertically into higher parts of the atmosphere without being impeded by naturally occurring or anthropogenic greenhouse gases, where condensation allows some of this released energy to escape into space.

Here is a drawing of mine that shows this:

The Stefan-Boltzmann law describes the intensity of thermal radiation emitted by matter as a function of the temperature of the matter. For an ideal absorber/radiator or black body, the Stefan-Boltzmann law states that the total energy emitted per unit area per unit time is directly proportional to the fourth power of the temperature of the black body, T:

If an area with a forest is 20°C warm, a vegetated field is 35°C warm and an open field is 50°C warm [the three have equal distances of 15°C], the difference in radiant power in W/m2 is 95 for forest/vegetated field and 110 for vegetated field/open field [so not equal, but “exponentially” increasing], see my graph below:


What does this mean now? The natural (as well as the anthropogenic) GHG effect is based on the “reflection” of incoming short-wave solar radiation into outgoing long-wave radiation by GHGs and clouds. If we now create warm surfaces on vast landscapes instead of water vapor that would pass through the greenhouse gases in the atmosphere, which emit long-wave radiation with its fourth power, which is reflected by the greenhouse gases and largely held in the lower part of the atmosphere, we increase the warming of the atmosphere enormously.

Question: How high would the warming effect of anthropogenic greenhouse gases in the atmosphere be without “land use change” as opposed to “land use change”? What role does the altered energy cycle – linked to the water cycle – play in anthropogenic climate change?

In my opinion, 4th power energy radiation and its influence on (naturally occurring, but also anthropogenically added) greenhouse gases is the key to the argument that greened versus ungreened/open/concreted areas are to be distinguished. And have not yet been taken into account in the climate change debate.

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