climate-debate

Earth Energy Imbalance: The Sun versus CO2

by A. May, Apr 25, 2026 in WUWT

This is the text of a talk I gave on a Tom Nelson podcast. To listen to the talk and see Tom’s interview of me go here.

Some believe that CO2 and other greenhouse gas infrared emissions are as effective at increasing ocean heat content (or OHC) as solar radiation. Some even think greenhouse gas (abbreviated “GHG”) radiation is more effective than solar. There are many generally agreed points that dispute this conjecture:

  1. The average photon energy in GHG IR (greenhouse gas infrared) is less than the photon energy in solar radiation because energy goes up as frequency increases (Planck-Einstein relation).
  2. Greenhouse gas-induced infrared radiation is absorbed almost entirely in the ocean’s top micrometers to one millimeter. This is the upper part of the thermal skin layer or “TSL,” and called the electromagnetic skin layer. Incoming solar radiation—particularly blue-green visible wavelengths—penetrate much deeper, typically over 10 meters (and up to 100+ meters in very clear waters), before being absorbed and heating the water column (Wong & Minnett, 2018).
  3. The atmosphere, on average, is cooler than the bulk ocean which is the essence of the “cool skin effect” (Fairall et al., 2026). Heat flow is normally from the ocean to the atmosphere.
  4. The infrared energy from greenhouse gases absorbed in the thermal skin layer cannot be conducted downward into the bulk ocean since the net heat flux is upward. Instead, it adjusts the ocean’s thermal skin layer temperature profile, reducing upward conduction from the bulk ocean (Wong & Minnett, 2018).

Solar radiation warms the ocean directly; greenhouse‑gas IR warms it indirectly by reducing upward heat loss. These mechanisms are not equivalent, and the relative magnitudes are uncertain. These points are discussed in more detail in three earlier blog posts (here, here and here). The posts generated more than 500 interesting comments on my website and on Wattsupwiththat. In this talk I’d like to summarize the comments to illuminate this complex issue.

The Ocean Skin Layer

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