Jim Steele

The atmosphere’s density regulates the greenhouse effect. Climate scientists estimate that around 30% of the downward infrared energy from greenhouse gasses that slow the earth’s surface cooling originates in just the lower 10 meters of our atmosphere, the densest layer. Over 80% of the downward infrared originates between the surface and 500 meters of altitude.

Low altitude clouds, like various stratus clouds, can increase the amount of downward infrared but decrease solar heating. Stratocumulus and stratus clouds shade roughly a fifth of the oceans, reflecting 30 to 60 percent of incoming solar radiation. However above 500 meters, the infrared emitted from clouds escapes more easily to space as decreasing air density reduces the greenhouse effect.

Cumulus-type clouds are the result of rising thermals as convection carries most of earth’s solar-heated surface warmth up and away. As clouds form, the latent heat stored in the air’s water vapor is released as that vapor condenses into liquid drops. Water vapor is the earth’s dominant greenhouse gas contributing at least half of any greenhouse warming. Vapor condensation in clouds dries the air above the clouds and reduces most of water’s greenhouse effect at those higher altitudes.

Cumulus clouds typically form at altitudes between 300 and 1500 meters. Anvil clouds (cumulonimbus) form where strong convection carries heat and moisture to the stratosphere (6000 to 20,000 meters) enabling heat to escape virtually un-impeded. Earth’s stratosphere on average is about as dense as Mars’ atmosphere. Even though 95% of Mars’ atmosphere consists of CO2, its atmosphere is not dense enough to intercept much escaping infrared. So, Mars’ night-time temperatures typically plummet by 83°C to 99° C below zero.

Anvil clouds are excellent indicators of where heat is being released unimpeded to the stratosphere. Overall, clouds can reveal where the greenhouse effect has become greatly reduced with little impact on our surface temperatures.

In addition, any decline in cloud cover not only reduces infrared heating from low-altitude clouds, fewer clouds will increase solar heating. When testing for natural contributions to global warming, most climate models only consider change in the sun’s irradiance but ignore how clouds control the intensity of solar heating, especially in the tropics. Since 1980, satellites have detected a significant drop in the percentage of cloud cover (graphic A). The warming effect of reduced clouds coincides with the hypothetical relationship between warming and rising CO2 concentrations.

Natural La Nina-like conditions have been shown to reduce cloud cover over the eastern Pacific. As seen in graphic B the eastern Pacific, most affected by La Nina conditions, is the region with the greatest flux of solar energy into the ocean. The solar heated waters are then circulated away from the equator towards the poles. The blue regions in graphic B, indicate where that heat is released. Due to this transport of heat, regions outside the tropics enjoy warmer temperatures than possible if only solar and greenhouse radiation alone is considered.

To understand why solar energy, not CO2 is heating the oceans, watch: Science of Solar Ponds Challenges the Climate Crisis

Lastly, that scientists report the Pacific Ocean shifted from El Nino-like conditions with more cloud cover during the Little Ice Age, to the dominance of La Nina-like conditions and reduced cloud cover in the eastern Pacific over the past 150 years. So it should be no surprise that oceans have absorbed more solar heat resulting in a warmer earth .