At one time the entire earth enjoyed a warm tropical environment and there was enhanced oxygen in the atmosphere

There is evidence that the atmosphere enveloping the early earth was very different than it is today. It seems that at one time the entire earth enjoyed a warm tropical environment and there was enhanced oxygen in the atmosphere. Organisms would have grown larger than their modern counterparts and could also have lived longer. For example, massive fossilized trees in the Florissant Fossil Beds National Monument of Colorado appear to be much older than their tree rings would indicate they actually were (Oard, Michael, “The Florissant Redwood Trees Deposited from a Flood Log Mat,” Journal of Creation, 2019, p. 91.)

Many creationists have attributed this special primeval atmosphere to a water vapor canopy that was created by God on the second day, the “waters above the firmament” (Genesis 1:7). This theory holds that a “vast blanket of invisible water vapor, translucent to the light of the stars but productive of a marvelous greenhouse effect which maintained mild temperatures from pole to pole, thus preventing air-mass circulation and the resultant rainfall (Genesis 2:5). It would certainly have had the further effect of efficiently filtering harmful radiation from space, markedly reducing the rate of somatic mutations in living cells, and, as a consequence, drastically decreasing the rate of aging and death.” (Morris, Henry, Scientific Creationism, 1984, p. 211.) Citing evidence of denser atmosphere in the past, Morris postulated that this vapor layer could have dramatically increased the atmospheric pressure on the surface of the early earth, again contributing to a healthier environment (like a natural hyperbaric chamber). Later the canopy would have collapsed in the form of rain (the “windows of heaven” in Genesis 7:11), contributing to the Flood water, and resulting in the dramatic drop-off in longevity after the deluge.

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