It took 2 billion years for all of the available reactive chemicals of the earth's surface, such as iron, to be oxidized to produce the sedimentary layers known as red beds. Granted, this set the stage for the development of the ozone layer, which shields us from ultraviolet light, and permitted the evolution of aerobic life, but it was very self-sacrificing on the part of the major life forms existing some 2 billion years ago. As the sun warms, rains increase. Water in the atmosphere combines with CO 2 to form a weak carbonic acid solution, and this could have weathered silicate minerals in the rocks on land. Formation of new sediments would store carbon, thus reducing its abundance in the atmosphere.
Gaian advocates fight back by arguing that soil bacteria play a role in the weathering reaction.
This is unresolved. The idea that climate and life influence one another is profoundly important. In some form or another, it has been recognized for a long time. But this is not to say that life somehow manages and self-optimizes its own environment. Influential Gaia , the weakest of the hypotheses, asserts that biota have a substantial influence over certain aspects of the abiotic world, such as temperature and the composition of the atmosphere.