In the debate over whether or not global warming is caused by an increase in atmospheric CO2, has anyone ever suggested that the reverse could be true, i.e., that global warming may lead to an increase in atmospheric CO2 concentration?
Submitted by: John Jednacz, Bixby, OK
Answer:
Yes, this idea has been put forward several times in a couple of different contexts. First, water can hold more dissolved CO2 when it is colder, so an increase in temperature would initiate an impetus for some of it to come out of solution and move into the atmosphere. Much of the large swings in atmospheric CO2 concentration between glacial and interglacial conditions may, in fact, be due to this phenomenon. Second, when temperatures rise, so too do rates of plant and microbial respiration, which also releases CO2 to the air.
Still, it's much like the proverbial "chicken and egg" conundrum (which came first?); for there are clearly some situations where CO2 is the prime determinant of temperature, as, for example, on waterless and lifeless Mars and Venus. In other cases, however, such as those described above, the opposite is true. As for which tendency currently prevails on earth, that has been the chief environmental question of the past few decades; and it will likely spill over into the new millennium before an answer that is satisfactory to all concerned is achieved.