It can be hard to know which is the most important factor in determining the world’s climate; clearly ocean and air oscillations are important, the amount of water vapour in the atmosphere is important, as is the amount of variable radiation received from the sun. However, which is the primal factor which drives all others, or is there no single important factor. The climate could simple be a chicken and egg situation, and it matters not which came first.
It is possible that we are closer to understanding that there is a single driving factor which changes the climate of our planet and that factor is the amount of atmospheric carbon dioxide.
Looking at the relationship between sea levels and the amount of atmospheric carbon dioxide gives us a clue. It seems that global sea level is largely determined by the volume of ice stored on land. The more ice, the lower the sea levels and the lower the atmospheric carbon dioxide the more ice is stored on land. This seems to imply that high levels of atmospheric carbon dioxide lead to lower levels of ice stored on land, over long periods of time.
This what Gavin L. Foster and Eelco J. Rohling have found, by looking at the relationship between atmospheric carbon dioxide and sea levels on geological time scales.
The research is not conclusive, but is a strong indication that atmospheric carbon dioxide plays a major role in determining the earth’s climate, because if the conclusions drawn from the research are correct, then it seems that the egg of carbon dioxide comes first and gives birth to the chicken of ocean and air oscillations which also affect climate conditions.
Messrs Foster and Rohling have described the probability of their research being right as 68%. They have inferred that at present levels of atmospheric carbon dioxide the long term effect on sea levels by melting ice (long term being over several centuries) is quite drastic. Sea levels will rise by nine metres. To avoid this, they deduce, we have to reduce atmospheric carbon dioxide to pre-industrial levels of about 250 parts per million, instead of the present 393 parts per million. (I have used the November 2012 readings from Mona Loa – other parts of the world have higher atmospheric carbon dioxide levels).
Filed under: carbon emissions, climate change, global warming | Tagged: atmospheric carbon dioxide, chicken and egg, climate, climate conditions, environment, global sea level, melting ice, Mona Loa, Mona Lua, Rohling & Foster, science, sea levels, stored ice on land |