However, critics argue that the 21-year averaging of temperature will always give a straight line of sorts, but to simulate deep warming from surface variations, by long-term averaging is entirely proper.
Note that a rise of 0.1 ºC corresponds to an increase of about 15ppmv in the atmosphere (150ppmv per ºC ~ 300Gt/ ºC carbon. Cumulative anthropogenic emission over the industrial age is estimated at about 140ppmv over two centuries, which is about the same as an ocean warming of 1 ºC.
Ocean acidification has become a major scare in the scientific literature and the media.
This chapter shows what is known about carbon dioxide in the oceans in order to understand how ocean acidification works and what effects it could cause.
The 'Keeling curve' from Mauna Loa may eventually dip again.
Compare this with 700Gt C in the atmosphere and 1170Gt C in the biosphere as mentioned above.Thus the oceans, while warming, do not absorb the extra CO2 from fossil fuel, but they do recycle it. Update Aug 2011: Endersbee's curve is heavily contested mainly because he took a period in which both temperature and CO2 were rising.However when earlier data is included to 1960, the linearity distorts.[for more about where the carbon is locked up on land, look at soil54]This diagram shows the latest figures (after Holmen, 2000) with residence times and today's atmospheric carbon at 700Gt.The land has been split in two compartments and the oceans in three.