Global temperatures

PERHAPS the Professor Emeritus would comment on the following:

Al Gore’s DVD and book show 1998 as the warmest year in the 160 years up to 2000.

However, in 2010, both the Met Office Hadley Centre and NO & AA (National Oceanic & Atmospheric Administration, National Climatic Data Centre of the US Dept of Commerce) confirmed that 1998 after 13 years was still the warmest and a report (Sept 2011) by the NO & AA suggests that 2011 will be the 11th warmest.

So the big question is how to explain that, while the CO2 levels have continued to rise, global temperature has not.

This is where maths gets a bit heavy, ie the increase in global temperature is not directly proportional to the increase in greenhouse gas levels, it is logarithmic.

This means that subsequent CO2 molecules have less effect than the previous ones.

I checked this with Prof Bob Carter of Queensland University, Australia, and his email reply was in typical Oz “you get less warming bang for every incremental CO2 buck ...”

Dr John Etherington also confirmed this in different words. The question is, does this mean that we have reached “saturation point”? In other words has CO2 almost ceased to be a threat as a greenhouse gas.

Brian Beck,