This is interesting. Reductions in the temperature of the lower stratosphere have hitherto been assumed to be a result of the ‘thickening’ of the troposphere by the increase in carbon dioxide, leading to increased absorption of surface emitted long-wave radiation and thus ‘global warming’. Now Susan Solomon, IPCC lead author seems to be introducing strong uncertainty into the issue. Extreme Ultra Violet light from the Sun is known to destroy ozone. EUV was at a long term peak while the Sun was highly active in the late C20th. This appears to raise the possibility that as well as being at least partly (possibly mainly) responsible for the ‘ozone hole’ which developed over the poles, more of the incoming solar radiation was reaching the surface due to this effect, thus contributing to late C20th warming.
Uncertainties in the evolution of stratospheric ozone and implications for recent temperature changes in the tropical lower stratosphere
- Susan Solomon
- Paul J. Young
- Birgit Hassler
|Journal publication date||14/09/2012|
|Journal||Geophysical Research Letters|
|Number of pages||4|
Three different ozone databases provide regression fits to the ozone observations, and are available for use in model studies of the influence of ozone changes on stratospheric and tropospheric temperatures. Differences between these ozone databases suggest that the estimated decreases of tropical lower stratospheric ozone in recent decades are uncertain by about a factor of two to three. The uncertainties in ozone decreases lead to similar uncertainties in cooling of the tropical lower stratosphere, a key area of focus in climate change studies.
I’ll add more detail from the paper later.