Whitefang wrote:Hey, according to 2010 models, the Ozone were set to recover this century:
So it seems that they just play dumb and ignorant on the methane issue, this JF Lamarque wrote a paper on PT Boundary Ozone collapse and even one on methane concentration and changes, a major cause of extinction.....
It helps to know something about the field before attacking scientists as being clueless. The vortex interior ozone loss is due to the PSC processing with existing levels of chlorine (from CFCs). Chlorine is the primary agent of ozone loss and it is activated on polar stratospheric cloud (PSC) particulates (nitric acid trihydrate (NAT) above 196 K, super-saturated ternary solutions (STS) between 188-196 K and ice for colder temperatures) through the release of Cl from reservoir species such as HCl and ClONO2 into active forms, Cl, ClO and Cl2O2 (
http://www.atmos-chem-phys-discuss.net/ ... 1-2010.pdf).
ESAS CH4 will affect ozone only when there are much higher concentrations than the current 1.8 ppmv. CH4 decomposes into CO2 and H2O in the stratosphere through both photolysis and reactions with OH. Only H2O can play a role under the right temperature conditions when the total PSC volume can be increased. Ozone cares primarily about chlorine and sulfate aerosols (these affect ozone at typical stratospheric temperatures and are the seeds for PSCs at low temperature). So geo-engineering schemes that plan to pump over 10 million tons of SO2 into the stratosphere every year will really act to destroy the ozone layer.
The conditions in the winter of 2010/2011 in the Arctic were a strong polar vortex with cold interior temperatures. This had two distinct effects on ozone loss:
1) Dynamical isolation of the polar vortex interior from mixing of mid-latitude air into the polar region. This is the same effect as with the Antarctic ozone hole. The reason why the Antarctic ozone hole has been a regular feature is that the Antarctic polar vortex is climatologically more intense than the Arctic vortex due to differences in the Rossby wave driving in the two hemispheres: there is less land mass in the southern hemisphere so the both the amplitude and spectrum of these waves is different.
2) Polar stratospheric cloud formation due to cold temperatures. The Arctic vortex is typically more disturbed and the amount of dynamical heating (think adiabatic descent of air parcels) is too high for all but some NAT formation. STS and ice are more effective surfaces for heterogenous chlorine chemistry.
The Montreal Protocol has been effective at reducing total chlorine in the stratosphere. There is already evidence of global total ozone recovery and as the chlorine keeps dropping so will the ozone continue to increase. This does not preclude PSC mediated ozone loss developing at high latitudes even when the total ozone column in mid-latitudes will be higher than in 1960. The chemistry climate models predict an ozone recovery together with sporadic PSC induced reductions of ozone at polar latitudes primarily in the southern hemisphere.
What is silly about all the chatter about ESAS CH4 is that there is no evidence of any significant increase in the last year. Read all the posts about 3.5 Gt/year emissions last year which were claimed. The widely accepted and confirmed by observations CH4 source figure is 600 Mt/year. Where is the evidence for a six-fold increase? Given the 10+ year lifetime of CH4 it should have worked itself from the ESAS to New York, London and Tokyo after less than half a year and to Cape Town by now. There is nothing to indicate any such trend from the global CH4 (and other trace gases) monitoring network.