Man at B&Q wrote:
What's different about AGW?
The huge amount of compelling evidence.
I would call it circumstantial, rather than compelling.
It is compelling enough to have persuaded most governments to take AGW
seriously. (Even China).
For there to have been no AGW you would have to accept either that
mankind had nothing to do with the 50% increase in CO2 concentrations or
that CO2 is not a greenhouse gas.
CO2 is a greenhouse gas, lets put that one to bed.
I don't think TMH has any intention of letting us.
So it reduces to "For there to have been no AGW you would have to
accept that mankind had nothing to do with the 50% increase in CO2
concentrations"
Why? Of course mankind is responsible for CO2, along with many other
emissions. You're making assumptions about the effect of CO2,
specifically that the measured increase is directly responsible for
any warming.
If the increase is not responsible for some warming then you are back to
the assumption that CO2 is not a greenhouse gas (or the deceitful
scientists are making it all up).
How long have accurate CO2 measurements been taken?
Judging but the last link below, since 1957.
How reliable is the proxy data for historic CO2 levels?
I haven't come across anything that suggests it is unreliable other than
a suggestion that nothing can be pinned down to a single year because
ice melt can effect adjacent layers.
Having written the above I thought I had better check and came across this:
http://climatescience.blogspot.com/2...deception.html
Mainstream science seems to find the ice core data reliable unlike the
very variable data from the early years of CO2 sampling. For obvious
reasons the sceptics have fastened on to the historic test results.
http://www.anenglishmanscastle.com/archives/003893.html
Tree ring data is apparently considerably more suspect. IIUC that leaked
e-mail about adding in the real temperatures relates to a problem trying
to match the proxy (or should that be poxy) data for the very recent
past to the real temperature which is known for sure.