Tim the Plumber wrote:
1 English vinyards have begun to spring up in places where the Romans had them since we have had warm climate recently and also (I expect) we have more hardy varieties now. The point is that the present climate's warmth is not hotter than the Roman period.
In England in the last 50 years or so? We know that localized cliamate varaiations impact the globe to some degree, but do not indicate a global problem or lack thereof without the global evidence. Where is the supporting evidence that 50 years of grape production means the temperature is "not hotter" than the Roman period?
2 My point about the temperature data being corrected is that it seems there are some questions as to the degree of reliability of such data sets. The degree to which they agree with the origional "Hockey stick" data from tree rings seems to be in proportion to the degree of correcting they have undergone. I accept that it has got warmer. The first question is the degree and if this is exceptional.
The tree ring data was adjusted to merge with the instrumental data where is became available. Why would one use a proxy where actual measurements were available? Since there was no similar adjustment to the decades prior the degree of change and the exceptional nature should be self evident from the graph.
The second question is; is this a problem?
Only to those seeking to maintain the status quo and anything they can use to delay action will become a "problem".
The third is; to what degree is it going to continue to warm and will it cause a net problem?
That is where there is an uncertainty. The answer is a strong probability of the warming continuing and beign a net problem.
Fourthly; What is the cost of trying to avoid it?
Compared to the cost of not mitigating or just the single view?
Personally I see no significat trouble coming from a slightly warmer world and a lot of benifits from increased rainfall and fertility.
Personally, I doubt your expertise in making such a determination would carry any weight with anyone other than yourself and someone who wishes to believe as you do. The rest of us would look to the experts in the field for their professional opinions.