In reply to Webster:
> and much of central and southern europe has been in the grips of a serious heatwave all month...
Indeed - we've been out in France the last couple of weeks and the first week was stiflingly hot - an unopened bottle of wine left in the shade broke the seal and pushed the cork part way out due to the heat expanding the contents. A French newspaper was talking about the "desertification of the south".
When global warming was first raised as a concern in the late 1980s, one of the predictions was that the UK/NW Europe would have both more extreme weather and"unseasonable" weather. Guess what we've been having? One other possibility raised was that increased melt of the west Greenland ice sheet would increase the cooling effect of the Labrador current on the Gulf Stream which could send NW Europe in to a new ice age despite rising temperatures elsewhere.
It's not just one indicator of rising global temperatures on which scientists base the concept of global warming but several independent ones all of which are in close correlation.