From	Ian Harris (Harry)	Date	Mon, 2 Jul 2001 10:24:05 +0100
To	list@norwichgreenparty.org
Subject	Re: [ngp-list] Press Release 'Global Warning' talk establishes West Norfolk Green Party
*sigh* At 9:43 am +0100 2/7/01, Williams, Derek wrote: >No, it's very dangerous to make predictions like this and IMO doesn't >help the cause. Even without human activities, natural things like big >volcanoes can easily disrupt the climate in such a way as to swamp the >signs of global warming and indeed produce severe weather conditions as >a casual glance at met records for the past couple of hundred years >quickly shows (frozen Thames etc) > >One example of how this could work: A big volcanoe errupting a massive ~~~~~~~~ hello Dan :-) >amount of ash could change the albedo of the earth by enough to counter >the warming effect of the increased CO2 (albedo - and sorry if the >selling is wrong - measures the reflectivity of the earth, more smoke in ~~~~~~~ *grin* >the atmoshere reflects more radiation back to space). Cutting the >forrests down has the same effect, both because of the smoke from the >burning trees and the resulting cleared ground, which is why on photos >of building sites the bare earth looks white. > >Over simplification does no-one any good. You're hardly any better, Derek: this is hardly a 'Nature' paper, is it? You're talking about volcanic events that have a very different duration than the warming effects we're talking about. Major eruptions show up very clearly in the tree ring records going back centuries, but that's because you can pick out a one-to-three year spike rather than a prolonged cooling effect. A rudimentary understanding of albedo is all very well, but since the radiative heat input from the Sun is still poorly understood (surprisingly) we can't deduce too much. In any case relying on mass deforestation or a prolonged series of major volcanic eruptions is hardly an attractive alternative to giving up burning what are finite resources anyway. Have a look at http://www.cru.uea.ac.uk/ - particularly http://www.cru.uea.ac.uk:80/cru/info/warming/. We're looking at an *unprecedented* acceleration in temperature, and it's not due to a sudden lack of volvanic eruptions. Even if it turns out to be naturally-occurring, who's willing to take that chance? We should be trying to wean ourselves off of unsustainable energy generation and use anyway. Cheers Harry -- Ian Harris - "Harry" Telephone: +44 1603 593818 Climatic Research Unit Email: i.harris@uea.ac.uk University of East Anglia Norwich NR4 7TJ The content of this email should not be construed to represent the views of the Climatic Research Unit as a whole, nor of any other member of the Unit. If in doubt, please seek clarification before attribution.