On May 23, 3:08*pm, The Natural Philosopher
wrote:
On 23/05/13 14:33, John Williamson wrote: Simon Brown wrote:

*
* "harry" wrote in message
* The other factor of course being global warming which will
* disprupt agriculture however it manifests itself.
*
* With relatively cold places like Britain, it may well be a good
* thing for agriculture if it actually does produce some warming.
*
* The global warming theory says that while the average global
* temperature will increase, local effects will often differ greatly.
* For instance, if the Arctic ice melts enough, the North Atlantic
* conveyor current may well slow down or stop, reducing the amount of
* heat it brings North. This will give the UK colder winters and,
* probably, wetter Summers.

And cause the arctic ice to reform...that's the bit they always leave
off, isn't it?

Or maybe, hotter, drier Summers. The
* increase in CO2 is likely to have more effect on crop growth than any
* temperature changes here.
*
Anything is possible of course if you cherry pick ideas that suit a
preconceived agenda.

http://www.youtube.com/watch?v=cdxaxJNs15s

Hah. You need to read this.
http://en.wikipedia.org/wiki/Oceanic_anoxic_event