On Oct 29, 8:27*am, Martin Brown
wrote:


There is no-one in the climate science community that doesn't think that
at least part of the warming in the past 150years is not due to the suns
luminosity increasing slightly. This is expected on strophysical grounds
over geological timescales output is increasing. Most practitioners
reckon that about half of all the increase is down to changes in TSI and
the rest which only became non-negligible after about 1970 is due to GHG
forcing. Even sceptical scientists admit to this since otherwise they
cannot balance the energy books for the Earth.

I am not sure if I can claim to be a member of the climate science
community, but if I am then there is at least one person who is not
convinced that the sun has contributed to the warming over the last
150 years. It seems to me that it is wishful thinking to believe that
the warming is not all due to Man, and it is quite possible that the
natural effects would have led to a cooling. Therefore, Jo Haigh's
results should not be dismissed because they do not fit within the
standard "groupspeak".

Moreover, on astrophysical grounds the climate should be cooling! The
effect of the Milankovitch cycles peaked about 10,000 years ago and
now are all leading to a cooling. See
http://en.wikipedia.org/wiki/Holocen...kovitch_cycles
(Negative years in the diagram are before present).

But as Len said in a previous post we do not yet have all the answers.
I suspect that it takes high energy photons to provide ice molecules
with enough energy to sublime. So it takes an Increase in the UV bands
of the solar spectrum to melt ice, even it the total energy from the
sun increases. The melting of ice affects the global albedo and hence
the global temperature. This fits with what Jo Haigh has found. But it
is only speculation.

Cheers, Alastair.

Regards,
Martin Brown