Thanks for your respectful words, Kieran.

The much-maligned computer modelers definitely include solar forcings in their models; it's unfair to say they don't look beyond the troposphere. It is accepted on both sides of this "fence" that the largest driver for warming from 1890-1940 was solar forcing.

Less convincing is the hypothesis (presented rather badly by Durkin) that solar activity is the driver behind *all* recent climactic change.

It is not disputed that human activity adds greenhouse gases to the atmosphere. It is not even disputed that increasing them will raise the temperature; the only thing even questioned is how much.

The preachers of complacency would have us believe that adding carbon dioxide to the atmosphere causes a mild effect which will level off logarithmically as concentrations increase, and suggest that the combined effect of different greenhouse gases is less than the sum of the effects, because of the saturation of certain frequency bands.

While it is true that some bands absorbed by water vapour are saturated on humid days at sea level, it is never the case that adding more of a greenhouse gas can have no additional effect, because in the troposphere pressures are low enough that there is no saturation. Warmth from the ground will be absorbed nearer to the surface than it is now. The absorbtion bands are also far narrower than they appear on most graphs.

Chaotic feedbacks make impossible to make firm predictions. The obvious, non-chaotic feedback of humidity may or may not be balanced by the highly-chaotic clouds (which have a greater warming effect at night than cooling by day, unless they are low). Even less predictable is the potentially very large feedback of additional methane.

If climate changes in past centuries did closely track solar activity, that makes it all the more alarming that the world has continued to warm rapidly through the last three decades as solar activity has fallen off: what was just an idea from 1880-1950, and merely a solid theory until the late 1980s, is confirmed.

Xoddam I keep returning to this examination of the question ... "how high carbon dioxide in the past has never prevented subsequent cooling". Perhaps for many people I will be perceived as a bit thick and somewhat complacent when persisting with the thought that the principal driver of the climate on earth is solar, driving all the other processes as effects although recognising the exception of minimal human emissions. (A pleasant way to gain some perspective is to zoom around the earth at a reasonable altitude using google earth and then begin to learn our true place by figuring out how to cope rationally with scales and inevitable change.)

Of course many people can have some concerns based on what you say here .... "If climate changes in past centuries did closely track solar activity, that makes it all the more alarming that the world has continued to warm rapidly through the last three decades as solar activity has fallen off: what was just an idea from 1880-1950, and merely a solid theory until the late 1980s, is confirmed."

But my thoughts on this would not yet be so alarmist because for one major reason ..... our earth and atmosphere are simply not expected to be in thermodynamic equilibrium with sunnyboy. This longer time frame to adapt, points more to a stronger cooling effect when it does happen. To put it another way, (cheeky me), we could be right now in a sharply cooling phase were it not for increased greenhouse gases due to solar and minimally to human input. We may also then exclaim thank goodness for that.