Some good questions from Alan Nicholl

This letter is one in a series of interchanges between Alan Nicholl and AGW believer Bob Hughes who have been battling it out in the Gisborne Herald for some weeks now. Alan poses some good questions:

Bob Hughes in his column on 15th January states “a half truth is a lie”.
How true.

Unfortunately for Bob when one considers the climate history
of the last 5,000 years the amount of truth he adheres to, amounts to
about 3% of this time span. Even then the whole truth of this 3% (150
years) time span is never spoken about.

Nick Smith made much of a supposed .9 degree centigrade increase in NZ temperatures over the last century. What he failed to mention was that from 1850 till 1900 temperatures fell up to .5 degree centigrade.

Couple this with a study undertaken by the Climate Coalition, of NIWA’s official temperature record, from which this figure was taken, we find that many of the
meteorological sites recorded falling temperatures over the last
century. Not increasing temperatures. NIWA had to alter them to get an
increasing trend. Where’s the truth in this?

In the interest of truth can Bob Hughes or anyone else, who believes
human produced CO2 is causing global warming, answer the following
questions:
 

Scientific studies of ice cores, sediment cores from seabeds and lakes
show a fluctuating climate with numerous warm and cool periods. Written
historical records confirm this.

What caused these temperature changes?

Can they explain why the Minoan, Roman and Medieval warm periods were
warmer than the late 20th century warming?                                                       Along with this theme the late 20th century warming was similar to the cool period between the Minoan and Roman warm periods:  why was this?

What caused the little ice age which ended in the early 1800's?               

Also, what caused the planet to end the last ice age?

When one considers that the earth has already experienced warmer periods
than now over recent millennia and not only survived but prospered,
why is this warming considered to be so devastating?

On the concept of CO2 causing warming,  can they explain why scientific
studies of the effects of CO2, show that doubling or even tripling the
atmospheric concentration would account for no more than 0.1 degree
centigrade temperature increase. Yet the IPCC expect a 6 degree
centigrade increase, how come?

Can they also explain where the required increase in infrared radiation
is to come from to activate this expected temperature increase?               The sun is emitting only a certain amount of infrared light and this is unlikely
to alter much.

Why is CO2 such a villain when both CO2 and water
vapour (which accounts for 90% plus of the green house effect) are
fighting over the very limited amount of infrared light available?

If they can answer these questions, then we may just begin to shed some
light on this whole question of Climate Change. Both warming and
cooling. I somehow think that the light that would eventuate (reading
between the lines) is not the type of light the Science Media Centre
would want to see.

Alan Nicholl