The Weather Makers

Where Next?
Bob Williams
Tue 28 Aug 2007 19:46
Position: 46 41.8 N 060 16.0 W
Course 200 Speed 3 knots
Wind SE 10 knots

Yesterday evening as we came in behind the shelter of Cape Breton the wind
left us so we stopped short of the entrance to the Bras D'or Lakes, choosing
to anchor for the night at Ingonish Bay. This morning we got off to a late
start and are now making slow time towards the lakes' entrance.

I have finished reading Tim Flannery's book, "The Weather Makers".
Unfortunately I found it to be a bit of a doomsayer's book painting a very
dark picture with a lot of conjecture of what might happen in the worse case
then treating it as a probable scenario. Again Fred Singer's book,
"Unstoppable Global Warming" appears more factual based; however "Climate
Change and the Greenhouse Effect. A briefing from the Hadley Centre.
December 2005", is by far the most comprehensive and objective document
while remaining entirely accessible to anyone of average intelligence that I
have found thus far. This document rebuts much but not all of what Fred
Singer's book has to say about climate change and out of the two I think the
Hadley Centre's document is far more credible. A flaw for non-UK readers is
that it has a strong UK focus (which is entirely reasonable seeing as it is
funded by the UK taxpayer).

Here are some key quotes from this document:

"Although the Earth's temperature has varied considerably over the last
1,000 years for natural reasons, the rise over the next 100 years due to
human activities is predicted to be very much larger than natural
variability, even with the lowest projected man-made emissions."

Re sea level rise predictions:
"Other models show different estimates for the components and for the total,
indicating the need to improve descriptions of all the included processes,
and the inclusion of additional ones such as permafrost melt and man-made
storage in reservoirs."

"The biggest uncertainty in climate predictions arises because climate
models are imperfect representations of the climate system. Clouds, for
example, have a great effect on climate. Low clouds reflect sunlight but
have little effect on the escape of infrared radiation, so they have a
cooling effect on climate. High clouds, on the other hand, trap infrared
radiation but do not reflect much sunlight; they have a warming influence.
The net effect in the present day is an overall cooling effect.
However, changes to the characteristics of clouds - their amount, height,
thickness or the size of their water droplets or ice crystals - can
drastically alter their climate properties, and hence could change the
cooling effect into a warming one. This would be a positive feedback on
climate from clouds. Many other processes in the climate system will change,
and cause similar feedbacks, positive or negative. Because different climate
models represent processes in different ways, the feedbacks from these
processes will be different, and this is the main reason why climate models
give different predictions for the future."

"The reduction in uncertainty in predictions is unlikely to be rapid,
depending as it does on hard won improvements in our understanding of how
the climate system works. Planners therefore wish to move away from the
current situation of having a large number of different predictions of
unknown credibility, to a situation where the probability of
different outcomes (for example, percentage changes in summer rainfall) is
known .... They can then use these probabilistic predictions in risk
assessments, to decide on the optimum adaptation strategy. Recognising that
models give different predictions because they use different representations
of the climate system, we are approaching this problem in the Hadley Centre
by building large numbers of climate models, each having different but
plausible representations of climate processes; so-called 'physics

"...whilst we cannot absolutely exclude natural variability as the cause of
warming over the past few decades, and it may have played some role, it is
very unlikely that this will have been the sole reason. Our best estimate is
that most recent warming is due to man's activities."

If you have followed me thus far I think we have to acknowledge that perhaps
this does not meet Singer's demand for certainty but it sure looks like a
very credible attempt to answer the first question honestly: Are greenhouse
gases certain to raise global temperatures significantly higher than they
rose during previous natural climate warming cycles? And in case I have
obscured the issue in my attempt to be objective I will refresh you with
probably the most important conclusion which was the first quote, namely:

"Although the Earth's temperature has varied considerably over the last
1,000 years for natural reasons, the rise over the next 100 years due to
human activities is predicted to be very much larger than natural
variability, even with the lowest projected man-made emissions."

The Hadley Centre's research does not try to predict what the climate change
will mean for human welfare, this they acknowledge is not their remit. So
we need to go elsewhere to answer the Singer's second demand that global
warming advocates must demonstrate that warming would severely harm human
welfare and the ecology. Flannery's book attempts to do this but not to my
entire satisfaction.

Again from the Hadley document:

"Q19: What will the impacts be of man-made global warming?
The impacts of climate change on society and economies will be many and
various, in sectors such as agriculture, water resources, ecosystems,
health, coastal communities, etc. It is too broad a topic to be covered in
this Q&A section, but is comprehensively addressed in the report from
Working Group 2 of the IPCC TAR, which also contains a shorter Technical
Summary and Summary for Policymakers. Recent UK research on the global
impacts can be seen in the April 2004 special edition of the journal Global
Environmental Change, edited by M. Parry."

The quest continues.

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