The main point of contention in Climate discussions seems to
be between:-
(a)
those who say “When carbon-dioxide does the same
in the atmosphere as it does in a confined container in the laboratory, then
the Earth’s energy budget will be out of balance so human emissions will cause continuous
catastrophic warming. We must follow the
precautionary principle of stopping CO2 emissions.” (see links to Kiehl-Trenberth Earth
Energy Budget Diagram, free OU course, Met Office website, Oxford Univ. Course)
(b)
the more cautious attitude of “How certain are
we? How has the theory been tested? Before we ask the world to impoverish
themselves and remove cheap energy from poor people, we must be very certain
that the natural weather systems won’t handle the additional CO2.” (Prof.
Roy Spencer, Prof Linzen, Dr. Bjørn Lomborg, Dr. Richard Tol)
The vast majority of sceptics agree that:-
·
The Earth is warming
·
Carbon-dioxide can cause warming
·
Humans can alter the climate e.g. cutting down
forests leads to desertification
With controversies over:-
·
How much of the warming could be due to natural
variability?
·
How much warming could be due to human emissions
(climate sensitivity)?
·
Over what timescale?
The same facts about current warming (both measured and
visible in the Arctic, glaciers etc.) can be used to support both sides of the
argument, with theoretical folk claiming climate is the long-term trend so they
never meant to imply it would be year-on-year rather than the trend over decades. Now that we’ve had 17 years of
pause (or slowdown), the IPCC defined climate timescales are 30-50 years
and longer and the computer models can now reproduce it. It fits well with the 300 year
step-wise warming of the historical record with its’ 15-25 year ‘steps’.
Unfortunately, the catastrophic AGW theory is untested because we can’t build
a model of an unconfined atmosphere; and the computer models are not good at
predicting even though they are continually tuned to the latest data.
Plenty of calculations are done from theory & data statistics.
However, statistics based on a Time-Series such as temperature is notoriously
unreliable unless it conforms to particular conditions (e.g. ‘stationary’ or
‘ergodic’) which is not proven.
For both main-stream and sceptic opinions see
Ø
US Senate Climate Change Committee July 18, 2013 evidence
(the science testimony is by Dr Roy Spencer here)
Ø
Climate Dialogue – the Dutch Parliamentary
initiative ‘to also involve climate skeptics in future studies on climate
change’. http://www.climatedialogue.org/
Kiehl-Trenberth
Earth Energy Budget Diagram (1997)
