http://www.thegwpf.org/content/uploads/2014/02/Oversensitive-How-The-IPCC-hid-the-Good-News-on-Global-Warming.pdf
it has become more and more clear over the last decade that the high feedback/high sensitivity numbers being proclaimed by many climate scientists are out of alignment with reality. it is this exaggeration that changes the relatively benign warming that we have been experiencing into the catastrophic anthropogenic global warming boogieman that we have been bombarded with for more than 25 years.
last fall I stated that I thought the IPCC would just ignore the new data and stay the course. they actually were more clever than that. they just buried the evidence and pretended that it wasnt worth mentioning, and didnt bother to rework their 'projections' with best estimates. that gives them plausible deniability. plausible deniability is also the reason why the leadership of large scientific organizations come out so strongly in defence of CAGW even though their membership has decidedly less confidence in the 'concensus'. it is much easier to survive a pessimistic prediction that doesnt happen than an optimistic one that turns out badly. the risk has been massively overstated, and the insurance policy we are being asked to buy is monsterously more expensive than even the exaggerated outcomes would be.
Climate sensitivity is an estimate of howmuch globalwarmingwill result from
a doubling of carbon dioxide concentrations, and is a key measure in the climate
policy debate.
Previously scientists have estimated climate sensitivitymainly fromcomputer
model simulations of the climate system. For the last two generations ofmodels,
the value for long-termwarming has averaged 3.2◦C per doubling. Due to
the moderating effect of the ocean, such warming takes many centuries to
be fully realised. Over a seventy year period – relevant to warming in the second
half of this century – duringwhich carbon dioxide concentrations double,
computer climate models show an average temperature rise of around 2◦C.
With these values the totalwarmingwill cross the iconic two degrees limit later
this century – perhaps in only about thirty years under the highest emissions
scenario.
Only in recent years has it become possible tomake good empirical estimates
of climate sensitivity from observational data such as temperature and ocean
heat records. These estimates, published in leading scientific journals, point
to climate sensitivity per doubling most likely being under 2◦C for long-term
warming, and under 1.5◦C over a seventy-year period. This strongly suggests
that climate models display too much sensitivity to carbon dioxide concentrations
and in almost all cases exaggerate the likely path of global warming.
Although these new results are reported in the body of the recently-published
Fifth Assessment Report of the Intergovernmental Panel on Climate Change
(IPCC), their impact is notmade clear and few readers of the report would learn
of them.
it has become more and more clear over the last decade that the high feedback/high sensitivity numbers being proclaimed by many climate scientists are out of alignment with reality. it is this exaggeration that changes the relatively benign warming that we have been experiencing into the catastrophic anthropogenic global warming boogieman that we have been bombarded with for more than 25 years.
last fall I stated that I thought the IPCC would just ignore the new data and stay the course. they actually were more clever than that. they just buried the evidence and pretended that it wasnt worth mentioning, and didnt bother to rework their 'projections' with best estimates. that gives them plausible deniability. plausible deniability is also the reason why the leadership of large scientific organizations come out so strongly in defence of CAGW even though their membership has decidedly less confidence in the 'concensus'. it is much easier to survive a pessimistic prediction that doesnt happen than an optimistic one that turns out badly. the risk has been massively overstated, and the insurance policy we are being asked to buy is monsterously more expensive than even the exaggerated outcomes would be.