On 3/29/2014 10:31 AM, John Clark wrote:
In the current issue of Science News is a article about clouds and it confirms that
clouds are the single biggest unknown in climate models. Everybody agrees that clouds
warm things through the greenhouse effect at night and cool things by reflecting
sunlight during the day, and everybody agrees that the cooling effect is larger than the
heating effect, but they disagree about just how much larger and on if we will have more
clouds in the future or less. And a recently discovered fact complicates things further,
clouds made of ice crystals and water droplets reflect light about equally but the ice
crystal clouds have a stronger greenhouse effect than water clouds. As a result of all
this confusion and uncertainty are rampant.
Back in 2007 the United Nations issued a report on climate change, it said that by 2100
things would be between 2 and 4.5 degrees warmer than now, a rather large amount of
uncertainty; but after spending millions of dollars and 7 years of hard work they just
issued a new report, and their uncertainty has actually INCREASED. Now they say between
1.5 and 4.5.
Doesn't exactly comport with the theory that it's all an environmentalist
conspiracy, does it.
The article also notes somewhat apologetically (Science News is a honest magazine but
always leans toward the environmentalist view) that after 3 decades of increasing
temperatures since 1998 the worldwide temperature has been roughly constant, and no
climate model in 1998 predicted this.
But GCMs with constant net insolation energy gain still predict hiatus periods in surface
warming:
Is the climate warming or cooling?
David R. Easterling and Michael F. Wehner
Received 18 February 2009; revised 25 March 2009; accepted 30 March 2009; published 25
April 2009.
Numerous websites, blogs and articles in the media
have claimed that the climate is no longer warming, and is
now cooling. Here we show that periods of no trend or even
cooling of the globally averaged surface air temperature are
found in the last 34 years of the observed record, and in
climate model simulations of the 20th and 21st century
forced with increasing greenhouse gases. We show that the
climate over the 21st century can and likely will produce
periods of a decade or two where the globally averaged
surface air temperature shows no trend or even slight
cooling in the presence of longer-term warming.
Geophys. Res. Lett.,36, L08706,doi:10.1029/2009GL037810.
http://onlinelibrary.wiley.com.proxy.library.ucsb.edu:2048/doi/10.1029/2009GL037810/pdf
Model-based evidence of deep-ocean heat uptake during surface-temperature
hiatus periods
Gerald A. Meehl, Julie M. Arblaster, John T. Fasullo, Aixue Hu & Kevin E.
Trenberth
There have been decades, such as 2000–2009, when the observed globally averaged
surface-temperature time series shows little increase or even a slightly negative trend1
(a hiatus period). However, the observed energy imbalance at the top-of-atmosphere for
this recent decade indicates that a net energy flux into the climate system of about 1 W
m−2 (refs 2, 3) should be producing warming somewhere in the system4, 5. Here we analyse
twenty-first-century climate-model simulations that maintain a consistent radiative
imbalance at the top-of-atmosphere of about 1 W m−2 as observed for the past decade. Eight
decades with a slightly negative global mean surface-temperature trend show that the ocean
above 300 m takes up significantly less heat whereas the ocean below 300 m takes up
significantly more, compared with non-hiatus decades. The model provides a plausible
depiction of processes in the climate system causing the hiatus periods, and indicates
that a hiatus period is a relatively common climate phenomenon and may be linked to La
Niña-like conditions.
http://www.nature.com.proxy.library.ucsb.edu:2048/nclimate/journal/v1/n7/pdf/nclimate1229.pdf
Brent
They conclude by saying "scientists say they need at least 20 to 30 years to determine
if clouds respond to global warming the way simulations predict".
I have to say all this doesn't exactly give me confidence that I should bet my life on
the fact that although they make lousy 17 year predictions climate models make wonderful
100 year predictions.
John K Clark
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