by Anthony Cox
The Bureau of Meteorology [BOM] has released its
report for Australian climate during 2013.
According to the BOM 2013 was the hottest year on record, in Australia.
However both satellite temperatures, RSS and UAH, and a global surface
temperature, GHCN,
all found other Australian years to be warmer:
Naturally the pro-AGW people have been all over the BOM report
claiming it as evidence for AGW, while ignoring the results from the
other equally valid sources for temperature. But even if the BOM report
is correct it is problematic whether AGW is the cause of the
temperature. It is doubtful because during 2013 and for at least a
decade the Diurnal Temperature Range [DTR] has not been decreasing but
increasing.
Given this a simple test of whether the hottest year in Australia was due to AGW would be to measure the DTR.
Ken Stewart has done this:
Since 1979 it is plain the gap between the maximum and minimum
temperature has increased. So, in fact the DTR in Australia has
increased not decreased.
Still, there is no doubt 2013 was a relatively warm year for
Australia. It was certainly warmer than the year in the Antarctic.
Professor Chris Turney and team of fellow scientists and media, and as
it turns out family members, hired a ship apparently at taxpayers'
expense and sailed to the Antarctic to
retrace Mawson's steps from 100 years ago.
There is a certain irony in an expert climate scientist being trapped
in sea ice. Despite this Professor Turney and his supporters such as
the well-known
Professor Lewandowsky have maintained the sea ice which trapped Professor Turney's boat, the
Akademik Shokalskiy, was due to AGW.
Turney
says:
-
The 120km long ice berg B09B that is grounded in Commonwealth Bay
broke away from the continent three years ago, very likely as a result
of climate change.
-
B09B collided with the Mertz Glacier, smashing a large ice tongue that released the ice into that area.
-
It was a mix of this ice that was blown across the path of the
Shokalskiy, which led to it being trapped and explains why much of the
ice surrounding the ship is old ice.
All of this incorrect. As the
Australian Antarctic Division notes:
B09B originally calved from the Ross Ice Shelf in 1987 and
drifted round to the east of Mertz Glacier by 1992. It was grounded for
many years and started moving in late 2009. - In mid-February 2010 B09B
collided with the Mertz Glacier tongue – a section of the glacier that
protruded about 100 km from the Antarctic coastline at about 145ºE. The
collision precipitated the calving of another massive iceberg, C28, from
the tongue, measuring 78 km long and between 33 and 39 km wide. This
calving event removed about 80% of the tongue, leaving only a 20 km-long
stub. The calving had been anticipated, as rifts cutting across the
tongue had been developing over many years, but the timing and collision
was not.
So the ice Turney says was from AGW in fact came from a calving event
which occurred 26 years ago. This event had been well documented but
there was no ice from this event in the area where Turney's expedition
became entrapped in ice. Unfazed Turney continues:
I believe you are probably aware of a number of papers this year
that show land ice on Antarctica is in decline and that only seasonal
sea ice has been expanding, likely due to the increase in westerly winds
and potentially because of the decrease in salinity.
This too is problematic. A
2012 NASA study by Zwally et al concluded that:
During 2003 to 2008, the mass gain of the Antarctic ice sheet
from snow accumulation exceeded the mass loss from ice discharge by 49
Gt/yr (2.5% of input), as derived from ICESat laser measurements of
elevation change.
This mass gain was notably in East Antarctic where Turney's expedition was heading.
In addition air temperature over the Antarctic has not increased since 1979:
Sea surface temperature [SST] has actually decreased during this period:
So we have sheet ice increasing, air temperature constant and SST
declining; all ingredients likely to lead to an increase in sea ice
which has been occurring for many years without any contribution from
AGW.
The 3
rd piece of AGW news of note comes from
Professor Steven Sherwood from the University of NSW Climate Change Research Centre. Sherwood's
new paper
concludes that things are worse than we thought because climate
sensitivity, the temperature reaction of the climate system to AGW, is
actually higher.
Sherwood reaches this conclusion by looking at which of his climate
models were best at modelling and predicting the mixing rate of clouds
and water in the lower atmosphere. Sherwood found that those models
which predicted the highest temperatures were best at predicting the
mixing rates.
The fallacy of this conclusion has several ingredients. Firstly even
Sherwood concedes that knowledge of clouds is lacking and is responsible
for most of the uncertainty with AGW predictions. How clouds form and
effect climate depends on much more than the mixing rates in the lower
atmosphere.
Just because Sherwood's warming models can model one aspect of cloud
behaviour doesn't mean they model well any other aspect of clouds or
climate. For instance In a critique of Sherwood's study
Michaels and Knappenberger note that Sherwood's models which predicted mixing best were worst at predicting temperature:
 |
Figure 1. Observed global average temperature evolution, 1951-2013, as compiled by the U.K's Hadley Center (black line), and the average temperature change projected by a collection of climate models used in the IPCC Fifth Assessment Report which have a climate sensitivity greater than 3.0°C (red line) and a collection of models with climate sensitivities less than 3.0°C (blue line) (climate model data source: Climate Explorer). |
This paper by Sherwood is only the latest in a long line of papers
where he has used models to prove AGW. For instance in 2008 Sherwood
produced
a paper
proving the existence of a Tropical Hot Spot [THS], an essential
prediction of AGW. In this paper, concerned that the temperature
instruments showed no THS, Sherwood repudiated the instrument data and
developed a windshear model which showed if there was windshear there
would be warming. The irony here was that the instruments which Sherwood
thought were not good enough for temperature were used by Sherwood to
establish windshear and the model predicted temperature.
Sherwood's new paper received
headline coverage,
as did the BOM report. The ice entrapment of the Turney expedition also
did but mention of the AGW purpose of the ill-fated expedition in the
media
was muted at best. Like the weather itself supporters of AGW run hot when the weather supports them and cold when it doesn't.