Subject: BREAKING: New Study Rocks Climate Debate! 'Nature not man responsible for recent global warming' |
From: "Marc Morano-ClimateDepot.com" |
Date: Thu, 23 Jul 2009 11:21:51 -0400 |
To: "'Marc Morano-ClimateDepot.com'" |
Peer-Reviewed Study Rocks Climate
Debate! 'Nature not man responsible for recent global warming...little or none of
late 20th century warming and cooling can be attributed to humans'
'Surge
in global temps since 1977 can be attributed to a 1976 climate shift in the
Pacific Ocean'
Wednesday,
July 22, 2009 - By Marc Morano – Climate Depot
A new
peer-reviewed climate study is presenting a head on challenge to man-made
global warming claims. The study by three climate researchers appears in the
July 23, 2009 edition of Journal of Geophysical Research. (Link to Abstract)
Full Press
Release and Abstract to Study:
July 23, 2009
Nature not man
responsible for recent global warming
Three
Australasian researchers have shown that natural forces are the dominant
influence on climate, in a study just published in the highly-regarded Journal
of Geophysical Research. According to this study little or none of the late
20th century global warming and cooling can be attributed to human activity.
The research, by
Chris de Freitas, a climate scientist at the University of Auckland in New
Zealand, John McLean (Melbourne) and Bob Carter (James Cook University), finds
that the El Niño-Southern Oscillation (ENSO) is a key indicator of global
atmospheric temperatures seven months later. As an additional influence,
intermittent volcanic activity injects cooling aerosols into the atmosphere and
produces significant cooling.
"The surge
in global temperatures since 1977 can be attributed to a 1976 climate shift in
the Pacific Ocean that made warming El Niño conditions more likely than they
were over the previous 30 years and cooling La Niña conditions less
likely"
says corresponding author de Freitas.
"We have
shown that internal global climate-system variability accounts for at least 80%
of the observed global climate variation over the past half-century. It may even be
more if the period of influence of major volcanoes can be more clearly
identified and the corresponding data excluded from the analysis.”
Climate
researchers have long been aware that ENSO events influence global temperature,
for example causing a high temperature spike in 1998 and a subsequent fall as
conditions moved to La Niña. It is also well known that volcanic activity has a
cooling influence, and as is well documented by the effects of the 1991 Mount
Pinatubo volcanic eruption.
The new paper
draws these two strands of climate control together and shows, by demonstrating
a strong relationship between the Southern Oscillation and lower-atmospheric
temperature, that ENSO has been a major temperature influence since continuous
measurement of lower-atmospheric temperature first began in 1958.
According to the
three researchers, ENSO-related warming during El Niño conditions is caused by
a stronger Hadley Cell circulation moving warm tropical air into the
mid-latitudes. During La Niña conditions the Pacific Ocean is cooler and the Walker
circulation, west to east in the upper atmosphere along the equator, dominates.
"When
climate models failed to retrospectively produce the temperatures since 1950
the modellers added some estimated influences of carbon dioxide to make up the
shortfall,"
says McLean.
"The IPCC
acknowledges in its 4th Assessment Report that ENSO conditions cannot be
predicted more than about 12 months ahead, so the output of climate models that
could not predict ENSO conditions were being compared to temperatures during a
period that was dominated by those influences. It's no wonder that model
outputs have been so inaccurate, and it is clear that future modelling must
incorporate the ENSO effect if it is to be meaningful."
Bob Carter, one
of four scientists who has recently questioned the justification for the
proposed Australian emissions trading scheme, says that this paper has
significant consequences for public climate policy.
"The close
relationship between ENSO and global temperature, as described in the paper,
leaves little room for any warming driven by human carbon dioxide emissions.
The available data indicate that future global temperatures will continue to
change primarily in response to ENSO cycling, volcanic activity and solar
changes.”
“Our paper
confirms what many scientists already know: which is that no scientific
justification exists for emissions regulation, and that, irrespective of the
severity of the cuts proposed, ETS will exert no measurable effect on future
climate.”
--
McLean, J. D.,
C. R. de Freitas, and R. M. Carter (2009), Influence of the Southern
Oscillation on tropospheric temperature, Journal of Geophysical Research, 114,
D14104, doi:10.1029/2008JD011637.
This figure from
the McLean et al (2009) research shows that mean monthly global temperature
(MSU GTTA) corresponds in general terms with the Southern Oscillation Index
(SOI) of seven months earlier. The SOI is a rough indicator of general
atmospheric circulation and thus global climate change. The possible influence
of the Rabaul volcanic eruption is shown.
Excerpted
Abstract of the Paper appearing in the Journal of Geophysical Research:
Time series for
the Southern Oscillation Index (SOI) and global tropospheric temperature
anomalies (GTTA) are compared for the 1958−2008 period. GTTA are represented by
data from satellite microwave sensing units (MSU) for the period 1980–2008 and
from radiosondes (RATPAC) for 1958–2008. After the removal from the data set of
short periods of temperature perturbation that relate to near-equator volcanic
eruption, we use derivatives to document the presence of a 5- to 7-month
delayed close relationship between SOI and GTTA. Change in SOI accounts for 72%
of the variance in GTTA for the 29-year-long MSU record and 68% of the variance
in GTTA for the longer 50-year RATPAC record. Because El Niño−Southern
Oscillation is known to exercise a particularly strong influence in the
tropics, we also compared the SOI with tropical temperature anomalies between
20°S and 20°N. The results showed that SOI accounted for 81% of the variance in
tropospheric temperature anomalies in the tropics. Overall the results suggest
that the Southern Oscillation exercises a consistently dominant influence on
mean global temperature, with a maximum effect in the tropics, except for
periods when equatorial volcanism causes ad hoc cooling. That mean global
tropospheric temperature has for the last 50 years fallen and risen in close
accord with the SOI of 5–7 months earlier shows the potential of natural
forcing mechanisms to account for most of the temperature variation.
Received 16
December 2008; accepted 14 May 2009; published 23 July 2009. [End Abstract
Excerpt]
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