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.”
Sea Level Rise: An Update Shows a Slowdown
the more folks study the issue, the more support builds for modest sea level rise—something on the order or a foot or two by century’s end—an amount ten times less than alarmist forecasts.AGW = BS.Here’s evidence.
In 2007, Simon Holgate of the U.K.’s Proudman Oceanographic Laboratory produced a history of global sea levels rise from 1904 to 2003 based upon a set of reliable, long-term observations from 9 tide gauge stations scattered around the world. The overall average rate of sea level rise in Holgate’s study period was found to be 1.74 ± 0.16mm/yr (about 0.07 in/yr, or 7 inches per century). In addition, he made two other notable findings, 1) the rate of sea level rise was, on average, greater in the first half of his record than the second, and 2) that there is a large degree of decadal variability in the rate of sea level rise. Figure 1 illustrates the latter of these findings. The blue curve is the rate of sea level rise during overlapping 10-yr periods as derived from his 9-station long-term record, and the magenta curve is the same quantity derived from a more globally complete 177 tide gauge network covering the period 1948-2002. Notice that the decadal rate of sea level rise fluctuates semi-regularly from rates exceeding 4 mm/yr to rates that are sometimes even less than zero (i.e. falling sea levels).
Figure 1. Decadal rate of global sea level rise as determined from a 9-station tide gauge network for the period 1904-2003 (blue curve) and from a 177-station tide gauge network for the period 1948-2002 (magenta curve) (Holgate, 2007).Now keep in mind that for that for the sea level to rise 10 feet above current levels by the year 2100, it needs to get going. Across the remaining 91 years between now and then, the rise in global sea level needs to average about 1.32 inches per year (33.5mm/yr)—about 20 times the average rate of rise during the 20th century. Even to get a three-foot rise by 2100 would require the average rate of sea level rise to be about 0.4 inches/yr (10 mm/yr)—about 5-6 times that 20th century average.
Are there any signs that sea level rise is speeding up?
Hardly.
There are, of course, claims that the rate of sea level rise is accelerating. These largely come about because sea level rise estimates made by satellites (over the past decade and a half) average about 3.1 mm/yr (0.12 in/yr) (Figure 2) compared with sea level rise estimates derived from tide gauges which average only about 1.8 mm/yr (0.07 in/yr). However, as mentioned, satellites have only been measuring sea level since about 1993, while the tide gauge history, as shown by Holgate, can be extended back to at least the early 20th century. Therefore, comparing the short-term trend from satellites to a long-term trend from tide gauges is hardly a robust comparison given the large degree of short-term variability as shown by Holgate (Figure1).
Figure 2. Sea level history as recorded by satellite-borne instrumentation, 1993-present (source: http://sealevel.colorado.edu/).The veracity of this satellite/tide-gauge comparison, or rather lack thereof, has not been lost on everybody. The IPCC (AR4, p. 5) cautioned:
The global average sea level rose at an average rate of 1.8 [1.3 to 2.3] mm per year over 1961-2003. The rate was faster over 1993 to 2003: about 3.1 [2.4 to 3.8] mm per year. Whether the faster rate for 1993 to 2003 reflects decadal variability or an increase in the longer-term trend is unclear.
Well, the very latest sea level rise data is helping to make things less “unclear.”
Notice that the in the past couple of years (the righthand portion of Figure 2) the rate of sea level rise has apparently slowed a bit. So it would be interesting to place the changes in the rate of sea level rise from the satellite data in the context of the historical changes in the rate of sea level rise derived by Holgate (in Figure 1).
Voila, Figure 3.
Figure 3. Decadal rate of sea level rise from satellites (red curve) appended to the decadal rate of global sea level rise as determined from a 9-station tide gauge network for the period 1904-2003 (blue curve) and from a 177-station tide gauge network for the period 1948-2002 (adapted from Holgate, 2007).We calculate the running 10-year trends in sea level as observed from satellites, and append it to the running 10-yr trends in sea level derived by Holgate from the tide gauge network. In this context, the satellite trends (red curve in Figure 3) don’t look unusual at all—they seem to fit squarely into the pattern of long-term fluctuations. And further more, they have been declining!
AND SURGING SEA LEVEL HYSTERIA IS BS2.
DON'T BE DUPED.
DISSENT ACCORDINGLY.
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