We still need to study nature’s contribution to trend
Published Saturday, September 27, 2008, Fairbanks AK News-Miner
Recent studies by the Hadley Climate Research Center (UK), the Japan Meteorological Agency, the National Oceanic and Atmospheric Administration, the University of East Anglia (UK) and the University of Alabama Huntsville show clearly that the rising trend of global average temperature stopped in 2000-2001. Further, NASA data shows that warming in the southern hemisphere has stopped, and that ocean temperatures also have stopped rising.
The global average temperature had been rising until about 2000-2001. The International Panel for Climate Change (IPCC) and many scientists hypothesize rising temperatures were mostly caused by the greenhouse effect of carbon dioxide (CO2), and they predicted further temperature increases after 2000. It was natural to assume that CO2 was responsible for the rise, because CO2 molecules in the atmosphere tend to reflect back the infrared radiation to the ground, preventing cooling (the greenhouse effect) and also because CO2 concentrations have been rapidly increasing since 1946. But, this hypothesis on the cause of global warming is just one of several.
Unfortunately, many scientists appear to forget that weather and climate also are controlled by nature, as we witness weather changes every day and climate changes in longer terms. During the last several years, I have suggested that it is important to identify the natural effects and subtract them from the temperature changes. Only then can we be sure of the man-made contributions. This suggestion brought me the dubious honor of being designated “Alaska’s most famous climate change skeptic.”
The stopping of the rise in global average temperature after 2000-2001 indicates that the hypothesis and prediction made by the IPCC need serious revision. I have been suggesting during the last several years that there are at least two natural components that cause long-term climate changes.
The first is the recovery (namely, warming) from the Little Ice Age, which occurred approximately 1800-1850. The other is what we call the multi-decadal oscillation. In the recent past, this component had a positive gradient (warming) from 1910 to 1940, a negative gradient (cooling — many Fairbanksans remember the very cold winters in the 1960s) from 1940 to 1975, and then again a positive gradient (warming — many Fairbanksans have enjoyed the comfortable winters of the last few decades or so) from 1975 to about 2000. The multi-decadal oscillation peaked around 2000, and a negative trend began at that time.
The second component has a large amplitude and can overwhelm the first, and I believe that this is the reason for the stopping of the temperature rise. Since CO2 has only a positive effect, the new trend indicates that natural changes are greater than the CO2 effect, as I have stated during the last several years.
Future changes in global temperature depend on the combination of both the recovery from the Little Ice Age (positive) and the multi-decadal oscillation (both positive and negative). We have an urgent need to learn more about these natural changes to aid us in predicting future changes.
Syun-Ichi Akasofu is a former director of the Geophysical Institute and the International Arctic Research Center, both on the campus of the University of Alaska Fairbanks.
garron (17:07:59) :
But, can anyone here cite one Venusian fact or theory significant to dealing with environmental and subsistence issues facing our great grand children?
Possibly not, but the same can be said, IMHO, about any and all of the other hotly debated issues, theories, SWAGs, and other surmissions. As long as politics, ‘greenness’, save-the-planet panic, emotional attachments, cap-and-tax ideas, and all the rest are dominating the discussion over the little science we know, we cannot make any societal decisions with good conscience, but will have to let each person for himself/herself act according to own judgment.
Personally, I think [and will not tolerate any opposition to this as I may be allowed to think as I please – although I’m aware of people positing otherwise] that Venus shows that CO2 is an important greenhouse gas and that this is also true on the Earth, although the effect of, say, a doubling of CO2 is not known. Similarly, variations of the Sun [if any can be found] may also have an effect, but again, of unknown [small] magnitude. Since most of the heat is stored in the oceans, on simple physical grounds one would expect to look there for influence on the climate. Finally, ‘external’ factors [such as orbital changes, impacts, super volcanoes – should Yellowstone blow, for instance] will overwhelm whatever small effects ensue from the ‘usual suspects’.
What I rail against is the tendency to ascribe all climate change to just one thing, AGW, the Sun, GCRs, etc. , and to cherry-pick data [of which there is plenty of every stripe] that happens to support one’s view. I realize that once you adopt a more nuanced view, so many % due to this, and so many % due to that, and so many % due to something else, then the politics falls by the wayside [to quote Dubbya Shrub “you are either with us or with the enemy” – or think of various religions that all have a monopoly on the truth] and that that is the main problem that stands in the way of a rational exploration of the issue, because the proponents of the various camps do not allow this more nuanced view: it is all or nothing.
I have tried to mainly stay with what I know something about and thus not discuss ocean circulation, atmospheric modeling [although I did some of that long ago, but that was primitive compared to today], land-use issues, temperature adjustments, etc. Many of the things that are bread-and-butter solar physics also happen to be important [or thought so by various people] in climate research, such as radiative transfer in gases, atmospheric circulation and heat flows, spectra, cosmic ray physics, and much more, so I occasionally spill over into these areas when I think I can clarify a detail or two.
On this journey I have both been encouraged by people that have expressed appreciation for my comments [which BTW takes considerable time and effort] and been dismayed by the few bad apples that always frequent fora like this, but on the whole my experience has been enjoyable [which is why I’m writing this right now] as I have always felt satisfaction from sharing knowledge and interacting with people that are serious about learning. Your questions have often been an inspiration to me and have often made me think about issues that I would not normally have done, and so have contributed to widening my own horizon.
Leif, I, for one, appreciate you taking the time to give us your perspectives on the issues of importance to you.
However, I don’t think CO2 is important unless you start getting to extreme levels. I mean, how does Venus’ CO2 concentration compare to that of Earth? Millions of times higher? How many doublings would it take to get there, and how long, at the most liberal estimate, would it take to get even halfway there?
I still don’t believe we can learn anything from Venus with our current knowledge. We’d need to study it, on the ground, at least as much as we’ve studied the Earth to have any kind of certainty about its past. Anything outside of our direct observations are just WAGs, not even SWAGs. IMHO.
Jeff Alberts (20:38:49) :
how does Venus’ CO2 concentration compare to that of Earth? Millions of times higher? How many doublings would it take to get there
It will take 18 doublings [~1/4 million times more than Earth].
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