Science Heresy - March 2011
The figure shows that the linear trend between 1880 and 2000 is a continuation of
recovery from the Little Icea Age (LIA). It shows also the predicted temperature rise by the IPCC after 2000.
Another possibility is also shown, in which the recovery from the LIA would continue to 2100,
together with the superposed multi-decadal oscillation. This possible progress beyond the peak
of an oscillation could explain the halting of the warming after 2000. The observed temperature
in 2008 is shown by a red dot with a green arrow.
Natural Components of Climate Change
A precis of a paper by S-I. Akasofu,
Two Natural Components of the Recent Climate Change:
(1) The Recovery from the Little Ice Age
(A Possible Cause of Global Warming)
(2) The Multi-decadal Oscillation
(The Recent Halting of the Warming)
Two natural components of the currently progressing climate change are identified. The first one
is an almost linear global temperature increase of about 0.5°C/100 years, which seems to have
started in 1800–1850, at least one hundred years before 1946 when manmade CO2 in the
atmosphere began to increase rapidly. This 150~200-year-long linear warming trend is likely to
be a natural change. One possible cause of this linear increase may be the earth’s continuing
recovery from the Little Ice Age (1400~1800); the recovery began in 1800~1850. This trend
(0.5°C/100 years) should be subtracted from the temperature data during the last 100 years when
estimating the manmade contribution to the present global warming trend. As a result, there is a
possibility that only a small fraction of the present warming trend is attributable to the
greenhouse effect resulting from human activities.
It is also shown that various cryosphere phenomena, including glaciers in many places in the
world and sea ice in the Arctic Ocean that had developed during the Little Ice Age, began to
recede after 1800 and are still receding; their recession is thus not a recent phenomenon.
The second one is oscillatory (positive/negative) changes, which are superposed on the linear
change. One of them is the multi-decadal oscillation, which is a natural change. This particular
natural change had a positive rate of change of about 0.15°C/10 years from about 1975 (positive
from 1910 to 1940, negative from 1940 to 1975), and is thought by the IPCC to be a sure sign of
the greenhouse effect of CO2. However, the positive trend from 1975 has stopped after 2000.
One possibility of the halting is that after reaching a peak in 2000, the multi-decadal oscillation
has begun to overwhelm the linear increase, causing the IPCC prediction to fail as early as the
first decade of the 21st century.
There is an urgent need to correctly identify natural changes and remove them from the present
global warming/cooling trend, in order to accurately and correctly identify the contribution of the
manmade greenhouse effect. Only then can the effects of CO2 be studied quantitatively. Arctic
research should be able to contribute greatly to this endeavor.
Important findings in this paper are:
- Natural components are important and significant in climate change, so they should not
be ignored in studying global temperature changes.
- Two natural changes after 1800–1850 are identified in this paper: an almost linear
increase of about +0.5°C/100 years and a multi-decadal oscillation of amplitude 0.2°C
and period of 50~60 years superposed on the linear change.
- The Earth as a whole experienced a relatively cold period, the Little Ice Age (LIA),
between 1400 and 1800. The Earth is still recovering from the LIA.
- It is quite likely that a significant part of the temperature rise after 1975 is due to the
multi-decadal oscillation, not the greenhouse effect as hypothesized by the IPCC.
- The reason why the global warming trend stopped in about 2000 is likely to be due to the
fact that after peaking in about 2000, the multi-decadal oscillation has started to have a
negative trend. There are other signs of the halting (Figures 10b, 14, and 17 as well as the
ocean heat content). The halting is not due to a La Niña.
- There is nothing unusual or abnormal about the present global warming trend and
temperature. There were a number of periods when the temperature was higher than the
present even after the recovery from the last Big Ice Age.
- It is insufficient to study climate change on the basis of data only from 1975.
- Two examples are presented in which GCM results can be used to identify natural
changes due to natural causes.
- Computers are incorrectly “taught,” “instructed,” or “tuned” to adjust to the observed
temperature rise during the last hundred years, and particularly after 1975, ignoring the
recovery from the LIA and the multi-decadal oscillation. Thus, the present GCMs do not
include processes associated with the LIA and the multi-decadal oscillation.
- The predicted temperature in 2100 by the IPC is simply an extension of the warming
trend between 1975 and 2000.
- As a result, the IPCC prediction during the first decade of the present century has already
- If most of the present rise is caused by the recovery from the LIA (a natural component)
and if the recovery rate does not change during the next 100 years, the expected
temperature rise by 2100 would be 0.5°C. This rough estimate is based on the recovery
rate of 0.5°C/100 years during the last 200 years. Multi-decadal oscillation could be
either positive or negative in 2100. Since its amplitude change is about 0.2°C, the
temperature in 2100 depends greatly on the combination of both effects, 0.5°C ± 0.2°C.