Vol.2, No.11, 1211-1224 (2010) Natural Science
Copyright © 2010 SciRes. OPEN ACCESS
On the recovery from the Little Ice Age
Syun-Ichi Akasofu
International Arctic Research Center, University of Alaska Fairbanks, Fairbanks, USA; sakasofu@iarc.uaf.edu
Received 28 July 2010; revised 30 August 2010; accepted 3 September 2010.
A number of published papers and openly avail-
able data on sea level changes, glacier retreat,
freezing/break-up dates of rivers, sea ice retreat,
tree-ring observations, ice cores and changes
of the cosmic-ray intensity, from the year 1000
to the present, are studied to examine how the
Earth has recovered from the Little Ice Age (LIA).
We learn that the recovery from the LIA has
proceeded continuously, roughly in a linear
manner, from 1800-1850 to the present. The rate
of the recovery in terms of temperature is about
0.5°C/100 years and thus it has important im-
plications for understanding the present global
warming. It is suggested on the basis of a much
longer period covering that the Earth is still in
the process of recovery from the LIA; there is no
sign to indicate the end of the recovery before
1900. Cosmic-ray intensity data show that solar
activity was related to both the LIA and its re-
covery. The multi-decadal oscillation of a period
of 50 to 60 years was superposed on the linear
change; it peaked in 1940 and 2000, causing the
halting of warming temporarily after 2000. These
changes are natural changes, and in order to
determine the contribution of the manmade
greenhouse effect, there is an urgent need to
identify them correctly and accurately and re-
move them from the present global warm-
ing/cooling trend.
Keywords: Little Ice Age
The Little Ice Age (LIA) is discussed in a large num-
ber of publications, including monographs (cf. Lamb 1;
Grove 2). Although it is generally believed that the
LIA ended more than two centuries ago, there has not
been much discussion about how the recovery from it. In
this paper, on the basis of published papers and some
openly available data, we learn that the LIA certainly
ended in about 1800-1850, but the recovery has con-
tinuously progressed to the present with superposed
‘fluctuations’. In this section, we briefly review data
from the LIA. In Section 2, ice core data, river
freeze/break-up dates, sea level changes, sea ice changes,
glacier changes, tree-ring data and cosmic-ray intensity
data, are examined, and we learn that the recovery pro-
gressed from 1800-1850 to the present. In Section 3,
having more accurate data after 1900, we learn that tem-
perature changes during the 20th century can be judged
as a continuation of the recovery, approximated by a lin-
ear change at the rate of about 0.5 C/100 years, with the
superposed multi-decadal oscillation. In Section 4, we
learn on the basis of changes of the cosmic-ray intensity
from the year 1000 to the present that solar activity was
relatively low during the LIA, but began to recover from
about 1800-1850. In Section 5, it is suggested that the
multi-decadal oscillation is halting the recovery from the
LIA temporarily and that this situation is similar to the
situation from 1940 to 1975. The summary is given in
Section 6 and the conclusion in Section 7.
There is little doubt that the Earth experienced a rela-
tively cool period after the Medieval Warm Period
around the year 1000. In this section, we briefly review
changes of temperature from about 1000 to the present
before examining details of the recovery from the LIA.
Figure 1(a) shows a typical example of tree-ring data
from the middle latitudes (Esper et al. 3; Frank et al.
4). Compared with the mean 1961-1990 level, the
temperature was relatively low from about 1100 to
1800-1850, indicating that the Earth experienced a rela-
tively cool period, the LIA. Our particular interest here
is the recovery that began in about 1800-1850, namely
the temperature increase here from 1800-1850 to the
present. It can be seen that the temperature rise from
1800-1850 to the present was continuous with super-
posed ‘fluctuations’ and that there is no sign of the end
of the recovery before 1900.
Figure 1(b) shows temperature changes from the year
900 to the present, which combines seven (including
Figure 1(a)) different research results (National Research
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Figure 1. (a) Temperature variations deduced from tree-ring records from 14 sites from 800. It
shows variance-adjusted data by Esper et al. 3, along with the unadjusted mean record. The
dashed line shows the mean 1961-1990 anomaly reference period (Frank et al. 4); (b) Recon-
structions of large-scale (Northern Hemisphere mean or global mean) surface temperature varia-
tions from seven different research teams (including Figure 2(a)) are shown along with the in-
strumental record of global mean surface temperature. Each curve portrays a somewhat different
history of temperature variations and is subject to a somewhat different set of uncertainties that
generally increase going backward in time, as indicated by the gray shading (National Research
Council 5); (c) Ice break-up scene at Lake Suwa in the central highland of Japan from 1450 to
2000. It produced a loud sound and it was thought that God crossed the lake. It is for this reli-
gious reason that a long record has initially been kept. The zero day refers to January 1. The dots
on the top show years when the break-up did not occur (Ito 6).
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Council 5). It is clear from Figures 1(a) and 1(b) that
the Earth experienced a relatively cool period from about
1100 to 1800, the LIA. Again, it may be noted that all
the data show clearly the continuous recovery from
about 1800-1850 to the present with the superposed
Figure 1(c) shows an interesting break-up date record
at Lake Suwa in the central highland of Japan from 1450
to 2000. The lake has a nearly circular shape, and this par-
ticular break-up phenomenon, called “Omiwatari”, mean-
ing ‘God’s crossing’, tends to occur during the early
freezing period, perhaps because of the pressure exerted
by the expanding ice. The delay of the break-up dates
indicates warming from 1800 to the present (Ito 6).
This is an example to show that the LIA occurred in Asia.
The presence of the LIA in the Indo-Pacific area is
documented by Nunn 7, Oppo et al. 8 and others (see
Lamb 1; Grove 2; Fagan 9). Indeed, many publica-
tions indicate that the LIA was a worldwide phenomenon.
(Keigwin 10; Tarand and Nordli 11; van Engelen et
al. 12; Pollack and Smerdon 13 ; Asami et al. 14;
Moberg et al. 15; Holmes et al. 16; Liu et al. 17;
Richey et al. 18; Aono 19).
In this section, we learn about climate change from
1800-1850 to 1900. Since we have much more accurate
data after 1900, climate change after 1900 will be dealt
with in the next section.
2.1. Ice Core Data
Figure 2(a) shows temperature changes from 1725 to
2000, which were deduced from ice cores at Severnaya
Zemlya, an island in the Arctic Ocean (Fritzsche et al.
20). This figure indicates that there occurred a con-
tinuous rise of temperature from 1775 to the present; this
record is particularly valuable, because we do not expect
any contamination by human activities. Figure 2(a) in-
cludes also a thermometer record from Vardo in northern
Norway. The bottom curve is temperature changes at
stations along the coastline of the Arctic Ocean (Polya-
kov et al. 21). The credibility of the ice core record is
supported by its similarity with both thermometer re-
cords; see also a similar result by Isaksson et al. 22. A
large positive change from 1910 to 1975 was caused by
the phenomenon called the polar amplification of the
multi-decadal oscillation (Alexeev et al. 23), which
will be discussed in Section 5.
Figure 2(b) shows both the break-up and freeze dates
of a number of lakes and rivers of the world from 1846
to 1995 (Magnuson et al. 24. It can be seen that the
break-up dates have almost steadily advanced to earlier
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Figure 2. (a) Late Holocene ice core record from Akademii Nauk Ice Cap, Severnaya Zemlya, Rus-
sian Arctic, by Fritzsche 20, together with temperature records from Vardo, Norway, and from sta-
tions along the arctic coast (Polyakov et al 21); (b) Freeze dates and break-up dates of lakes and riv-
ers in the Northern Hemisphere from 1845~1993 (Magnuson et al 24; (c)Global sea level change
from 1700 to the present (Jevrejeva et al 26; (d) Upper, retreat of sea ice in the Norwegian Sea
(Vinje 27; note that the downward slope indicates a northward shift. Lower, satellite data corre-
sponding to the period between 1970 and 1998; (e) Variations of the occurrence of sea ice at the coast
of Iceland from the year 800. This work was done by L. Koch (Lamb 1.).
dates in the year, while the freeze dates seemed to shift
steadily to later dates. Similar ice break-up data are also
available by Tarand and Nordlie 11 and van Engelen et
al. 12.
2.3. Sea Level Changes
The linear trend of the recovery from the LIA can also
be seen in sea level changes (Jevrejena et al. 25,26.
Figure 2(c) shows the global sea level from 1800. It is
clear that the sea level began to increase in about 1850
and continued rising almost linearly to the present.
2.4. Sea Ice Changes
There is no accurate Arctic Ocean data until satellite
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observations became available in the 1970s. The only
long-term observation of sea ice is available from the
Norwegian Sea. Figure 2(d) shows changes in the south-
ern edge of sea ice in the Norwegian Sea. It has been
receding from about 1800 to the present at almost the
same rate (Vinje 27. In the lower part, satellite data are
shown. Although a drastic decrease in 2007 (not shown
here) was widely reported, it is found that winds and
many other factor were responsible for it (Zhang et al.
28,29; in fact, the ice has shown a steady recovery since
then (Muskett 30. The large ‘fluctuations’ between 1910
and 1975 are likely related to the multi-decadal oscilla-
tion, which is discussed in Section 5.
Figure 2(e) shows variations of the occurrence of sea
ice on the coasts of Iceland (see the figure caption for
the reference). The decline after 1800 corresponds to the
northward shift shown in Figure 2(d). Another impor-
tant piece of evidence to notice is that, as Figure 4(b)
shows later, there was a gradual build-up of sea ice, be-
ginning in about 1200 or after 1400, at the beginning of
the LIA.
2.5. Glaciers
Figures 3(a-f) show records of glaciers in Alaska,
New Zealand, the European Alps, and the Himalayas.
These glaciers have been receding from the time of the
earliest available records, about 1800 and an accurate
terminus records. There are also a large number of simi-
lar records from the European Alps, Alaska, and else-
where (Grove 2; Molnia 31). Molnia’s examples are
shown in his figures 33, 34, 81, 107 (same as Figure
3(a)) and 301. Thus, it may be said that many glaciers in
the world have been retreating from 1800-1850 to the
present; the retreat is not a phenomenon that began only
in recent years. In a large number of recent publications,
photograph sets of the same glaciers taken early and late
in the 1900s are shown as evidence of the effect of CO2
(cf. ACIA 32; Strom 33). However, Figure 3(a-f)
demonstrate that those recent photographs are mislead-
ing as evidence of the sudden warming after 1900 and of
the greenhouse effect. Therefore, such a set of photo-
graphs cannot be used as evidences supporting the
greenhouse effect of CO2.
It is interesting to examine glacier changes before 1800.
Figure 3(d) shows radiocarbon datings related to glacial
advances in some of the Juneau outlet glaciers (Grove
34. Each advance killed trees and left in situ stumps for
analyses. These advances occurred before Glacier Bay
glaciers began to recede in about 1800 (Figure 3(a)).
Figure 3(e) shows changes of the Mer de Glace gla-
cier in the Alps. It began to retreat in about 1852. Figure
3(f) shows its changes in more detail (von Michael Kuhn
35. This particular glacier began to build up after 1550
(namely during the LIA) and began to retreat after 1850
(Holzhausen et al. 36).
There are also various reports about advancing gla-
ciers during the LIA in Scandinavia (cf. Lamb 1).
Therefore, it is clear that many glaciers advanced during
the LIA before starting to retreat in about 1800-1850.
Altogether, long- te r m glacier data presented here show
that glaciers advanced from about 1400 and began to
retreat rather steadily after 1800-1850. These facts con-
firm that the Earth experienced the LIA and began to
recover from it as evidenced by a number of natural
phenomena, such as retreating glaciers and sea ice from
about 1800-1850 to the present. A large number of his-
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Figure 3. (a) Retreat of glaciers in Glacier Bay, Alaska (Molina 31; (b) Retreat of the Franz Josef Glacier in New Zealand; the
coloring is added by the present author for emphasis (Grove 2); (c) The Gangotri Glacier in the Himalayas (Kargel 37). It
shows clearly that the retreat began even before 1800; (d) Radiocarbon dates related to glacial advances in the Juneau glaciers
(Grove 34); (e) The location of the terminus of the Mer de Glace glacier after 1644 (von Michael Kuhn 35); (f) Details of the
changes of the Mer de Glace glacier after 1550 (von Michael Kuhn 35).
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torical documents are also available that describe cool
weather conditions during the LIA, such as freezing of
the River Thames in the 1600 (Lamb 1; Crowley and
Nort 38; Fagan 9).
3.1. The Linearity of the Recovery
In the previous section, we learned that the recovery
from the LIA was continuous, although there are super-
posed ‘fluctuations’, which will be discussed in Section
5. In this section, we learn, on the basis of more accurate
data gathered during the last century, that climate change
examined in the previous section has continued to the
present. With these data, we can examine more carefully
the changes and, specifically the linearity of the changes.
A recent study of sea level changes by Holgate 39 is
shown in Figure 4(a). It shows the last part of Figure
2(c). First of all, Holgate noted that the rate of sea level
rise was about 1.7 mm/year. The sea level change is
known to reflect the thermal expansion of seawater and
glacier melting during the last half century. Comparing
Figure 4(a) and Figure 2(c), it can be seen that the re-
covery from the LIA is a continuous process, without
major change of the rising rate. This coverage is suffi-
cient to show the linearity of the change from 1900 to
2000. Actually, comparing the slope between 1907–1960
and 1960–2000, the gradient has become smaller (1.4
mm/year) in the latter period (Holgate 39). In fact, the
rise of sea level nearly stopped after 2005 (Nerem et al.
40). This point will be discussed in Section 5.
Figure 4(b) shows changes of the global average tem-
perature from 1890 to 2007 (the Japan Meteorological
Agency (JMA) 41); the red line is added by the JMA.
Very similar figures have been published by NASA
(GISS), NOAA, and others. In Figure 4(b), the amount
of CO2 released in the atmosphere is added; it can be
seen that it began to rise rapidly in 1946. Although the
global average temperature (T) changes can be approxi-
mated by a linear relation as a function of time (t) (T =
at), CO2 changes are more like T =bt2.
Figure 4(c) presents schematically the above inter-
pretation of global average temperature changes from
1880, indicating that the linear increase is superposed by
‘fluctuations’. Changes above the linear line are shown
in red and below in blue.
In examining the linearity of temperature changes
during the last century, Bryant 43 noted that there are
only a few points outside the 95% confidence limits of
the linear approximation. The gradient of the straight
line is about 0.5 °C/100 years. A much more detailed
analysis of the trend was conducted by Wu et al. 44;
N.E. Huang, Research Center for Advanced Data Analy
sis, National Central University, Taiwan, called my at-
tention to their paper after a draft of this paper was
nearly completed. Figure 4(d) shows their results. The
solid line indicates what we approximated by a linear
line. Note that the gradient of the solid line from 1900 to
2000 is approximately 0.5 C/100 years. The dashed line
will be discussed in Section 5.
There have been a number of discussions of the tem-
perature during the LIA. It ranges from 0.5 C to 1.5 C
below the present temperature (see Lamb 1 1982;
Grove 2). If we take it to be 1.0 C mainly on the basis
of Figures 1a and 1b, the rate of increase during the last
200 years, namely between 1800 and 2000, is about
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Figure 4. (a) The mean sea level record from nine tide
gauges over the period 1904-2003 based on the decadal
trend values for 1907-1999 (Holgate 39); (b) Global av-
erage temperature (the Japan Meteorological Agency,
JMA, 41). The red straight line was drawn by the JMA.
The amount of CO2, which began to rise rapidly in 1946,
is added for comparison; (c) An interpretation of Figure
4(b), showing temperature changes that consist of a linear
change and ‘fluctuations’ superposed on it. The tempera-
ture record (thin blue line) is taken from the NOAA report
42 (see the insert in Figure 9), which is basically a
smoothed version of the 5-year mean in Figure 4(b). The
thick blue line from 1975 to 2000 will be discussed in
Section 6; (d) The rates of temperature changes (per year)
for the gradual increase (solid line) and the multi-decadal
changes (dashed line) from 1850 to 2000 (Wu et al. 44).
0.5C/100 years.
3.2. Did the Recovery from the LIA End
before 1900 ?
On the basis of the above studies, we have learned
that the recovery has continued to the present. The next
question is “ Did the recovery end before 1900?” A cas-
ual inspection of Figures 1(a) and 1(b) might give an
impression that the Earth has recovered from the LIA, if
we consider that the present level is the normal level.
However, in meteorology and climatology, it is not pos-
sible to define the absolute normal level (baseline) from
which deviations (warming or cooling) can be measured
or the end of the LIA can be determined. When one ex-
amines data over a longer period (say, 2000 and 10,000
years), the present temperature can be below the average
temperature for chosen periods. In Figure 5, one can see
clearly that the average temperature of the 20th century is
not useful in examining our question in this subsection.
Similar long-period records were obtained by Keigwin
10 and Dale-Jensen et al. 45.
Further, it is very important to note that the tempera-
Figure 5. Ice core temperature at the GISP-2 site in
Greenland, extending to 2000 years (left hand side and
10,000 years (right hand side), respectively (Alley 46.
ture is in a rising trend in the last part. Thus, although it
is generally believed that the recovery from the LIA
ended some time ago, there is no basis to define the
ending year of the LIA. It is more likely that the Earth is
still in the process of recovery. What we have learned so
far has a significant implication for understanding the
temperature rise in the 20th century. This point will be
discussed in Section 6 (see Figure 9).
It is not the purpose of this section to discuss any ma-
jor causes of climate change. We learn only, on the basis
of the valuable cosmic-ray intensity data, that solar ac-
tivity was low in general during the LIA and began to
recover about 1800 . A number of studies have suggested
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that the LIA coincided with the Maunder Minimum pe-
riod (cf. Burroughs 47). This is because the Maunder
Minimum happened to occur during the LIA. We see
here a much longer period record.
The fact that the cosmic-ray intensity varied during
the LIA suggests that non-terrestrial forces, more spe-
cifically solar activity, are involved in some components
of climate change (cf. Lang 48; Burroughs 47). Fig-
ure 6 shows the solar modulation function deduced from
10Be and 14C records from 1000 to 2000 (Muscheler et
al. 49). When the solar modulation function is low,
solar activity is low (but, the cosmic-ray intensity is
high), while it is high, solar activity is high (but, the
cosmic-ray intensity is low). It is known that solar activ-
ity is represented by the sunspot number and its changes
are well correlated with changes of the solar irradiance
(Lean et al. 50).
Therefore, Figure 6 represents the trend of changes of
solar activity from 1000 to 2000, which may be com-
pared with Figure 1(a) or 1(b). It can be seen that solar
activity was relatively low during the LIA and began to
recover in about 1800. Therefore, it may be speculated
that solar irradiance is involved in causing the LIA and
its recovery.
Changes of the solar irradiance during the sunspot cy-
cle are rather small (1.3W/m2). However, the difference
between the LIA period and the present may be a few
times greater than 1.3W/m2 (Lean et al. 50. Therefore,
although Nozawa et al. 51 showed that the solar effect
on temperature changes during the 20th century was
small, this subject requires much more detailed study
with newer Global Climate Models by taking into ac-
count a prolonged period of a low solar irradiance
(Scafetta and West 52), at least as its triggering effects.
Note that as Figure 1(a) and 1(b) show, the LIA began
in about 1200 or 1300, and such a prolonged period of
low solar irradiance may cause a significant climate
change (cf. Scafetta and West 52,53). In this paper, we
are mainly interested in possible causes of a long period
change like the LIA. On the other hand, Soon 54 ex-
amined the solar effect of a shorter period (130 years)
and found a significant correlation with arctic tempera-
ture variations.
In Figure 6, several minima, the Oort Minimum
(1000-1100), the Wolf Minimum (1250-1350), the Spoer
Minimum (1380-1510), and the Maunder Minimum
(1620-1720), may be noted (cf. Dehau and de Jager 55).
Intermittent increases of the solar modulation function
(thus, low cosmic-ray intensities) were caused by a high
solar activity. In fact, as Figure 1(a) and 1(b) suggest,
the LIA was not a continuously cool period (see Lamb
1 and Fagan 9). Since it is known that the solar activ-
ity represented by the sunspot number correlates well with
Figure 6. The solar modulation function of cosmic rays de-
duced from 10Be and 14C records (Muscheler et al. 49).
the solar irradiance, Figure 6 represents the general
trend of changes of the solar irradiance among others.
It is not the purpose of this section to discuss the
multi-decadal changes in detail. The sole purpose is to
explain why the warming has halted after 2000, despite
the fact that we concluded in the previous sections that
the Earth is still in the recovery process from the LIA.
Figure 7 shows this halting (Kerr 56).
In Section 3, we suggested that the prominent ‘fluc-
tuations’ superposed on the linear recovery are the
multi-decadal oscillation. Figure 4(d) shows its rate of
changes. From Figures 4(c) and 4(d), the multi-decadal
oscillation peaked in 1940, and the temperature actually
decreased from the level of the linear increase from 1940
to 1975 and then increased after 1975 to 2000. Thus, it
may be speculated that the situation in 2000 is similar to
that in 1940, so that it is predicted that the temperature
change will be flat or in a slightly declining trend during
the next 30 years or so (see Section 6 and Figure 9). That
is to say, the halting does not mean the end of the recov-
Figure 7. The global average temperature changes during the
last several decades (Kerr 56).
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Figure 8. The PDO wind pattern and the PDO
index (University of Washington 57). The bot-
tom diagram is the same as Figure 4(c).
ery from the LIA. The halting after 2000 can be ob-
served in sea level change (Nerem et al. 40), a decrease
of the heat content of the oceans (Pielke, Sr. 58) and
other factors.
The multi-decadal oscillation can be seen in other
phenomena. Figure 8 shows the pattern of the Pacific
Decadal Oscillation (PDO), which is a natural phe-
nomenon (University of Washington 58). Top part
shows the observed wind pattern over the Pacific Ocean.
The middle part shows the PDO index. It is interesting to
note a striking resemblance of changes between PDO
and the multi-decadal oscillation (at the bottom, Figure
4(c) is reproduced for comparison.). Although there is
some phase difference between them, this similarity
supports the inference that the fluctuations superposed
on the linear change (the recovery from the LIA) are in
part the multi-decadal oscillation. The Pacific Ocean is
large enough to contribute to the global average tem-
perature. Polyakov et al. 59 showed that the Arctic
Ocean shows a similar trend.
6. Summary
It may be appropriate to summarize results in sections
Figure 9. The figure shows that the linear trend between 1880 and 2000 is a continuation of recovery from the LIA, together
with the superposed multi-decadal oscillation. It shows also the predicted temperature rise by the IPCC after 2000. It is as-
sumed that the recovery from the LIA would continue to 2100, together with the superposed multi-decadal oscillation. This
view could explain the halting of the warming after 2000. The observed temperature in 2008 is shown by a red dot with a
green arrow. It has been suggested by the IPCC 60 that the thick blue line portion was caused mostly by the greenhouse ef-
fect, so their future prediction is a sort of extension of the blue line.
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1-5 on the basis of Figure 9. The large box is the same
as Figure 4(c). The figure suggests that temperature
changes from 1800 to 2000 can be explained mainly as a
combination of the linear increase from about 1800-1850
and the multi-decadal oscillation. The blue line is taken
from the NOAA data shown in a small box above the
large box. The meaning of the linearity of the recovery
from 1800-1850 is crucial in considering the cause of the
warming in the last century (the amount of CO2 in 2000
was at least 14 times greater than that in 1900 and was
even much greater in 1850), so it is difficult to associate
the linear warming only with CO2. The temperature rise
from 1800-1850 to the present is fairly steady. Therefore,
it is not unreasonable to assume the rise after 1900 is a
continuation of the same process, namely the recovery
from the LIA. Assuming that the recovery from the LIA
and the multi-decadal oscillation would continue during
the next 100 years or so, the future trend until 2100 is
predicted in Figure 9. The observed temperature in 2008
is shown by a red dot with a green arrow. It has been
suggested by the IPCC 60 that the thick blue line por-
tion was caused mostly by the greenhouse effect, so their
future prediction is a sort of extension of the blue line.
In this paper we learned:
1) The Earth experienced the Little Ice Age (LIA)
between 1200-1400 and 1800-1850. The temperature
during the LIA is expected to be 1C lower than the pre-
sent temperature. The solar irradiance was relatively low
during the LIA.
2) The gradual recovery from 1800-1850 was ap-
proximately linear, the recovery (warming) rate was
about 0.5°C/100 years. The same linear change contin-
ued from 1800-1850 to 2000. In this period, the solar
irradiance began to recover from its low value during the
3) The recovery from the LIA is still continuing today.
4) The multi-decadal oscillation is superposed on the
linear change. The multi-decadal oscillation peaked in
about 1940 and also in 2000, causing the temporal halt-
ing of the recovery from the LIA.
5) The negative trend after the peak in 1940 and 2000
overwhelmed the linear trend of the recovery, causing
the cooling or halting of warming.
6) The view presented in this paper predicts the tem-
perature increase in 2100 to be 0.5°C ± 0.2C, rather
than 4 C 2.0C predicted by the IPCC.
I would like to thank a large number of colleagues from many dif-
ferent fields of arctic science. Without their help, it would not have
been possible to synthesize results from a great variety of subjects for
the purpose of examining the recent climate change.
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