Memorandum by Professor Nils-Axel Mörner,
Head of Paleogeophysics & Geodynamics, Stockholm University,
Sweden President, (1999-2003) of the INQUA Commission on Sea Level
Changes and Coastal Evolution, Leader of the Maldives Sea Level
Project
FACTS AND FICTION ABOUT SEA LEVEL CHANGE
MAY LOW-LYING ISLANDS AND COASTAL AREAS BE FREED FROM THE CONDEMNATION
TO BECOME FLOODED IN THE NEAR-FUTURE
Climate is becoming increasingly warmer we hear
almost every day. This is what has become known as Global Warming.
The driving idea is that there is a linear relationship between
CO2 increase in the atmosphere and global temperature. The fact,
however, is that temperature has constantly gone up and down.
From 1850 to 1970, we see an almost linear relationship with Solar
variability; not CO2. For the last 30 years, our data sets are
so contaminated by personal interpretations and personal choices
that it is almost impossible to sort up the mess in reliable and
unreliable data.
Most remarkable in the record of climatic changes
during the last 600 years are the cold periods around 1450, 1690
and 1815 and their correlation with periods of Solar Minima (the
Spörer, Maunder and Dalton Solar Minima). The driving cyclic
solar forces can easily be extrapolated into the future. This
would call for a new cold period or "Little Ice Age"
to occur at around 2040-50. Still, we hear nothing about this.
It is as if IPCC and the Kyoto Protocol enthusiasts want to "switch
off the Sun itself". Let us take this, at least, as a piece
of information to rise our awareness and curiosity.
In the global warming concept, it has been constantly
claimed that there will be a causal rise in sea level; a rise
that already is in the accelerating mode, in the near future to
cause extensive and disastrous flooding of low-lying coastal areas
and islands. "It will be the death of our nation",
says the President of the Maldives, and the people of Tuvalu in
the Pacific claim that the flooding has already commenced.
Is this facts or fiction? It is true that we
are flooded by this information. But what lies behind this idea?
And, especially, what do the true international specialists think?
The recording and understanding of past changes
in sea level, and its relation to other changes (climate, glacial
volume, gravity potential variations, rotational changes, ocean
current variability, evaporation/precipitation changes, etc) is
the key to sound estimates of future changes in sea level.
The international organisations hosting the
true specialists on sea level changes are to be found with the
INQUA commission on sea level changes and the IGCP special projects
on sea level changes. When I was president of the INQUA Commission
on Sea Level Changes and Coastal Evolution, 1999-2003,
we paid special attention just to this question; ie proposed rise
in sea level and its relation to observational reality. We discussed
the issue at five international meetings and by Webb-networking.
Our opinion is illustrated in Fig 2. In view of the Fig 1 prediction,
I have later revised the estimate for year 2100 to: +5 cm ±
15 cm.
Prior to 5000-6000 BP, all sea level curves
are dominated by a general rise in sea level in true glacial eustatic
response to the melting of continental ice caps. In the last 5,000
years, global mean sea level has been dominated by the redistribution
of water masses over the globe. In the last 300 years, sea level
has been oscillating close to the present level, with peak rates
in the period 1890-1930 (Fig 3).
It is true that sea level rose in the order
of 10-11 cm from 1850 to 1940 as a function of Solar variability
and related changes in global temperature and glacial volume.
From 1940 to 1970, it stopped rising, maybe even fell a
little. In the last 10-15 years, we see no true signs of any rise
or, especially, accelerating rise (as claimed by IPCC), only a
variability around zero. This is illustrated in Fig 3.
With the TOPEX/POSEIDON satellite mission in
1992, we now have new means of recording actual sea level changes.
The record from 1992 to early 2000 (Fig 4) lacks any sign of a
sea level rise; it records variability around zero plus a major
ENSO even in year 1997.
When we three years later have the same record
extended into year 2003 on the Webb, a tilt has been introduced.
This tilt does not originate from the satellite altimetry readings,
however, but represents an inferred factor from tide-gauge interpretations.
In order to get back to true satellite data, we have to tilt the
whole record back to its original data of Fig 4. When this is
done, there is no sea level rise to be seen—only a variability
around zero plus a number of high-amplitude ENSO oscillations
(Fig 5). This is why I in Fig 3 conclude that the sea level remained
stationary at around zero for the last 10-15 years (as further
discussed in Mörner, 2004a and 2005).
The tide-gauge introduced into the satellite
data on the Webb seems to violate observational facts at sites
spread all over the globe; not least our NW European data covering
both uplifted areas (Fennoscandia, Scotland) as subsiding areas
(the North Sea).
From 2000 to the present, we have run a special
international sea level project in the Maldives including six
field sessions and numerous radiocarbon dates. Our record for
the last 1,200 years is given in Fig 6. There are no signs of
any on-going sea level rise. It seems all to be a myth.
Tuvalu in the Pacific is often said already
to be in the flooding mode. The tide-gauge record (Fig 7) for
the last 25 years does not show any rise, however. The truth seems
to be that a Japanese pineapple industry had subtracted too much
freshwater by that forcing saltwater to invade the subsurface.
Fig 7. The Tuvalu tide-gauge record 1978-2003
showing stability around a zero level plus three negative ENSO
events (from Mörner, 2004c).
Venice is notorious for its flooding problems.
It lies on a delta area subjected to subsidence. Therefore, the
sea level variations are superposed on a long-term subsidence
trend (Fig 8). Any rise in sea level would immediately worsen
the situation. The last 30 years lack signs of any rise or accelerated
rise, on the contrary sea level fell (partly as a function of
engineering work).
Fig 8. Observes sea level changes (purple) superposed
on a long-term subsidence trend (blue). At 1970 (green arrow),
there is a marked change in tendency, partly due to engineering
work, but certainly seriously contradicting a sea level rise and
especially an accelerated sea level rise.
In conclusion; observational data do not
support the sea level rise scenario. On the contrary, they seriously
contradict it. Therefore, we should free the world from the condemnation
of becoming extensively flooded in the near future.
There are more urgent natural problems to
consider on Planet Earth like tsunamis, earthquakes, volcanic
eruptions, etc.
30 March 2005
Some recent scientific papers by the author
The INQUA Commission—www.pog.su.se/sea
Authors homepage—www.pog.su.se.
Mörner, N-A, 2005. Sea level changes and
crustal movements with special aspects on the eastern Mediterranean.
Z Geomorph. NF, Suppl Vol 137, p 91-102.
Mörner, N-A, 2004d. Changing Sea Levels.
In: Encyclopedia of Coastal Science (M Schwartz, Ed), p
284-288.
Mörner, N-A, 2004c. Sea level change: Are
low-lying islands and coastal areas are under threat? In: "The
impacts of climate changes. An appraisal for the future",
p 29-35. International Policy Press.
Mörner, N-A, 2004b. The Maldives Project:
a future free from sea level flooding. Contemprary South Asia,
13 (2), p 149-155.
Mörner, N-A, 2004a. Estimating future sea
level changes. Global Planet. Change, 40, 49-54.
Mörner, N-A, Tooley, M & Possnert,
G, 2004. New perspectives for the future of the Maldives. Global
Planet. Change, 40, 177-182.
Mörner, N-A, 2002. Livello dei mari e clima
(Sea Level Changes and Climate). Nuova Secondaria, 10/2002,
p 43-45.
Mörner, N-A, 2001. Global and local sea
level changes: the interaction of multipleparametres (hydrosphre,
cryosphere, lithosphere, ocean dynamics and climate). Schr.
Deutschen Geol. Gesellschaft, 14, 3-4.
Mörner, N-A, 2000b. Sea level changes in
western Europe. Integrated Coastal Zone Management, Autumn
2000 Ed, p 31-36, ICG Publ. Ltd.
Mörner, N-A, 2000a. Sea level changes and
coastal dynamics in the Indian Ocean. Integrated Coastal Zone
Management, Spring 2000 Ed, p 17-20, ICG Publ. Ltd.
Mörner, N-A, 1999. Sea level and climate.
Rapid regressions at local warm phases. Quaternary International,
60, 75-82.
Mörner, N-A, 1996b. Rapid changes in coastal
sea level. J. Coastal Res, 12, 797-800.
Mörner, N-A, 1996a. Sea Level Variability.
Z Geomorphology NS, 102, p 223-232.
Mörner, N-A, 1995. Earth rotation, ocean
circulation and paleoclimate. GeoJournal, 37, 419-430.
Mörner, N-A, 1995b. Recorded sea level
variability in the Holocene and expected future changes. In: Climatic
Change: Impacts on Coastal Habitation (D Eisma, Ed), pp 17-28.
Mörner, N-A, 1995a. Sea Level and Climate—The
decadal-to-century signals. J Coastal Res., Sp I 17, 261-268.
Plus numerous sea level papers in the period
1969-95.
See also:
Lars Mortensen, 2004; Doomsday Called Off,
TV-documentary, Danish TV, Copenhagen.
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