How North and Baltic Sea contribute to warming of North Europe!
Demonstrated by means of temperature data during winter 2020/21
Post: February 08, 2021,
New: The winter 1940 and 2021 in
comparison; see box at the end of the post; publ. Feb.12, 2021
oceans are still the greatest unknown in the climate change scenario. Oceans cover 71% of Earth and they contain 99.93% of
the thermal energy (“heat”) on the surface. Is it a too big issue for
increasing understanding the matter? Certainly if you lump everything together!
Progress requires selection! Focus on smaller regions, distinction between the
seasons and on observations where people are particularly active. Then you
would quickly look at the North and Baltic Seas. So the question could be: What
is the contribution of the wind-offshore industry, shipping, and fishery
towards the Northern Europe’s mild winters?
temperature of the North Sea has risen twice as fast as the oceans of the world over the past 45
years. In the last 100
years, the Baltic Sea has warmed 0.3°C per decade, however after 1990 significantly
faster at 0.59°C per decade.
European winters are getting warmer and warmer at a rate higher than global
average. Can anthropogenic activities in the North Sea, Baltic and coastal seas
be made partly responsible? Presumably yes! Stirring the sea during autumn and
winter the sea increase the release of heat stored during the summer season.
A recent paper
assumes: In the North Sea and Baltic, the
thermal air-sea coupling is strongly controlled by the seasonal cycle of the
air-sea temperature difference, which changes its sign twice a year. In
addition to that, winds and storm have an active large impact on the mixed
layer depth. The mixed layer thickness in turn controls how fast the ocean will
adapt to changes in the atmosphere and how fast a new equilibrium is reached
This view is too
narrow. More mechanisms are at work. Several thousand offshore facilities reach
the bottom of the sea or anchored offshore wind turbines, divert currents at
sea and influence tides and currents as a permanent resistance against the
normal flow of huge amounts of ocean water. Many ship propellers are plowing
through the sea stirring the surface layer to a depth of 15 meters. In the
North Sea and Baltic there are continuously ten thousand motor ships at sea.
The result is like
stirring soup, or a baby bathing water.
During the winter season warm water will come to the surface and the
heat will supply the atmosphere with warmth. The air will become warmer and the
winters will be milder. The correlation is not to be underestimated. Climate
research or agencies overseeing marine activities pay little attention for such
considerations. They actually ignore it completely.
2. Stronger than
The situation at the
beginning of the evaluation is obvious. Over recent years the rate of increase
in sea surface temperature in all European seas has been about 10 times faster
than the average rate of increase during the past century. In five European seas
the warming occurs even more rapidly. In the North and Baltic Seas temperatures
increased five to six times faster than the global average, and three times
faster in the Black and Mediterranean Seas. .
In about 1995 SST
(sea surface temperature) between the North Atlantic, North Sea and Baltic were
at the same level (Fig. 1), while the latter show a dramatic increase since.
With 11.4 ° C as annual average, the temperature of the North Sea surface water
was 1.5°C higher than the long-term average (Fig.2).
The same is reported
about the Baltic. This had a direct influence on air temperatures. During the
period 1871 – 2004 there were significant positive trends in the annual mean
temperature for the northern and southern Baltic Sea basin, being 0.10
°C/decade on average to the north of 60° and 0.07°C/decade to the south of
60°N. The trends are larger than for the entire globe which amount to 0.05
°C/decade (1861 – 2000), assessed a BALTEX Conference in 2006.
According to the
BACCII Report 2015  in recent years (1990-2004) all years except for one,
1996, had a mean temperature above normal for most of Europe, and that daily
minimum temperature has increased much more than the daily maximum. This interesting
aspect with regard to shipping is – inter alias – discussed later on. The
Report furthermore suggests changes in seasonality:
The length of the growing season and the sums of
positive degree days have previously been shown to increase, whereas the length
of the cold season and the frost days has decreased. The start of late autumn
(i.e. the end of the growing season, indicated by a continuous drop in daily
mean air temperature below 5°C) occurred 8 days later and the start of winter
(indicated by the formation of a permanent snow cover) 17 days later. The
duration of summer increased by 11 days and of ‘early winter’ by 18 days, while
the duration of winter proper has decreased by 29 days. The length of the
growing season (defined by a daily mean air temperature permanently above 5°C)
increased by 13 days.
Commission (HELCOM) confirmed in 2013 that “On average since the late 19th
century” the increase in annual average surface air temperature has been 0.11˚C
per decade in the northern Baltic and 0.08˚C in the southern Baltic compared to
the global average of 0.05˚C per decade.” .
between North and South can be explained by the fact that the southern Baltic
is shallower than the eastern Baltic. That means there is less volume of water
available for storing heat (summer) and releasing it (winter). The over
proportional warming of water and air is self-evident. To link this to global
warming cannot be convincing. How can global warming lead to specific higher
warming in these regional seas? During winter when the nights are long and
sun-ray remote? Rather, it should be asked; have shipping and offshore
activities contributed to pronounced reginal warming?
By means of shipping, windfarms, fishery, and
more, the North and Baltic Sea were warmed
excessively by late summer, which
increased air temperature until next February,
a case of warming Europe!
3. The effect of
water temperatures consist in a sea water column, due to internal or external
forcing, an exchange between the sea layers happens at any time. As already
mentioned winds and storms are observed factors . But about human forcing
‘obstacles’ little is taken into account, although it is well known that there
is a strong interaction between a physical structure and a flow field (Fig.3).
All offshore wind
turbine units are connected with the sea floor, either by platform or anchored
as floating units. The former is usually used for water depth of up to 60
meters. A floating structure consists of one or more steel cylinder filled with
ballast of water and rocks, which can extend 100 meters or more beneath the
sea’s surface. Currently used on most offshore wind projects, the foundation consists
of a large base constructed from either concrete or steel which rests on the
seabed, whereby one or more piles are driven 10 to 20 meters into the seabed.
Every pile has several meters in diameter. A ‘natural’ current system, whether
due to temperature difference and salinity (density currents) or tide, will be
Of not less impact is
shipping. On one hand the vessel draught effects directly only the sea surface
layer accordingly, on the other hand much more intensive as offshore structures
due to motor propulsion. At a speed of 18 knots a ship travels about 800
kilometers in 24 hours, leaving a mixed water column behind down from few to a
According to HELCOM ‘two thousand sizable ships’ navigate the Baltic at any
time . By rough calculation this means, that the entire Baltic sea surface
down to 10 meters and more is mixed in about two weeks’ time, or 30 times per
year. That means: During the summer season more heat will be forced into deeper
layers, in winter more heat comes out of the water body.
4. More heat input –
More heat output.
4.1 General overview
The mean water depth
of the Baltic is 52m (Nord Sea 94m) and is less in the south-west than in the
eastern Baltic. The salinity is very different from location to location, but
in average considerable higher in the North Sea (32-35psu), low in the western Baltic
(about 8psu), and Gulf of Bothnia near zero. As a general rule the water
temperatures vary over the seasons in the upper 50 meters water column, below
that depth the water is cold and remains fairly unchanged throughout summer and
winter. That applies either to the North Sea as well as to the Baltic Sea. As
an example may serve a quarterly vertical profile from the Eastern Baltic
(close to Gdańsk Bay) (Fig. 4).
For a more detailed
review of the situation at the end of the summer season, when intake of heat
ends and reverse, the next graph indicate the temperature profiles in the two
seas. In a North Sea cross section along Latitude 56,5° North during September
the huge temperature the difference between the warm and cold water body is
well indicated (Fig.5). Below about 40-50 meters the heat intake in summer is
very moderate, as the statistical minimum from March to May is 6°C.
Since mankind, during
the course of a year, agitates the water column of North Sea and Baltic by
stirring, more warmth is taken to deeper water in the summer season and rises
to the surface from lower layers in the winter period, where heat is exchanged
with the air until sea icing is observed. This is a process that can be seen
from the beginning of September until the end of March.
4.2 Sea Ice as indicator for human activities
Sea ice conditions in
the Baltic have been systematically monitored for more than a century. But
never the question has been raised whether human activities have ever
contributed to the fact, that the last near complete ice-cover in the Baltic
Sea occurred one quarter Century ago (1986). During most recent winters the
Gulf of Bothnia remained almost free of sea ice, and reached by mid-March only
a fraction of normal.
play a much bigger role in time factor and duration of ice formation. If the
sea surface temperature has already reached the freezing point, any vessel
shovels warmer water to the surface, or vice versa, forcing a more rapid melt.
Some indications can be found in this respect, mentioned by the BACCII-Report:
“Ship-induced waves are known to prevent the formation
of a permanent ice cover in autumn and also to enhance break-up of the ice
cover in spring, and so an increase in the size of vessels and the intensity of
shipping activity could also affect ice conditions.”.
How can it be ignored
that the water body below a sea surface of zero degrees is usually warmer, and
ships and other obstacles force warmer water to the surface. The shrinking ice
cover correlates well with an increase in human activities, and subsequently
leading to higher air temperature throughout the region.
A. Regional seas in
Northern Europe are minor from size and volume in global ocean affairs. Weather
is “done” elsewhere, but every location contributes to the global picture. In
the case of N-Europe it may be more significant as weather can be divided in
maritime and continental influence, and due to the global air circulation from
West to East, it is a gate. It may support the flow of warm wet air eastward
(low pressure), or stem it by dry and cold continental air (high pressure), by
diverting low pressure areas – in extreme circumstances - towards the Bering
Sea or Mediterranean. In so far the North Sea and Baltic play a crucial role in
how to open or close this gate.
But according to SST
statistics, the gate sea area warming increase more than in other sea areas in
Europe, and here stronger than the oceans worldwide (Fig.1). This phenomenon is
not explained with a general reference to ‘global warming’. A reasonable
explanation is pending. Many “weather factors” may play a role, such as river
runoff, precipitation, cloudiness, sea ice cover, but that has not yet lead to
a sufficient conclusion, as none of them can be regarded as a driver in
The major player in
this respect is water, and the genuine mass of it is contained by the oceans
and seas. Smaller water bodies are no exception. Geographical features, as the
Norwegian high mountain range, which hinders the free flow of Atlantic air
eastwards, provide a particular scenario to study and understand how much the
water body in lee of the barrier contributes to the regional weather and
climate. The sea water condition in the North Sea is not less interesting, as
it is the main gate on how the west-wind flows.
B. Basically only
three facts are established: higher warming, a small shift in the seasons, and
a decreasing sea ice cover. In each scenario the two sea’s conditions play a
decisive role. These conditions are impaired by wind farms, shipping, fishing,
off shore drilling, under sea floor gas-pipe line construction and maintenance,
naval exercise, diving, yachting, and so on, about little to nothing has been
investigated and is understood. The little that can be done is to do
If SST rise in the
North Sea more than elsewhere (section 2) and human activities rise as well,
the influence on the temperature profile is a serious issue. During summer more
heat is pushed down, but available for release during the winter season. The
down push is a merrily mechanical exercise, while the interaction between the
sea surface and the atmosphere is a highly complex matter requiring certain
conditions. Thus it is easier to force heat mechanically into the sea body,
while it takes some time until ‘natural processes’ release the ‘additional’
heat according the laws of physics.
It is almost
unthinkable that the seasons remain stable (section 2). Until June the water
body is still fairly cold, whereas the upper surface layer gets lots of sun
rays and warms. Any moving vessel replaces the warm layer with colder water.
The air gets fewer vapors, which support high pressure, continental condition
with fewer clouds and more sunshine. For famers the growing season may start
earlier. For a clearer picture one would need data, from many hundred stations
alone in the Baltic, with many dozen collectors from the sea surface to the sea
The winter season is
a much easier situation for climate research. The reason is simple. The
ultimate factor in the climate system, the sun, has a low inclination, the
nights are long, and the sea receives only a moderate amount of sunrays. The
scene is governed by lows from the Atlantic, continental highs, and the heat
release from North Sea and Baltic. The surface layer transfers more heat to the
atmosphere as it receives from the sun, and cools down quicker than sub-layers
(Fig. 7). The interchange between the layers depends primarily on internal
physical processes (temperature, salinity, and others), and on external forcing
such as wind and numerous human activities. Both factors force a much higher
and rapid heat transfer. The winters are getting warmer. It surprises that
science pays so little attention on the mechanism during the winter season, and
neglects the impact of human activities.
Presumably an even
more convenient case for studies is sea ice condition. The annual period for
analyses is shorter (about December to April). From the moment sea ice has
established, the influence by wind diminishes. Human activities rise to a big
player in the sub-surface temperature and salinity water structure. Motor
vessel impact goes much further than: “Ship-induced
waves prevent the formation of a permanent ice cover in autumn and also to
enhance break-up of the ice cover in spring” (section 4.2).They churn a
water column down to ten meters and more.
SST can easily change
from zero to several plus degrees. Very critical is the impact of vessels
navigating in ice-fields, when the water body is cut-off from interaction with
the atmosphere. As warmer water is less heavy as colder water any vessel’s wake
spreads below the ice bottom. Although sea ice mechanism and duration is
intensively observed and studied in the Baltic Sea since the 19th
Century  the impact by human activities in the marine environment received
hardly any attention.
C. The biggest
impediment to explain the disproportionate warming convincingly is of a
fundamental nature. The dominant role of the sea in climatic affairs needs to
be more recognized. Without this requirement, a sustainable scientific work
cannot be organized. So an organization then requires a major effort in terms
of concepts, data, computer capacity, competent researchers and a lot of money.
A much cheaper way –
at least about the role of the sea in climate affairs – to analyze and explain
the extraordinary war winters in Europe, particularly 1939/40, 1940/41 and
1941/42 (Fig.8) most likely primarily caused by naval warfare. Although with
the start of naval war in September 1939 also a pronounced global cooling commenced
lasting until the mid-1970s science has not shown any interest.
From September 1st, 1939 until Pearl Harbor in
December 1941 naval warfare was primarily a European affair, and the bulk of
naval activities took place in North Sea and Baltic, releasing too much heat
stored in the sea too early, thus allowing cold air from Siberia to take reign
over Western Europe up to the Ireland (section 5.A.). Across large parts of
Europe temperatures dropped to Little Ice Age level.
The facts are
conclusive. ‘Global Climate Change’ cannot cause a special rise in temperatures
in Northern Europe, neither in the North Sea nor the Baltic or beyond. Any use
of the oceans by mankind has an influence on thermo-haline structures within
the water column from a few cm to 10m and more. Noticeable warmer winters in
Europe are the inevitable consequence.
Summary: The marine
environment of North Sea and Baltic is one of the most heavily strained by
numerous human activities. Simultaneously water and air temperatures increase
more than elsewhere in Europe and globally, which cannot be explained with
‘global warming’. The climatic change issue would be better understood if this
extraordinary regional warming is sufficiently explained. The regional features
are unique for in-depth studies due to different summer-winter conditions,
shallowness of the seas, geographical structure, and main pathway for maritime
weather patterns moving eastwards. The impact of sea activities on the seasonal
sea water profile structure is contributing to stronger regional warming,
change in growing season, and less severe sea ice conditions. The impact of the
man, whether small or large, should be understood very soon and very
thoroughly. (Reference below next box)
shorted version of a paper published 2015:
Feb 1940 and 2021 in comparison
Even though there is
a cold spell the
Naval war since
Sept. 1939 contributed to
the cold in Europe
In winter 1940
the Baltic was
full covered on
08 March 1940
In winter 1940 many
Don't miss to read
he text about
More Temperature Maps
1. Gröger, Matthias; Dietrich, Christiab; Meier Markush
H.E.; Schminake, Semon, 2015; „Thermal air–sea coupling in hindcast simulations
for the North Sea and Baltic Sea on the NW European shelf”; Tellus A 2015, 67,
26911, http://dx.doi.org/10.3402/tellusa.v67.26911; PDF, page 2.
2. European Environment Agency (EEA), 2015;”Rising sea
surface temperature: towards ice-free Arctic summers and a changing marine food
chain”; http://www.eea.europa.eu/themes/coast_sea/sea-surface-temperature BALTEX
Assessment of Climate Change for the Baltic Sea Basin, 2006; International
Conference Göteborg, Sweden 22 – 23 May 2006; http://www.baltex-research.eu/BACC/material/IBS_No35_BACC; PDF, page 7.
3. The BACC II Author Team (Editor), 2015; “Second
Assessment of Climate Change for the Baltic Sea Basin, Regional Climate
Studies”, Open access at SpringerLink.com, pages 501 (Chapter 4, A. Rutgersson
et al, p. 83f).
4. The BACC II Author Team (Editor), 2015; “Second
Assessment of Climate Change for the Baltic Sea Basin, Regional Climate
Studies”, Open access at SpringerLink.com, pages 501 (Chapter 4, A. Rutgersson
et al, p. 83f).
2013; “Sea Surface Temperature in the Baltic Sea in 2013”; Press release
27/09/2013 11:01; http://www.helcom.fi/news/Pages/Warming-in-the-Baltic-Sea-region-is-expected-to-continue-and-alter-the-marine-ecosystem.aspx
7. The BACC II
Author Team (Editor), 2015; op. cit.; (Footnote 4), Jari J. Haapala et. al.,
Chapter 8, p. 153
8. op. cit.
(Footnote 7), p. 145.
Weekly T°C Anomaly
since January 2021
Forecast for February 2021 (over six weeks)
last week January 2021
EUROPE - Air and SST anomalies
in comparison since 24th December 2020
based on "[Data/Image] from Climate Reanalyzer
(https://ClimateReanalyzer.org), Climate Change Institute, University
of Maine, USA
El Niño in
Winter 2015/16 –versus- Winter 1939/40
15th Post - March 12, 2016 /April 04/
14. June 2013: Met Office
bad weather, titles THE GUARDIAN – 13. June 2013 (ocl-7-9)
April 2013: Met-Off
loose talk on cold March 2013?
North and Baltic Sea should not be ignored! (ocl_9-8)
April 2013: 'Urgent'
need to see if Arctic affects UK extreme cold? No! MetOffice should
investigate the impact of human activities in the North- and Baltic
Sea ! (co_9-4)
03 April 2013: Did
the cold March 2013 came from Siberia ? A not well founded claim!
29 March 2013: Cold
March 2013 in company with March 1942 & 1917 (co 10-2)
27. March 2013: Strong
Start – Strong Ending; Winter 2012/13. About the Role of North-
and Baltic Sea (2007seatraining 1310)
26. March 2013; March
2013 snow in the UK and the North Sea . Did human activities
contributed? (ocl 10_2)
21 March 2013; Cold
March 2013 in UK and North Europe science should be able to explain!
07 March 2013: Winter
2012/13 for Northern Europe is over! The Baltic and North Sea will
prevent a surprise in March! (ocl-10_4)
19. January 2013: Northern
Europe's bulwark against Asian cold from 19-31. (oc_12-8)
14. January 2013: North-
and Baltic Sea influence Europe ’s winter 2012/2013 until now.
December 2012 (+ 21 & 26 Dec) : Are
we heading to severe Baltic Sea ice conditions by 30th December
on arctic warming causes cold winters
Tang et al 2013 Environ. Res. Lett. 8
Cold winter extremes in northern continents linked to Arctic sea ice
results suggest that the winter atmospheric circulation at high
northern latitudes associated with Arctic sea ice loss, especially
in the winter, favours the occurrence of cold winter extremes at
middle latitudes of the northern continents.”