The impact of shipping on ocean and global warming
 15^th December 2012

by Dr. Arnd Bernaerts

Graphics are enlargeable

  The ocean dimension is huge, either is the growing impact of shipping, navies, fisheries on the oceans tremendous (HERE). During the last 150 years sea traffic has been growing several thousand times, and the earth warming correspondingly (Fig.1 & 2). Discussed: HERE Every vessel at sea is churning, turning, and mixing the

surface layer down to 15 meters. The new MS MARCO POLO  (fig.3)has a draught of 16 meters, length 396 m, a beam of 53,6 m  and a maximum speed of 25.1 knots (46.5 km/h). Within 24h a distance of 1’000 km can be covered, which means that a sea area of about 5x5 km and down to 16 meters the temperature and salinity structure has been thoroughly mixed. The difference between top and bottom of the layer of either several degree temperatures or per mille salinity may have been changed to a uniform level. That has an impact on the weather and climate, because the deeper sea surface heat from the sun is pushed down to a lower level, the higher the heat content of the ocean (see e.g. day and night time T°C at 0,5 and 1 m in the Skagerrak and Baltic Sea; Fig. 4, 5 & 6). The warmer the ocean upper layer get, the more we observe “global warming”, (as far as one ignores mixing within the entire water column of an ocean that has an average temperature of about 4 degrees Celsius.) .

  The mixed layer plays an important role in the physical climate. Because the specific heat of ocean water is much larger than that of air, the top 2.5 m of the ocean holds as much heat as the entire atmosphere above it. Thus the heat required to change a mixed layer of 25 m by 1 °C would be sufficient to raise the temperature of the atmosphere by 10 °C. (wikipedia/Ocean mixed layer). According Hong Zhang et al , (PACOMS-2008-P08-22) Wind, wave and current interactions control the boundary fluxes, momentum and energy exchange between the atmosphere and the ocean, and within the water column. For low wind speed, the wave effect is not significant, but at wind speeds above 10 m/s, the magnitude of the surface stress can be doubled.

               below : Figure 7, enlargeable
Several ten thousand sizable vessels with a draught of more than three meters mix a sea area of a huge sea area every day, and 365 days per year. The mixing takes place regardless of wind and wave conditions. Up to a wind speed of 4-5 Beaufort (Bft), the wind impact on the upper sea level is negligible (Fig.8). This is situation in about 40-45 % in average with regard to wind, while vessels do the mixing alone. Between 5-8 Bft wind and vessels compete with another (Fig.9). Above 8 Bft the wind is defiantly a much bigger force than shipping. However it accounts only less than 10% of the overall wind force available. But even a severe hurricane is unlikely to cause a mixing lower than about 50 meters. Sea surface mixing by merchant, navy, fishing vessels is a matter to reckon.

  HERE the news from IPCC-DRAFT (2012), AR5, Supplement for Policymaker
 (available via source: WUWT):

_p.4/Line33__Largest warming is found near the sea surface (>0.1°C per decade in the upper 75 m),

_p.4/Line40__Warming of the ocean accounts for more than 90% of the extra energy stored by the Earth between 1971 and 2010.

AND THAN THAT:

__p.10/41__It is very likely that more than half of the ocean warming observed since the 1970s is caused by external forcing, mainly due to a combination of both anthropogenic forcing and volcanic eruptions.

 WHAT DO THEY THINK IS THE IMPACT OF SHIPPING?
IGNORING IT IS IRRESPONSIBLE.  

200 years ago one person understood more from the global weather and climate system as many ten thousand scientists today: 

Everything comes from water!!
Everything is maintained through water!
Ocean, give us your eternal power.
Drama: Faust II; J. W. v. Goethe (1749-1832)