1. Climate change and its
effects on transport flows
and risks
Debontridder Luc – Operational
scientist – Climatologist
Royal Meteorological Institute of
Belgium

2. Topics
• Freak or so called rogue waves.
• Frequency of winter storms.
• Hurricanes - Typhoons.
• North Pole ice.

3. Freak or rogue waves
• What ?
• Occurances ?
• Causes and types ?
• Draupner wave
• Maxwave project
• Link with climate change unknown

4. What ?
Rogue waves have been part of marine folklore for centuries. They are
generally considered to be unexpectedly high waves which in some
instances come from a direction different from the predominant waves in
the local area. A single rogue wave has certainly been known to spell
disaster for the mariner. They have, over the past twenty or thirty years,
come to be recognized as a unique phenomena albeit with several
possible causes.
How strong are they? The force of a breaking freak wave is tremendous.
A 12-meter wave in the Linear Model has the force of about 6 MT/m2. A
rogue wave, however, has a force of about 100 MT/m2. Modern day
vessels are designed to withstand only 15 MT/m2. It is therefore
understandable why some ships do not survive freak waves.

7. Occurances
Ship accidents between 1995 and 1999 from Hapag Loyds accident
database.

8. Causes and types
1) Constructive interference.
Several different wave trains of differing speeds and directions meet
at the same time. The heights of the crests are additive so that an
extreme wave may result when very high waves are included in the
wave trains.
2) Focusing of wave energy.
When storm forced waves are developed in a water current counter
to the wave direction an interaction can take place which results in
a shortening of the wave frequency. The result is the superimposing
of the wave trains and the generation of extreme waves. (ex.
Agulhas current). → Extreme wave developed in this regime tend to
be longer lived.

9. 3) Normal part of the wave spectrum.
The generation of waves on water results not in a single wave
height but in a spectrum of waves distributed from the smallest
capillary waves to large waves. The random nature of waves implies
that individual waves can be substantially higher than the significant
wave height. In fact, observations and theory show that the highest
individual waves in a typical storm with typical duration to be
approximately two times the significant wave height. Some reported
rogue waves are well within this factor of two envelope. Waves
higher than roughly twice the significant wave height fall into the
category of extreme or rogue waves.

10. The Draupner Wave
On New Year’s Day 1995, the Draupner oil rig was in the middle of a
storm in the North Sea. Its radar sensors were regularly recording waves
with heights of 12 meters, when it was suddenly hit by a freak wave 26
meters high
The Draupner wave, January, 1, 1995.

11. The MAXWAVE Project
The European Project MAXWAVE deals with both theoretical aspects of
extreme waves as well as new techniques to observe these waves using
different remote sensing techniques. The final goal was to improve the
understanding of the physical processes responsible for the generation of
extreme waves and to identify geophysical conditions in which such waves are
most likely to occur.
Partners of the project
GKSS Research Center, Germany
Institute of Hydroengineering, Polish Academy of Sciences
Norwegian Meteorological Institute (Met No)
German Aerospace Center (DLR)
UK Meteorological Office
Instituto Superior Tecnico (IST), Portugal
Meteo France
Ocean Waves, Germany
Catholic University of Leuven, Belgium
Technical University of Berlin, Germany
Det Norske Veritas (DNV), Norway

13. Frequency of winter storms.

14. Maximum daily wind speed in De Bilt between 1962 and 2005, and the four climate
scenarios for 2050 (coloured points). The thick black line represents the 30-year
moving average of the observations. The thick coloured and dashed lines connect
each climate scenario with the baseline year 1990. The grey band represents the
year-to-year variation, derived from the observations.
Storm surges along the Dutch and Belgian coast are associated with storms coming
from western to northern directions. The model calculations used for the four
scenarios show only small changes in the number of storms from these directions.

15. Frequency of hurricanes - typhoons
Frequency of North Atlantic Hurricanes depends on multi-decadal changes in surface
sea water temperatures and methods of observation !!!!!!

16. • There is a common misconception that since the global temperature has increased, hurricanes
also must increase in number and intensity.
• The primary factor in the ability of a hurricane to strengthen or weaken is the wind shear
profile of the atmosphere - not water temperature.
• The recent upturn in tropical cyclone activity was predicted long before Global Warming
became a household name.
• As we have noted, the number one factor in tropical cyclone intensity is related to the
atmospheric wind shear profile. There is even some research that suggests that higher
temperatures could actually increase the wind shear profile resulting in a decrease in hurricane
activity.
• The upward cycle in hurricane numbers is expected to continue for several more years. If this
trend were to continue for a considerably longer period, only then could one draw a conclusion
that warmer temperatures have played some part to cause an increase in tropical cyclone
formation.
• There is no proven scientific evidence that there is a link between climate change and the
number of hurricanes in the Atlantic basin. In the pacific there is even no change at all. There is
a possibility (IPCC 2007) that there will be an increase in intensity, especially in rainfall
quantities and not in wind speed.

17. North pole ice navigation
Sea ice extent north pole

20. ● It seems unthinkable, but for the first time in human history, ice is on course to disappear
entirely from the North Pole this year.
● The disappearance of the Arctic sea ice, making it possible to reach the Pole sailing in a boat
through open water, would be one of the most dramatic – and worrying – examples of the impact
of global warming on the planet. Scientists say the ice at 90 degrees north may well have melted
away by the summer.
● Seasoned polar scientists believe the chances of a totally ice-free North Pole this summer are
greater than 50:50 because the normally thick ice formed over many years at the Pole has been
blown away and replaced by huge swathes of thinner ice formed over a single year.
● Each summer the sea ice melts before reforming again during the long Arctic winter but the
loss of sea ice last year was so extensive that much of the Arctic Ocean became open water, with
the water-ice boundary coming just 700 miles away from the North Pole.
● Technological advances and changing climatic circumstances are bringing us new challenges
and opportunities. One of those is increasing maritime transport in Arctic waters, even the
possibility of a new sea route across the North Pole linking the North Atlantic and the North
Pacific in closer commercial relations than ever before.
● At the same time new shipping routes will bring new economic opportunities to the
communities in the North. This applies in particular to Iceland that will be in a key location for
servicing the Northern Sea Route in the future.

21. “Breaking the Ice : Arctic Development and Maritime Transportation”
Government of Iceland in Akureyri on March 27-28, 2007