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"Ice to the Cape" – the debate continues...

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Dr Olav Orheim believes that the concept of “Ice to the Cape” can become a reality in the near future

In response to an article titled Are icebergs a realistic option for augmenting Cape Town’s water supply? in the December 2017 edition of SAEON eNews, we received this letter to the editor from Dr Olav Orheim, initiator of the ship-borne iceberg observation programme under the Scientific Committee on Antarctic Research (SCAR) and First Chair of Committee for Environmental Protection under the Antarctic Treaty:

Dear editor,

The most recent issue of SAEON eNews had an article titled "Are icebergs a realistic option for augmenting Cape Town’s water supply?" Although it is clearly written and has some interesting observations, it also contains fundamental errors that should be corrected – as we believe that the question of "Ice to the Cape" is possible and shall become a reality if this concept receives serious evaluation.

1. Most importantly, the article is totally unrealistic with regards to iceberg sizes and properties. It discussed towing "a decent-sized (say 20 km long) iceberg". This is meaningless, being magnitudes larger than any towable berg. To put it in perspective, an Antarctic iceberg 20 km long x 10 km wide is more than 10 000 times larger than the largest object so far moved by humans. A realistic towable iceberg, in our opinion, is 1.0 x 0.5 km in above-water dimensions. This size could provide Cape Town with 200 000 m³ fresh water daily for about one year.

The article further seems not to appreciate the particular nature of the large Antarctic icebergs, as compared to Arctic icebergs. These Antarctic icebergs are flat "tabular" slabs of ice, and although many have internal flaws and therefore may break up, they do not roll over until their horizontal dimensions are reduced to approximately the same as the vertical dimension, which is generally around 250 m.

2. The article claims that the presence of the iceberg would affect ocean circulation and local weather. That will not be the case for a "small" tabular iceberg of the dimensions given above. The iceberg will be stranded many kilometres offshore, and its impact on local air and water temperatures will only be discernable immediately around the iceberg, with very minor impacts on the local ecosystem.

3. The article suggests that an iceberg rolling over could cause a "mini-tsunami" with hazards to both shipping and coastal structures. Certainly, ships should avoid travelling close to such an iceberg. However, roll-over by a realistic-sized berg would not cause a tsunami to be felt ashore, many kilometres away.

4. The article asserts wrongly that it will be illegal to tow icebergs from the Southern Ocean, and refers to the Antarctic Treaty. The Treaty does not discuss ice harvesting, which most likely is not covered by the Environmental Protocol under the Treaty. In any case, any towed iceberg would be picked up far north of 60°S, i.e. north of, and outside of the boundary of the Treaty. It would be an object floating on the High Seas, slowly melting on its eastward passage around the southern oceans or awaiting to be harnessed by the first who could do so.

5. There are at any time around 200 000 icebergs floating in the Southern Ocean. While 20 km long bergs are very rare, approx. 20 000 of the icebergs have length above 0.5 km. Of course, a very small proportion of these will have suitable position, size and strength for towing towards Cape Town.

6. Each year approx. 2 000 km³ of ice enters the ocean from the Antarctic ice sheet, while the towable bergs discussed above are around 0.1 km³. Clearly, bringing 0.005% of the total bergs 20o to 30o further north before they melt cannot significantly affect regional ocean or weather conditions.

7. The article states that the cost of towing a huge iceberg near to the Cape would run into billions of US dollars. We estimate that towing, or guiding, realistic icebergs into the Benguela Current and making a landfall north of Cape Town offshore of St Helena Bay, would be less than the cost per cubic metre of desalinated water schemes presently approved by the Western Cape Government.

We believe that with venture capital, the concept of "Ice to the Cape" will become a reality in the near future, and certainly within the next five to ten years!

Yours sincerely,

Dr Olav Orheim (Initiator of the ship-borne iceberg observation programme under SCAR and First Chair of Committee for Environmental Protection under the Antarctic Treaty)

Ing. Georges Mougin (Director of former company "Iceberg Transport International" and now of the company "WATER and POWER from ICEBERG")

Captain Nicholas Sloane (Director Resolve Marine Group Founder; Cape Ice – for the Cape)

Enquiries can be directed to Dr Orheim.

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