After the publication two days ago in the PNAS (Proceedings of the National Academy of Sciences of the United States of America) of an article from G. W. Kling et al. "Degassing Lakes Nyos and Monoun: defusing certain disaster", I received a lot of correspondence (emails, phone calls). People are asking me whether I can give some additional details on the degassing project performed by Kling and colleagues.

First I would ask the reader to refer to the EOS paper we published in July 2004 in which the exact contribution of each participant is explicitly mentioned (Degassing the "Killer Lakes" Nyos and Monoun, North West Province of Cameroon, Halbwachs et al., EOS, 85, 281, 2004).

Second, let me add some details regarding who has done what.
On several instances (in news media, magazines, web sites, conferences, workshops, and now in a scientific article) the degassing of lakes Nyos and Monoun has been presented by the American and Japanese scientists as an ordinary civil engineering project, cause for international funding, but not worth citing as influential in determining the nature of the reported work. Beside accounts of the response of the lakes to degassing, degassing operations per se constitute an indisputable long-range scientific project. Those who contributed significantly to its design, achievement, implementation and field trials ought to be given appropriate credit

The Americans and the Japanese scientists seem now to be trying to take over a project in which they have in no way participated.

The real truth is that this huge task was accomplished by more than 12 French scientists, engineers and technicians from various disciplines who worked enthusiastically for nearly 20 years on the project. For these guys it is amazing that anyone would want to steal their thunder! Or their water spout!

The real chronology of events looks something like this:

- 1987: publication of the "Livre blanc" on the degassing project of lakes Nyos and Monoun by J. C. Sabroux, French Ministry of Environment,
- 1990: first demonstration of the self-siphon process at Nyos and Monoun with one cm diameter pipes,
- 1992: successful self-siphon at Monoun using 50 mm and 145 mm diameter pipes,
- 1995: successful experiment at Nyos: a 20 metres fountain was triggered using a 145 mm diameter pipe,
- 2001 the first permanent degassing fountain at Nyos (50 m in height),
- 2003: the first permanent fountain at Monoun (8 m in height).
- 2006: implementation of two additional columns at Monoun

So just to get it straight (again!): the American and Japanese teams never worked on the existing degassing projects. They did not participate at any level in the conception, design or construction of the degassing device. They did not participate, they just attended (with their cameras) some experimental phases.


So what did the Americans do?
The US participation in the degassing project was only financial. Regarding the foreign funding directly involved in the degassing project, approximately 400 000 USD was provided by the USAID/OFDA while 575 000 Euros of the support came from the French Embassy in Yaoundé, the European Community and a French sponsor "Fondation Gaz de France".
The major part of the overall funding (two degassing columns at Monoun, logistic support, roads construction, buildings…) came directly from the Cameroonian Government.


I hope so.

Michel Halbwachs, September 28th, 2006


I am not going to spend time discussing the contents of the PNAS article in detail. However, as a physicist, its content seems to me to be, at the least, bizarre.
And yet this article deals with an important subject which could have seriously adverse consequences for the safety of the population living in the area around the lakes. Thus, I must insist here that the G. Kling definition of the stability parameter E* is absolutely wrong on the scientific level.
The Reader should refer to the annex "A tentative lakes safety state evaluation" in the present web site. The model I have employed, based on the calculation of the potential energy barrier that needs to be surpassed in order to produce an explosion of gas, leads to conclusions diametrically opposed to those now published by G. Kling.
If, for example, one takes the case of Lake Monoun - the most dangerous at the moment - the model I propose indicates that safety is at its maximum in the deepest layers of the lake, whereas it is minimal in the model proposed by G. Kling.