“I endeavoured to explain to my people the nature of that ’white thing’, for which no name exists even in the language of Jagga itself. … It made a singular impression on my mind in the view of the beautiful snow mountain so near to the Equator…”
— Johannes Rebmann, 1849To most people, the occurrence of glaciers in equatorial regions of the World is unexpected, and an apparent anomaly of Nature. In fact, glaciers near the Equator are found in only three regions of the World: the Ecuadorian Andes, the cordilleras of New Guinea, and the high mountains of East Africa. For this very reason, equatorial glaciers are of particular interest to the glaciologist.
In 1981, Stefan Hastenrath published an exciting monograph on the glaciation of the Ecuadorian Andes since the Pleistocene. The existence of snow and ice in the equatorial Andes had been known since the 1500s and there are excellent historical accounts available to the researcher. Hastenrath has now transported himself from South America to Africa to deal with a similar problem. The 5000–6000 m glaciated mountains of East africa were only discovered in 1848 by Rebmann. His claimed observations of snow on Mount Kilimanjaro and Mount Kenya were met at that time with total scepticism. However, since then many explorers and scientists have studied this region′s snow and ice cover, and today there is an abundance of sound scientific information.
One must say at the outset that this book is not for the casual reader but for the serious-minded scientist. Its careful description and detailed referencing, backed up by numerous maps, diagrams and photographs, are quite sufficient evidence that the author has researched his topic thoroughly. In a book of this nature, it is surprising to find so much intricate detail: on one page there are diagrams, illustrating “surface resultant wind directions and speeds", contrasting with “annual rainfall” and even photographs of stone stripes, earth ribbons, and stone polygons several pages later. The whole environmental setting is well described and places the reader in the correct frame of mind to digest later chapters.
It is quite clear that the history of glaciation in East Africa extended back in time to the Pleistocene, but the evidence presented by various authors is somewhat tenuous and really needs much more critical evaluation. The sequences of moraines have led to the establishment of a time-scale which could be modified substantially on the basis of more detailed correlation. However, it is even clearer that in Recent times there has been marked deglaciation and retreat of most glaciers. The Recent glaciation′s extent is well documented and illustrated both with historical maps and photographs.
Perhaps it is not surprising to discover that almost half the book is devoted to Lewis Glacier on Mount Kenya. Easy of access for the University expedition, much useful work has been done on this glacier and its documentation is unparalleled as far as equatorial glaciers are concerned. Certainly, every conceivable glaciological parameter has been documented and experiments recorded in the minutest of detail. It is encouraging to note the extent of knowledge available for this glacier.
The author has shown his concern for the reader in providing an extensive bibliography, both author and subject indexes, and end maps. The appendices, citing lists of topographic maps, air photographs and satellite imagery, historical photographs and drawings, and data for the world glacier inventory, give the newly recruited researcher an unparalleled advantage. This book is a masterly compendium for those glaciologists seeking knowledge slightly outside their own specific fields of research.
Perhaps Stefan Hastenrath will now voyage to the cordilleras of New Guinea and complete the trilogy!
