Dear friends in the blogosphere, I received a precious gift from a Dutch friend a little while ago. Living on the Edge: Wetlands and Birds in a Changing Sahel is a massive book, comprising 564 pages in full color and countless stunning photographs (see footnote for publication details). The tragic story of the Senegal River Delta described in this book reminded me of Roger Pielke’s studies of climate change in Florida, caused by the drainage of swamps and the southward march of citrus plantations over the last century. In 1985, I saw with my own eyes how the River Jordan is drained to a trickle flow to irrigate the fertile soil at the foot of the Carmel Ridge. I know of the enormous amount of water drained from the Colorado River to irrigate California’s Central Imperial Valley, and, like many others, I worry what will happen to the western prairie states after the Ogallala Aquifer, from which 26 billion cubic meters of water is extracted annually, has been depleted.
There is much more to climate change than the rallying cries about Global Warming suggest. Nowhere is this made clearer than in the Sahel, a narrow strip of African countryside between the Sahara Desert in the North and the rain forest along the Gulf of Guinea in the south. The annual rainfall in the Sahara is only 20 millimeters, but 400 kilometers to the south the annual precipitation reaches 2000 millimeters or more. In the Sahel, plants, animals and people live on the edge of what is ecologically sustainable. Living on the edge of the cliff, as it were. The title of the book projects an apocalyptic image.
This problem became acute around 1965, when the entire Sahel threatened to succumb to desertification. No one less than Jule Charney, the great meteorologist we all admired, studied this issue in great detail. In conversations with George Platzman, he said : “at that time we were getting news of the terrible drought in the Sahel, and it occurred to me that the overgrazing, which I ascertained occurred over an enormous area – I mean the cow, since there’s very little forage in the first place, could crop whatever brush or grass exists over an enormous area, that it was not unreasonable to take an area the order of 400 kilometers in the north-south direction, and going across the whole Sahara …. I proposed to Jastrow and Halem at the Institute for Space Studies that they should take their model and simply raise the albedo over this particular strip and see what happened. And indeed, that resulted in a about a forty or fifty percent reduction in rainfall. And there I became interested in the general climatological question of how alteration of surface properties could influence regional climate. It is not only albedo, but also soil moisture, because evaporation is a very important thing” …. (pp. 78-79 in The Atmosphere – A Challenge, AMS 1990).
Fortunately, the threatening desertification proved to be reversible. Rainfall increased again after 1973, and the Sahel also survived a second dry period, between 1981 and 1987. The nightmare of the mid-eighties is still imprinted on my friend’s retina. The media focused on the hardship for the local people, and their struggle for life, but the authors of Living on the Edge describe the devastating impact of drought on migratory birds. Breeding from Greenland to Siberia and wintering in the Sahel, these include more than a hundred species and 4,500 millions of individuals. Within the last 40 years we have lost at least a third of that population. Apocalyptic numbers, but people, members of that superior species, don’t seem to care.
Tales of alternating dry and fertile periods made me think of Egypt’s viceroy Joseph, who implemented a cereal storage system to ride out seven lean years in similar climatological conditions 3600 years ago. The bibliography of Living on the Edge contains several recent papers by Latif, Palmer, Hulme, and others that deal with possible causes for this periodicity. It appears that the surface temperatures of the tropical oceans surrounding Africa strongly affect Sahel rainfall. The meridional temperature gradients in the Atlantic and Indian oceans exert some influence, too. In any case, Hulme (2001) concluded that rainfall in the western Sahel may decrease 20% or more in the foreseeable future. Prospects are bleak.
The Sahel suffers from a confluence of threats to its people and its ecosystem. Explosive population growth, 3% or more annually, will overwhelm the scarce resources of the region before too long. Imported cereals are needed as it stands; the rapid expansion of irrigated rice fields cannot keep up. Floodplains, havens for millions of migratory birds, are disappearing fast. The progress of urbanization makes matters worse: city dwellers aspire to mimic the consumption patterns of people in the industrial world. Malaria is rampant, thanks to the ban on DDT. The delta of the Senegal River has been tamed by dams and levees twenty times as fast as the delta of the River Rhine, where I live. The Niger River suffers a similar fate. Four countries border on Lake Chad; no politician there seems to care about its future.
Living on the Edge describes the fate of twenty-seven species of birds in detail. For this review I will focus on White Storks (Ciconia ciconia). When they arrive in the Sahel in fall, the rainy season has just ended and there is an abundant food supply. Storks forage voraciously then, adding a kilogram of fat to their 3.5 kg bodies. One would think they are fattening up in preparation for their return trip, but they are not. They are preparing themselves for the dry months of early spring, in which the food shortage can become severe if the ITCZ shifts position too early. In a bad year, they are in far less than optimal condition when they have to cross the Sahara on their way back to their European breeding grounds. That can lead to massive mortality. Typically, 25% of juveniles die on their way back. Another 25% is killed in collision with high-voltage power lines, mainly in Spain. The mortality from that cause alone is 4 birds per kilometer per year.
I will never forget one horrible detail that I came across in the book. Fat birds are excellent sources of protein and lipids, so locals hunt them with a vengeance. Storks are soaring birds, with relatively weak flight muscles. Fattened up, they are an easy prey. So what do the locals do? They break the arm bones of these birds, so they can’t fly anymore. Broken wings – a nightmare. Subsequently, the captured storks are kept as pets, until they are wanted in the frying pan. Such customs, however excusable in a situation with scarce food supplies, make one ashamed of belonging to the human race. The treatment of animals in the meat industry of Eurasia and both Americas is far worse.
Living on the Edge details an ecological nightmare. It never fails to grip my throat whenever I am browsing through. Comparing this book with the thousands of pages produced by IPCC every five years, full of abstract intellectual exercises and bureaucratic theorizing, I realize better than ever before what the principal shortcoming of the “traveling climate circus” is. The crowd that follows IPCC lacks empathy. Global Warming is a cocktail-party hobby of well-educated city dwellers in Europe and elsewhere, people who cannot imagine the life of a farmhand in India or Senegal, people who do not contemplate the suffering of a stork with broken wings.
On Mary Black’s album “Speaking with the Angel” are these lyrics:
But these broken wings won’t fly
These broken wings won’t fly
These broken wings won’t fly at all
And oh how we laugh but maybe we should crawl
And ask to be excused
We shout loudly, have answers to it all
Oh but we have been refused
Yes, IPCC adherents shout loudly, and have answers to it all. Perhaps they should ask to be excused for not realizing that all of us are Living on the Edge, not just the people and the birds in the Sahel.
Footnote: Living at the Edge – Wetlands and Birds in a Changing Sahel, by Leo Zwarts, Rob Bijlsma, Jan van der Kamp, and Eddy Wymenga (2009, ISBN 978 90 5011 280 2) is published by KNNV Publishing, Zeist, Netherlands (www.knnvpublishing.nl). The book is not cheap: approximately $85. Keep your credit card ready.