Guest Post by Willis Eschenbach
The Sahel, that stretch of harsh territory south of the Sahara desert, is a bleak region. I did some work there, in a couple three countries. I came away with the conviction that if every day, every person in the Sahel planted one fruit tree and killed one goat, in about twenty years it would be worth visiting.
Figure 1. Map of the Sahel region, shown in orange.
Anthony highlighted some science by press release in “Climate change blamed for dead trees in Africa“. The press release is about a paper that won’t be published until this coming Friday. The lead author provided the following quotes for the press release. (emphasis mine)
“Rainfall in the Sahel has dropped 20-30 percent in the 20th century, the world’s most severe long-term drought since measurements from rainfall gauges began in the mid-1800s,” said study lead author Patrick Gonzalez, who conducted the study while he was a visiting scholar at UC Berkeley’s Center for Forestry. “Previous research already established climate change as the primary cause of the drought, which has overwhelmed the resilience of the trees.”
I thought, “Really”? Because I was sure I remembered all kinds of recent articles about the “greening of the Sahel”. In any case, I’ll take any excuse to learn something new. So I went off to see what the rainfall records had to say about the “world’s most severe long-term drought”.
I found three rainfall records that covered the Sahel in the time period from 1901 to the present. Two (CRU and GPCC) are available from KNMI Climate Explorer, and one (Sahel Index) can be downloaded from the University of Washington. I used the same geographical area as used by the University of Washington, from 10-20°N, and from 10°W to 20°E. The results are shown in Figure 2.
Figure 2. Three different estimates of rainfall in the Sahel region, 10-20°N, 10°W-20°E. Bright red line shows the 9 year Gaussian average of the median of the three estimates. Photo is of the Sahel region, Senegal
I’m sorry, but I’m not seeing either a “severe long-term drought”, or a drop of “20-30 percent in the 20th century”, or a human fingerprint in that record. Modern times are drier than mid-20th century, but not much different from the first part of the century. Rainfall has gone up, and it has gone down, and then back up again. Nor is there any obvious correlation with the general warming of the planet over the same time period. Given the close agreement of the three records, I think we can have reasonable confidence in the data.
I did enjoy his claim that “Previous research already established climate change as the primary cause of the drought.” Climate change causes droughts? Interesting theory. Does climate change also cause not-droughts? I wonder what else is caused by climate change, given that the climate has always been changing.
Finally, I was not mistaken that I remembered articles about the “greening of the Sahel”. Here’s information from the Encyclopedia of the Earth, from National Geographic, and from the Global Warming Policy Foundation regarding how the Sahel has been getting, not drier and browner, but wetter and greener ever since the 1980s.
Conclusions? My only conclusion is that folks are getting desperate for funding, and that the manufacturing of climate pseudo-catastrophes is a booming cottage industry.
w.
PS—I’m dead serious about planting trees and killing goats. The main cause of what desertification occurs in the Sahel is humans, but not by way of CO2. We do it by burning whatever will burn to cook our food, and by letting the goats destroy the rest.
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I’ve mentioned before how impressed I was by the reforesting of parts of the western Ghats of India, and the difference I saw between a visits in 1974 and 2000. They still had goats, but the boys who herded the goats were educated to stop climbing up into trees and snapping off branches. In the shade of the young trees grasses grew, which I didn’t see in 1974. There was even some light rain in November, which is the start of the dry season. However the biggest change was the use of propane for cooking, rather than wood and dung. Fossil fuels made the difference. (Some vehicles ran on propane, too, replacing horse-drawn and oxen-drawn carts.)
In Africa the French were trying to reforest areas, but when nations became independent they wanted to be rid of all signs of their oppressors, and unfortunately the little trees were a symbol of oppression, and got cut down.
During the MWP the American Southwest was apparently much moister. Where we see bare, red sandstone buttes and mesas today, green vegetation climbed the sides, and grew on the tops. The winters were warmer but, interestingly, the summers were cooler, due to clouds and rain which the vegetation likely enhanced. At the start of the LIA there was a 100-year-drought, which wiped out some Mound-builder cultures to the east, as the Anasazi hung on, due to their amazing irrigation systems. However the buttes and mesas were denuded of vegetation, as people needed fuel for the colder winters, and this may have meant that, when rains returned, the run-off was of the gully washer sort we see today, which totally destroyed the irrigation systems.
The cycles of climate bring changes in rainfall. I think man can make deserts bloom, if they apply careful thought, care for the land, a great deal of hard work, and have patience. However sitting about stirring swizzle sticks in Durban, playing king-of-the-world with other people’s money, involves reckless thought, ignorance of the land, no work whatsoever, and a complete lack of patience.
I was also in N Nigeria recently for a few years and I would agree that tree killing and goat population are the two main problems for trees.
Both of these are, of course, driven by human population which is certainly not decreasing…
Climate, changing or otherwise, is the least of the trees problems.
Nothing points to the dishonesty of the CAGW ‘movement’ than this topic. The graph clearly shows that the worst drought of the 20th century occurred during the coolest period not the warmest.
There was a sliver of truth that slipped out from them explaining the increase of US snow fall in the last few winters being due in part to the air holding more moisture. That appears to work as well in Africa as well as North America.
@Garrett: I read the abstract of the paper referenced. It starts out: (my bold)
It goes on to equivocate about the fact that there is correlation between tree density and climate change. I don’t see that as causation. Trouble is, I don’t have the $31.50 needed to get the whole paper so perhaps you can quote some key parts from it here.
Yep, me too, I worked in Africa for years, and Willis has it spot on. Goats are the single worst thing that has ever happened to Africa – continent wide north and south, yet there are some idiots who actively encourage it:-
http://www.oxfam.org.uk/shop/oxfam-unwrapped-animal-lovers/OU5028LS
But don’t get me started on Oxfam, They were in Kenya when I was there in 1965, oh yes, that’s right, they were sorting things out nearly 50 years ago.
Er, not doing too well are they? Be like me avoid them like the plague.
Willis,
Holy cow/goat!
5 more minutes of investigation revealed two interesting documents:
http://www.saheleco.net/docs/emilie_smith_MSc_agroforestry_dissertation-2.pdf
“Although numerous trees and their final products are central to local livelihoods and their decline of particular concern to all villagers, in cultivated fields, trees generally represent a nuisance because they complicate animal traction, compete with crops and attract birds, bees, snakes and harvesters. The lack of tradition in managing indigenous trees, the slow growth and vulnerability of indigenous fruit tree seedlings remains a major factor discouraging farmers from fencing and protecting them.
http://pure.au.dk/portal/files/17477342/Lykke_etal_2004_SEREIN17_2004.pdf
Ecotretas
Willis,
At the risk of sounding like an animal rights nut, I must inform you that you sound too anti-goat for my liking. I raise goats. They are friendly, and will follow me when I hike, and, unlike my dog, they don’t rush off to chase cats, and never get a face-full of porcupine quills. They have taken a pasture I have that was overgrown with brush, and turned it back into an open field of lush, green grass. Their milk is better for people who have trouble digesting lactose than cow’s milk is. Their meat is lean and not “marbled” with fat, and tastes better than lamb, in my opinion. Africa needs protien. You can starve, eating fruit.
Of course, goats sneer at fences. Mine have a habit of visiting neighbors that makes me unpopular, however that is not their fault. That is my fault.
Don’t blame the goats for over-grazing or killing trees or eating the neighbor’s flowers. Blame the goat-herders.
“if every day, every person in the Sahel planted one fruit tree and killed one goat, in about twenty years it would be worth visiting”
Been there and have to say it’s hard to disagree…..
Africa should be able to feed itself rather well without bush meat and ghastly primitive farming methods – but the parasites that are the governments and bankers always seem to grab/plunder every entire successful crop from a static farm.
I’m minded of the tribulations of the rather brave Zimbabweans who set out to farm in Nigeria.
Google Serach
35 years ago (when the Sahel, was, well, really Sahellish) I went to a talk about it at my HS (a peace love and granola school hence talks about the Sahel). The guy claimed that Israeli scientists had fenced in a piece of desert to keep out the goats and within 5 years it was a blooming place. I have always wanted to look up that research, but that was the days of libraries, wonder if I could find it now, or whether it was a trope among those that worked in those areas. However, as Hexe points out, the main sticking point is that goats are a reliable, cheap source of meat. Food comes first.
http://jisao.washington.edu/data/sahel/sahelprecip19002011.big.gif
look at this
Good information on rainfall patterns in the western Sahel since 1800 was published in 2001 by Dr. Sharon Nicholson (Florida State University) in the journal Climate Research, 17: 123-144. The abstract notes: (a) the recent late 20th Century severe drought was not unprecedented; (b) a similar dry episode prevailed during most of the first half of the 19th C; (c) the few changes in temperature that have been demonstrated during the late 20th C drought were ‘small scale’; (d) ‘recent decades of dry conditions in the Sahel are not in themselves evidence of irreversible global change’; (e) Sahel rainfall is driven by ocean temperatures. Possible exacerbating effects of human land use (misuse) on rainfall are noted as requiring much more detailed and extensive data. Such facts ashould now be becoming available.
One such source of data is the recent (2009) book ‘Living on the Edge’ (L.Zwarts et al.) published in English by KNNV Publishing, Holland. The Dutch ecological team graphically show how rapidly the western Sahel is being degraded rapidly by intensifying human activities ranging from over-stocking with grazers (cattle, sheep) and browsers (goats) by pastoralists, the removal of trees and scrub, and not least by governments damming major rivers and causing loss of wetlands. The region is fast becoming an ecological disaster area. An essential read.
In the eastern Sahel (Sudan),where I worked in the late 1950s-early 1960s, much vegetation has since been destroyed by human activities – largely a result of the protracted war conflicts in many areas but also due to mis-guided government agro-schemes (UNEP Environmental EIA Resource Manual, Case Study 4, c.1998).
I thoroughly endorse Willis’ comments. The AGW alarmists completely ignore other factors (natural and human-caused) in their statements and prophesies concerning the on-going and adverse changes to this once ecologically rich Sahelian zone.
Aw come on Willis not another goat kills man story 🙂
Great post but they do seem to make it easy for you?
“Plant a tree. Kill a goat.” Words to live by. I see we’ve already heard from the “Goat Anti-defamation League”. You may also expect a howl from “The Society for Prevention of Human Interference with Natural Tree Reproduction.”
Which is another reason why distribution of bottled gas for cooking is probably one of the most important development steps imaginable: addressing deforestation in the Sahel, and all the terrible environmental and health consequences of the “Asian Brown Cloud”, caused by the use of biomass for cooking.
LPG – you know it makes sense 🙂
There’s another scare story in today’s Independent by Steve Connor. Apparently in the Arctic north of Siberia there are bubbling froths of methane which is ‘a dangerous greenhouse gas’ allied to all the usual scaremongering.
If it is bubbling, which is more likely:
a. Some kind of vent on the sea bedreleasing warm gases?
b. Spontaneous release from a sea bed warming uniformly?
My take is that if it is temperature related, the bubbles would be uniform across the region, whereas if it were vents, it would be more locallised.
I’m no expert, perhaps those that are would care to comment?
Great article, Willis. It is interesting what you get when you Google “greening of the Sahel”. Here is the Voice of America results:
“Niger is located in the Sahel area south of the Sahara. The west African country is largely hot, dry desert. But since the nineteen eighties Niger has gotten a lot greener.“
It is completely meaningless to compare the Australian wheat belt or the Palouse with the Sahel simply based on rainfall. You must account for rainfall patterns, evaporation, soil types, topography etc.
The Palouse is cold with negligible evaporation for most of the year. The summer is hot but brief.
The Australian wheat belt typically has relatively high winter and spring rain fall.
Wheat is a deep-rooted heat tolerant annual crop that evolved in the Middle East. If it manages to reach the subsoil moisture after germination it will survive to maturity without additional rainfall.
The Sahel is hot all year round, has very high evaporation and summer rainfall. This means that any vegetation must survive many months without water. The Sahel is also extensively overlain with sand which means the soil drains rapidly and little nutrition is available for plant growth.
There are many regions in Australia with a similar climate to the Sahel. They rely very heavily on irrigation to grow crops and raise livestock.
>> Climate change causes droughts?
they have discovered that climate change causes climate change. Brilliant.
Give them another grant and they may be able to show when the weather changes the weather is different.
Ah, how lovely, Garrett. Yet another peer-reviewed article, presenting research paid for (I am quite certain) by federal funds (that is, us), that we can download for the modest price of $31.50. Or yes, since I can go through Duke I can get it for the price of five minutes of additional effort to hook up through LibX, charging the taxpayers yet again (who ultimately pay Duke’s subscription fees).
So yes, we can read the abstract of the actual article at your link, but even the abstract is indeed made more dubious by the graph generated by Willis up above. Quite a lot more dubious, because it does indeed show that while rainfall is indeed quite variable in the Sahel on a multidecadal scale over the 20th century, the overall trend is quite clearly almost flat. There is a 30% max-to-min variability, but the overall trend is perhaps a 5% decrease, if that. Do you need Willis to actually fit a line to the data to see that? Or would you prefer to cherrypick a fit just to the stretch from 1955-1980 to be able to claim 30% reduction? Or would you rather cherrypick specific sub-regions in the Sahel that were drier than this overall average (so you can ignore the ones that were wetter to produce this overall average)?
The climate is always varying. Everywhere. Some places get wetter, some get drier. The US “dust bowl” drought was back in the 30’s, for example. Try to blame this event on global warming. Or try to write a paper attributing the lack of a drought to global warming. In NC, the worst droughts in (tree-ring) recorded history were the series of droughts from 1560 to 1650 — the Spanish Mission drought, the Lost Colony drought, and the infamous Jamestown drought. The Lost Colony drought was the most extreme 3 year drought in the last 800 years. The Jamestown drought was the most extreme 7 year drought in 770 years. In both cases it simply didn’t rain (much) for 3 or 7 years at a time, dwarfing the 2 year drought I experienced myself in NC back in the 1980s, when I used to drive my car 1/4 mile out onto the lake bed of Lake Michie to park to get close enough to the waterline to launch a boat.
If either of these were strongly correlated with a “temperature” event, it would have to be the incipient Maunder Minimum and LIA — indeed the worst seven year event in the last 800 years ended in 1215 and was likely correlated with the end of the MWP. But then, the two year drought in the 80’s was correlated with relatively warm weather.
This illustrates the extreme silliness of looking at 100 years slices of local climate in carefully selected locations to attempt to prove a global phenomenon. If one looks back at an 800, or 1000 year record of Sahel rainfall and temperature, there are almost certainly droughts that were as severe and prolonged as any in the 20th century, although given the size of the Sahel you might be able to carefully cherrypick an outlier region that had the most extreme drought in the 20th century (just as if you pick over the entire US you might find the dust bowl and be able to show that it was more extreme than the Jamestown drought). The worst drought in the US, however, was the one that occurred in the Younger Dryas (return to ice age conditions ~9000 BP). Or was that the US? Southwest was unusually wet, Midwest and East extreme drought.
This article perfectly demonstrates the fundamental problem with Climate Research these days. That problem is confirmation bias and its close cousin, cherrypicking. This problem is the elephant in the room that no one dares look at. CAGW is a global hypothesis of weather that is supposed to be extreme over geological time scales. How, then, can this hypothesis be supported at all by the reporting of any extreme weather event carefully selected by region and time period to be “global” neither in space nor in time?
No, Hurricane Katrina wasn’t “proof of CAGW” — it was extreme only if one limits one’s window of observation strictly in space and time. Excessive rainfall in Bangladesh (another favorite example of Al Gore) is not “proof of CAGW”, it too is extreme only if one limits one’s “historical window” strictly in space and time. Interestingly, if one plots the total energy released in tropical storms, if anything it has been diminishing in recent years even as global temperatures were supposedly increasing — and that doesn’t necessarily mean anything “globally” either except that tropical storms thrive on temperature differences (like any heat engine) so that more uniform temperatures warmer or cooler probably will reduce the available free energy that drives them.
Somewhere on Earth records are set every day for extremes in weather — hottest high, lowest low, wettest wet, driest dry. Somewhere, every year, an “extreme” weather even occurs — a “drought” or “flood” year for a region, or a really big hurricane. Someone infected with CAGW-CB (Catastrophic Anthropogenic Global Warming — Confirmation Bias) disease quite literally cannot help but to be drawn to these extreme events, because they are interesting and because they do real damage so people care. They don’t care that they aren’t extraordinary on either a global spatial scale or a global temporal scale — they are extraordinary on a human lifetime scale, especially to the people that live through them on the spatial scale of human habitation.
And here’s the rub. An honest job of refereeing would simply reject the CAGW-event conclusion in any paper that made a local claim as supporting the global hypothesis. Period. A really honest job of refereeing would require the CAGW hypothesizers to make concrete predictions that could falsify the hypothesis if those predictions were unmet, and only allow papers to address the conclusion if they were in some way double blind controlled so that negative evidence was presented along with positive evidence.
Sadly, that seems not to happen. Al Gore claims that polar bears are drowning as sea ice vanishes, that hurricanes are getting stronger, that droughts are getting droughtier, that flood are floodier and it is All Our Fault and because he can support each and every assertion with some piece of published crap, with some photograph taken out of context, with some extreme event that happened somewhere (ignoring even more extreme events that took place long ago or far away or both) people become, and remain, panicked and concerned. Steig et. al. publish a paper asserting that Antarctica is getting warmer, when the opposite is true — one peninsula in Antarctica is getting warmer — the continent itself is almost without exception in a cooling phase — and yet this paper — with the most garish color scheme possible — is yet another cover story in Nature “proving” warming. Science immediately does move in to criticize, and eventually it becomes clear that this result is bullshit, but does Nature ever publish a cover story entitled “Never Mind, Sorry, Antarctica is Cooling After All”?
One can go down the list. There are so very many places where the evidence for CAGW does not fit the neat little pattern associated with the hypothesis — especially if one considers the global, geological time data — but those places never receive equal attention. Indeed, they don’t receive public attention at all!
CAGW supporters had damn well better end up being right, or they will have dealt a blow to scientific credibility that will take a century to heal. Unfortunately, at this point the entire careers of hundreds of people are irrevocably bound up in “proving” the hypothesis, and scientists from front line researchers (and paper reviewers) to journal editors to politicians stand to lose “everything” if negative evidence is presented or if it is conclusively shown that CAGW-CB disease has run amok in the community or both. Career ending stuff, stuff that would embarrass everybody from the Nature editorial board to the Nobel committee (how do you take back a Nobel Prize when the science it was granted for turns out to be not only flawed, but deliberately mispresented to accomplish a political goal?).
Nature, of course, could give a rat’s ass for human politics. Mere confirmation bias cannot obscure a true sea-change in the weather for very long, and every day the physics improves. We quite literally haven’t had the tools (computational or observational) needed to address the problem until the last two or three decades — not long enough to accumulate a full complement of data global data through even a single round of the multidecadal oscillations that we know are a dominant determinant of the global climate and that are strongly correlated with weather extremes in a systematic way. We have been handicapped in that the world has been coming down off of a multi-cycle Grand Solar Maximum, the longest, strongest set seen for 9000 years, and we have (really) no truly reliable data that permit the reconstruction of global temperature averages over that kind of time scale — even satellites are proving an elusive source of global temperatures accurate to within 1 degree absolute, and land or sea based thermometer data is notoriously unreliable (no matter how you choose to try to “correct” its reliability, an ad hoc correction of unreliable data is less reliable, not more reliable, especially if one is trying to use the data to address a hypothesis that closely depends on the correction selected, see CAGW-CB disease).
Still, for 30 years the temperature record from satellites is at least moderately accurate — the most accurate and only truly spatially global record of temperature we have. A tragically short time period — completely inadequate to address temporal variation on even a locally meaningful time scale (given that a complete solar cycle is 22 years, multidecadal oscillations have period on the order of 30-60 years) but one that gives us hope that as we actually do see the PDO and NAO at long last change their phase while we are watching from the sky with accurate instrumentation, with the Sun returned to a far more normal state, we might finally get enough data over the next 30 years to be able to build a quantitative model that has some actual predictive skill. In the meantime, we might even learn or figure out more physics connecting solar state to climate, and be able to quantitatively put the various hypotheses that describe this (or entirely new ones) to the test.
rgb
Just got done reading 1493. Good read and I recommend it highly.
1492 saw the beginning of the Columbian exchange, the movement of peoples, animals, insects, plants, and microorganisms from their native habitats into new areas.
Earth worms were extinct in North America prior to 1492; ice sheets scrapped the top soil away. Europeans needed something to provide ballast for ships arriving in North America intended for the shipment of tobacco (another part of the Columbian exchange). Soil from Europe filled the bill nicely, which contained earth worms.
Without earth worms, leaves tend to pile up in the forests, favoring trees and bushes with shallow root systems. Earth worms consume the leaves, depositing droppings underground, favoring trees and bushes with deep roots. This process continues to the present with the spread of earth worms.
Honey bees were introduced from Europe for their honey and pollination of fruit trees, also brought over from Europe. Peach trees of Georgia and the Carolinas are not indigenous, they are invasive species. Same with apples and cherries. Honey bees are notoriously promiscuous in they will pollinate any plant and take up residence in any hollow space.
Would this mean no cherry picking in North America without the Columbian exchange?
Indians called honey bees the ‘white man’s’ fly. It represented the invasion and destruction of their homes, fittingly armed with stings.
Europeans also brought over horses, cows, goats, and pigs. The latter are very destructive of Indian style gardens, viewed by Europeans as uncultivated collections of maize, gourds, and beans.
Potatoes, tomatoes, maize, and sweet potatoes were introduced into Europe, bringing an end to the periodic famines of Northern Europe. Peasants in France were convinced potatoes caused leprosy, until a patch of potatoes was guarded until harvest time. They thought it must be valuable as a rich man was guarding something valuable. France did not accept the potato until the French revolution.
Potato helped fuel the Industrial Revolution because the common man now had a secure source of cheap and plentiful food.
China received the sweet potato and maize along with silver via trade routes to the Philippines. Chinese farmers could now grow something in the sandy, dry soils above the river plains. This led to the cultivation of land on hills, leading to erosion and a population explosion. There was now more than rice to grow in China.
Rubber tree plantations in Southern China and Northern Indochina are now replacing the native forests, even as I write this. This has led to changes in regional climates and great prosperity for the farmers there. There is still no substitute for real rubber. It is inevitable the fungus responsible for rubber tree blight with eventually find its way to these new rubber plantations. This will denude the monoculture on the region because all the other types of trees have been removed.
Goats in Sahel, rubber trees in Indochina, smallpox in North America; it’s all the same story, just different players. We live in a different world than we had five hundred years ago. Some of it has been bad, most very good.
Has nothing to do with a trace gas, which has very little to do with ‘climate change’.
Thanks Willis. I was surprised by the amount of rainfall, expected less than what we get in Colorado, where we grow peaches, wheat, sugar beets etc.
It’s been fifty some odd years since I took Geography 100 — which turned out to be a very interesting course. I don’t think things have changed much in that world. Basically, the Sahel is part of a worldwide desert belt that lies between the tropics and the mid-latitudes in many (not all) parts of the world. The tropics are wet and dominated by East to West windflows. The mid-latitudes are wet and are dominated by West to East windflows. In that model, global warming pushes the desert zone North, cooling pushes it South. That’s very simplistic — with lots of exceptions.
But it does suggest that “average railnfall” across the Sahel is likely to be a dubiously meaningful metric. 400mm (about 16 inches — same as Santa Barbara) might mean 25 inches in Tunis and 5 in Khartoum … or vice versa.
Hi Willis
I found the rainfall graph very interesting. During the 30s and 50s there was also a lot of rain here in Florida. The lakes in north Florida were full to overflowing. I used swam in those lakes as a youth and went to summer camps located on the shores of those lakes. Many of them are now nothing more than damp prairies. I really do hope this is a cycle and that I may once again see some of those lakes filled again. I have no idea how what’s happening in Florida might be correlated with what’s happening in Africa but it’s interesting.
Thanks
I think what I like best is how this precip graph looks very much like the 20th century temperature graph: temperature goes up, precip goes up. Temperture goes down, precip goes down. It would seem the people of this region should be happy with global warming.