Climate change blamed for dead trees in Africa

Dec 12, 2011
A dead ironwood tree (Prosopis africana) in Senegal, West Africa, is one of many trees that have died due to climate change. Credit: Patrick Gonzalez

Trees are dying in the Sahel, a region in Africa south of the Sahara Desert, and human-caused climate change is to blame, according to a new study led by a scientist at the University of California, Berkeley.

"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."

The study, which is scheduled for publication Friday, Dec. 16, in the Journal of Arid Environments, was based upon climate change records, aerial photos dating back to 1954, recent satellite images and old-fashioned footwork that included counting and measuring over 1,500 trees in the field. The researchers focused on six countries in the Sahel, from Senegal in West Africa to Chad in Central Africa, at sites where the average temperature warmed up by 0.8 degrees Celsius and rainfall fell as much as 48 percent.

They found that one in six trees died between 1954 and 2002. In addition, one in five tree species disappeared locally, and indigenous fruit and timber trees that require more moisture took the biggest hit. Hotter, drier conditions dominated population and soil factors in explaining , the authors found. Their results indicate that climate change is shifting vegetation zones south toward moister areas.

Rainfall in the African Sahel declined more than anywhere else in the world in the period of recorded measurements, causing increased aridity, as evidenced by this dust storm in Senegal. Credit: Patrick Gonzalez

"In the western U.S., climate change is leading to tree mortality by increasing the vulnerability of trees to ," said Gonzalez, who is now the scientist for the National Park Service. "In the Sahel, drying out of the soil directly kills trees. Tree dieback is occurring at the biome level. It's not just one species that is dying; whole groups of species are dying out."

The new findings put solid numbers behind the anecdotal observation of the decline of tree species in the Sahel.

"People in the Sahel depend upon trees for their survival," said Gonzalez. " provide people with food, firewood, building materials and medicine. We in the U.S. and other industrialized nations have it in our power, with current technologies and practices, to avert more drastic impacts around the world by reducing our greenhouse gas emissions. Our local actions can have global consequences."

Explore further: Study finds Europe's habitat and wildlife is vulnerable to climate change

add to favorites email to friend print save as pdf

Related Stories

Climate change forces major vegetation shifts

Jun 04, 2010

(PhysOrg.com) -- Vegetation around the world is on the move, and climate change is the culprit, according to a new analysis of global vegetation shifts led by a University of California, Berkeley, ecologist ...

The desert is dying

Feb 14, 2007

Researchers from University of Bergen have found that trees, which are a main resource for desert people and their flocks, are in significant decline in the hyper-arid Eastern Desert of Egypt.

Climate change predicted to drive trees northward

Dec 03, 2007

The most extensive and detailed study to date of 130 North American tree species concludes that expected climate change this century could shift their ranges northward by hundreds of kilometers and shrink the ranges by more ...

Recommended for you

Australia approves huge India-backed mine

15 hours ago

Australia has given the go-ahead to a massive coal mine in Queensland state which Environment Minister Greg Hunt said Monday could ultimately provide electricity for up to 100 million Indians.

User comments : 25

Adjust slider to filter visible comments by rank

Display comments: newest first

Nanobanano
4.2 / 5 (5) Dec 12, 2011
Honestly, this is a little misleading.

The region in this study is one of the most sensitive in the world to NATURAL climate change, and has been experiencing tremendous desertification and climate change for all of recorded history.

There are even several dry mega-lakes in the region which predate recorded history by thousands of years, having apparently dried up 1 or 2 thousand years before the Egyptian civilization even existed.

Lake Chad is a last remnant of that.

I'm not being denialist. It's just plain facts.

In this case, the majority of the changes really are natural variation continuing to do what it has always done for seven thousand years now.
HROLLER
1.4 / 5 (10) Dec 12, 2011
There's GEOENGINEERING going on throughout the world! This is causing abnormal weather. Where's the reporting on these facts???
Nanobanano
4 / 5 (4) Dec 12, 2011
There's GEOENGINEERING going on throughout the world! This is causing abnormal weather. Where's the reporting on these facts???


If by "geoengineering" you mean dams, levees, tunnels, and irrigation, then yes it causes abnormal weather.

Entire basins have been drained in the U.S., not by global warming, but by diverting river waters for drinking and irrigation.

This caused desertification which was unrelated to CO2, simply because if you dry up a very large lake you alter the micro-climate of the surrounding area, and lower the humidity, etc.

Now they even had to install sprinklers in some locations to wet the soil in the dry lake bed and surrounding land to keep it from being blown away in the wind!!

No joke.

They pumped it dry for drinking water, and now they have to pump water back in to try to prevent further environmental damage.

This started like 100 years ago. It's a complete catastrophe.
Pirouette
2.3 / 5 (6) Dec 12, 2011
The Everglades swamp in Florida has been continuously drained as much as possible for the purpose of drinking water for the huge amount of population in southern Florida. This is also the case in southern Georgia where the Okeefenokee (sp) has been slowly drained in many parts of it, thus creating a climate for forest fires that burn hundreds or thousands of acres with the acrid smoke affecting many towns and cities according to the prevailing winds. The problem is that of increasing population and where farms and ranches were bought up and converted to housing developments, strip malls and parking lots to accommodate the people moving to Florida and Georgia. These measures increase the chances of limited rainfall and dead and dying plant life. The wild animal population suffers accordingly. People don't generally retire to Idaho. They prefer warm climates and that taxes the natural environment because of too many humans living in any given area.
Pirouette
2.3 / 5 (6) Dec 12, 2011
What was once a natural setting in Florida for good amounts of rainfall, has been criss-crossed with canals bringing drinking and irrigation water to Miami and other cities of southeast Florida. Due to the fact that southeast Florida now gets a lot less rainfall than normal, certain water companies have attempted to bail out the water problem by conning the central and northern Florida city governments to allow these companies to bottle the water from their natural springs and/or to build pipes underground to pipe that water to south Florida, which, of course, would then deplete the water supplies for the more northern latitudes of Florida. The water companies would also have made a fortune selling that water to local gov'ts in the southern areas at the expense of the North. Nobody in their right mind in central and north Florida would agree to such a ridiculous and callous offering. I hope common sense continues.
Nanobanano
4.3 / 5 (3) Dec 12, 2011
If you did solar boliers properly, you could do desalination and make net gain in electric power simultaneously.

Been saying it for several years now, but nobody seems to listen.
Pirouette
1.8 / 5 (4) Dec 12, 2011
Well, yes. . .the Sunshine State could do that, but it would take a lot of desalinated seawater to make fresh drinking water. A large portion of offshore deep water would be needed and miles of piping, but how could the seawater be retained so that there is no recontamination after desalination? I can't formulate an answer to that. I doubt they would want to build a desalination plant close to the shoreline. You know that Florida isn't that high above sea level, right?
Shelgeyr
1 / 5 (1) Dec 12, 2011
@Nanobanano said:
If by "geoengineering" you mean dams, levees, tunnels, and irrigation, then yes it causes abnormal weather.


Grudgingly, reluctantly, and as if by its own volition, a state of "being in agreement with Nanobanano" forces its way through my consciousness and out through my hands.

There! I said it! But I will retain possession of my soul, thank you, by modifying your statement somewhat:

"If by "geoengineering" you mean dams, levees, tunnels, and irrigation, then yes it CAN cause abnormal weather, and this is sometimes a great improvement. Look at Texas, for example. In its native condition, the Lone Star State had arguably only part of one natural lake. All of the rest - in a huge state now covered in lakes - are man-made. This has caused quite a beneficial change to our climate and weather."

Not for nothing was Texas stereotyped in the olden days as being a desert.

(Hmmm... I wonder if they'll take the bait...)
_nigmatic10
3 / 5 (2) Dec 13, 2011
So, please save the trees cause...
Quote-""People in the Sahel depend upon trees for their survival," said Gonzalez. "Trees provide people with food, firewood, building materials and medicine."-end quote

..because..
Quote-"Trees are dying in the Sahel, a region in Africa south of the Sahara Desert, and human-caused climate change is to blame"-end quote.

Which means if the trees are not being used up so much, we could see them rebound more?(course, that goes for the world in general)
Pirouette
1 / 5 (3) Dec 13, 2011
Well that explains it then. . .that close to the Sahara. . .the desert wind is sending out grains of its sand and creeping up on Sahel. . .only to overwhelm it at some point. . .maybe in a few years, a few decades. . .or a century. That's what deserts do, for pete's sake. . .they spread out, wind driven. . .the mighty hand of Mother Nature at work. And you can quote me on that. :)
ubavontuba
1.7 / 5 (11) Dec 13, 2011
This is the worst climate article I have ever seen on Physorg.

Did anyone else notice how old the data is?

Did anyone notice the dead tree pictured is one of well more than a dozen trees (not one of six) - and that only includes trees which lie directly behind it?

This article is nothing but a fabrication. The Sahel has been greening, and greening significantly. Even from the time of this article's "data" it was greening.

"Analyses made by several independent groups of temporal sequences of satellite data over two decades since early 1980s, showed a remarkable increasing trend in vegetation greenness."

http://www.eoeart...hel#gen2

This map is from the period of 1982-1999:

http://maps.grida...getation

And, Sahel farmers plant lots of trees:

http://www.voanew...649.html

Eric_B
4 / 5 (2) Dec 13, 2011
So, the man gist of the comment here is, "Oh, my g-d, THIS CAN'T BE HAPPENING!!!"

I was just contemplating how here is Chicago, when I was a child we used to have Stag Beetles and Junebugs all over the place, every summer. Then, every 7 and 14 years an army of cicadas would emerge from the earth. I also used to remember finding caterpillars here and there.

Haven't seen anything like that for YEARS! The cicadas come out half on the wrong year and 10% of what they used to be.

But, it can't be that this observable and quantifiable phenom could be caused by man-made global warming. Why?

Because then we would have to get off our lazy butts and make sacrifices to do something about it ("or else", which is not good and seems to be the direction towards which most of y'all don't seem to mind collectively dragging us.)
MarkyMark
2.3 / 5 (3) Dec 13, 2011
This is the worst climate article I have ever seen on Physorg.

Did anyone else notice how old the data is?

Did anyone notice the dead tree pictured is one of well more than a dozen trees (not one of six) - and that only includes trees which lie directly behind it?

This article is nothing but a fabrication. The Sahel has been greening, and greening significantly. Even from the time of this article's "data" it was greening.

"Analyses made by several independent groups of temporal sequences of satellite data over two decades since early 1980s, showed a remarkable increasing trend in vegetation greenness."

http://www.eoeart...hel#gen2


Hmm wonder why you havent used more recent data? It couldnt be due to biassed cherrypicking couldnt it?

Naaaaaa!
GSwift7
2.3 / 5 (6) Dec 13, 2011
Another factor in tree loss in much of the Sahel is, ironically, French Colonial policies designed to preserve them. It was decreed by French Colonial Governments in that region that all trees were the property of the Government. That lead to the locals not being interested in growing or preserving trees on thier property. Trees became the target of deliberate sabotage in favor of things other than trees, such as grazing forage. That had a chain reaction effect of allowing wind to transport more sand, which contributed to even more dead trees and drier soils.

The locals have learned that planting trees as wind breaks is a good thing though, so things are starting to recover in more recent decades.

As said above, the "greening of the Sahel" has made headlines on quite a few occasions, and you can easily google it.
Howhot
2.8 / 5 (9) Dec 14, 2011
In the Sahel, drying out of the soil directly kills trees. Tree dieback is occurring at the biome level. It's not just one species that is dying; whole groups of species are dying out.


Typical effect of global warming and climate change. I can't believe the morons posting excuse this as some local effect and even claim the Shahel are to be greening, when long term its a desert from AGW.

Geeze these rightwingers are toally goofy in the head.
ubavontuba
1.7 / 5 (11) Dec 14, 2011
Hmm wonder why you havent used more recent data? It couldnt be due to biassed cherrypicking couldnt it?
Uh... maybe it was because I was arguing the data and conclusions of the article? Did you think of that? Can you say, "D'oh!"

Besides, I did use some recent data, particularly in regards to tree planting (May 9, 2011). Can you say, "Double d'oh!"

ubavontuba
1.8 / 5 (10) Dec 14, 2011
@Orac, er... I mean Howhot:
Typical effect of global warming and climate change. I can't believe the morons posting excuse this as some local effect and even claim the Shahel are to be greening, when long term its a desert from AGW.

Geeze these rightwingers are toally goofy in the head.

What's the matter, are you having difficulty reading the references?

GSwift7
2.1 / 5 (7) Dec 14, 2011
What's the matter, are you having difficulty reading the references?


Just ignore her. She's obviously just a troll.
Howhot
2.5 / 5 (8) Dec 15, 2011
From the article: "In the Sahel, drying out of the soil directly kills trees. Tree dieback is occurring at the biome level. It's not just one species that is dying; whole groups of species are dying out." ER-go its a global warming issue. I was wondering why trolls where all over this story like syrup on a pancake.

ubavontuba
1.8 / 5 (12) Dec 15, 2011
From the article: "In the Sahel, drying out of the soil directly kills trees. Tree dieback is occurring at the biome level. It's not just one species that is dying; whole groups of species are dying out." ER-go its a global warming issue. I was wondering why trolls where all over this story like syrup on a pancake.
Like I said, the article is full of it. Tree death cycles are natural.

For instance, it meantions the bark beetle death of U.S. trees. This is an occurence that happens naturally during dry years, because the trees can't produce enough sap to push the beetles out. But, if this was a long-term problem, deforestation would be the result. However, U.S. trees are thriving like never before. There's so many that during the dry months they pose a significantly increasing fire risk.

MarkyMark
1 / 5 (3) Dec 15, 2011
Hmm wonder why you havent used more recent data? It couldnt be due to biassed cherrypicking couldnt it?
Uh... maybe it was because I was arguing the data and conclusions of the article? Did you think of that? Can you say, "D'oh!"

Besides, I did use some recent data, particularly in regards to tree planting (May 9, 2011). Can you say, "Double d'oh!"


Still see you cherrypicking ;)
ubavontuba
1.7 / 5 (11) Dec 16, 2011
Still see you cherrypicking ;)
How is using the Encyclopedia of Earth cherrypicking? D'oh!

How is using United Nations Environment Programme (UNEP) data cherry picking? Double d'oh!

How is using the Voice of America's Special English Agriculture Report cherry picking? Triple d'oh!

If you don't like my references, explain why and find your own dang references which refute them.

I doubt you can, or will. Can you say, "Quadruple d'oh!"

Howhot
3 / 5 (6) Dec 20, 2011
Like I said, the article is full of it. Tree death cycles are natural.


Not like this! Your another right wing plant aren't you? If not, you certainly didn't even read the article. Here is the conclusion of the article;

Hotter, drier conditions dominated population and soil factors in explaining tree mortality, the authors found. Their results indicate that climate change is shifting vegetation zones


That must all be caused by conservative wishful thinking. Actually is man made global warming from burning fossil fuels.
The best part about this AGW joke is it's going get worst.

ubavontuba
1.5 / 5 (8) Dec 21, 2011
Not like this! Your another right wing plant aren't you? If not, you certainly didn't even read the article. Here is the conclusion of the article;
Oh, so because it's in this particular article, it must be true? No other data matters? D'oh!

That must all be caused by conservative wishful thinking. Actually is man made global warming from burning fossil fuels.
The best part about this AGW joke is it's going get worst.
The biosphere is actually booming, as a result of CO2 production. D'oh!

Here's data from the same era as from the article (not that it'll matter to your faith-based alarmist mentality):

http://www.scienc...abstract

ryggesogn2
1.5 / 5 (15) Dec 21, 2011
'Climate change blamed for .........'.

Fill in the blank.