Countries build 9 mile wide tree wall across Africa to prevent Sahara advancing (2014)

http://www.alearned.com/green-wall-of-africa/

by Circumnavigate • 6 years ago

54 13 6 years ago

alearned.com

leblancfg• 6 years ago

Now that’s a wall I can get behind.

padraic7a• 6 years ago

Unfortunately the Great Wall doesn't seem to be doing so well.

This article is from 2024. I looked for updates and found the Wikipedia page.

It contains some contradictory statistics but this is the most recent: "In September 2020 it was reported that the Great Green Wall had only covered 4% of the planned area".

https://en.m.wikipedia.org/wiki/Great_Green_Wall

woofie112• 6 years ago

That's common in the region. You announce major new projects, start them, and don't finish them. New leadership comes in, ignores the old projects, and starts a new set. You don't fix or finish old things started by your predecessor. You start building new ones.

Someone2• 6 years ago

https://catalogue.unccd.int/1551_GGW_Report_ENG_Final_040920... says they pivoted a bit:

“The aim of the GGW was originally to create a long vegetation barrier between the 100 and 400 mm isohyets, including ramps, and over a length of at least 7000 km along the Sahel, being roughly 15 km wide. In recent years this vision has evolved into an integrated ecosystem management approach, striving for a mosaic of different land use and production systems, including sustainable dryland management and restoration, the regeneration of natural vegetation as well as water retention and conservation measures”

I think that makes it hard to report % completed. Also, 4% is a lot of land (that same PDF says they currently target about 1½ million km² of land. That’s a lot more than that 7,000 by 15 km band originally envisioned (For comparison, the USA and Canada each are about 10 million km², so that would be about 7½% of North America), in the poorest part of the world.

As https://www.pri.org/stories/2016-05-02/africas-great-green-w... says “it will take at least a generation to make it a reality”

irthomasthomas• 6 years ago

The world is turning into a desert. Run for the hills! "Desertification is a fancy word for land that is turning to desert," begins Allan Savory in this quietly powerful talk. And terrifyingly, it's happening to about two-thirds of the world's grasslands, accelerating climate change and causing traditional grazing societies to descend into social chaos." https://m.youtube.com/watch?v=vpTHi7O66pI

Back on planet Earth, a review of the current scientific literature would appear to disprove this thesis. IF the Sahara desert is expanding, it is a local issue. Elsewhere, the deserts are retreating and on average the trend is to global greening.

E.g.

Greening of the globe and its drivers - Nature 2016 https://www.nature.com/articles/nclimate3004 "Satellite records from 1982–2009 show a persistent and widespread increase of leaf area (greening) over 25% to 50% of the global vegetated area, whereas less than 4% of the globe shows decreasing leaf area (browning). Ecosystem models suggest that CO2 fertilisation effects explain 70% of the observed greening trend, followed by nitrogen deposition (9%), climate change (8%) and land cover change (4%)."

Elevated CO2 as a driver of global dryland greening - Nature 2016 https://www.nature.com/articles/srep20716 "Recent regional scale analyses using satellite based vegetation indices such as the Normalized Difference Vegetation Index (NDVI), have found extensive areas of “greening” in dryland areas of the Mediterranean, the Sahel, the Middle East and Northern China, as well as greening trends in Mongolia and South America. More recently, a global synthesis from 1982-2007 showed an overall “greening-up” trend over the Sahel belt, Mediterranean basin, China-Mongolia region and the drylands of South America."

Global Greening Is Firm, Drivers Are Mixed - Harvard 2014 http://adsabs.harvard.edu/abs/2015AGUFM.B31A0515K "Evidence for global greening is converging, asserting an increase in CO2 uptake and biomass of the terrestrial biosphere. Global greening refers to global net increases in the area of green canopy, stocks of carbon, and the duration of the growing season. The growing seasons in general have prolonged while the stock of biomass carbon has increased and the rate of deforestation has decelerated. Evidence for these trends comes from firm empirical data obtained through atmospheric CO2 observations, remote sensing, forest inventories and land use statistics."

Rise in CO2 has 'greened Planet Earth' http://www.bbc.co.uk/news/science-environment-36130346 Prof Judith Curry, the former chair of Earth and atmospheric sciences at the Georgia Institute of Technology, added: "It is inappropriate to dismiss the arguments of the so-called contrarians, since their disagreement with the consensus reflects conflicts of values and a preference for the empirical (i.e. what has been observed) versus the hypothetical (i.e. what is projected from climate models).

I hope all you empiricists will join me in celebrating this good news. Cheers!

lioeters• 6 years ago

Thanks for presenting this "contrarian" view about desertification. I was surprised to learn about global greening due to rising CO2.

Carbon Dioxide Fertilization Greening Earth, Study Finds - https://www.nasa.gov/feature/goddard/2016/carbon-dioxide-fer...

While it sounds like good news for the ecology, I think the overall destructive effects of human activity on the global environment far outweighs any accidentally beneficial effect of rising CO2. Celebrating it as "global greening" seems to be just as much of an oversimplification as the fear-mongering of desertification.

cbozeman• 6 years ago

Well... plants breathe CO2, so. :)

I actually wonder if, in 100 years, how the oxygen content will increase if this greening continues?

It'd be wild to consider a 27% oxygen environment on Earth in the year 2100. Which would also cause problems of its own, as I imagine you might have a higher risk of fires, since you have more available oxygen.

hedora• 6 years ago

These peer reviewed projections for the US are dire. They are 4 years newer than the sources you cite, and incorporate the consensus conclusions the scientific community has drawn from the empirical discrepancies.

They do show parts of the US greening, but much of the South is likely to be unfit for human life or agriculture:

https://projects.propublica.org/climate-migration/

pram• 6 years ago

Considering the humidity in places like coastal Mississippi or the Florida panhandle, they're already unfit for human life ;P

PicassoCTs• 6 years ago

So what does protect this wall from human nature on a economic downturn? Everyone can build a wildlife preserve from thrust-fund money, that will be a paradise/oasis, until the money runs out. What makes this project sustainable? As in, when the money runs out, the dessert will return because its human nature to turn all but the sturdiest surroundings into a war-torn desert. Where does this redirect/change human nature?

Someone2• 6 years ago

If you believe “its human nature to turn all but the sturdiest surroundings into a war-torn desert”, all hope is lost, indeed.

If, on the other hand, you believe people can learn, or if you believe people can’t learn, but are driven by money, this project has a chance. As the article says, this forest brings jobs. Also, stopping the Sahara from growing protects arable land. So, I think he idea is that profit will protect this wall.

The project has a site (https://www.greatgreenwall.org/), by the way. It has more (likely biased to some degree) information on the project.

Countries build 9 mile wide tree wall across Africa to prevent Sahara advancing (2014)

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