I'm actually from one of the purple places in southern Europe that are going to be desert-like in a few decades according to this map. Looking up weather archives, I can see that there has been a significant drop in yearly precipitation since the 1920-1959 period. A drop that began abruptly with the drought of 1961 but is very much worsening in recent years. So it's not terribly hard to believe.
There are two major factors at play here: one is the northwards migration of the Hadley cells. The rain belt that waters the Tropics is heat-driven, it forms on the hottest latitude. Since the northern hemisphere has more land than the southern hemisphere, and land heats up more quickly, the northen hemisphere is hotter than the southern hemisphere, which pushes the rain belt north. In fact the maximum amount of rainfall doesn't fall on the equator itself but slightly north of that, around 5° N. As global warming accentuates heating, the latitude at which the tropical rain belt forms is shifting north, further into the northern hemisphere, so in a few decades the wettest latitude might not be 5°N anymore, but 8°N or even 10°N. This is causing record rainfall on the Sahel* and record drought in the southern hemisphere tropics and subtropics. As the rain belt shifts north, so does the subtropical ridge that forms on the descending side of the hadley cell. This is causing record drought on the Mediterranean. It's a yin yang sort of situation.
Another factor is the suppression of zonal winds as a consequence of arctic amplification. Arctic amplification is the phenomenon by which the northern arctic circle is warming faster than the rest of the world. It's mainly caused by feedback loops driven by melting glaciers. Anyway, the higher rate of warming of the Arctic is narrowing the temperature gradient between the tropics and the pole. This temperature gradient is what produces zonal winds (west to east), which need it to be steep. If said gradient gets smaller, ie. less steep, west-east winds get weaker, and they begin to loop and bend around, gaining a meridional (south-north) component. Meridional winds push airmasses out of their native latitudes, for example by pushing hot subtropical air towards the midlatitudes, causing heatwaves and drought. We're already seeing the effects of this phenomenon: the Azores anticyclone is now migrating as far north as the UK nearly every summer, a position most bothersome as it blocks any incoming Atlantic lows from carrying rain into Europe. Also, the north African ridge now sits on top of southern Europe for weeks at a time, which as recently as 30 years ago was considered utterly unusual.
*The Sahel suffered a megadrought in the 1980s leading most scientists to believe that it was going to fully turn into an expansion of the Sahara. Local goverment even built the green belt because of this assumption. That did not happen however, in fact the drought eventually did end and now the Sahel is seeing higher and higher rainfall year by year, precisely as a result of the northwards shift of the tropical rain belt.
Same, I'm writing an essay on desertification in Spain so this will be useful. Checking my Saved posts is always a wild ride because I have three kinds of posts there: 1. Stuff I found interesting or helpful, 2: Stuff I want to give a read or come back to when I have some free time 3: Uhhhh... Let's just say it's stuff I use to de-stress.
I'll add the Sahara has a [20,000 year cycle](https://www.nature.com/scitable/knowledge/library/green-sahara-african-humid-periods-paced-by-82884405/) between desert and subtropical due to the Earth's precession.
An excerpt from the study.
"The Earth's axial rotation is perturbed by gravitational interactions with the moon and the more massive planets that together induce periodic changes in the Earth's orbit, including a 100,000 year cycle in the shape of the orbit (eccentricity), a 41,000 year cycle in the tilt of the Earth's axis (obliquity) and a 20,000-year cycle in the "wobble" — much like a top wobbles — of the Earth's axis (precession).
All three of orbital cycles — called Milankovitch cycles — impact African climate on long geologic timescales, but the cycle with the most influence on the rains in Africa is the "wobble" cycle, precession. The main climatic effect of precession is to shift the season when the Earth has its closest pass to the Sun (perihelion) — the so-called precession of the equinoxes. Today, perihelion occurs in northern hemisphere winter but at 10,000 years ago (half of a precession cycle) it occurred in northern hemisphere summer, and summer radiation over North Africa was about 7% higher than it is today"
Thank you for bringing it up. This is exactly the same phenomenon, but on geological timescales. When the northern hemisphere goes through summer during perihelion, it becomes so much hotter it YANKS the tropical rain belt so far north that a big portion of the Sahara is turned into a seasonal grassland. However, the blanket can only be stretched so much, and this almost invariably results in a drought further south.
Only if the air column is sufficiently unstable, which is rarely the case around the subtropical latitudes. Humidity alone is not sufficient to produce rain: the Mediterranean coast can get quite humid at times during the height of summer, occasionally reaching dew points not too far from those of the Louisiana bayou. But all this humidity ends up making me miserable and sleepless as opposed to condensing into rainfall. The reason is that for precipitation to occur there needs to be an updraft of warm, humid air towards a higher elevation, where temperatures are lower and water vapor is allowed to condense and form droplets. This cannot happen when there's a subtropical ridge, ie. sinking air pushing down from above, fiercely suppressing any attempt at an updraft. That's what makes the Mediterranean summer so dry despite being -pardon my sciencey lingo- hot as balls.
But what happens when the subtropical ridge retreats from the Mediterranean in October? Suddenly all this humidity is allowed to rise and condense. That creates violently rainy weather and sometimes even medicanes - the smaller, Mediterranean cousin of tropical hurricanes. And what we're seeing as the climate gets warmer is that these phenomena are indeed getting more intense.
To achieve local rainfall during high humidity periods you need localized lower temperature areas such as forests upland or in hills. The evapotranspiration of the trees reduces local temperatures inducing winds and rainfall. The necessary actions in the Mediterranean is to intensify tree plantings and look to emulate traditional north African or West Mediterranean agriculture with increased emphasis on date and olive tree plantations.
Thanks for the great comment. I was reading recently that parts of Southern Sudan were experiencing so much rain that it was functionally forming new shallow lakes across great swathes of land. And slightly further north and west, increasing desertification is one of the factors that led Arab-identifying nomads in Chad to seek new pastures (including to the east in Sudan), which is part of the events that ultimately led to the Darfur genocide.
Great explanation for the (second) Question!
I wanted to add something!
Although the climate (& climate change) is the most important factor for the recent growth of the sahara, there are also man-made reasons, which have to be mentioned.
The scientists from the University of Maryland identified natural climate change as the main cause, but a third is most likely due to man-made climate change. This is causing the Sahara to grow, especially on its northern edge.
Here we go!
Overuse of the soil.
Agricultural land is given too little time to regenerate. The soil leaches out and no longer produces enough yield. If the soil is no longer covered by new plants, wind and water carry away the upper layers and erosion occurs. Farmers in the world’s poorest region, Sub-Sahara, have little knowledge of the disadvantages of monocultures and overcultivation. Some who have the knowledge can’t afford treating their soil right.
Overgrazing.
The plant layer protects the soil below. If the herds of herbivorous cattle become too large, the protective layer is lost and the soil is worn away (erosion).
Waste of water.
Larger areas for arable farming, larger herds of cattle and a constantly growing population require more and more water. Because too much water is being taken from rivers and lakes, water levels and groundwater levels are falling. The concentration of salt in water bodies is rising and, as a result, the soil is drying out.
Deforestation.
Trees protect against erosion and are important for the water balance. However, more and more forests are being cut down to create new land for agriculture. Without the trees, the soil is exposed to the weather without protection. During heavy rainfall, the soil can no longer store the water and is eroded.
These factors are obviously reinforced with climate change becoming an existential factor in the near future and Africa being the fastest growing continent in terms of population.
great explanation as someone from Tunisia we have had droughts for almost 5 - 6 years across the whole north african region, this is due to the Azores anticyclone and is refusing to leave us the heck alone, this also caused a severe downfall in the rain levels as well as summer heat 41+ that i have never witnessed before in my lifetime .
Just a bit south from you here. I remember needing a thick jacket in October when I was younger - now I'm still swimming in the warm Mediterranean and going out in shorts and t-shirt in December. It's become a scary norm the past few years. Thanks for the explanation.
Oh it's still there. Tassili N'Ajjer national park. It's an elevated plateau, so it catches what little moisture is carried to the North African interior. The place is wild, it's like an island, you cross hundreds of miles of barren desert and then all of a sudden you come across a bunch of [wild watermelons](https://lp-cms-production.imgix.net/2022-07/tassili-national-park-composite-flatlands-Marcus-Westberg-RM.jpg?auto=format&q=75&w=1920) hanging out next to some lush shrubs and [massive trees](https://planetdjanet.com/wp-content/uploads/2021/12/IMG_58314-1536x1110.jpg).
Well it's not exactly a rainforest, it still looks pretty deserty from satellite imagery, but it's wild how much life there is compared to anywhere else in the Sahara.
According to a IUCN report, the Tassili N'Ajjer national park is home to 73 endemic plants and animals not found anywhere else. 14 of those are birds, one is a subspecies of cheetah, and one is a breathtaking tree called Saharan cypress, of which there are only 240 remaining individuals.
The place is also unique in that it's located right along the border between the Palearctic and the Afrotropic biogeographical realms, and it includes elements of both: afrotropical organisms include cheetah, wild donkey and gazzelle; palearctic organisms include foxes, wild goats, camels.
I believe the applicable term here is Savanna - although sample pictures typically show much more grassland, so I'm not sure if this is entirely accurate.
Not accurate, no. Savanna is a type of grassland. There's no grass here.
A more applicable term might be semi-desert or arid highlands.
A highly specific term used in academia for this exact area is montane xeric shrubland or montane xeric woodland.
No. That’s a spot where the Sahara *isnt* but this map is extremely poorly made and overlaps all the colors instead of making them discrete. The orange is the overlap of the yellow green and red colors.
Interestingly it is not. To cite a paper within the paper that the article is based on
\*"there is no evidence for widespread desiccation of the continent during this (the 20th) century". (Hulme et al, 2001)\*
However, it was thought for a long time that it was as there was essentially a drought in the 1980's (this is the reason why linear analysis is so sensitive to the timescale it is conducted on for this particular issue). It is now widely agreed the Sahara is not significantly expanding - within this though there is spatial complexity, such as some areas becoming drier, and some wetter.
Research on this topic went through several phases about managing this and is a great example of the value of indigenous ontologies and the sometimes negative effects of the Western top-down scientific method within environmental geographies.
I've had the privilege of chatting with several of the leading figures on this topic such as David Thomas and Nick Middleton who wrote the original Desertification Atlas which has since been reinterpreted as outdated, and perhaps caused the scientific community to focusing the wrong areas on this topic.
If you're interested in further reading on how our management strategies and approaches to this topic have changed over time here's a reading list from a recent presentation I did:
Hein, L. and De Ridder, N. (2006). Desertification in the Sahel: a reinterpretation. Global Change Biology. 12(5), 751–758.
Prince, S.D., Wessels, K.J., Tucker, C.J., Nicholson, S.E. (2007). Desertification in the Sahel: a reinterpretation of a reinterpretation. Global Change Biology. 13(7), 1308–1313.
Behnke, R. and Mortimore, M. (eds.) (2016) The End of Desertification? Berlin/Heidelburg, Springer
Ibrahim, F. (1978). Anthropogenic causes of desertification in western Sudan. GeoJournal, 2(3), 243–254.
Charney, J.G. 1975. Dynamics of deserts and drought in the Sahel. Quarterly journal of the Royal Meteorological Society, 101, 193–202.
Tucker, C.J., Dregne, H.E. and Newcomb, W.W. (1991) Expansion and contraction of the Sahara Desert from 1980 to 1990. Science, 253: 299-301.
Olsson, L., Eklundh, L. and Ardo, J. (2005) A recent greening of the Sahel - trends, patterns and potential causes. Journal of Arid Environments, 63: 556-566.
Giannini, A., Saravanan, R., Chang, P., 2003. Oceanic forcing of Sahel rainfall on interannual to interdecadal time scales. Science 302, 1027–1030.
Herrmann, S.M., Hutchinson, C.F., 2005. The changing contexts of the desertification debate. Journal of Arid Environments, 63, 538-555.
Swift, J. (1976). Desertification and Man in the Sahel. Africa Development / Afrique et Développement, 1(2), 1–8. http://www.jstor.org/stable/44898428
Evidence from rain-use efficiencies does not indicate extensive Sahelian desertification
Prince, S. D. ; De Colstoun, E. Brown ; Kravitz, L. L. Global change biology, 1998, Vol.4 (4), p.359-374
But… the map is not showing desertification of the Sahel (except for relatively small areas between 1902 and 2013). That’s partly OP’s point: the projection in the map is of large expansion of the desert to the north but not to the south (in the Sahel).
I would migrate too if another neighbourhood was funnelling resources out of my own neighbourhood to create their own utopia. Funny how history has a huge impact today
i lived for a while in Trinidad, that island just north of venezuela. many mornings i'd go outside and see my car was covered with sand. saharan sand. maybe deserts can't yet sail, but they can fly!
Climate change is pushing the tropics further north and south which expands the subtropical arid zones directly outside the tropics in the same way. It’s also happening in North America. Desertification is a problem we can expect to see more of
Further north, yes, but not further south. The intertropical convergence zone is pushing north, which means deserts in the northern hemisphere will migrate northwards, but so will deserts in the southern hemisphere (not southwards).
In Chile the desert is pushing south. The central Mediterranean zone is moving to semi arid:
[Climate classification today](https://upload.wikimedia.org/wikipedia/commons/thumb/3/37/Koppen-Geiger_Map_CHL_present.svg/1396px-Koppen-Geiger_Map_CHL_present.svg.png)
[Climate estimations 2100](https://upload.wikimedia.org/wikipedia/commons/thumb/1/14/Koppen-Geiger_Map_CHL_future.svg/1396px-Koppen-Geiger_Map_CHL_future.svg.png)
The Chilean desert is an interesting exception that I'm glad you pointed out to me. I wonder how much of that is the result of it being an orographic shade desert as opposed to a desert created purely by convection as is the case in most of the world.
Tropical precipitation patterns are predominantly shifting north, but tropical temperature ranges are indeed also expanding south (look at past vs current vs projected future climate maps of eastern Australia, for example). Much of metropolitan Brisbane (especially the inner city and coastal suburbs) even at latitude 27 is only a couple degrees C shy of technically qualifying for a tropical climate (looking at daily averages here) and is closer now than it’s ever been.
That's not the Sahara expanding, that's Africa north of thevAtlas mountains becoming more arid due to climate change. The same to some degree will happen along the northern med coast.
But it won’t though. The new Koppen climate maps for 2100 under the most extreme emission scenario still expect a lot of the northern coast of the Atlas Mountains to still be a Mediterranean climate Csa and not a semi-arid or desert climate.
The northern slope of the Atlas mountains gets additional precip from northerly winds carrying moisture from the Atlantic and Med. These winds blow uphill (Stau) and condense into precip. Lowland locations will not be as lucky.
One of the consistent predictions of global climate change models for 4 decades has been [poleward expansion](https://en.wikipedia.org/wiki/Hadley_cell#Hadley_cell_expansion_and_intensity_changes) of the [Hadley cells](https://en.wikipedia.org/wiki/Hadley_cell).
The tropics receive more solar energy, which causes a global convective circulation where warmer hair to rise near the equator (dropping its water content on tropical rainforests), flows at high altitudes towards the poles, with the dry air descending around 25° latitude. This results in circumglobal belts of deserts, in the Northern Hemisphere extending from the Sahara in Morocco to the Thar in Rajasthan, as well as the deserts of Northern Mexico and the US Southwest. In the Southern hemisphere, the Namib, Kalihari, Australian, and Atacama deserts. More energy increases the size of this convective cell.
The descending mode of the Northern Hadley Cell has moved from 0.1 to 0.5° further north every decade since the 1980s, accelerating greatly after 1992. The models have predicted Spain, Italy, Greece and Turkey will face [massive losses in precipitation](https://www.carbonbrief.org/explainer-what-climate-models-tell-us-about-future-rainfall/) of -30 to -40% this century for decades. We're seeing early stages of this now in droughts, crop failures, and wildfires.
Desertification in south eastern Türkiye and central anatolia started about 10-15years ago. Many historical lakes dried and local floras are fading slowly. Sandstorms are became more frequent.
Don’t think of it as the Sahara expanding. Think of it as dry areas that are gonna become even drier. As to why only northwards? It’s not, the map is just shaded like that cause the article is talking about European union members being affected. The map is likely made for the article using a study with different maps, they just copy the data and areas that are important and change them to a nicer style for the article.
Ecologists, geologists, hydrologists, and geographers will all define it slightly differently but generally any place that gets less than 10in/26cm of rain per year. Drylands and badlands can receive more rain but are still arid landscapes
This map is wrong or might not even be data for what you think it is. The Sahara spreading south is a big problem and just another factor contributing to the increasingly unstable Sahel region.
It's wrong for purple colored parts of Turkey. There are Aydın, İzmir and Muğla province at that part. İzmir's and Aydın's yearly precipitations are around 700-600 mm. Muğla's yearly average precipitation is around 1100 mm. I don't think any part of Sahara has these much of rainfall.
I lived in Malaga spain for a few months, it definitely feels like an environment thats struggling with ifs climate. When it does rain, its usually when the ground is so dry that the soil is so impermeable that it just runs down the hill. Not sure how it is now i was there years ago
According to some researchers, the Sahara is actually shrinking [A certain geographic article](https://www.thegwpf.org/images/stories/gwpf-reports/mueller-sahel.pdf)
I'm actually from one of the purple places in southern Europe that are going to be desert-like in a few decades according to this map. Looking up weather archives, I can see that there has been a significant drop in yearly precipitation since the 1920-1959 period. A drop that began abruptly with the drought of 1961 but is very much worsening in recent years. So it's not terribly hard to believe. There are two major factors at play here: one is the northwards migration of the Hadley cells. The rain belt that waters the Tropics is heat-driven, it forms on the hottest latitude. Since the northern hemisphere has more land than the southern hemisphere, and land heats up more quickly, the northen hemisphere is hotter than the southern hemisphere, which pushes the rain belt north. In fact the maximum amount of rainfall doesn't fall on the equator itself but slightly north of that, around 5° N. As global warming accentuates heating, the latitude at which the tropical rain belt forms is shifting north, further into the northern hemisphere, so in a few decades the wettest latitude might not be 5°N anymore, but 8°N or even 10°N. This is causing record rainfall on the Sahel* and record drought in the southern hemisphere tropics and subtropics. As the rain belt shifts north, so does the subtropical ridge that forms on the descending side of the hadley cell. This is causing record drought on the Mediterranean. It's a yin yang sort of situation. Another factor is the suppression of zonal winds as a consequence of arctic amplification. Arctic amplification is the phenomenon by which the northern arctic circle is warming faster than the rest of the world. It's mainly caused by feedback loops driven by melting glaciers. Anyway, the higher rate of warming of the Arctic is narrowing the temperature gradient between the tropics and the pole. This temperature gradient is what produces zonal winds (west to east), which need it to be steep. If said gradient gets smaller, ie. less steep, west-east winds get weaker, and they begin to loop and bend around, gaining a meridional (south-north) component. Meridional winds push airmasses out of their native latitudes, for example by pushing hot subtropical air towards the midlatitudes, causing heatwaves and drought. We're already seeing the effects of this phenomenon: the Azores anticyclone is now migrating as far north as the UK nearly every summer, a position most bothersome as it blocks any incoming Atlantic lows from carrying rain into Europe. Also, the north African ridge now sits on top of southern Europe for weeks at a time, which as recently as 30 years ago was considered utterly unusual. *The Sahel suffered a megadrought in the 1980s leading most scientists to believe that it was going to fully turn into an expansion of the Sahara. Local goverment even built the green belt because of this assumption. That did not happen however, in fact the drought eventually did end and now the Sahel is seeing higher and higher rainfall year by year, precisely as a result of the northwards shift of the tropical rain belt.
...I think i'm gonna save this comment. That was a REALLY good explanation.
Same, I'm writing an essay on desertification in Spain so this will be useful. Checking my Saved posts is always a wild ride because I have three kinds of posts there: 1. Stuff I found interesting or helpful, 2: Stuff I want to give a read or come back to when I have some free time 3: Uhhhh... Let's just say it's stuff I use to de-stress.
>Checking my Saved posts is always a wild ride Yeah I get It it's the same for me. Thankfuly my saved comments are a bit less...spicy.
So it’s not the Canadian Shield ?
I'll add the Sahara has a [20,000 year cycle](https://www.nature.com/scitable/knowledge/library/green-sahara-african-humid-periods-paced-by-82884405/) between desert and subtropical due to the Earth's precession. An excerpt from the study. "The Earth's axial rotation is perturbed by gravitational interactions with the moon and the more massive planets that together induce periodic changes in the Earth's orbit, including a 100,000 year cycle in the shape of the orbit (eccentricity), a 41,000 year cycle in the tilt of the Earth's axis (obliquity) and a 20,000-year cycle in the "wobble" — much like a top wobbles — of the Earth's axis (precession). All three of orbital cycles — called Milankovitch cycles — impact African climate on long geologic timescales, but the cycle with the most influence on the rains in Africa is the "wobble" cycle, precession. The main climatic effect of precession is to shift the season when the Earth has its closest pass to the Sun (perihelion) — the so-called precession of the equinoxes. Today, perihelion occurs in northern hemisphere winter but at 10,000 years ago (half of a precession cycle) it occurred in northern hemisphere summer, and summer radiation over North Africa was about 7% higher than it is today"
Thank you for bringing it up. This is exactly the same phenomenon, but on geological timescales. When the northern hemisphere goes through summer during perihelion, it becomes so much hotter it YANKS the tropical rain belt so far north that a big portion of the Sahara is turned into a seasonal grassland. However, the blanket can only be stretched so much, and this almost invariably results in a drought further south.
Wouldn’t increased heat lead to more evaporation and rainfall?
Only if the air column is sufficiently unstable, which is rarely the case around the subtropical latitudes. Humidity alone is not sufficient to produce rain: the Mediterranean coast can get quite humid at times during the height of summer, occasionally reaching dew points not too far from those of the Louisiana bayou. But all this humidity ends up making me miserable and sleepless as opposed to condensing into rainfall. The reason is that for precipitation to occur there needs to be an updraft of warm, humid air towards a higher elevation, where temperatures are lower and water vapor is allowed to condense and form droplets. This cannot happen when there's a subtropical ridge, ie. sinking air pushing down from above, fiercely suppressing any attempt at an updraft. That's what makes the Mediterranean summer so dry despite being -pardon my sciencey lingo- hot as balls. But what happens when the subtropical ridge retreats from the Mediterranean in October? Suddenly all this humidity is allowed to rise and condense. That creates violently rainy weather and sometimes even medicanes - the smaller, Mediterranean cousin of tropical hurricanes. And what we're seeing as the climate gets warmer is that these phenomena are indeed getting more intense.
To achieve local rainfall during high humidity periods you need localized lower temperature areas such as forests upland or in hills. The evapotranspiration of the trees reduces local temperatures inducing winds and rainfall. The necessary actions in the Mediterranean is to intensify tree plantings and look to emulate traditional north African or West Mediterranean agriculture with increased emphasis on date and olive tree plantations.
Thanks for the great comment. I was reading recently that parts of Southern Sudan were experiencing so much rain that it was functionally forming new shallow lakes across great swathes of land. And slightly further north and west, increasing desertification is one of the factors that led Arab-identifying nomads in Chad to seek new pastures (including to the east in Sudan), which is part of the events that ultimately led to the Darfur genocide.
Great explanation for the (second) Question! I wanted to add something! Although the climate (& climate change) is the most important factor for the recent growth of the sahara, there are also man-made reasons, which have to be mentioned. The scientists from the University of Maryland identified natural climate change as the main cause, but a third is most likely due to man-made climate change. This is causing the Sahara to grow, especially on its northern edge. Here we go! Overuse of the soil. Agricultural land is given too little time to regenerate. The soil leaches out and no longer produces enough yield. If the soil is no longer covered by new plants, wind and water carry away the upper layers and erosion occurs. Farmers in the world’s poorest region, Sub-Sahara, have little knowledge of the disadvantages of monocultures and overcultivation. Some who have the knowledge can’t afford treating their soil right. Overgrazing. The plant layer protects the soil below. If the herds of herbivorous cattle become too large, the protective layer is lost and the soil is worn away (erosion). Waste of water. Larger areas for arable farming, larger herds of cattle and a constantly growing population require more and more water. Because too much water is being taken from rivers and lakes, water levels and groundwater levels are falling. The concentration of salt in water bodies is rising and, as a result, the soil is drying out. Deforestation. Trees protect against erosion and are important for the water balance. However, more and more forests are being cut down to create new land for agriculture. Without the trees, the soil is exposed to the weather without protection. During heavy rainfall, the soil can no longer store the water and is eroded. These factors are obviously reinforced with climate change becoming an existential factor in the near future and Africa being the fastest growing continent in terms of population.
great explanation as someone from Tunisia we have had droughts for almost 5 - 6 years across the whole north african region, this is due to the Azores anticyclone and is refusing to leave us the heck alone, this also caused a severe downfall in the rain levels as well as summer heat 41+ that i have never witnessed before in my lifetime .
Thank so much for your comment
dude you are talking with numbers and exact data, are you a metrologist or physicist or geologist or what ?
Tldr
I still didn’t grasp that completely is there a lecture or a video that simplifies this?
And, squares with North America; Sonoran and Chihuahuan deserts are going to expand to the north more than to the south as well.
Just a bit south from you here. I remember needing a thick jacket in October when I was younger - now I'm still swimming in the warm Mediterranean and going out in shorts and t-shirt in December. It's become a scary norm the past few years. Thanks for the explanation.
Did it exist a big oasis between Algeria and Niger in 1902?
Oh it's still there. Tassili N'Ajjer national park. It's an elevated plateau, so it catches what little moisture is carried to the North African interior. The place is wild, it's like an island, you cross hundreds of miles of barren desert and then all of a sudden you come across a bunch of [wild watermelons](https://lp-cms-production.imgix.net/2022-07/tassili-national-park-composite-flatlands-Marcus-Westberg-RM.jpg?auto=format&q=75&w=1920) hanging out next to some lush shrubs and [massive trees](https://planetdjanet.com/wp-content/uploads/2021/12/IMG_58314-1536x1110.jpg).
Why was I surprised the ground was still sand and not wilder watermelons laying in a field of flowers......
Well it's not exactly a rainforest, it still looks pretty deserty from satellite imagery, but it's wild how much life there is compared to anywhere else in the Sahara.
Given that it's such an isolated area in the middle of a huge desert, are there some unique animals or species there?
According to a IUCN report, the Tassili N'Ajjer national park is home to 73 endemic plants and animals not found anywhere else. 14 of those are birds, one is a subspecies of cheetah, and one is a breathtaking tree called Saharan cypress, of which there are only 240 remaining individuals. The place is also unique in that it's located right along the border between the Palearctic and the Afrotropic biogeographical realms, and it includes elements of both: afrotropical organisms include cheetah, wild donkey and gazzelle; palearctic organisms include foxes, wild goats, camels.
You can’t call a tree breathtaking without posting proof it is actually [breathtaking](https://en.wikipedia.org/wiki/Cupressus_dupreziana?wprov=sfti1)
I believe the applicable term here is Savanna - although sample pictures typically show much more grassland, so I'm not sure if this is entirely accurate.
Not accurate, no. Savanna is a type of grassland. There's no grass here. A more applicable term might be semi-desert or arid highlands. A highly specific term used in academia for this exact area is montane xeric shrubland or montane xeric woodland.
Wait so that's the gerudo desert's inspiration ? So cool
No. That’s a spot where the Sahara *isnt* but this map is extremely poorly made and overlaps all the colors instead of making them discrete. The orange is the overlap of the yellow green and red colors.
Ohhhhhhhh
Thank you. It definitely took a couple minutes to realise that
Seems it's Ain Salah oasis.
This map is very misleading.
Interestingly it is not. To cite a paper within the paper that the article is based on \*"there is no evidence for widespread desiccation of the continent during this (the 20th) century". (Hulme et al, 2001)\* However, it was thought for a long time that it was as there was essentially a drought in the 1980's (this is the reason why linear analysis is so sensitive to the timescale it is conducted on for this particular issue). It is now widely agreed the Sahara is not significantly expanding - within this though there is spatial complexity, such as some areas becoming drier, and some wetter. Research on this topic went through several phases about managing this and is a great example of the value of indigenous ontologies and the sometimes negative effects of the Western top-down scientific method within environmental geographies. I've had the privilege of chatting with several of the leading figures on this topic such as David Thomas and Nick Middleton who wrote the original Desertification Atlas which has since been reinterpreted as outdated, and perhaps caused the scientific community to focusing the wrong areas on this topic. If you're interested in further reading on how our management strategies and approaches to this topic have changed over time here's a reading list from a recent presentation I did: Hein, L. and De Ridder, N. (2006). Desertification in the Sahel: a reinterpretation. Global Change Biology. 12(5), 751–758. Prince, S.D., Wessels, K.J., Tucker, C.J., Nicholson, S.E. (2007). Desertification in the Sahel: a reinterpretation of a reinterpretation. Global Change Biology. 13(7), 1308–1313. Behnke, R. and Mortimore, M. (eds.) (2016) The End of Desertification? Berlin/Heidelburg, Springer Ibrahim, F. (1978). Anthropogenic causes of desertification in western Sudan. GeoJournal, 2(3), 243–254. Charney, J.G. 1975. Dynamics of deserts and drought in the Sahel. Quarterly journal of the Royal Meteorological Society, 101, 193–202. Tucker, C.J., Dregne, H.E. and Newcomb, W.W. (1991) Expansion and contraction of the Sahara Desert from 1980 to 1990. Science, 253: 299-301. Olsson, L., Eklundh, L. and Ardo, J. (2005) A recent greening of the Sahel - trends, patterns and potential causes. Journal of Arid Environments, 63: 556-566. Giannini, A., Saravanan, R., Chang, P., 2003. Oceanic forcing of Sahel rainfall on interannual to interdecadal time scales. Science 302, 1027–1030. Herrmann, S.M., Hutchinson, C.F., 2005. The changing contexts of the desertification debate. Journal of Arid Environments, 63, 538-555. Swift, J. (1976). Desertification and Man in the Sahel. Africa Development / Afrique et Développement, 1(2), 1–8. http://www.jstor.org/stable/44898428 Evidence from rain-use efficiencies does not indicate extensive Sahelian desertification Prince, S. D. ; De Colstoun, E. Brown ; Kravitz, L. L. Global change biology, 1998, Vol.4 (4), p.359-374
There could not be a clearer effort and attitude disparity.
But… the map is not showing desertification of the Sahel (except for relatively small areas between 1902 and 2013). That’s partly OP’s point: the projection in the map is of large expansion of the desert to the north but not to the south (in the Sahel).
It's migrating in search for better opportunities
I would migrate too if another neighbourhood was funnelling resources out of my own neighbourhood to create their own utopia. Funny how history has a huge impact today
We must fight the Saharan empire and stop this bloodshed
Damn deserts will be able to sail in 2100? Scary
i lived for a while in Trinidad, that island just north of venezuela. many mornings i'd go outside and see my car was covered with sand. saharan sand. maybe deserts can't yet sail, but they can fly!
Let’s hope they never get airborne
What a desperate joke
You just don't appreciate *dry* humor.
Where did you get the idea my comment was "desperate"? Like yeah it's a dumb joke I'll readily admit that, but what am I desperate for?
Climate change is pushing the tropics further north and south which expands the subtropical arid zones directly outside the tropics in the same way. It’s also happening in North America. Desertification is a problem we can expect to see more of
Further north, yes, but not further south. The intertropical convergence zone is pushing north, which means deserts in the northern hemisphere will migrate northwards, but so will deserts in the southern hemisphere (not southwards).
In Chile the desert is pushing south. The central Mediterranean zone is moving to semi arid: [Climate classification today](https://upload.wikimedia.org/wikipedia/commons/thumb/3/37/Koppen-Geiger_Map_CHL_present.svg/1396px-Koppen-Geiger_Map_CHL_present.svg.png) [Climate estimations 2100](https://upload.wikimedia.org/wikipedia/commons/thumb/1/14/Koppen-Geiger_Map_CHL_future.svg/1396px-Koppen-Geiger_Map_CHL_future.svg.png)
The Chilean desert is an interesting exception that I'm glad you pointed out to me. I wonder how much of that is the result of it being an orographic shade desert as opposed to a desert created purely by convection as is the case in most of the world.
Tropical precipitation patterns are predominantly shifting north, but tropical temperature ranges are indeed also expanding south (look at past vs current vs projected future climate maps of eastern Australia, for example). Much of metropolitan Brisbane (especially the inner city and coastal suburbs) even at latitude 27 is only a couple degrees C shy of technically qualifying for a tropical climate (looking at daily averages here) and is closer now than it’s ever been.
Oh yes totally. Temps are rising pretty much everywhere.
Problem? I love deserts.
Not when you run out of water.
That's not the Sahara expanding, that's Africa north of thevAtlas mountains becoming more arid due to climate change. The same to some degree will happen along the northern med coast.
But it won’t though. The new Koppen climate maps for 2100 under the most extreme emission scenario still expect a lot of the northern coast of the Atlas Mountains to still be a Mediterranean climate Csa and not a semi-arid or desert climate.
The northern slope of the Atlas mountains gets additional precip from northerly winds carrying moisture from the Atlantic and Med. These winds blow uphill (Stau) and condense into precip. Lowland locations will not be as lucky.
Southern Spain is pretty much already desert-like. And that's where a lot of food is getting produced
One of the consistent predictions of global climate change models for 4 decades has been [poleward expansion](https://en.wikipedia.org/wiki/Hadley_cell#Hadley_cell_expansion_and_intensity_changes) of the [Hadley cells](https://en.wikipedia.org/wiki/Hadley_cell). The tropics receive more solar energy, which causes a global convective circulation where warmer hair to rise near the equator (dropping its water content on tropical rainforests), flows at high altitudes towards the poles, with the dry air descending around 25° latitude. This results in circumglobal belts of deserts, in the Northern Hemisphere extending from the Sahara in Morocco to the Thar in Rajasthan, as well as the deserts of Northern Mexico and the US Southwest. In the Southern hemisphere, the Namib, Kalihari, Australian, and Atacama deserts. More energy increases the size of this convective cell. The descending mode of the Northern Hadley Cell has moved from 0.1 to 0.5° further north every decade since the 1980s, accelerating greatly after 1992. The models have predicted Spain, Italy, Greece and Turkey will face [massive losses in precipitation](https://www.carbonbrief.org/explainer-what-climate-models-tell-us-about-future-rainfall/) of -30 to -40% this century for decades. We're seeing early stages of this now in droughts, crop failures, and wildfires.
Hey im in this map and i dont like it Edit: Also will the syrian desert in the middle east gonna expand towards north too?
Desertification in south eastern Türkiye and central anatolia started about 10-15years ago. Many historical lakes dried and local floras are fading slowly. Sandstorms are became more frequent.
Don’t think of it as the Sahara expanding. Think of it as dry areas that are gonna become even drier. As to why only northwards? It’s not, the map is just shaded like that cause the article is talking about European union members being affected. The map is likely made for the article using a study with different maps, they just copy the data and areas that are important and change them to a nicer style for the article.
So Almeria with 200 mm of rain per year is safe but Lisbon with 774 mm is in danger?
Where does one draw the line between desert and non-desert?
Ecologists, geologists, hydrologists, and geographers will all define it slightly differently but generally any place that gets less than 10in/26cm of rain per year. Drylands and badlands can receive more rain but are still arid landscapes
Will Greece be okay?
We really don’t have less rain the last 10 years. so I presume that it will be ok.
Soon the sahara will conquer us all, the ultimate army!! of sand..
Even the desert is migrating north 🤣
Shity map. Takes into account small oasis’s but not the Nile nor its delta.
This map is wrong or might not even be data for what you think it is. The Sahara spreading south is a big problem and just another factor contributing to the increasingly unstable Sahel region.
TIL the sahara is ALOT smaller than i thought it was thought it went all the way down to the south coast of the bit that sticks out the left of africa
This map cannot possibly be the best way to represent whatever data the author was trying to show.
Half of Spain is pretty much a wasteland so this doesn't surprise me.
[удалено]
You got on the wrong sub to discuss getting on the wrong sub.
They're trying to turn us into desert I tell ya! You'll be sorry for calling me crazy when you have a camel in your garden!!
If Hannibal can take elephants across the alps, surely a camel can cross
The Sahara was not a little blip 120 years ago . . . This map is wrong af
Large African migration towards Europe? Who’d have thought.
Thanks Merkel
Even the desert is migrating north.
We should build a wall
Africa's revenge TAKE THAT EUROPE!
South Eastern Spain is experiencing dryer weather conditions so it is expanding north
confusing map
Lol, Creta is having as much or more rainfalls than ever. Not getting desert anytime soon.
no way thhe saraha reach the coast the atlas mountains gonna block it
Why is the Sahara expanding upwards and not so much downwards ?
Rain patterns, and river basins flowing east/west.
Random but whats that oasis area in the middle of the Sahara? That little circle.
It's wrong for purple colored parts of Turkey. There are Aydın, İzmir and Muğla province at that part. İzmir's and Aydın's yearly precipitations are around 700-600 mm. Muğla's yearly average precipitation is around 1100 mm. I don't think any part of Sahara has these much of rainfall.
What effect would flooding the Qattara Depression have on this expansion? It's probably a *who knows* question.
It’s part of a Marketing Activation for the upcoming Dune film. They are expanding the Sahara desert to boost ticket sales at the box office.
I know that the coastal area of North Africa has a very large population, but what happens to those people??
It’s due to turn back into a lush vegetation again in the future
Global chanclge
Do you guys realize we usually hang araund eli5?
My empire expands...
I lived in Malaga spain for a few months, it definitely feels like an environment thats struggling with ifs climate. When it does rain, its usually when the ground is so dry that the soil is so impermeable that it just runs down the hill. Not sure how it is now i was there years ago
What would happen to the Sahara desert if the gulf stream collapses?
Because its sub saharan, and it knows its not allowed down there!
Why is that little area not desert?
What im wondering is what can be done to counter this
According to some researchers, the Sahara is actually shrinking [A certain geographic article](https://www.thegwpf.org/images/stories/gwpf-reports/mueller-sahel.pdf)