It’s not often that the UK feels as hot as the central Sahara, but there were certainly a few days in the summer of 2022 when that was the case. Such heat waves can occur when the Sahara arrives on our doorstep on the back of unusual winds. How do these events work and what can we expect from them in the future?
Heat waves are made in several ways, starting with intense sunshine. But as the early weeks of the summer of 2023 in the UK have shown, you can have noticeably cool air and bright, near-peak summer sunshine at the same time.
What really raises the temperature is the importing of heat from somewhere else. That process is often very efficiently carried out by the wind and that somewhere is the Sahara, when a southerly wind blows for long enough. We have come to call these events African plumes, or sometimes Iberian plumes as you may have heard them described in recent weather forecasts. They only visit the UK a few times a year.
Where plumes come from
African plumes are characterised by a hazy atmosphere laden with dust from the Sahara – the biggest source of that material anywhere on the planet come the summer months in the northern hemisphere.
Very large particles of dust are raised from the desert surface by gusts blowing over hundreds of kilometres, produced by the outflow of energy from thunderstorms. The big bonus following the arrival of this air in the UK is very colourful sunsets, as the setting rays are scattered by the dust, leaving only the red colours of the more elusive longer wavelengths of light for us to see.
While the process of importing heat from afar might sound exotic, it isn’t really. That is exactly what the weather is geared to do. Every day the Earth’s atmosphere has to respond to a never-ending problem of being inundated by an unfathomable amount of energy from the sun and to make things interesting, that energy is unevenly distributed so that some regions, such as the tropics and subtropics receive lots and other regions, notably the high latitudes and polar regions, very little.
Earth’s climate system redistributes heat from sun-drenched equatorial regions. ManuMata/Shutterstock
Outside the tropics, the number one method for sorting out that discrepancy in energy is to move heat in the winds. In the northern hemisphere, winds from the south are warm and those from the north cool. A constant supply of cool northerly wind has been a key reason why decent June sunshine hasn’t raised temperatures just yet this summer. By crossing latitudes, cool winds going south and warm winds going north help to even up the problem of uneven heating from the sun.
At the latitudes of the UK, weather systems transport more than 3 petawatts of heat polewards. That is about 300 times the installed electricity generation capacity worldwide. If the climate system is so good at carrying out this heat transport, what is it that makes the African plume events infrequent?
First, to line up a wind which blows all the way from the Sahara to the UK takes a special configuration of pressure systems. No one low or high pressure system is quite big enough to do this on its own. And second, that configuration has to stay in place for at least three days because the wind has to travel the better part of 3,000 km.
Assuming those things are to hand, the UK can experience Sahara-like conditions. Of course, the temperature of the wind will be modified as it makes its journey, in this case, cooling slightly the further it gets from the furnace of the Sahara. But that cooling process is much less efficient than you might think. Air retains the conditions at its origin quite stubbornly, and crossing the hot Iberian Peninsula as African plumes have often done in the past – a part of the world which is warming steeply as a result of climate change – doesn’t help.
What the future has in store
Will warming in the UK in future decades result in more African plumes? Well, here’s the surprise. Meticulous work by the Met Office which involved slicing up British weather into 30 different types showed that three out of four of the patterns which can generate southerly winds from the overheated Sahara are actually projected to become less frequent in future, and only one (a southerly wind driven by a high pressure system over Scandinavia) is expected to increase.
Likewise, the persistence or longevity of those weather patterns (and remember, to get the Saharan heat to the UK requires it persisting for three days or more) decreases for three out of four patterns, again only increasing in the case of the Scandinavian high. Meanwhile, there are also weather patterns which can transport heat from central Europe to the UK. And the Met Office work shows that these patterns are set to increase in frequency in the future – and also extend into the autumn months.
Dry soils over Europe reinforce the heat-making pressure pattern. Sunshine warms a dry surface much more readily than a wet one. So Europe is a source of intense heat for Britain too, with temperatures not far off those of the Sahara.
This plume of heat forecast for early June is a good example. We might lose those striking sunsets made of Saharan dust, but the heat is here to stay.
ROME, May 8 2023 (IPS)* – Less than a decade ago, Africa was home to 60-65% of the world’s uncultivated arable land and 10% of renewable freshwater resources, as reported by the African Union in 2016, while concluding that African farmers could feed the world.
Is it still the case?
Droughts are a growing threat to global food production, particularly in Africa. Credit: Busani Bafana/IPS
A major consequence is that that very percentage (60-65%) of the world’s uncultivated and arable land is now affected by degradation, with nearly three million hectares of forest lost… every single year.
Great walls
The steadily advancing degradation and desertification of major African regions have led the continent to build great green walls.
One of them – the Great Green Wall, is the largest living structure on the Planet, one that stretches over 8.000 kilometres across Africa, aiming at restoring the continent’s degraded landscapes and transforming millions of lives in the Sahel, and ushering in a new era of sustainability and economic growth.
Launched in 2007 by the African Union, this African-led Great Green Wall Initiative. The project is being implemented across 22 African countries and is expected to revitalise thousands of communities across the continent.
It is about “helping people and nature cope with the growing impact of the climate emergency and the degradation of vital ecosystems, and to keep the Sahara desert from spreading deeper into one of the world’s poorest regions,” according to the UN Environment Programme (UNEP).
Vast tracts of land along the Great Green Wall have already been restored by local communities. And so far, 80% of the 19 billion US dollars have been pledged, as reported by the UN Convention to Combat Desertification (UNCCD).
But not enough…
The extraneous factors that have been pushing Africa towards the abyss of extremely severe droughts, unprecedented floods, the advancing degradation of its land and water resources, have led this continent on Earth to rush to build more and longer and larger walls.
For instance, the Southern Africa region is currently busy preparing a similar programme, with all 16 countries in the Southern African Development Community (SADC) committed to accelerating multi-sectoral transformation through a regional initiative inspired by the Great Green Wall in the Sahel, or SADC Great Green Wall Initiative (GGWI).
The SADC member countries are: Angola, Botswana, Comoros, DR Congo, Eswatini, Lesotho, Madagascar, Malawi, Mauritius, Mozambique, Namibia, Seychelles, South Africa, Tanzania, Zambia and Zimbabwe.
A wall for Southern Africa
Their Initiative aims to create productive landscapes in the Southern Africa region that contribute to regional socially inclusive economic prosperity and environmental sustainability.
Together with member countries and key partners the goal is to initiate multi sectoral partnerships and to acquire pledges of an indicative 27 billion US dollars by 2025.
10 Million square kilometres at risk of desertification
Covering a total land area of 10 million square kilometres, Southern Africa faces immediate effects of desertification, land degradation and drought, as well as challenges driven by climate change, biodiversity loss, and unsustainable development practices in agriculture, energy and infrastructure sectors, reports the UN Convention to Combat Desertification (UNCCD).
“The Great Green Wall is part of a broader economic and development plan – if we restore land but are not able to reap the benefits of that healthy and restored land due to lack of access to renewable energy and infrastructure, hindering access to markets and livelihoods, then we are only halfway there with our vision,” on this said UNCCD’s Louise Baker.
And a great wall for the Middle East
In addition to the above two new natural wonders, there is another one: the Middle East Green Initiative, a regional effort led by Saudi Arabia to mitigate the impact of climate change on the region and to collaborate to meet global climate targets.
50 billion trees?
It aims at planting 50 billion trees across the Middle East, equivalent to 5% of the global afforestation target, and to restore 200 million hectares of degraded land.
A fifth (10 billion) trees will be planted within Saudi Arabia’s borders, with the remaining 40 billion set to be planted across the region in the coming decades.
Across the Middle East and North Africa, extreme weather events including droughts and heavy rains will become more common in the region if global temperatures continue to increase, according to the Saudi-led project.
A green corridor for East Africa… and elsewhere
In addition to developing an Eastern Africa corridor soon, other similar initiatives under the umbrella of the African Union’s NEPAD are ongoing, such as the African Forest Landscape Restoration Initiative (AFR100).
In 2015, AFR100 was founded in Durban by a group of 10 African countries, each committing to restore a certain number of hectares of degraded landscapes within their borders.
Twenty-eight African countries have now committed to restoring 113 million hectares, which, if achieved, will exceed the initiative’s namesake goal of 100 million hectares across the continent under restoration by 2030.
Not only trees
Forest landscape restoration is more than just planting trees,” said Mamadou Diakhite, leader of the AFR100 Secretariat.
On a continent that is expected to account for half the global population growth by 2050, reducing and sequestering greenhouse gas emissions is a welcome byproduct of returning those natural landscapes to health and profitability; but it’s not the first focus, reported Gabrielle Lipton, Landscape News Editor-in-Chief.
“Restoring landscapes that have been degraded by the effects of climate change and human development through planting trees and encouraging sustainable farming and herding must first and foremost provide food, jobs and homes for people, as well as preserve their cultures that are based on the products of their lands.”
Moreover, as more than 1 in 5 people in Africa are undernourished, and forced migration across country borders increases due to climate change and conflict, African economies continue to struggle hard to create jobs for young people.
Any chance that Africa recovers soon from the impacts of so much extraneous damage, which this continent of nearly 1.4 billion humans continues to struggle to reverse?
Cornell University in a research supported by Qatar Foundation concluded a study that holds that deserts ‘breathe’ water vapor. So what? Did we know that in the MENA region that is at more 90% desert?
Deserts may seem lifeless and inert, but they are very much alive. Sand dunes, in particular, grow and move – and according to a decades-long research project, they also breathe humid air.
The findings show for the first time how water vapor penetrates powders and grains, and could have wide-ranging applications far beyond the desert – in pharmaceutical research, agriculture and food processing, as well as planetary exploration.
Michel Louge, professor of mechanical and aerospace engineering, pictured here in Qatar in 2012, has been using capacitance probes to study the moisture content in sand dunes since the early 2000s.
The project, led by lead author Michel Louge, professor of mechanical and aerospace engineering in the College of Engineering, has spanned not only a great deal of time but also a variety of terrain. It began nearly 40 years ago when Louge was studying the behavior of fluids, gasses and solid particles.
Wanting to measure matter with greater sensitivity, he and his students developed a new form of instrumentation called capacitance probes, which use multiple sensors to record everything from solid concentration to velocity to water content, all with unprecedented spatial resolution.
When a colleague at the University of Utah suggested the technology might be helpful in imaging the layers of mountain snowpacks and assessing the likelihood of avalanches, Louge went to his garage, grabbed some probes and tested them out in a snowstorm. Soon he struck up a partnership with a company, Capacitec Inc, to combine their respective skills in geometry and electronics. The resulting probes also proved useful in hydrology research.
In the early 2000s, Louge began collaborating with Ahmed Ould el-Moctar from University of Nantes, France, to use the probes to study the moisture content in sand dunes to better understand the process by which agricultural lands turn to desert – an interest that has only become more urgent with the rise of global climate change.
“The future of the Earth, if we continue this way, is a desert,” Louge said.
Whereas other probes can measure large volumes of matter, Louge’s probes go deep and small, collecting data on a millimetric scale to pinpoint the exact amount of moisture in – and the density of – sand. To function in a new environment, though, the probes needed to be modified. And so began a decadelong process of trial and error, as Louge made periodic trips to deserts in Qatar and Mauritania experimenting with different versions of the probe.
The probe eventually revealed just how porous sand is, with a tiny amount of air seeping through it. Previous research had hinted this type of seepage existed in sand dunes, but no one had been able to prove it until now.
“The wind flows over the dune and as a result creates imbalances in the local pressure, which literally forces air to go into the sand and out of the sand. So the sand is breathing, like an organism breathes,” Louge said.
That “breathing” is what allows microbes to persist deep inside hyper-arid sand dunes, despite the high temperature. For much of the last decade, Louge has been collaborating with Anthony Hay, associate professor of microbiology in the College of Agriculture and Life Sciences, to study how microbes can help stabilize the dunes and prevent them from encroaching into roads and infrastructure.
Louge and his team also determined that desert surfaces exchange less moisture with the atmosphere than expected, and that water evaporation from individual sand grains behaves like a slow chemical reaction.
The bulk of their data was gathered in 2011, but it still took Louge and his collaborators another decade to make sense of some of the findings, such as identifying disturbances at the surface level that force evanescent, or nonlinear, waves of humidity to propagate downward through the dunes very quickly.
“We could have published the data 10 years ago to report the accuracy of our approach,” Louge said. “But it wasn’t satisfying until we understood what was going on. Nobody really had done anything like this before. This is the first time that such low levels of humidity could be measured.”
The researchers anticipate their probe will have a number of applications – from studying the way soils imbibe or drain water in agriculture, to calibrating satellite observations over deserts, to exploring extraterrestrial environments that may hold trace amounts of water. That wouldn’t be the first time Louge’s research made its way into space.
But perhaps the most immediate application is the detection of moisture contamination in pharmaceuticals. Since 2018, Louge has been collaborating with Merck to use the probes in continuous manufacturing, which is viewed as a faster, more efficient and less expensive system than batch manufacturing.
“If you want to do continuous manufacturing, you have to have probes that will allow you, as a function of time, and everywhere that’s important, to check that you have the right behavior of your process,” Louge said.
Co-authors include Ould el-Moctar; Jin Xu, Ph.D. ’14; and Alexandre Valance and Patrick Chasle with the University of Rennes, France.
The research was supported by the Qatar Foundation.
Groundwater Nourishing Life by Dr Irfan Peerzada and published by Greater Kashmir applies to all areas of the planet, particularly to those regions that are at the forefront of the sweeping global warming.
It should be noted that this threat has been taking on an alarming dimension for several years. Risks and vulnerability analyses of the Climate Change effects on the MENA region were carried out on behalf of certain authorities in charge of the environment. Most came up with findings on the fragile sectors of agriculture and water resources and established maps from local and international data such as the “drought severity” map based on the World Resources Institute.
These analyses of risks and vulnerability to climate change developed by these experts for several years also indicated that climate change will cause the MENA region generally a rise in temperatures, a decrease in total rainfall but also a greater instability of the distribution of precipitation during the year. It will lead to a degradation of the vegetation cover and soils resulting in greater erosion and acceleration of desertification.
In the above-featured image “Groundwater is also critically important to the healthy functioning of ecosystems, such as wetlands and rivers. “Flickr [Creative Commons]
Reliance on groundwater for food production continues to increase globally
Groundwater is invisible, but its impact is visible everywhere. Out of sight, under our feet, groundwater is a hidden treasure that supports our lives.
Almost all the liquid fresh water in the world is groundwater. Life would not be possible without groundwater. Most arid areas of the world depend entirely on this resource.
Groundwater supplies a large proportion of the water we use for food production and industrial processes. Groundwater is also critically important to the healthy functioning of ecosystems, such as wetlands and rivers.
Groundwater: The invisible ingredient in food
Population growth, rapid urbanisation, and economic development are just some of the factors driving increased demand for water, energy and food. Agriculture is the largest consumer of the world’s freshwater resources. Feeding a global population expected to reach 9 billion people by 2050 will require a 50 per cent increase in food production.
Today, approximately 70% of global groundwater withdrawals are used in the agricultural sector, for the production of food, livestock and industrial crops. Reliance on groundwater for food production continues to increase globally, resulting in more use for irrigated agriculture, livestock and related industrial processes.
Indeed, about 30 per cent of all the water used for irrigation is groundwater, with regions heavily reliant on groundwater for irrigation such as North America and South Asia.
Groundwater has already lifted millions of people out of poverty and significantly improved food security, especially in India and East Asia, since technologies for drilling and energy sources for pumping were made widely available for rural farmers in the latter half of the 20th century.
Groundwater: a finite resource
Groundwater is being over-used in many areas of the world, where more water is abstracted from aquifers than is naturally recharged by rain and snow.
Continuous groundwater over-use can lead to depletion of this resource, compromising significant groundwater-dependent ecosystems and threatening to undermine basic water supply, agricultural production, climate resilience and food security.
Avoiding the problems of groundwater depletion requires increased management and governance capacity at multiple integrated levels and in inter-sectoral approaches. Reducing food waste can also play an important role in lowering water consumption.
Groundwater pollution
Groundwater is polluted in many areas and remediation is often a long and difficult process. This increases the costs of processing groundwater, and sometimes even prevents its use.
The use of chemical and organic fertilizers in agriculture is a serious threat to groundwater quality. For example, nitrate is the most common contaminant of groundwater resources worldwide. Other diffuse contaminants of concern to groundwater from irrigated agriculture include pesticides and antimicrobial-resistant bacteria.
Laws and regulations need to be enforced at all levels to prevent or limit diffuse groundwater pollution from agriculture, to preserve ecosystems and human health.
What can we do about groundwater?
Groundwater has always been critically important but not fully recognized. We must protect groundwater from pollution and use it sustainably, balancing the needs of people and the planet. Groundwaters’ vital role in agriculture, industry, ecosystems and climate change adaptation must be reflected in sustainable development policymaking.
Monitoring groundwater
In some areas of the world, we do not even know how much groundwater lies beneath our feet, which means we could be failing to harness a potentially vital water resource.
Sustainable groundwater use requires continuous monitoring of water consumption, particularly in irrigation systems serviced from non-renewable aquifers.
Satellite technologies offer cost-effective opportunities for estimating groundwater consumption and abstraction levels by measuring actual evapotranspiration in near-real time, over large areas.
Dr Irfan Peerzada, Department of Agriculture, District Bandipora
The Nile Delta’s Disappearing Farmland is a story by Adam Voiland based on NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey.
The above image is for illustration and is of The Nile, Egypt.
During the time of the pharaohs, the fertile soils along the Nile River likely supported a civilization of roughly 3 million people. Now there are 30 times that number of people living in Egypt, with 95 percent of them clustered in towns and cities in the Nile’s floodplain. Much of the growth has come in recent decades, with the Egyptian population soaring from 45 million in the 1980s to more than 100 million now.
Just 4 percent of Egypt’s land is suitable for agriculture, and that number is shrinking quickly due to a wave of urban and suburban development accompanying the population growth. “It’s not an exaggeration to say that this is a crisis,” said Nasem Badreldin, a digital agronomist at the University of Manitoba. “Satellite data shows us that Egypt is losing about 2 percent of its arable land per decade due to urbanization, and the process is accelerating. If this continues, Egypt will face serious food security problems.”
The pair of Landsat images below shows how much farmland has been lost to development around the city of Alexandria between the 1980s and 2021. Cultivated areas appear green; towns and cities are gray. According to one analysis of Landsat observations, the amount of land near Alexandria devoted to agriculture dropped by 11 percent between 1987 and 2019, while urban areas increased by 11 percent. The images above show urbanization eating into farmland around the cities of Tanta and El Mahalla El Kubra and between the Rosetta and Damietta branches of the Nile.
July 25, 1984 – August 16, 2021
While the conversion of farmland to human settlements here has occurred for decades, multiple researchers observed sharp increases in the practice after the “Arab Spring” roiled the political and economic climate in Egypt starting in 2011. In recent years, Egyptian authorities have vowed to put an end to unlicensed building on farmland, though it remains a difficult practice to stamp out.
Urbanization is not the only process putting pressure on Egypt’s farmland. Sea level rise of 1.6 millimeters per year has contributed to problems with saltwater intrusion and the salinization of farmland in Egypt, particularly in the fringes of the delta southwest of Alexandria. About 15 percent of Egypt’s most fertile farmland has already been damaged by sea level rise and saltwater intrusion, according to the UN Food and Agriculture Organization. While global warming is responsible for about half of the sea level rise affecting the Nile Delta, the sinking of the land (subsidence) is responsible for the other half. Natural compaction, as well as the extraction of groundwater and oil, contribute to subsidence.
One response to the loss of farmland has included efforts to reclaim and green-up parts of the desert. For instance, Farouk El-Baz, Boston University scientist and a member of the Apollo 11 field crew, has long promoted a plan to build an extensive corridor of highways, railways, water pipelines, and power lines to spur development and the establishment of new farmland in deserts west of the delta.
July 25, 1984 – August 16, 2021
While that project has not come to full fruition yet, large swaths of desert have been converted to farmland in recent decades. The pair of images below shows new farmland and the emergence of several new towns along the Cairo Highway. A mixture of center-pivot irrigation and drip irrigation—fed by groundwater pumps—makes farming in this area possible, explained Badreldin. While small-scale sustenance farming is common in the main part of the delta, most of the growers on the desert edge raise grains, fruits, and vegetables for export abroad.
“It is certainly possible to establish new farmland from the desert by tapping groundwater resources, but it’s a difficult, resource-intensive, and expensive process,” said Badreldin. “The poor soils and the intensive resources needed to farm in the western desert are a poor replacement for the richer, more fertile soils in the delta.”
Boston University researchers Curtis Woodcock and Kelsee Bratley have analyzed decades of Landsat observations as part of a Boston University effort to track how the availability of farmland in the delta is changing over time. “We certainly see expansion into the desert, but there’s nuance to this story,” said Woodcock. “After being farmed for a time, we also see a significant amount of that new farmland being decommissioned and reverting to desert.”
Generations of travelers have stood before the “ksars” of Djado, wandering their crenellated walls, watchtowers, secretive passages and wells, all of them testifying to a skilled but unknown hand.
Originally posted on DESERTIFICATION: Heidelberg Earth scientists study natural climate fluctuations of the past 500,000 years – https://www.labmanager.com/news/desertification-threatens-mediterranean-forests-30224 With a view towards predicting the consequences of human-made climate change for Mediterranean ecosystems, Earth scientists from Heidelberg University have studied natural climate and vegetation fluctuations of the past 500,000 years. Their primary focus was the effects…
Originally posted on HUMAN WRONGS WATCH: Human Wrongs Watch (UN News)* — Disinformation, hate speech and deadly attacks against journalists are threatening freedom of the press worldwide, UN Secretary-General António Guterres said on Tuesday [2 May 2023], calling for greater solidarity with the people who bring us the news. UN Photo/Mark Garten | File photo…
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