A growing global population increasingly living in cities has led to a spiralling rise in the extraction of sand and aggregates, with serious environmental, political and social consequences.
Sand and coarse aggregates form the backbone of the modern world and, through land reclamation, the ground on which we live, of the materials we take for granted: concrete, glass and asphalt. A point in case, Archinect News looking at Construction is feeding a global sand crisis, per a new study confirms it.
Construction is feeding a global sand crisis, says new study
The study, published in the journal One Earth, notes that “sand, gravel, and crushed rock, together referred to as construction aggregates, are the [world’s] most extracted solid materials. Growing demand is damaging ecosystems, triggering social conflicts, and fueling concerns over sand scarcity. Balancing protection efforts and extraction to meet society’s needs requires designing sustainable pathways at a system level.”
In total, around 50 billion tons of sand, gravel, and crushed rock are used by humankind each year. As a key ingredient in the production of concrete and glass, sand plays an important role in the construction of almost every component of the built environment, from buildings and walls to bridges and tunnels.
As a global shift from rural to urban areas continues, it is expected to that eight cities the size of New York will be built each year for the next thirty years. As a result, global use of sand, gravel, and crushed rock is set to dwarf the use of all other solid materials on Earth, hitting over 50 gigatons per year by 2060. Torres’ study also makes the ironic point that coastal responses to climate change, which will involve significant construction and upgrading of sea walls and flood defenses, will also contribute to an increased demand for sand mining.
Despite our reliance on sand, the global supply network is poorly regulated and managed, leading to a lack of data and understanding over the quantities and impact of the network on both the environment and social fabrics. To overcome this, the latest paper departs from its predecessors, which tended only to focus on excavation sites, and instead undertook a broader overview of the network. “We take a broad look at the physical and socio-environmental dimensions of sand supply networks,” Torres told Gizmodo, “linking extraction, logistics, distribution, economics, policy, to gain an understanding of the stresses on both nature and people.”
The paper sets out some of the environmental and social hazards associated with the sand supply network as it exists today. For example, sand mining can lead to riverbed collapse and increased erosion along coastal settlements. In parts of India and Vietnam, this phenomenon has forced coastal populations to move inland to larger urban areas, which only adds further to sand supply needs. The paper also describes the risk of conflict associated with sand mining, which has already triggered conflict and displacement in Singapore, and a dangerous black market in Southeast Asia. Gizmodo notes that sand mining gangs have also depleted enough sand to cause 24 Indonesian islands to disappear from erosion.
To combat these issues, the paper calls for more regulated, monitored networks to manage global sand resources. The authors also note the need to decrease our reliance on sand, whether through crushing rocks to create more a sustainable alternative to sand, or a requirement by governments that the rubble from demolished buildings is recycled as a replacement to new concrete. The authors also point to the need to embrace alternatives to concrete, such as hempcrete and timber, and call for the construction of buildings with a longer operating life.
Planting trees, although a very commendable effort, could not be an end in itself. Carbon180 in ‘We can’t just plant our way out of the climate crisis’ holds that ‘while forestry is a key piece of the complicated CDR puzzle, it’s no silver bullet — no solution is.’
In late March, Saudi Arabia’s leader, who aims to transform the petrostate’s economy and society, plans to plant 10 billion trees over the coming decades to increase the area covered by existing trees by twelvefold. This is, if at all possible because of the prevailing climate, would perhaps require more maturing, notably through Carbon180’s stuff. Here it is.
We can’t just plant our way out of the climate crisis
by Maya Glicksman, policy advisor and Ugbaad Kosar, deputy director of policy
As technological carbon removal has garnered widespread attention, one response resurfaces again and again: Why complicate climate solutions with expensive, experimental technology when Earth’s most efficient carbon removal machines already exist in nature? Why not just plant more trees?
While we understand the uncertainty that comes with any burgeoning technologies, it’s risky to paint any approach (even trees!) as a silver bullet solution. In fact, an oversimplified “this-or-that” mentality can do more harm than good — it shuts down nuanced conversations, ignores the complexity of different CDR pathways, and pits tech- and land-based solutions against each other. In reality, we’ll likely need a combination of tech, land, and cross-solution pathways to achieve necessary gigaton-scale removals by mid-century.
First, the merits of forestry approaches
It’s true that forests are valuable carbon sinks — trees can remove and store huge amounts of carbon for decades to centuries, and US forests alone capture nearly 12% of national annual emissions. If expanded and restored at scale, US forests could remove nearly 700 million tonnes of carbon dioxide per year for as low as $5 per ton.
On top of their carbon-storing power, forests provide a wide range of benefits that serve community health, local economies, and climate resilience needs. These myriad benefits make forests key to meeting equitable carbon removal goals, supporting a strong case for their protection, restoration, and sustainable management.
But scaling up tree planting is no easy feat
New research revealed that US nurseries face a serious shortage of tree seeds and seedlings, a limiting factor in ramping up reforestation. To replant about half of the total reforestable area in the US by 2040, the study estimates that nurseries would need to produce an additional 1.7 billion seedlings per year — 2.3 times the current rate of production.
The scarcity of seedlings presents a real challenge, but it’s not just about seedlings — it’s also about people. The same study found that only 32% of nurseries currently produce at full capacity, citing workforce shortages as the greatest barrier to expansion. Specifically, nurseries depend heavily on a seasonal migrant workforce, and survey respondents cited immigration policy as their single largest concern.
Forest carbon removal also raises complex land use concerns, as many of these approaches require large swaths of arable land. Planting can intensify competition with other uses like agriculture or depend on land that is not suitable for long-term carbon storage under a changing climate. The way we reforest is key — the site, scale, and mix of tree species must be selected to protect whole ecosystems and the services they provide.
A disproportionate dependence on forest carbon removal
Our exploration of carbon offsets highlighted the blurred line between removals and reduction efforts in forestry projects, undermining the quality of these offsets and their total carbon impacts. Most corporate, national, and international emissions targets depend on forests to meet climate goals, but these projects depend on a handful of carbon accounting assumptions that, in many cases, overestimate the carbon stored in forests and perpetuate global injustices.
Land-based pathways are used to offset emissions from fossil fuels, assuming all forms of carbon are equivalent when, in reality, they are not. Fossil carbon trapped underground naturally cycles much slower than biotic carbon found in forests — fossil carbon can stay put underground for hundreds of millions of years, while forest carbon turns over every few centuries. This million-fold difference reflects that there is simply a lot more carbon stored in fossil reservoirs beneath the Earth’s surface (aka millions of years worth of sedimentary rock) than in forest ecosystems. The assumption of carbon equivalence ignores these enormous differences in both pace of carbon cycling and the size of these natural reservoirs.
Because they belong to this shorter-term, smaller-scale carbon cycle, forest carbon sinks have finite capacity that reflects losses over time, primarily due to disturbances like land use change. In other words, planting trees restores carbon that forest ecosystems have already lost — but this restoration can’t account for the vast amounts of carbon humans have released from fossil sources, which took millions of years to accumulate underground.
Carbon removal solutions (and climate action in general) typically work under the assumption that the specific site of removals or emissions doesn’t matter because carbon dioxide is diffused equally across the Earth’s atmosphere. This assumption of geographic equivalenceallows wealthy countries and corporations to finance removal projects elsewhere to meet emissions targets in an international exchange of mitigation responsibilities. The exchange usually includes Global North countries paying for forest offset projects in the Global South — a system of transactions coined by some as carbon colonialism.
Pursuing large-scale forest carbon removal requires governance frameworks that protect the livelihoods and well-being of vulnerable communities. While some geographies are simply more suited to certain types of carbon removal, project developers can’t ignore the complex social, political, and cultural factors for communities that exist within those geographies. Forest carbon removals must not come at the expense of communities’ access to and sovereignty over ancestral forests, key natural resources, and economic vitality.
No silver bullets
While forestry is a key piece of the complicated CDR puzzle, it’s no silver bullet — no solution is. We are in the midst of a climate emergency and need to deploy all solutions at our disposal. We should view different approaches as additive and complementary in the solutions landscape, each with unique merits, opportunities, and restraints.
Many forestry approaches are shovel-ready today and can be fully realized with policies that support carbon removal, community well-being, and ecosystem resilience. Here are five key recommendations to support an equitable and durable scale-up of forest carbon removal.
1. Increase investments across reforestation activities to ensure that regional seedling supply can meet accelerating planting demand.
USFS should address the backlog for replanting public lands, as outlined by the REPLANT Act. The government should also expand investment in public and private nurseries to address the national seedling shortage, as outlined in the SOS for Seedlings Act.
2. Expand and create new federal corps programs to support job creation and workforce development in forestry within vulnerable and underemployed communities.
Developing local expertise and workforce capacity in forest stewardship and climate mitigation will support long-term community resilience and economic diversification. The Public Lands Corps, AmeriCorps, and Job Corps should reorient to prioritize forest restoration and management projects, tailoring programs to meet local community employment and ecosystem needs. A new Civilian Climate Corps could serve as an important workforce development opportunity, building on President Biden’s recent executive order.
3. Advance forest carbon monitoring, reporting, and verification (MRV) technologies and approaches.
Robust MRV will be critical to accurately measure how much carbon is stored in forests across geographies, species, and management approaches. Combining high-resolution remote sensing, field data, and modeling can help improve these efforts, given the growing interest in monetizing forest carbon.
4. Explore policy options to separate land-based and fossil-derived carbon accounting to reflect their different carbon sinks and cycling rates.
Policy can lay the groundwork for regulating carbon removals by sector, e.g. land-based removals for land-based emissions and technological removals with geologic storage for fossil emissions. By limiting cross-industry reliance on land carbon removal, this transition would spur innovation in tech CDR and emissions reductions efforts to decarbonize industries dependent on fossil fuels.
5. Increase international collaboration to support equitable and global scale-up of carbon removal.
The government should support efforts that promote international collaboration and provide technology, information, and funds to Global South countries for carbon removal RDD&D. The US should work to ensure that Global South countries have the tools and autonomy to make decisions about the suite of carbon removal projects they want to see deployed on their lands.
Alongside robust and justice-oriented tech CDR policy, these recommendations can support a multi-pronged approach to carbon removal, maximizing the carbon impacts of each pathway while supporting an equitable transition.
This article republished from The Conversation is about Sudan’s ‘forgotten’ pyramids that risk being buried by shifting sand dunes and take with them all related history.
Rampant desertification expansion towards the north does not meet any counter-movement. But, conversely, in the south, one ambitious African-led reforestation project is leading the way. To combat sand movement and desertification by increasing the vegetation cover along the southern edge of the Saharan desert, a Green Wall is proposed. It is being implemented throughout the continent from ocean to ocean. In the southern edge of the MENA region, we sadly do not share the same concern and do not consecrate to date more than little attention paid to it. Is it the force of habit or what else?
Sudan’s ‘forgotten’ pyramids risk being buried by shifting sand dunes
The word “pyramid” is synonymous with Egypt, but it is actually neighbouring Sudan that is home to the world’s largest collection of these spectacular ancient structures.
Beginning around 2500BC, Sudan’s ancient Nubian civilisation left behind more than 200 pyramids that rise out of the desert across three archaeological sites: El Kurru, Jebel Barkal and Meroe, in addition to temples, tombs and royal burial chambers.
Despite being smaller than the famous Egyptian pyramids of Giza, Nubian pyramids are just as magnificent and culturally valuable. They even offer a crowd-free experience for intrepid tourists.
Built of sandstone and granite, the steeply-sloping pyramids contain chapels and burial chambers decorated with illustrations and inscriptions carved in hieroglyphs and Meroitic script celebrating the rulers’ lives in Meroe – a wealthy Nile city and the seat of power of Kush, an ancient kingdom and rival to Egypt.
Located about 220km north of the capital Khartoum, the cultural gem of Meroe is now one of Sudan’s most significant Unesco world heritage sites. However a lack of preservation, severe weather conditions and negligent visitors have all taken their toll on its monuments. Back in the 1880s, for instance, the Italian explorer Giuseppe Ferlini blew up several pyramids in his search for Kushite treasure, leaving many of the tombs missing their pointy tops. Many more of Sudan’s other pyramids were subsequently plundered and destroyed by looters.
These days sandstorms and shifting sand dunes pose the biggest threat to Sudan’s ancient heritage sites. This phenomenon is nothing new, and was even chronicled thousands of years ago. An inscription found in a temple from the 5th century BC describes a Kushite king giving an order to clear out sand from the pathway:
His Majesty brought a multitude of hands, to wit, men and women as well as royal children and chiefs to carry away the sand; and his Majesty was carrying away sand with his hand(s) himself, at the forefront of the multitude for many days.
But today the threat has been exacerbated by climate change, which has made the land more arid and sandstorms more frequent. Moving sands can engulf entire houses in rural Sudan, and cover fields, irrigation canals and riverbanks.
The best way to combat sand movement and desertification is to increase the vegetation cover, and one ambitious African-led reforestation project is leading the way.
Bringing together more than 20 nations, the Great Green Wall is a multi-billion dollar movement to stop the spread of the Sahara Desert by restoring 100 million hectares of land across the continent from Senegal in west Africa to Djibouti in the east. The intention is to cultivate the largest living barrier of trees and plants on the planet, with Sudan having the longest stretch of the “wall”.
Only 4% of the target area has been covered so far, with big variations from country to country. When it is more complete, this experimental project will hopefully limit the frequency of dust storms and slow the movement of sand onto fertile lands and Unesco sites in northern Sudan. It will also contribute to tackling the extreme heatwaves in semi-arid areas such as the capital Khartoum, where the temperature goes well above 40°C during summer.
However, monitoring the impact of the project, which spans 5,000 miles across Africa, requires “big picture” data. This comes from the latest satellites and remote sensing technologies.
Satellite imagery can provide valuable information about sand movement. For instance satellites are used to monitor the dust storms that transport sand from the Sahara across the Atlantic Ocean to supply the Amazon rainforest with essential fertilising nutrients.
But what about on a smaller scale? How do you predict if and when sand will submerge a field, a watering hole – or a pyramid?
In my own research I have previously used multiple overlapping images taken from aeroplanes to generate digital elevation models for sand dunes in northern Sudan. That led to my current PhD research which focuses on monitoring the movement of sand dunes using satellite optical and radar images, airborne laser imagery and other techniques. My research also investigates the influence of factors such as wind speed and direction, presence of vegetation and topography.
Colleagues and I ultimately want to develop our understanding of how sand dunes grow in size and how they migrate across the desert. This will enable us to monitor the effectiveness of interventions such as vegetation barriers, helping to combat desertification and climate change and to ensure people in Sudan are able to grow enough food. And we may even be able to predict when and where those pyramids will be buried – and what we can do to prevent it.
Originally posted on globalrhythmz: The music Aziza Brahim makes reflects both the sorrow and the hope of these people. She grew up in one of those camps in the Algerian desert, along with thousands of other Saharwai who were removed from their homes in the Western Sahara. The refugee camp was the place that formed…
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