The Sand-Climate Nexus
Sand plays a critical—if somewhat underappreciated—role in modern society. It is a primary ingredient in construction materials, is essential to the production of electronics, and is possibly one of the most useful tools we have in the global effort to avoid the impacts of climate change. Sand is needed for many of the world’s most effective emissions mitigation strategies, but is also used to reclaim land that has been lost to sea level rise and coastal erosion. All over the world, efforts to mitigate and adapt to climate change are driving increased demand for sand, creating a Sand-Climate Nexus.
Sand and gravel account for 85% of all mined resources on earth each year, and the only natural resource that we use more of is water. Some of the news stories form recent years would have you believe that the world is running out of sand. This is not strictly speaking true, but acquiring the right kind of sand is becoming more and more challenging and expensive. Just since 2007, the average cost of sand in the United states has grown by over 20%, with no sign of slowing down. If the cost of sand continues to rise at this rate, it could potentially limit the growth of sand-dependent industries, many of which are critical to achieving a global reduction in greenhouse gases.
Most mined sand is used in the manufacturing of two of the most common-place materials in modern construction: concrete and glass. As cities around the world attempt to accommodate growing populations and improve their energy efficiency, the construction demand for sand continues to climb. However, as the world grapples with the effects of climate change, other emerging uses of sand are beginning to significantly add to global demand.
In the United States, natural gas has started to out-compete coal in electricity generation and this transition is expected to significantly reduce grid-level carbon emissions in the coming years. This fuel switch has been made possible by hydraulic fracturing technology which has sharply decreased the cost of natural gas. Sand—particularly very hard, round, course sand is an essential ingredient of fracking fluid. It is pumped into cracks in the shale formation and prevents those cracks from sealing up when the fluid pressure is released. A single fracking well uses millions of pounds of sand, the cost of which can represent between 5 to 7% of the total costs of the well. Increasing costs of sand could significantly impact the supply of unconventional natural gas; hurting its competitive edge over coal.
Several renewable energy technologies also depend on cheap and abundant sand. Over 90% of the solar panels in today’s growing market are made from thin sheets of metallic silicate which is mostly manufactured from high-purity silica sand (SiO2), similar to the sand used in glass production. As demand for glass continues to grow, traditional silicate-based photovoltaics could become more expensive and less competitive with other sources for electricity. So called “thin film” photovoltaics, which do not use silica, are in production but they must be housed in watertight housing, often made of glass. Recent developments in solid state batteries also suggest that glass could be used as a viable electrolyte. If either of these emerging technologies are adopted, that could further increase the demand glass and silica sand.
One of the largest climate-influenced demands for sand is land reclamation and other efforts to extend coasts or to replace the land lost to coastal erosion. Every year, beaches along the U.S. coast are “nourished” with sand that is dredged from offshore, making more attractive for visitors and providing coastal communities with a protective storm buffer. However, this buffer doesn’t last long and some beaches need to be nourished every few years. In total, beach reclamation projects in the United States have moved more than 1.15 billion cubic meters of sand, costing at least $100 million a year. Without this nourishment, it is estimated that coastal real estate would eventually lose between 17 to 34% of its value, representing billions of dollars to the U.S. economy. Singapore— another prominent example—has imported hundreds of millions of tons of sand from nearby countries to expand its overall landmass by more than 20%.
As climate change pushes sea levels higher, coastal erosion will accelerate, as will demand for land reclamation. As these adaptive efforts continue, competition for available sand resources could threaten our response to climate change by increasing construction and low-carbon energy production costs. In order to prevent limited sand resources from impacting our ability to address climate change, it is essential that we embrace adaptation strategies that do not depend on land reclamation, as well as develop construction and energy technologies that can use alternative resources.