Sea levels in the 20th century rose faster than at any time in the last 3,000 years. And in the 21st century, the tides will climb ever higher—by at least 28 cms (11 inches) and possibly by as much as 130 cms (51 inches), according to two new studies.
Human activity is implicated in both studies and although neither delivers a new conclusion, each represents a new approach to studies of sea level rise as a consequence of climate change and each is a confirmation of previous research.
Robert Kopp, a climate scientist and Earth historian at Rutgers University in the U.S. and colleagues reveal in the Proceedings of the National Academy of Sciences that they tried to look at the greenhouse century—the 100 years in which oil, gas and coal combustion began to change the mix of carbon dioxide in the atmosphere and trigger a rise in planetary average temperatures—in the context of the last 27 centuries.
New Approach
They compiled a geological database that stretched back to the Bronze Age, which lasted, with regional variations, from the fourth to the first millennium before the Christian era. And they developed a new statistical approach to examine the sea-level indicators retrieved from marshes, coral atolls and archaeological sites around the world.
They report that although sea level rise might have happened without human action, it would have been less than half the observed 20th century increase and might even have fallen.
Had humans not piled greenhouse gases into the atmosphere, more than half the 8,000 coastal floods recorded at U.S. tide gauges in the last century might never have happened. On average, sea levels rose 14 cms between 1900 and 2000.
“The 20th century rise was extraordinary in the context of the last three millennia—and the rise over the last two decades has been even faster,” Dr. Kopp said.
In the same journal, a team led by Matthias Mengel, a postdoctoral researcher at the Potsdam Institute for Climate Impact Research, Germany, report that they took a new look at what might happen to sea levels before 2100.
They modeled three scenarios for greenhouse gas emissions, incorporated the latest 20th-century data on melting glaciers and warming oceans and played with the mathematical approach in a new way to predict a set of outcomes.
Projected Increase
The most hopeful—based on the agreement by 195 nations last December at the UN climate change conference in Paris—led to a projected increase of between 28 and 56 cms. The most alarming outcome proposed a possible range of sea level rise from 57 to 131 cms.
The two studies are designed to give practical information to city authorities and coastal planners.
Even a 60 cm rise means nations will have to think about coastal protection.
“With all the greenhouse gases we have already emitted, we cannot stop the seas from rising altogether, but we can substantially limit the rate of the rise by ending the use of fossil fuels,” said Co-Author Anders Levermann, a professor of climate system dynamics who is based both at Potsdam and at Columbia University’s Lamont-Doherty Earth Observatory in the U.S.
“This is quite a challenge, but less expensive than adaptation to unabated sea level rise, which in some regions is impossible,” Prof. Levermann said. “If the world wants to avoid the greatest losses and damage, it now has to rapidly follow the path laid out by the UN climate summit in Paris a few weeks ago.”
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Though made in large part of plastic, glass, ceramics, gold and copper, they also contain critical resources. The gallium used for LEDs and the camera flash, the tantalum in capacitors and indium that powers the display were all pulled from the ground — at a price for nature and people.
"Mining raw materials is always problematic, both with regard to human rights and ecology," said Melanie Müller, raw materials expert of the German think tank SWP. "Their production process is pretty toxic."
The gallium and indium in many phones comes from China or South Korea, the tantalum from the Democratic Republic of Congo or Rwanda. All in, such materials comprise less than ten grams of a phone's weight. But these grams finance an international mining industry that causes radioactive earth dumps, poisoned groundwater and Indigenous population displacement.
Environmental Damage: 'Nature Has Been Overexploited'
The problem is that modern technologies don't work without what are known as critical raw materials. Collectively, solar panels, drones, 3D printers and smartphone contain as many as 30 of these different elements sourced from around the globe. A prime example is lithium from Chile, which is essential in the manufacture of batteries for electric vehicles.
"No one, not even within the industry, would deny that mining lithium causes enormous environmental damage," Müller explained, in reference to the artificial lakes companies create when flushing the metal out of underground brine reservoirs. "The process uses vast amounts of water, so you end up with these huge flooded areas where the lithium settles."
This means of extraction results in the destruction and contamination of the natural water system. Unique plants and animals lose access to groundwater and watering holes. There have also been reports of freshwater becoming salinated due to extensive acidic waste water during lithium mining.
But lithium is not the only raw material that causes damage. Securing just one ton of rare earth elements produces 2,000 tons of toxic waste, and has devastated large regions of China, said Günther Hilpert, head of the Asia Research Division of the German think tank SWP.
He says companies there have adopted a process of spraying acid over the mining areas in order to separate the rare earths from other ores, and that mined areas are often abandoned after excavation.
"They are no longer viable for agricultural use," Hilpert said. "Nature has been overexploited."
China is not the only country with low environmental mining standards and poor resource governance. In Madagascar, for example, a thriving illegal gem and metal mining sector has been linked to rainforest depletion and destruction of natural lemur habitats.
States like Madagascar, Rwanda and the DRC score poorly on the Environmental Performance Index that ranks 180 countries for their effort on factors including conservation, air quality, waste management and emissions. Environmentalists are therefore particularly concerned that these countries are mining highly toxic materials like beryllium, tantalum and cobalt.
But it is not only nature that suffers from the extraction of high-demand critical raw materials.
"It is a dirty, toxic, partly radioactive industry," Hilpert said. "China, for example, has never really cared about human rights when it comes to achieving production targets."
Dirty, Toxic, Radioactive: Working in the Mining Sector
One of the most extreme examples is Baotou, a Chinese city in Inner Mongolia, where rare earth mining poisoned surrounding farms and nearby villages, causing thousands of people to leave the area.
In 2012, The Guardian described a toxic lake created in conjunction with rare earth mining as "a murky expanse of water, in which no fish or algae can survive. The shore is coated with a black crust, so thick you can walk on it. Into this huge, 10 sq km tailings pond nearby factories discharge water loaded with chemicals used to process the 17 most sought after minerals in the world."
Local residents reported health issues including aching legs, diabetes, osteoporosis and chest problems, The Guardian wrote.
South Africa has also been held up for turning a blind eye to the health impacts of mining.
"The platinum sector in South Africa has been criticized for performing very poorly on human rights — even within the raw materials sector," Müller said.
In 2012, security forces killed 34 miners who had been protesting poor working conditions and low wages at a mine owned by the British company Lonmin. What became known as the "Marikana massacre" triggered several spontaneous strikes across the country's mining sector.
Müller says miners can still face exposure to acid drainage — a frequent byproduct of platinum mining — that can cause chemical burns and severe lung damage. Though this can be prevented by a careful waste system.
Some progress was made in 2016 when the South African government announced plans to make mining companies pay $800 million (€679 million) for recycling acid mine water. But they didn't all comply. In 2020, activists sued Australian-owned mining company Mintails and the government to cover the cost of environmental cleanup.
Another massive issue around mining is water consumption. Since the extraction of critical raw materials is very water intensive, drought prone countries such as South Africa, have witnessed an increase in conflicts over supply.
For years, industry, government and the South African public debated – without a clear agreement – whether companies should get privileged access to water and how much the population may suffer from shortages.
Mining in Brazil: Replacing Nature, People, Land Rights
Beyond the direct health and environmental impact of mining toxic substances, quarrying critical raw materials destroys livelihoods, as developments in Brazil demonstrate.
"Brazil is the major worldwide niobium producer and reserves in [the state of] Minas Gerais would last more than 200 years [at the current rate of demand]," said Juliana Siqueira-Gay, environmental engineer and Ph.D. student at the University of São Paulo.
While the overall number of niobium mining requests is stagnating, the share of claims for Indigenous land has skyrocketed from 3 to 36 percent within one year. If granted, 23 percent of the Amazon forest and the homeland of 222 Indigenous groups could fall victim to deforestation in the name of mining, a study by Siqueira-Gay finds.
In early 2020, Brazilian President Jair Bolsonaro signed a bill which would allow corporations to develop areas populated by Indigenous communities in the future. The law has not yet entered into force, but "this policy could have long-lasting negative effects on Brazil's socio-biodiversity," said Siqueira-Gay.
One example are the niobium reserves in Seis Lagos, in Brazil's northeast, which could be quarried to build electrolytic capacitors for smartphones.
"They overlap the Balaio Indigenous land and it would cause major impacts in Indigenous communities by clearing forests responsible for providing food, raw materials and regulating the local climate," Siqueira-Gay explained.
She says scientific good practice guidelines offer a blueprint for sustainable mining that adheres to human rights and protects forests. Quarries in South America — and especially Brazil — funded by multilaterial banks like the International Finance Corporation of the World Bank Group have to follow these guidelines, Siqueira-Gay said.
They force companies to develop sustainable water supply, minimize acid exposure and re-vegetate mined surfaces. "First, negative impacts must be avoided, then minimized and at last compensated — not the other way around."
Reposted with permission from DW.