TITLE: 45% of China's urban land is rapidly sinking due to manmade development
https://newatlas.com/environment/urban-china-subsidence/
EXCERPT: A perfect storm is brewing for China's most densely populated areas due to rising sea levels and subsiding land that has been accelerated beyond normal fluctuations. Scientists have sounded the alarm that, without intervention, urban areas below sea level could triple in size by 2120, impacting up to 128 million people.
It's a grave warning for a nation that has rapidly urbanized like nowhere else on the planet. In 1980, those living in cities and surrounds accounted for around 20% of the population; in 2023, it was more than 65%. Now, it's expected to reach 80% in the next decade. The growth has exceeded earlier modeling, which forecast it would not reach the current numbers until well after 2030.
In population ecology, every species population within its environment has a carrying capacity – the maximum number of individuals that can be sustained before a 'tipping point' results in a decline to below that threshold. Resources – food, shelter, for example – are limiting factors that ultimately control population size. While humans defy many laws of nature, in this case our ability, through wealth and industry, or both, to generate more resources for a given environment's sustained growth, we have been able to stretch our carrying capacity well beyond what would otherwise be unsustainable.
Though us long-living humans may not experience the 'boom-bust' population cycle seen in many species such as rodents and locusts, this latest research by an international team of scientists thrusts our carrying capacity into sharp focus – and, much like in nature, a demand on resources required to support rapidly increasing numbers is at the center of it.
A double threat – rapid industrialization and development to support the population coupled with the negative environmental impact of that, like rising sea levels through anthropogenic climate change – is what urban China is now facing, according to this new study.
In fact, the study suggests that the two-fold impact, without intervention, could see the urban areas of China below sea level tripled by 2120, impacting up to 128 million people.
In the research, scientists looked at subsidence data for 82 Chinese cities, which some 700 million people call home. What they found was that in 45% of these urban areas, the land beneath them showed distinct signs of subsidence. Of that percentage, 16% – including Beijing – were sinking at 10 mm or more each year.
For coastal cities such as Tianjin, even what sounds like a small amount of subsidence makes these areas far more vulnerable to the growing threat of sea-level rise. The researchers also highlighted China's largest city, Shanghai, which has subsided three meters (10 ft), and continues to sink.
"Subsidence jeopardizes the structural integrity of buildings and critical infrastructure and exacerbates the impacts of climate change in terms of flooding, particularly in coastal cities where it reinforces sea-level rise," said Professor Robert Nicholls, from the Tyndall Centre for Climate Change Research at the University of East Anglia (UAE). While not involved in the Chinese study, Nicholls' research expertise is sea-level rise, erosion and flooding – and how we can respond to these challenges.
Subsidence – largely caused by human activity in urban areas – is not a new phenomenon in China, or in many other parts of the world. But this study shows just how much accelerated development is impacting cities, and calls for scientists to work on responses to mitigate the threat.
"Subsidence leads to ground fissures, damages buildings and civil infrastructure, and increases the risk of floods," the researchers noted. "Over the past decades, subsidence-related disasters in China have already incurred an annual direct economic loss of more than 7.5 billion yuan (US$1.04 billion), accompanied by hundreds of fatalities or injuries per year."
Accelerated subsidence is largely caused by the population above it. Weight of buildings (though, the researchers note, often the heavier buildings are not the culprit, due to the depth of their anchoring beneath the surface), transport networks and groundwater removal are all big factors in the changing landscape.
TITLE: How to stop a state from sinking
https://www.technologyreview.com/2024/04/15/1090733/louisiana-sinking-climate-change-flooding/
EXCERPT: The $6.8 billion Southwest Coastal Louisiana Project is betting that raising residences by an average of three to five feet and nonresidential buildings by three to six, coupled with extensive work to restore coastal boundary lands, will keep Louisianans in their communities and a local economy that helps power the country’s oil industry running. The project, a collaboration between the US Army Corps of Engineers and the Louisiana Coastal Protection and Restoration Authority (CPRA), is focused on roughly 4,700 square miles of land inthree parishes in the southwestern corner of the state: Cameron, Vermilion, and Calcasieu, where Lake Charles is the parish seat. More than 3,000 homes have been identified as being at risk of imminent flooding, and therefore as candidates for elevation funding.
Ultimately, it’s something of a last-ditch effort to preserve this slice of coastline, even as some locals pick up and move inland and as formal plans for managed retreat—or government funding for community relocation—become more popular in climate-vulnerable areas across the country and the rest of the world.
Since 1932, Louisiana has lost some 1.2 million acres of coast to erosion—an area nearly twice the size of Rhode Island.
Now, after eight years of surveys, paperwork, and waiting for cash, the pilot phase of the project is finally moving forward and raising 21 homes. As it does so, project staff and locals alike will be forced to grapple with a looming existential question: Can a region facing some of the nation’s most alarming climate predictions build its way out of an accelerating crisis?
Darrel Broussard, the project’s senior manager, sees its work as the region’s best chance at reducing damage over the next 50 years and safeguarding the roots residents have put down over generations. “This is Louisiana. This is where everyone lives. This is where we work. This is where the economy comes from,” he says. “There are models out there trying to predict the future. They’re just models. Right now, we currently have communities, neighbors, all living there.”
At the same time, some environmental experts worry that this may be too rosy an outlook, with time and nature conspiring against lasting success. “The sooner we can shift our mindset towards managed retreat, the better,” says Torbjörn Törnqvist, a geology professor at Tulane University. “This is a very tough issue. This is a part of the country that’s just going to disappear.”
TITLE: Listing of luxury waterfront home slashes price by nearly 75% as major erosion concern washes value away: 'The price mitigates the risk'
https://www.thecooldown.com/green-business/luxury-waterfront-home-coastal-erosion-discount/
EXCERPT: In September, a three-bedroom, two-bathroom waterfront home in the small island town of Nantucket went on the market for $2.3 million. Just a few months later, the asking price plummeted to $600,000.
According to Fortune, which cited a report from The Boston Globe, the dramatic price decrease was related to an overheating planet — in a matter of a few weeks, the shoreline surrounding the property lost 70 feet from erosion due to rising seas.
Still, this didn't stop New York resident Brendan Maddigan, who frequently visits Nantucket, from laying down an all-cash offer on the property after the price drop.
"The home is amazing. The location is amazing," he said, per Fortune. "And the price mitigates the risk to a good degree. I'd like to think that it'll be there for a while, but I was definitely aware of the risk of any particular storm causing a problem in the future."
"As sea levels continue to rise, we're also seeing land areas sink, both due to the increased temperatures from human caused climate change," Kathleen Biggins, founder and president of nonpartisan climate change education organization C-Change Conversations, told Fortune.
She added that this will make certain areas uninsurable or extremely costly to insure.
This is concerning, as nearly 40% of Americans live in coastal areas. Besides sea level rise and erosion, coastal communities face other climate-driven weather threats such as high-tide flooding and hurricanes, according to the National Oceanic and Atmospheric Administration. Globally, 37% of people live within about 62 miles of a coast.
TITLE: Warming of Antarctic deep-sea waters contribute to sea level rise in North Atlantic, study finds
https://phys.org/news/2024-04-antarctic-deep-sea-contribute-north.html
EXCERPT: A new study published in the journal Nature Geoscience led by scientists at University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science, and the National Oceanic and Atmospheric Administration's Atlantic Oceanographic and Meteorological Laboratory, found that human-induced environmental changes around Antarctica are contributing to sea level rise in the North Atlantic.
The research team analyzed two decades of deep sea oceanographic data collected by observational mooring programs to show that a critical piece of Earth's global system of ocean currents in the North Atlantic has weakened by about 12% over the past two decades.
"Although these regions are tens of thousands of miles away from each other and abyssal areas are a few miles below the ocean surface, our results reinforce the notion that even the most remote areas of the world's oceans are not untouched by human activity," said the study's lead author Tiago Biló, an assistant scientist at the Rosenstiel School's NOAA Cooperative Institute for Marine and Atmospheric Studies.