Skip to content

In the Climate Fight, “Blue Carbon” Soaks Up Fresh Attention (and Emissions)

Scientists are exploring how wetlands along the Hudson River and beyond may be doing more than their share to absorb carbon dioxide..

by Cheyenne MacDonald
Share:

All around us, there are natural systems that soak up carbon dioxide from the atmosphere. Forests may be the first thing that comes to mind when we think of “carbon sinks,” or those areas that absorb and store more of the element than they emit. But it isn’t just green spaces that sequester carbon — “blue” spaces do it, too. Take, for example, the wetlands along the Hudson River. 

More than half of the Hudson River’s 315-mile span is a tidal estuary, meaning where “salty sea water meets fresh water running off the land,” the Department of Environmental Conservation explains. There is an estimated 7,000 acres of tidal wetlands surrounding it, including marshes, wet meadows, and swamps.

Environments like these are increasingly coming up in the conversation around climate change and greenhouse gas mitigation. Studies have shown that coastal ecosystems can remove carbon from the atmosphere at rates that outpace tropical forests and, more crucially, store immense amounts of carbon. The carbon captured at such sites and by the ocean is often referred to as “blue carbon.” 

Constitution Marsh (Putnam County). (Photo: Pierce Johnston / Scenic Hudson)
Constitution Marsh (Putnam County). (Photo: Bernard Kessler)

For coastal wetlands, the blue carbon impact isn’t so much about the dent they’ll make in removing greenhouse gases from the atmosphere, given their relatively small spread, but the amount of carbon they can contain. These ecosystems have dwindled over the ages due to factors like human development and sea level rise, particularly in the U.S., and continue to face such threats.

“Not only are [coastal blue carbon sites] important in terms of being really efficient at capturing carbon, but they store a ton of the carbon in their soils, in particular,” says Sylvia Troost, a senior manager with the Conserving Marine Life in the United States project from the Pew Charitable Trusts. “This is the same for freshwater wetlands as well, this kind of storage capacity. If these coastal wetlands are left undisturbed, they can hold that carbon for hundreds, if not thousands of years.” 

Stockport Flats (Columbia County). (Photo: Jeff Mertz)

The key to all of this is in the sediment and the vegetation that thrives there. In sites like Rockland County’s Piermont Marsh, you’re bound to encounter lots of cordgrass — a staple of coastal wetlands. Though these grasses in the genus Spartina are best recognizable for their tall, wispy appearance, there’s a lot going on beneath the surface, too. 

“When you look at a salt marsh plant — and this is probably true not just for salt marsh plants, but a lot of wetland plants — whatever you see above ground, there’s an equivalent amount of material below ground, and sometimes much more,” says Anne Giblin, senior scientist and director at the University of Chicago’s Marine Biological Laboratory. 

RamsHorn-Livingston Sanctuary (Greene County). (Photo: Robert Rodriguez, Jr.)

Giblin, whose work focuses on salt marshes, currently leads a longterm ecological project in the Plum Island area of Massachusetts investigating the effects of things like increased nitrogen and sea-level rise on these systems. The sediments in environments like a salt marsh are waterlogged and largely lacking oxygen, Giblin explains, which causes material there to break down more slowly. Yet, they are extremely productive for vegetation. 

“They’re growing and they’re injecting organic matter, their roots and rhizomes [underground stems], directly into these anaerobic [low oxygen] soils where they tend not to break down, or break down slowly,” Giblin says. “So in that material that’s being stored is a fair amount of carbon.”

Constitution Marsh (Putnam County). (Photo: Tyler Blodgett)

“Its impact on global carbon budgets is, frankly, probably pretty negligible,” she adds. “But the other way to look at it is, if you now take all that carbon that was stored for the last 3,000 years, and you lose salt marshes, not only do you lose this small sink but you also produce a big source.”

In addition to their role in the carbon cycle, these environments are also home to unique animal species. Over 200 species of fish and birds rely on the Hudson River estuary habitat, and it remains a major nursery site for fish like sturgeon and striped bass. Some of this, roughly 100 miles, encompassing 4,838 acres, is protected under the Hudson River National Estuarine Research Reserve.

Constitution Marsh (Putnam County). (Photo: Michael O’Donnell)

Organizations like the Northeast Carbon Alliance (which Scenic Hudson founded) are beginning to study these kinds of habitats in greater detail with both marine habitat and carbon storage in mind.

As more is discovered, the reasons for the continued protection of tidal wetlands, salt marshes, and related coastal and estuarine habitats are many, advocates say. 

Salt marshes and other coastal wetlands “do so many other things” beyond trapping carbon, Giblin notes. “They protect us from storm surges. They’re great nursery ground for fishes. They’re great for recreation. So even if they turn out on a global basis not to be a huge carbon sink,” she says, “I hope people appreciate their vital importance in the coastal ecosystem.”

RamsHorn-Livingston Sanctuary (Greene County). (Video: Jon Bowermaster / Oceans 8 Films)

Related Content

Editors' Picks

Climate Solutions
How to Get in on the Refillability Game
Land + Air + Water
Restoring Resilience to Mawignack Preserve
Land + Air + Water
Can Hops Make a Comeback in New York?
A close view of a hop growing on a vine. Behind it is a red barn.
Land + Air + Water
Protecting Forests by Managing the Exploding Deer Population
Climate Solutions
Floatovoltaics Makes Waves Approaching the Valley

Search Viewfinder:

Hudson Valley Viewfinder is a collaborative, community digital magazine sharing what inspires us about the beautiful Hudson Valley. We publish original stories and multimedia content about all things sustainable in the region along the Hudson River — including agriculture, science, wildlife, outdoor recreation, green transportation, environmental justice, and more.

Our mission is to immerse you in the storied history, fresh happenings, and coming solutions for making the Hudson Valley greener and more livable long-term.

Viewfinder is published by Scenic Hudson, the celebrated nonprofit credited with launching the modern grassroots environmental movement in 1963. With over 25,000 passionate supporters, Scenic Hudson’s mission is to sustain and enhance the Hudson Valley’s inspirational beauty and health for generations to come. Viewfinder supports that mission, because the better people understand what makes this place special, the more they will invest in protecting it. 

Keep up with the latest stories by subscribing to Scenic Hudson’s monthly digital newsletter, and connect with us on social via Facebook, Instagram, Twitter, LinkedIn, and Threads.

Our mission is to immerse you in the storied history, fresh happenings, and coming solutions for making the Hudson Valley greener and more livable long-term.

Viewfinder is published by Scenic Hudson, the celebrated nonprofit credited with launching the modern grassroots environmental movement in 1963. With over 25,000 passionate supporters, Scenic Hudson’s mission is to sustain and enhance the Hudson Valley’s inspirational beauty and health for generations to come. Viewfinder supports that mission, because the better people understand what makes this place special, the more they will invest in protecting it. 

Keep up with the latest stories by subscribing to Scenic Hudson’s monthly digital newsletter, and connect with us on social via Facebook, Instagram, Twitter, LinkedIn, and Threads.

Lynn Freehill-Maye
Managing Editor
editorial@scenichudson.org 

Riley Johndonnell
Director Creative Strategies & Communications
rjohndonnell@scenichudson.org

Lynn Freehill-Maye
Managing Editor
editorial@scenichudson.org 

Riley Johndonnell
Director Creative Strategies & Communications
rjohndonnell@scenichudson.org

We’re always looking for ideas around our main topic areas of Climate Solutions, Land + Air + Water, Plants + Animals, History + Culture, Outdoors, and Community.
  • Journalists and writers who have deep familiarity with New York and the Hudson Valley, we’d love to have you contribute! Please do introduce yourself by email, sharing writing samples and any relevant pitches you may have.
  • Photographers and videographers, we’d love to hear from you and see what you do. Please send along a portfolio with images or footage that showcases your best and/or most relevant work, with an emphasis on anything captured outdoors. 
  • Illustrators, we commission artwork on the regular. Drop us a note with some of the beauty you’ve created.
  • Media Partners & Social Media Influencers, we welcome opportunities to team up on series and campaigns. Reach out with any background about yourselves and your ideas.
We’re always looking for ideas around our main topic areas of Climate Solutions, Land + Air + Water, Plants + Animals, History + Culture, Outdoors, and Community.
  • Journalists and writers who have deep familiarity with New York and the Hudson Valley, we’d love to have you contribute! Please do introduce yourself by email, sharing writing samples and any relevant pitches you may have.
  • Photographers and videographers, we’d love to hear from you and see what you do. Please send along a portfolio with images or footage that showcases your best and/or most relevant work, with an emphasis on anything captured outdoors. 
  • Illustrators, we commission artwork on the regular. Drop us a note with some of the beauty you’ve created.
  • Media Partners & Social Media Influencers, we welcome opportunities to team up on series and campaigns. Reach out with any background about yourselves and your ideas.
  • We love to collaborate with media outlets, especially on episodic series (like these) of interest to our shared audiences. Past collaborations have included radio interviews, panel discussions and other events, original artwork, and e-blasts, all furthering the campaign’s excitement and reach. 
  • We also love to partner with other organizations whose missions align with Scenic Hudson’s. Feel free to reach out with some background on your group and its work.
  • Writers, photographers, and creatives, if you have an idea for a series or content campaign that might be a good fit, drop us a line!

Businesses, please note that as a nonprofit, Scenic Hudson is restricted from advertising or promoting for-profit companies, through Viewfinder or other outlets. While we understand content managers may wish to alert us to your company’s role in a relevant topic, we are unable to add links to businesses to our stories.

  • We love to collaborate with media outlets, especially on episodic series (like these) of interest to our shared audiences. Past collaborations have included radio interviews, panel discussions and other events, original artwork, and e-blasts, all furthering the campaign’s excitement and reach. 
  • We also love to partner with other organizations whose missions align with Scenic Hudson’s. Feel free to reach out with some background on your group and its work.
  • Writers, photographers, and creatives, if you have an idea for a series or content campaign that might be a good fit, drop us a line!

Businesses, please note that as a nonprofit, Scenic Hudson is restricted from advertising or promoting for-profit companies, through Viewfinder or other outlets. While we understand content managers may wish to alert us to your company’s role in a relevant topic, we are unable to add links to businesses to our stories.

Subscribe!

Get the latest articles delivered right to your inbox  — for FREE!