A man gazes out over a levee on the San Joaquin River to a buoy where a group of sea lions are barking. Even here, 50 miles inland, some of California's most productive farmland is close to the ocean. At any moment, a weak spot in the levees that protect the islands in the river Delta could unleash a salty deluge, threatening not just crops, but the drinking water for 27 million Californians.
A breach that would suck in tens of billions of gallons of river water and draw ocean water in its wake is referred to as "The Big Gulp." It would take a heavy rain, a moderate earthquake, and even a hard-working gopher to get through the barriers.
It wouldn't be the first time.
A levee failed on a sunny day in 1972, an hour's drive from San Francisco. Four feet of water ran over the land. The boats smashed against the embankment. Several people were seriously injured while fleeing rising waters. It happened again in 2004. The water turned 12,000 acres of farmland into a lake, costing $100 million in damages.
The Delta is in danger if the Pacific can't flood it. He would like to pay for it with carbon credits.
Thirty years have passed since Deverel tried to head off the Big Gulp. He wants climate change. His project, funded to date by California state agencies and the University of California, has flooded 1,700 acres of Delta farmland and transformed them into wetlands. New plants growing in the restored wetlands will suck carbon dioxide out of the atmosphere and store it in the muck to help protect the dikes from collapse.
The American Carbon Registry issued credits for 52,000 tons of CO2 removed by the experiment, which is still in its very early stages. According to Steve Crooks, a wetlands scientist and global expert in the field of "carbon-farming" from coastal wetlands, this is the first project of its kind in the US.
The Delta project is one of the few that has a huge promise.
Wetlands sequester an estimated 35% of the world's carbon on land, making them the largest natural carbon sink on land. The restoration of wetlands is seen as a huge potential source of carbon credits as countries and corporations ramp up their commitments to cut greenhouse gas emissions. It would be more eco-friendly to rehabilitate the earth's wetlands than it would be to do carbon projects in the forest.
Managing these landscapes is more complicated than just flooding fields. The Delta project has shown a way forward, according to Deverel. Peat is the key.
After the end of the last ice age, the Delta was covered by a freshwater inland sea. Over the course of thousands of years, moss, mud, and vegetation accumulate. Peatland can hold a lot of carbon. The CO2 is trapped in the plants as they die and can't be released into the ocean. Farmers who came to this area after the Gold Rush discovered the benefits of draining the peat. The farmers, known as "swamplanders," hired Chinese laborers to build the levees and drain the marshes, and planted rows and rows of corn and alfalfa.
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Scientists didn't realize the farmers were harvesting their own ruin until more than 100 years later.
There is a problem known asidence. Each year, the Delta islands of about an inch in height are robbed by the drying out of peat. The islands provide a buffer against the water pressure on the levees as they shrink.
It is possible to stand on a grassy field 300 feet from the levees and watch ships pass by. The Delta islands are now more than 20 feet below sea level. There is more to the threat than the threat of water someday flowing over the levees. It is already under them in some places. Farmers are forced to fortify embankments while draining their land.
A bigger threat is also present. Carbon sinks can be found in soggy peatlands. When the peat dries out, things change. It releases CO2 when it oxidizes. In the Delta, this means an area of about 150,000 acres of soil turned into a chimney that releases carbon dioxide.
Each year, each of the acres of dried-peat farmland emits ten tons of CO2, equivalent to the emissions of 217,000 gas-powered cars.
They see this as a chance.
Allowing the bulrushes and cattails to return would stop the emissions immediately and store carbon as new plants grow. The process could start to reverse the subsidence by adding as much as two inches of soil a year as watery plants die. It could take 150 years to return to sea-level. The levees are under a lot of pressure.
There are many benefits to restoring Delta wetlands. Climate change will cause more devastating droughts and rising sea levels and all services are in demand. The Delta project could use carbon credits to help adapt to the effects of climate change in the future.
The director of climate and nature-based solutions for The Nature Conservancy is very hopeful about what the project will mean for California's sustainable future. The international non-profit, which owns an entire Delta island, has recently begun working with Deverel to greatly expand the scope of his plan, converting 4,000 acres from corn to rice. Passero hopes to create a model for others to follow by generating carbon credits from the project in the next few years.
The science, the expense, and the politics of wetlands conversion are some of the obstacles that the Delta's defenders still need to overcome.
The scientific calculations didn't add up in the first US attempt to farm carbon
In December of last year, Tierra Resources, a small environmental restoration firm based in New Orleans, announced that the American Carbon registry had approved its "revolutionary new tool" to restore degraded wetlands in the Gulf of Mexico.
The company canceled its pilot project after seven years. Sarah Mack said that the problem was high uncertainty with the data. Carbon farmers have to prove they are doing what they said they would do every time they submit a monitoring report.
Mack was a consultant on the California Delta project. She said that the fact that it can be done will encourage other scientists to do the same.
Mack acknowledged that the Delta project had advantages over her own efforts. After 30 years of studying and measuring emissions from the land, Deverel has more scientific certainty. Methane is 25 times more powerful than CO2.
Wetlands emit methane as soil organisms digest plants. Mack had wetlands in the Gulf of Mexico. The potential to reduce so much CO2 that it would more than compensate for new methane emissions can be achieved by inundating the land.
Peat's promise is already inspiring some mega-projects in swamp forests and fens thousands of miles away from the Delta. The Katingan Metaya Project in Indonesia claims to be generating 7.5 million carbon credits per year, avoiding emissions equal to those of France. A fast- fashion billionaire in Scotland is working on a project to farm carbon from peatlands. Scientists in North Carolina have looked into the possibility of a carbon farm on 10,000 acres of wetlands.
The time is running out. The "weird little chimneys" are popping up all over the planet as the peatlands are drying out. The economic and political challenges of wetlands restoration are more important than ever.
The Delta carbon project is an example of how costly wetlands restoration can be. According to Bryan Brock, an engineer for the California Department of Water Resources, state agencies have spent $17 million restoring and managing wetlands in the project area. Had the land not been owned by DWR, the bill would have been a lot bigger. Ten eddy covariance stations, which can cost $50,000 each, were used to measure gas flows and temperature changes over the wetlands.
The project needs to be financially sustainable. The project has yet to make any money. Due to rules forbidding profits from publicly funded projects, carbon credits have gone to the project owner.
To finance more wetlands restoration, the Delta team needs to convince thousands of farmers to convert at least some of their land from profitable crops to marsh or rice, and then keep them that way for at least 40 years. Carbon prices are rising, but they are not enough to change people's minds.
The Delta carbon-farming proposal is a bit ridiculous according to Bruce Blodgett. Is it possible to buy seeds with carbon credits?
The state will force farmers to participate. He doesn't want to change the way the Delta farmers deal with subsidence because he doesn't want the water to keep flowing. He says, "We have one area in the whole state of California that we know we can still be farming 150 years from now."
Mother Nature has begun placing her finger on the scales. Farmers have to pay more to keep draining their land as salty water under the levees threatens crops. The price of carbon credits could be raised if governments act more aggressively due to the threats from climate change. The problem can be solved if we get to 100 a ton.
While he waits, he continues with his research and plans for the next phase of the project, on The Nature Conservancy land, continuing with the work that has consumed more than half of his life. If you are the sort of person who tends to doom scroll climate news, progress so far has been small and slow.
Deverel isn't a fan of doom- scrolling. He says he's called to do this now. I don't need to worry about the whole stairway.
This story was originally published in Hothouse and is part of a global journalism collaboration.
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