NORTH KOHALA — Looking mauka up Kohala’s leeward slope, it’s not easy, at first, to picture the dry forest that once dominated this landscape with koaia, iliahi and other native trees and shrubs.
But as Yishan Wong traces his finger along the path of a drip line that winds its way across the ground, blushes of green start to appear. Approach one of these revived pockets and there stands a sapling of koaia yearning to make its way skyward.
It’s a sign of hope for an endeavor with global and local consequences: both part of what Wong sees as the best solution to turn the tide of climate change, and at the same time an opportunity to restore one of the islands’ most diverse yet endangered ecosystems.
“It’s not just, ‘Oh we need to do reforestation.’ We can do reforestation here,” Wong said on Christmas Eve at his 45-acre property in leeward North Kohala. “We can restore ancient sandalwood forests that were culturally important to this place.”
In 2017, the Global Carbon Project estimated that all human activities, including the use of fossil fuels, industry and land use changes, would put 41 gigatons — or 45 billion US tons — of carbon dioxide into the atmosphere that year.
A single gigaton, for context, is a billion metric tons, more than the collective weight of six million blue whales.
That adds up to what can seem like an infinite amount of carbon dioxide in the atmosphere and a near impossible challenge to face.
But it is a specific number, Wong said, and it describes the specific scope of the problem. And having a specific scope of the problem offers a path to finding a specific scope of the solution.
His solution? A global effort to restore the Earth’s forests — 3 billion acres, an area larger than the United States and Mexico combined. The effort would rely on trees’ natural process of carbon fixing, in which plants turn carbon dioxide into organic compounds as part of photosynthesis, to remove the greenhouse gas from the atmosphere.
Planting that many trees, though, will take a lot of land and a lot of freshwater, resources which aren’t becoming easier to find. That’s why Wong is proposing to use solar-powered desalination facilities to make fresh water from saltwater, then use that water to rehabilitate the world’s deserts and degraded lands and irrigate swaths of new forests around the globe.
It’s an ambitious effort, but Wong’s crunched the numbers to show how it can work.
In just 20 years, he said, the planet’s new forests would be self-sustaining to the point they’d no longer need irrigation and would be pulling enough carbon dioxide out of the atmosphere to offset all emissions.
Wong believes if his project can work here in Hawaii, where costs and environmental factors pose more of a challenge than most other places, it can work anywhere on the planet. And if it can work everywhere, a united effort of turning deserts into forests can prove a potent weapon for combating carbon dioxide in the atmosphere.
And that’s starting here with the dry forest of North Kohala.
CENTURIES OF CHANGE
Long before humans arrived to the island, North Kohala was likely forested below where Kohala Mountain Road now runs, said the Department of Land and Natural Resources Division of Forestry and Wildlife. In addition to koaia, the forest would have been populated by trees like wiliwili, iliahi and mamane. Common shrubs, the agency said, would have included aalii, akia and ulei.
Wong’s plan is to bring back a part of that forest to his property in North Kohala and restore the koaia, iliahi — sandalwood — and other species.
He’s partnering with Jill Wagner, a forestry consultant and horticulturalist, who said at the end of December that she’s excited about the challenges that come with restoring a completely denuded landscape.
“It’s got a lot of challenges, but it will be so beautiful to see a native forest there,” she said. “And I think it’ll inspire other people.”
The dry forest ecosystem is the most species-rich of all Hawaii’s ecosystems, Wagner said. It’s also among the most endangered, both in the islands and the world. It’s a fact that pushes her to do as much dry forest work as she can.
The dry forest occurs along the islands’ leeward sides, and while most species make appearances in the various regions, Wagner said some species dominate from place to place. A section of Kona’s dry forests, for example, might be dominated by lama, while koaia, alahee and aweoweo might be more common in a portion of dry forest in Kohala.
All of the island’s ecosystems have long been shaped and reshaped, going back to the first Polynesians to arrive on its shores, DLNR said. The agency said rats, known to cause detrimental impacts on island ecosystems, were “likely stowaways” on early voyages. Ground-dwelling and nesting birds were likely among the first to disappear as the result of rats and people.
Other early factors would have come as native ecosystems, especially those in areas with nearby freshwater, were changed to support agriculture. Similarly, the harvest of iliahi, such as during the sandalwood trade, “surely would be detrimental,” DLNR said.
More recently, sweeping changes came with the introduction of grazing animals like cattle.
The agency likened the cumulative impacts of all these changes to a domino effect.
Beyond the reduced biodiversity, the agency said water recharge is “almost certainly reduced” with the loss of forest cover, and it’s possible that areas where the forest cover dropped experienced reduced rainfall, although, there’s only anecdotal evidence of this.
Rather than focus on how the land got this way, though, Wong emphasized that his focus is on advocating for and restoring the forest here.
FROM SEA TO THE MOUNTAINS
To overcome the stark environment, Wong is irrigating with freshwater produced via on-site desalination powered by a half-acre of solar panels, an approach he said is going to be critical in providing freshwater for his 3-billion-acre reforestation plan.
Research group Project Drawdown counts roughly 1.08 billion acres of land worldwide, made up of degraded grassland and forest, where new forests could grow. But that’s not enough, nor is there even a guarantee that the land would be made available for forestation by its owners.
To solve the issue, Wong is looking to the world’s deserts.
As it turns out, the United Nations Convention to Combat Desertification has identified approximately 4.7 billion acres on the planet that have been affected by drought or desertification but have the potential to be restored. That much land, collectively double the size of China, offers what Wong sees as ample opportunity for reforestation provided there’s a way to irrigate it.
Because the planet’s current freshwater resources are effectively spoken for to meet the needs of people and agriculture, Wong’s turning to desalination.
The facility on his North Kohala property is capable of producing 34,000 gallons of freshwater a day via reverse osmosis to provide water for the budding forest. It’s powered by a half-acre of solar panels on the site rated at approximately 128 kilowatts of generating power connected to battery storage of 300 kilowatt-hours.
For perspective, if the facility were its own utility grid, it could provide power to between 15 and 20 homes.
The facility produces freshwater and effluent at a roughly 50-50 rate, meaning for every gallon of water that goes in, out comes about a half gallon of freshwater.
The rest comes out twice as salty as the input. But because the process uses brackish water, the effluent is still only about half as salty as straight seawater.
So far, Wong said, they haven’t lost any trees to under-watering.
This is the first project Wagner has worked on that uses desalinated irrigation. It’s a big deal, she said, comparing it to another site she’s in that relies on brackish water.
“And it’s a killer for plants,” she said. “They do not like high salt, and it really does hinder growth and the success of plants. Even if they do grow, they might be in a poor state.”
Without the desalination component to produce freshwater for irrigation, she said, the reforestation project at Wong’s property might not work at all.
Success for any restoration project, she said, has three markers. One is when the plants no longer require irrigation and can survive on their own; another occurs when plants start seeding and flowering. The final sign post for a successful project, she said, is when those seeds regenerate and start growing into the next generation of the forest.
Both Wong and Wagner emphasized that reforestation isn’t just about the trees. It’s also about all of the elements that make up the ecosystem — a process Wong referred to as “rewilding.”
“The end goal is to create an ecosystem: a healthy, functioning ecosystem,” Wagner said.
That means starting with some of the hardier elements. For example, given the wind that comes through this particular site, it requires native plants appropriate to the region that can also tolerate the wind so the ecosystem can be built from there.
“That’s the tricky part,” she said. “Every site is different, and you can’t use the same practices that you use for another site.”
Wagner said she spent about six months studying the area before planting got underway. And she anticipates the forest at Wong’s property could be self-sustaining even faster than the 20-year standard Wong outlined.
“These plants want to be there. They’re comfortable. They do well,” she said. “If you put the right elements and methods together, you can make it happen.”
CRUNCHING THE NUMBERS
Consideration of a large-scale tree-planting effort for tackling climate change isn’t a new idea itself.
As far back as 1991, researchers were looking at the potential for a “massive tree-planting program” in the tropics as a response to the buildup of carbon dioxide in the atmosphere.
But, Wong said, it was only a couple years ago, in 2018, that the levelized cost of energy (a measure to compare costs across different generation methods) for solar power dropped to the same price of new fossil fuel plants, making solar-powered desalination economically feasible on a large scale.
Wong estimates the project would take a one-time cost of $3 trillion to cover the cost of planting. That would be followed by the cost of irrigation at $3 trillion a year for 20 years, the approximate length of time he said it takes for a forest to be self-sustaining and no longer require irrigation.
Annually, that comes to less than 4% of the 2018 world gross domestic product. It also, Wong said, assumes a worst-case scenario in which all 3 billion acres are planted on reclaimed desert and all of the irrigation is sourced via desalination.
Doing nothing, one report suggests, doesn’t come cheap either.
A June 2019 analysis from Moody’s Analytics cited a report that said a global temperature increase of 2 degrees Celsius above pre-industrial levels would cost the global economy $69 trillion by the end of this century. The report attributed the cost to the impact rising temperatures and changes in weather patterns would have on workers’ health and productivity as well as countries’ infrastructure and resources.
Wong’s proposal remains ambitious compared to similar undertakings.
The Bonn Challenge, a massive worldwide reforestation effort launched in 2011 by the German government and the International Union for Conservation of Nature, is aiming to reforest 370 million acres by this year and more than 864 million acres by 2030. As of the start of this year, it’s received commitments from 62 countries and entities for more than 425 million acres of new forest.
But Wong, whose career trajectory has taken him through companies like PayPal, Facebook and Reddit, said his experiences have prepared him for a venture like this.
“At every single one of those companies, I was there during times when, essentially, people did not believe in the company. There was a lot of public doubt — and openly in the press,” he said. “And I have noticed that people who don’t have that experience are very easily made to turn to self-doubt.
“Whereas if you’ve been through that experience multiple times and you’ve come out successful or the group you were in came out successful, you gain a certain measure of self-confidence,” he continued, “as well as being able to tell when you’re right and when you’re wrong, because you have to know that.”
He also emphasized the importance of getting community buy-in on projects like this one, saying that the decentralized nature of the desalination facilities offers the opportunity to engage directly with communities with barren or degraded land and create a solar-powered desalination facility to generate the water and energy needed to restore their forest.
“Because one of the most important things is after we grow these forests, we have to make sure we don’t cut them down,” he said. “So every community has to feel ownership over this forest that they have created.”
It also helps, he said, that it’s hard to object to a forest.
“If the solution to climate change was some big magical machine that happened to be really ugly and we had to build a million of them … people wouldn’t want them in their backyard,” he said. “But people love forests. If this were koaia forest, that would be great. You would love to see that. That’s what I want to see.”
And while he said he’s heard criticism that efforts advocating reforestation as a priority to combat climate change reduces the urgency to curb emissions themselves, the solution, he said, is going to require both.
Curbing emissions alone won’t remove the carbon dioxide that’s already in the atmosphere, and reducing emissions certainly makes his job easier.
“The degree to which we successfully reduce fuel emissions means fewer trees I have to plant,” he said, laughing. “And this is a lot of work.”
And already, the North Kohala project is creating new opportunities to preserve native species locally.
Wagner, who is also the director of the Hawaii Island Seed Bank, said they’ll also be keeping their ohia collections and other native seed collections on the property as well.
DIFFICULT BUT NOT IMPOSSIBLE
There’s no question that climate change is a difficult issue, a “very, very, very difficult” one, as Wong put it.
But just like 45 billion tons of carbon dioxide isn’t the same as infinity, “‘very, very, very difficult,’” he said “is not the same as ‘impossible.’”
“Mankind’s greatest quality is that by working together, we have repeatedly achieved incredibly difficult goals. Our ancestors worked together, and did the best they could, and today we have the technology and wisdom they gave us,” he said. “What I am doing here in Kohala is just what one single person can do. Entire communities together can also do this, large and small, all over the world, a billion times more than I can do alone. We can do it — all of us.”
And amid a conversation dominated by talk of gigatons and a seemingly insurmountable challenge, the saplings of koaia are a visual glimpse into what a solution can look like.
“Here in Hawaii, I think showing that it can be done locally with a forest that has cultural, historical significance makes it more real,” Wong said. “Because the whole, ‘We’re going to regreen the Earth, we’re going to solve climate change,’ that can be like a big abstract, technical problem. But it is also a personal thing, like every community, every nation planting trees.”
As he sat in his pickup truck following an afternoon of discussing his project and vision, Wong looked mauka.
Behind him, the Pacific Ocean extended into the horizon. Ahead of him, Kohala’s ancient slope rose toward the sky.
“I would like to stand there one day,” he said, pointing to a knoll on the mountain that jutted back toward the sea. “I would like to look and see koaia and sandalwood — like this entire vista — and then to know at that point that similar things are happening all around the world.”
Yishan Wong can be reached at firstname.lastname@example.org
Cameron Miculka is a freelance journalist based in Kealakekua.