Donald Trump has called global warming a Chinese “hoax” and has erroneously claimed that cutting emissions to avert catastrophic climate change will ruin the US economy. He plans to withdraw the US from the Paris climate agreement and is undoing many of the policies President Barack Obama put in place to fight climate change.

In short, he’s been a disastrous president so far for the climate.

Among those deeply vexed by the Trump administration’s attitude toward climate change are three environmentalists based in New Zealand, all in their 20s: a French-New Zealander entrepreneur named Adrien Taylor, a British climate scientist named Dan Price, and an American political scientist named Jeff Willis.

In January, they came up with an idea: Why not counter Trump’s inaction on climate by planting a proverbial “Trump Forest”?

“We know Donald Trump likes his name on things,” they cheekily wrote on their website. And the planet could use a lot more trees to sink some of the carbon in the atmosphere.

Originally, the idea was to plant a tree every time Trump uttered the words “climate change.” But that was nixed after it became obvious Trump rarely uses the words. (Various departments in his administration have even since discouraged or banned the term’s usage.)

On March 29, the group decided it was go time. The day before, Trump had signed an “energy independence” executive order with the message that climate change doesn’t matter to his administration. Included in the order was the intention to dismantle Obama’s signature policy, the Clean Power Plan.

So Taylor, Price, and Willis decided they would try to plant enough trees to make up for the greenhouse gas emissions that would occur without the Clean Power Plan.

In practical terms, that means 10 billion new trees, which Price says is a rough estimate for what would be needed to prevent 650 million tons of carbon dioxide from entering the atmosphere. (That’s what an analysis in Nature suggests the Clean Power Plan would do if fully implemented over eight years.)

The organizers admit their goal of 10 billion trees “sounds ridiculous,” but they also insist that it’s not completely out of reach. In just the past four weeks, the number of trees planted or pledged increased from 50,000 to 500,000, according to the tally they update on their website every day.

Trump Forest doesn’t actually handle any money, and it doesn’t ever plan to. The founders tell me that they all have regular day jobs and have no intention to make anything off of Trump Forest. Instead Taylor, Price, and Willis say they simply wish to connect people who want to do something about the climate with reputable organizations that will help them plant trees.

While many of the tree-planters are American, they say they’ve also seen a lot of support come from Europe and other places. "People all around the world realize that we’re all going to pay for his [Trump’s] actions,” says Taylor, whose sustainable hat company Offcut Caps provided the first pledge of 1,000 trees.

“Obviously it’s a big challenge,” Price says of their goal of planting 10 billion trees. “We are looking to cover an area about the size of Kentucky or the North Island of New Zealand or Iceland,” he explains. “These aren’t huge areas, especially when you break them down by country. Split that between 200 countries around the world, and it’s not too bad.”

Unlike Trump Hotels, Trump Steaks, Trump Water, or the myriad other products with the Trump name on it, neither the president nor his family has a stake in Trump Forest. But the creators of Trump Forest say that they’d love if he found out about it, and they are keen to work out an arrangement should he be interested in endorsing their project.