The "Trump Forest" is a project to plant trees to offset President Donald Trump's pro-coal energy policy.

The group has received enough pledges to plant one million trees, and the donations keep rolling in from around the world.

Forests are one of the world's most important sources of oxygen and carbon storage.

Donors have funded the planting of over one million trees as part of the "Trump Forest," a project to combat President Donald Trump's pro-fossil-fuel energy policy.

The project began just under a year ago, when Trump pledged to pull the US out of the Paris climate agreement. Since then, over 3,300 people have made donations to fund the planting of new forests around the world.

"Trump wants to bring back coal," Trump Forest's website reads. "So we’re planting a forest to soak up the extra greenhouse gases Trump plans to put into our atmosphere."

Trump's decision to pull out of the Paris agreement would cause the US to add an extra 1.4 gigatons per year of carbon dioxide into the atmosphere by 2025, adding up to a 3% increase in global emissions, according to a recent study from Climate Interactive.

The coal industry sent 1.2 gigatons of carbon dioxide into the atmosphere in 2016, according to the US Energy Information Administration.

Adrien Taylor, one of the three founders behind the "Trump Forest" project, posted a video message on Monday thanking donors for hitting the million-tree milestone.

"You've not only offset some of the carbon emissions that have come out of the Trump administration, you've also helped reforest communities, and you've helped create a small silver lining in the very dark cloud of ignorance which is in the White House," Taylor said.

Taylor, who runs a sustainable hat company called Offcut, manages the project along with Dan Price, a British climate scientist, and Jeff Willis, a Ph.D. candidate.

All of the trees are being planted by the Eden Reforestation Project, a nonprofit dedicated to restoring forest ecosystems. The planting is divided between Madagascar, Nepal, Ethiopia, and Chile.

Forests are one of the most important sources of oxygen in the world and act as carbon sinks, since trees need carbon dioxide for photosynthesis. According to the US Global Climate Change Research Program, forests around the world store 14% of annual carbon dioxide emissions.

Carbon dioxide and other greenhouse gases get released into the atmosphere by human activity, and wind up trapping more of the sun's heat than would otherwise stay on Earth. That leads to a rise in average global temperatures over time — last year was the second hottest ever, behind only 2016. According to a recent study, the world may get up to 15% hotter than climate scientists initially thought by 2100 because of increased concentrations of such greenhouse gases.

A warming world poses many dangers: The frequency of costly natural disasters, like wildfires, and hurricanes, can increase, and it can harm wildlife including endangered sea turtles.