For more than four billion years of its history, the earth was a world without forests. Before those forests emerged, the earth’s atmosphere contained ten times as much carbon-dioxide, and just half the oxygen, and the average surface temperature on the planet was 10 degrees Celsius hotter than today.

The forests that evolved in the last few hundred million years sequestered huge quantities of carbon-dioxide, releasing equal amounts of oxygen and water vapor into the atmosphere in exchange. Photosynthesis combined with the long-term storage of the carbohydrates it produces — in wood and in the organic matter of forest soils — changed the chemistry of the atmosphere, cooling the planet and making the earth a far more hospitable place for most of the diversity of life we know today, including us.

Forests were, and continue to be, nature’s large-scale carbon capture and storage technology. It’s a pertinent planetary history lesson for the International Day of Forests proclaimed by the United Nations General Assembly.

The earth’s forests are still at work, sponging up 30 percent of the carbon-dioxide that we spew into the atmosphere by burning fossil fuels, helping to keep the earth’s climate at least a half-degree Celsius cooler than it would otherwise be. According to the Intergovernmental Panel on Climate Change, that half-degree difference saves the global economy tens of trillions of dollars in avoided costs.

So if protecting the world’s forests is in our collective self-interest, why are we collectively failing? The 30 by 30 initiative(committing to protect 30 percent of global terrestrial and marine areas by 2030) that many nations are embracing is a step in the right direction, but much more needs to be done.

The local and regional impacts of forests on temperature and rainfall rival the global impacts, and deforestation is taking an even heavier toll on climate than carbon emissions alone would suggest. In Brazil, hydroelectric production is threatened by loss of rainfall associated with deforestation.

The second harvest of grains that gives Brazilian agribusiness a huge advantage over its northern competitors is similarly at risk. And large swaths of the southeastern Amazon basin may soon be so hot and dry that they become as uninhabitable as the world’s desert regions, as forests are lost and changed climatic conditions — including more frequent wildfires — make their return unlikely.

A vast amount of evidence indicates that Indigenous Peoples and other local communities with strong traditions of collective rights to land and resources do a better job of protecting the forests they depend on than private landowners — better even than most national governments. Except where ignored, government designation of protected area status has helped. But we need more areas of both community-controlled and government protected forests.

Unfortunately, land speculation, commodity agriculture, and extractive industries — whether for timber, minerals, metals, or fossil fuels — have all advanced, and continue to advance, depleting forests and contributing to growing inequality and inequity. Illegality and corruption are rampant in many of the world’s most wild places, often driven by the attractiveness of land and resource investments for laundering money from other criminal activities.

The fundamental problem is that we mostly take for granted the benefits that forests provide to us, and their “invisible” services — like climate regulation — remain largely unmonetized. As a result, the implicit value we usually assign to forest protection is zero, even though the costs we incur in a world without forests are extraordinarily steep. This is a market failure with profound consequences, and we continue to destroy and degrade millions of hectares of forests each year at our peril.

Can we fix this fundamental problem? We’re mostly focused on the symptoms, rather than the underlying cause. Symptoms matter, and commitments to address them — like those made at the Glasgow Climate Conference at the end of last year — are hugely important. But those commitments don’t actually value our forests for the essential work they are doing that protects us from harm. That value extends beyond climate regulation to include biodiversity conservation, Indigenous Peoples’ livelihoods and culture, and public health.

Instead of valuing the forests, we value the land they grow on for what it can produce when the forests are destroyed and replaced by cattle, feed, fiber, or vegetable oil crops. This approach does not even take into account that demand for agricultural products could instead be met through improved management of land that’s already been cleared. Instead, it preferences short-term private benefits without accounting for the enormous costs that are incurred more broadly.

The climate crisis is the clearest indicator that we can no longer afford to allow public goods to be destroyed for private gains. So on this International Day of Forests, let’s remember that we know enough about a world without forests to know that it’s not a world we want. Nonetheless, it is the direction in which we’re headed. Let’s stop and reconsider — for the sake of the forests and ourselves.

Daniel Zarin is Executive Director for Forests and Climate at WCS (Wildlife Conservation Society).