Nature is not only pretty, it is also valuable. And humans are squandering its value with behavior that will grievously harm future generations. That is the bottom line of a landmark report on biodiversity that the United Nations released in Paris on Monday.

Too often, advocates for ecological preservation talk about conserving irreplaceable natural beauty, which is, indeed, a key justification for setting aside lands and waters. But that argument only goes so far when one is referring to a peat bog, a tangled mangrove forest or a tiny bird's scrubby habitat — especially when humans struggling with poverty see opportunities to develop zones that are unsightly and seemingly unused.

In fact, these areas, particularly the threatened tropics, hold vast value to humans. "An estimated 4 billion people rely primarily on natural medicines for their health care and some 70% of drugs used for cancer are natural or are synthetic products inspired by nature," the report notes. "More than 75% of global food crop types, including fruits and vegetables and some of the most important cash crops such as coffee, cocoa and almonds, rely on animal pollination."

Plants, the oceans and other natural features clean the air and water, and they suck up much — though not enough — of the planet-warming carbon dioxide emissions that threaten human society. Preserving biological diversity preserves options and opportunities — to develop the next lifesaving drug, improve crops or adapt to environmental changes.

Yet "the rate of global change in nature during the past 50 years is unprecedented in human history." Degradation has cut productivity across a quarter of the planet's lands. A quarter- to a half-trillion dollars in agricultural production could be lost as pollinators die off. The disappearance of coastal protections such as coral reefs puts hundreds of millions of people at risk of flood and storm surge. More than 85% of Earth's wetlands are gone. Coral reefs are perishing. Overall, land-based native species have dropped by at least a fifth. "Around 1 million species already face extinction, many within decades, unless action is taken to reduce the intensity of drivers of biodiversity loss," the report finds.

Governments first must stop encouraging the degradation. Some $345 billion in fossil fuel subsidies translate into total costs of $5 trillion when the decline in nature's bounties is factored in. Relying on massive bioenergy production could decimate natural habitats.

Setting aside lands in national parks helps and should continue, particularly as climate change drives species out of existing sanctuaries, but just as important is enforcing those protections.

Developed countries are doing a better job of managing their fisheries, but the developing world must crack down on rampant overfishing. Transforming urban environments to include more green roofs, parks and water bodies can help. Perhaps most important is reforming agriculture so more can be grown on less land and with less disturbance of nearby unexploited areas.

Business as usual is not acceptable.

FROM AN EDITORIAL IN THE WASHINGTON POST