Pretend you’re exploring an imaginary wildlife sanctuary in a tropical, oceanfront mangrove forest. Here are ten animals you might see. Can you guess which ones are abundant today, which are vulnerable or endangered—as in there’s a risk there may be no more of them on Earth someday—and which are already extinct?

That was a trick question, by the way—all of these animals are vulnerable or endangered. And that means that some of the creatures you might see today could be gone tomorrow. The threats to these animals aren’t all the same, but taking the dangers they face seriously, and finding ways to protect them and the places where they live, is crucial.

To understand how to save these animals, it’s important to know more about where and how they live and whether the environments they live in are at risk too. Since all of the animals we’ve talked about can be found in mangrove forests, let’s take a closer look at them.

What are mangroves? Basically, these are shrubs or small trees that you can find on coasts around the world, making up a special type of forest. These plants are unique because they can survive even in very salty water (which kills a lot of other plants), and the tropical forests they’re part of serve as a crucial link between oceans and inland communities.

Let’s trek into the mangroves.

How does McKinsey fit into any of this? For starters, we help people understand the value of natural resources such as mangroves in a way everyone can easily understand: putting a price on what it would cost to replace such resources, for example.

So we came up with a “business case” for nature—basically, a convincing argument for why something should be done, which usually shows how it can help people save money or make more of it.

To make this business case, we built on the work of other researchers, such as the scientists that looked at how much money would be lost if we removed the mangroves.

People tend to forget all the benefits of nature, including mangrove forests, because they don’t cost us anything. Reminding everyone about the value of mangroves by using such big numbers is how McKinsey sometimes contributes to conversations with facts and data, so governments and other organizations can try to find ways to preserve these natural resources for animals and people.

The way we got to the math was by using maps and something called geospatial analysis. Images of the Earth’s surface, taken by satellites, showed a bird’s-eye view of mangrove forests, as well as many other types of natural areas all around the globe. For a given area, we looked at nature’s actual (sometimes shrinking) size, what species of plants and animals live there, and how close they are to (growing) human settlements. And seeing that made it easier to understand how natural areas benefit humans and wildlife and to calculate how they reduce the amount of CO₂ in our air.

This let McKinsey come up with a “before and after” picture that then allowed us to prove that conserving mangroves would have a lot of benefits without a lot of costs. And when you add it all together, we hope others will find there’s a lot to like in this math.

Many scientists and conservationists studying climate change are urging global leaders to protect nature—doubling what is protected today by 2030. It could create hundreds of thousands of jobs in nature conservation too. And it could reduce the risk of another pandemic such as COVID-19 because zoonotic diseases (ones that are transmitted to humans by animals that maybe shouldn’t have been in such close proximity) tend to spread more widely when animals’ natural habitats get disrupted by human activity. It could even protect endangered species, like those ten animals we met earlier.