By Laurie Casey

We've all heard of capital. It's king, right? Plus, there's venture capital: wealth that creates new businesses. Human capital? Yep, we know that by the sweat on our brow.

And then there's natural capital. Ever heard of it? Paddy Woodworth, author of Our "Once and Future Planet," will come to Oak Park to help us understand the concept of restoring natural capital and how this idea is transforming the way the world values and uses nature.

Here's a preview, but please come see him speak at 7 p.m. Tuesday, Nov. 10, at First United Church of Oak Park (848 Lake Street, next to the Oak Park Public Library). This West Cook Wild Ones meeting is free and open to the public.

As a long-time environmental journalist and author, the aptly named Woodworth has traveled internationally to discover amazing projects and meet leading movers and shakers. His talk next Tuesday promises to be a lively, wide-ranging discussion.

Q: What is the concept of natural capital?

A: When you begin to understand it, it's surprising we haven't talked about it before. This is an attempt to find a common language between economists and ecologists. Economists look at the way we do business with each other. Ecologists look at the way we deal with the natural world.

Indian banker Pavan Sukhdev has a great quote: "We use nature because it's valuable, we lose it because we think it's free."

There's great danger in thinking that nature is free. Our human culture is built on natural materials.

Nature is a limited resource. Just as in your personal finances, economists tell you that in order to live prudently, invest the principal to make interest, and live off the interest. Don't spend the principal. But what we're doing with nature, we are reducing the principal, the raw stock, all the time.

Imagine if there were an invisible debit in our account that we didn't notice until our funds were depleted. That's what our approach to the natural world is like. We need to recognize this is happening.

Here's an example of the value of restoring natural capital: New York's water purification system broke down in the 1990s. They had to rebuild it entirely at a cost of $6 billion. Some people said, "Maybe if the water wasn't arriving at these treatment plants in such bad condition, it would be easier to treat." So they looked at the idea of restoring the natural capital of the water by looking upstream at the watersheds in the surrounding mountains. They helped farmers there pay to plant trees near the water and fence off the cattle from the river so cow dung would stay on the land. They took a series of these kinds of measures. And they were able to restore the natural capital of the water.

Some people don't like this way of talking about "natural capital." They think it commodifies nature. The truth is, nature has always been for sale, but we haven't put a right price on it.

Q: Who does this kind of restoration work?

A: A huge range of people. It's surprising. Citizen volunteers do restoration projects, such as Chicago Wilderness members doing larger projects and Wild Ones members planting natives in their yards. There are corporations, and governments, too. I was just at a United Nations conference on desertification in Turkey, where 195 nations committed to restoring 12 million hectares of land a year.

But there is a danger-- as with so many buzzwords in the environmental movement -- people talk about restoration a little too glibly.

Some people aim for a target to bring a site back to what it was prior to disturbance. That's not possible. All ecosystems are dynamic and changing over time. If you can imagine an ecosystem on train tracks, you want to get it on the track or historical pathway it was on once. That's a high bar and not easy to achieve.

And then there's the other problem: a mining company might claim to restore a mountain, but if you cut the top off, you can't restore it. And then they'll plant nonnative conifers, which have no ecological benefits.

Q: What can we do as individuals and communities to make a difference – in our public lands and even in our own backyards?

A. Two things. First, look for a restoration project and get involved in it.

Then, think critically about that project. A chapter in my book explores a project in Chicago that ran into trouble because it did not consult adequately with the surrounding communities.

We need to embrace restoration, but let's take a scientific approach and see new evidence as it arises. We are beginners in this. Ecological restoration is based on young science that's only been developed in the last 25 years. We need to adapt our management if it turns out that what we are doing is not the right thing.