SYDNEY -- I participated in the World Parks Congress in Sydney last week and learned a new phrase: “a black elephant.”

A black elephant, explained the London-based investor and environmentalist Adam Sweidan, is a cross between “a black swan” (an unlikely, unexpected event with enormous ramifications) and the “elephant in the room” (a problem that is visible to everyone, yet no one still wants to address it) even though we know that one day it will have vast, black-swan-like consequences.

“Currently,” said Sweidan, “there are a herd of environmental black elephants gathering out there” -- global warming, deforestation, ocean acidification, mass extinction and massive freshwater pollution.

“When they hit, we’ll claim they were black swans no one could have predicted, but, in fact, they are black elephants, very visible right now.” We’re just not dealing with them at the scale necessary.

If they all stampede at once, watch out.

No, this is not an eco-doom column. This one has a happy ending - sort of.

The International Union for Conservation of Nature holds the parks congress roughly every 10 years to draw attention to the 209,000 protected areas, which cover 15.4 percent of the planet’s terrestrial and inland water areas and 3.4 percent of the oceans, according to the IUCN.

I could have gone to the Brisbane G-20 summit meeting, but I thought this was more important -- and interesting.

A hall full of park exhibits and park rangers from America, Africa and Russia, along with a rainbow of indigenous peoples, scientists and environmentalists from across the globe - some 6,000 - focused on one goal: guarding and expanding protected areas, which are the most powerful tools we have to restrain the environmental black elephants.

How so?

It starts with a simple fact: Protected forests, marine sanctuaries and national parks are not zoos, not just places to see nature.

“They are the basic life support systems” that provide the clean air and water, food, fisheries, recreation, stable temperatures and natural coastal protections “that sustain us humans,” said Russ Mittermeier, one of the world’s leading primatologists who was here.

That’s why “conservation is self-preservation,” says Adrian Steirn, the South Africa-based photographer who spoke here.

Every dollar we invest in protecting natural systems earns or saves multiple dollars back. Ask the people of Sao Paulo, Brazil. They deforested hillsides, destroyed their watersheds, and now that they’re in prolonged drought, they’re running out of water, losing thousands of jobs a month. Watch that story.

Walking around the exhibit halls here, I was hit with the reality that what we call “parks” are really the heart, lungs, and circulatory systems of the world -- and they’re all endangered.

Onodelgerekh Batkhuu, the director of the Mongol Ecology Center, stops me to explain that Lake Hovsgol National Park in Mongolia, which holds 70 percent of the surface freshwater of Mongolia -- 2 percent of the world’s freshwater -- and is the headwaters for 20 percent of the world’s freshwater that is in Lake Baikal in Siberia, is now under huge pressure from hoteliers.

“How do we get them to understand that the value of that lake staying pristine is more valuable than any hotels?” she asks.

John Gross, an ecologist with the U.S. National Park Service, who has worked in Yellowstone for 20 years, uses a NASA simulation to show me how the average temperature in Yellowstone has been rising and the impact this is having on the snowpack, which is now melting earlier each spring, meaning more water loss through evaporation and rapid runoff, lengthening the fire season.

But, hey, it’s just a park, right?

People forget: Yellowstone National Park is “the major source of water for both the Yellowstone and the Snake Rivers,” said Gross.

“Millions of people” - farmers, ranchers and communities - “need those two rivers.”

Yellowstone’s snowpack is their water tower, and its forest their water filters. Its integrity really matters. What happens in Yellowstone, doesn’t stay in Yellowstone.

Via Skype, I got to interview the heroic Emmanuel de Merode, director of Virunga National Park, a UNESCO World Heritage site famous for its mountain gorillas in the Democratic Republic of Congo.

Two of his rangers were killed last week -- bringing the total to 140 rangers killed since the park was founded -- protecting the park from anti-regime rebels, marauding bands poaching wildlife or fronting for oil prospectors.

“No park in Africa has this diversity of species,” said de Merode, who has been shot several times.

But, again, this isn’t just an outdoor zoo.

With just a little investment, explains de Merode, the park’s rivers could provide 100 megawatts of electricity from hydropower, as well as fisheries, eco-tourism and sustainable agriculture that would create thousands of jobs for the poor communities on its border.

Indeed, if the war-ravaged Democratic Republic of Congo is ever to be stabilised, it will likely start from Virunga. “You have a core of Congolese (park) rangers who have maintained their work when every other institution (in the country) has broken down,” he said.

Virunga has “become an island of stability.” This is a park holding up a country, not the other way around.

Carlos Manuel Rodriguez, Costa Rica’s former minister of environment and energy and now a vice president of Conservation International, explains to me the politics of parks -- and the difference between countries that have their forest service under the minister of agriculture and those where the forest service is under the minister of environment or independent.

Agriculture ministers see natural forests and parks “as timber that should be chopped down for something ‘productive,’ like soybeans, cattle or oil palm,” Rodriguez said.

Forest services and environment ministers “see their forests as carbon stocks, biodiversity reservoirs, water factories, food production plants, climate adaptation machines and tourism sites,” and protect them.

Guess who’s in the first group?

Honduras and Guatemala, where many people live on degraded hillsides.

Some 50,000 children have been sent from Central America to the U.S. this year -- unaccompanied. Where did they come from? Honduras, Guatemala and El Salvador, Central America’s most deforested states.

They cut their forests; we got their kids.

I promised you good news --sort of. It’s how many people are now focusing on the economic and national security value of their ecosystems.

But the power that financiers and corrupt politicians still hold in setting the limits on what we can and cannot destroy in nature -- as opposed to the scientists and biologists -- remains the bad news.

As Adam Sweidan put it, in too many places we’ve still got “the vampires in charge of the blood banks.”

It has to stop, not so we “save the planet.”

The planet will always be here. This is about us.