Editor's note: TED is a nonprofit organization devoted to "Ideas worth spreading," which it makes available through talks posted on its website. Beverly and Dereck Joubert, who are National Geographic explorers in residence based in Botswana, have filmed and photographed wildlife and nature for nearly 30 years. They have received five Emmys, as well as other awards.
(CNN) -- As you will see in our TED talk, Beverly and I have spent enough time in the bush with lions to understand that we have a problem -- rapidly declining big cat populations.
This much time alone in the wild makes us socially inept, but there is no substitute for doing the time.
As we've delved into this more, we have learned more about the problems facing these extraordinary creatures. All the problems focus on human-predator conflicts, from the collection of hunting trophies as sport -- an activity that is terribly damaging to wild populations of cats -- to flashpoints between the cats and cattle cultures.
The real miracle is that we do still have this last remnant of lions at all. Just 50 years ago there were 450,000; today there are possibly as few as 20,000. These are the last lions.
As Beverly points out in the TED talk, the death of one male lion can have drastic effects on the whole pride. A new male comes into the area and takes over the pride, killing all the cubs and possibly some of the females defending their cubs.
So we've estimated that from 20 to 30 lions are killed when one lion is hanging on a wall somewhere in a far-off place.
If we don't do something, collectively, within the next few years, we will be seeing the last of the lion populations in Africa. That is why we have produced a film for theatrical release, in theaters in the U.S. in February, called "The Last Lions."
We're hoping that our work will galvanize a movement to save them -- but it is going to take a universal effort and action on an emergency basis. In association with National Geographic we founded the Big Cat Initiative to roll up our sleeves and save cats, right now.
So who cares? Well, the first thing to appreciate is that the world's large predators, like lions, are not just a luxury for us to look at, to photograph, or to shoot. They are the most vital center point in many ecosystems. If we lose them, we can anticipate eventual collapse of whole environments, right down to the water systems, as prey shifts or migrations stop, and species overgraze and destroy the integrity of important vegetation, especially along rivers.
Erosion follows, rivers silt up, and fish die, all because we took out a few lions.
There is as great an economic need to preserve lions. In Africa an $80 billion-a-year business in ecotourism feeds parks, airlines, safari businesses, and local crafts and helps pump up economies important to the entire continent.
Communities thrive on this cash, and it keeps them above the poverty line, gives them dignity and hope, and alleviates the need for aid. It gives people resources to better educate their kids. Better education breeds health and less exposure to diseases such as AIDS.
Also, within those communities there is a deep spiritual connection to the land and its wildlife. When creatures such as lions disappear, a destructive ripple effect weakens our care for the planet and our understanding of who we are.
Everything hinges on people being connected to a planet that is whole; and predators, although scary to live with, actually glue all this together. It's something we've known and lived with for 3 million years.
We have to decide if we are a part of the planet and its life forms or if we want to try to live apart from it all. With the specter of The Last Lions will come, and not that far behind, the potential sequel -- The Last Humans.
The opinions expressed in this commentary are solely those of Dereck Joubert.