Yes, it's charming and thought-provoking and amazing. But for those of us in the green world, the really striking thing about the animated film Wall-E is that a plant is the object of desire, the grail, the Ark of the Covenant. This happens so rarely in movies. (One exception is an obscure but admirable satire, released a couple of years ago, called Idiocracy, in which the hero teaches really dumb people on an apocalyptic future Earth that plants need to be properly tended so that people will have food to eat and air to breathe.)
The precious little green thing on which the Wall-E plot turns consists of just a few leaves clasping a viney stem.
To get a botanist's perspective on the plant as plot-driver, I took Gerry Moore, director of the Department of Science at the Brooklyn Botanic Garden, to the movie. Moore, who monitors the rise and fall of plants within a 50-mile radius of New York City, was looking quite collegiate in shorts and a Phillies baseball cap that belied his weighty résumé. He was modest and flexible enough to say, "I hate to impose scientific rigor on a movie."
Maybe the exercise he got pushed into (I paid for his ticket) is a bit on the literal side, but it is interesting to see where he found the movie departing from credibility.
The movie's setup: Apparently nothing is left on Earth but ruins, piles of trash, and Wall-E, a solar-powered, trash-compacting robot. It seems that the only living thing around is a single cockroach. Earth's human population has fled to a gigantic space colony. A scout from the space ship, the feminine and graceful robot Eve, meets Wall-E and returns to the ship with a plant he's discovered. The small green plant registers with some back at the colony as a foreign contaminant, dangerous to the status quo, but with others—including the good-guy captain—as a sign that life on Earth might be possible again.
The biggest problem for Moore is that only one plant was found. "It's a stretch to believe that the Earth could be restored to life-sustaining status because of the presence of a single live plant," he said over dinner after the movie.
Behind the closing credits, we saw plant life unfurling quickly on Earth—sunflowers, fruitful vines, trees.
"They're down to one plant—a seedling of some kind of vine," observed Moore. "There's no way a single individual plant could give rise to wheat, grapes, and re-vegetate the earth. Not in human time, anyway. In evolutionary time, of course, that's what really happened."
Still, Moore was thrilled to have green things seen as important. "The story line puts plants front and center. It wasn't the roach they were looking for."
One of the merits of the movie is that it avoids being obviously didactic; no one ever uses the word photosynthesis. But, implicitly, the movie stresses the life-giving talent plants have—that is, to make an organic product from strictly inorganic ingredients.
Provide a little carbon dioxide, water, and sunlight, combine those with a molecule of the green pigment chlorophyll, and the plant can feed itself and, happily for us, release oxygen as a byproduct.
We know there is sunlight on the degraded Earth; Wall-E himself is solar-powered. He finds the precious plant in a closed refrigerator, which is worrisome from a scientific point of view. Green plants can't live long without sunlight. But, even without light, a plant can sprout and live for a while by using the reserves in its seed coat.
The plant, rooted in some soil in a boot, gets tossed around like a football in the chase scene on the space ship. I wondered how realistic that was, considering the care we gardeners take not to jostle our petunias as we drive them home in the back of the Forester. "That, I can live with," said Moore, "Think what you see plants go through in vacant lots."
The space colony's captain says, "You made it somehow, little guy. You didn't give up." Because there was no green growing thing in evidence on the ship, Moore observed, "A plant is not only front and center, but it's assumed that human beings passed the concept of a plant down through many generations."
"Life is sustainable now," says the captain to his passengers. "Look at this plant. It's green and growing."
The movie's last utterance from a human being is the captain speaking to toddlers as they disembark on Earth and plant the little vine: "This is called farming."
We get a glimpse of a hill with other plants, but they're the same kind as the little vine. It's going to take a long time, especially with no pollinating insects, to spread out from monoculture.
It's good the movie ends there, with the line about farming, Moore said. I thought so, too, because the next line might be: "Who here knows how to find clean water or build a latrine?"
We agreed on what we believed to be the two major lessons from the movie. First, honor your trash collectors. Not since pitcher John Franco regularly wore a New York Department of Sanitation T-shirt under his Mets uniform as a tribute to his father has a garbage man been as honored. Wall-E is a hero. This, too, happens rarely in movies.
Second, treasure the wide variety of plants we have and, for god's sake, save seeds. The 52 acres of the Brooklyn Botanic Garden are home to 10,000 species of plant from all over the world. (The whole state of New York has only about 4,000 naturally occurring species.) The Millennium Seed Bank based at Kew Gardens is well underway, so we're already far more provident than the human beings depicted in the movie.
Incidentally, and maybe this is a hopeful note, the trash piles alone wouldn't have wiped out almost all plant life. Moore and I assumed there must have been some additional catastrophe—to kill plants you need long-lasting drought or dramatic temperature change, which the optimists among us think can still be avoided.