Generally, when thinking of actors and actresses championing environmental causes we concentrate on Hollywood’s new-ish guard — Brad Pitt, Alicia Silverstone, Adrian Grenier, Leonardo DiCaprio, Natalie Portman and others — and often forget about the green thespians who have been gracing the silver screen for a bit longer.

Case in point is Sigourney Weaver. For many filmgoers, Weaver is best known as the tough-as-nails heroine Ripley from the Alien franchise and the unfortunate Upper West Side apartment renter Dana Barrett in the Ghostbusters films. However, this three-time Academy Award-nominated actress has spent just as much time defending the planet as she has battling hyper-salivating extraterrestrials and ridding her one-bedroom pad of also-slimy Sumerian demons.

Weaver first arrived on the environmental scene thanks in part to her role as Dian Fossey in 1988’s Gorillas in the Mist and more recently was “the voice” of Planet Earth, the Emmy-award winning documentary series. Now, Weaver can be heard narrating and seen promoting Acid Test: The Global Challenge of Ocean Acidification, a Natural Resources Defense Council-produced short film about “the other carbon problem,” ocean acidification.

Ocean acidification, described by Weaver as “the last piece of the puzzle for climate change,” may not be what comes to mind when we think of CO2-related environmental degradation. When examining the effect of man’s collective carbon footprint on Earth, we often look to the earth and to the sky but rarely to the oceans because they’re mysterious — or as Weaver puts it, “quite alien to us” — and something that mankind views as resilient, indestructible, forgiving. As Acid Test — one part stunning nature documentary and one part advocacy film — hopes to prove, the oceans aren’t as unbreakable as we think. In fact, they’re suffering greatly.

The fact that acid is created when carbon dioxide mixes with ocean water is not a recent discovery. In fact, the ocean has always naturally absorbed carbon; nothing new there. But as humans burn fossil fuels at an accelerated rate — since the rise of industrialization, oceans have absorbed 530 billion tons of CO2 — and the pH levels of Earth’s oceans decrease, the environmental and scientific communities have become alarmed. They’ve noticed that ocean acidity has begun to wreak corrosive havoc on organisms like plankton and coral, the foundation of the marine life food chain. This, of course, does not bode well for the rest of the oceanic food chain.

Acid Test, despite its Timothy Leary-inspired title, encourages us to turn on, tune in, but certainly not drop out when it comes to awareness of ocean acidification. As Acid Test enters its third run on Planet Green, MNN had a chance to view the 22-minute film at a special screening and reception last week at New York City’s Museum of Arts & Design that was attended by Weaver, the filmmakers, commercial fisherman/activist Bruce Steele, and representatives from the NRDC, including scientist Lisa Suatoni.

Before the screening, MNN sat down with Weaver, a longtime friend and former college roommate of NRDC President Frances Beinecke. Weaver, although quick to point out that ocean acidity is “not a political issue,” emphasized that to make an impact, writing letters to politicians is an effective first step since “we can’t stop ourselves, but Congress can.” Weaver also pointed out that “it’s much easier to slow down and stop the damage rather than reverse it.”

Weaver is promoting Acid Test as a “true wakeup call” and an ideal film to view over the holidays with our families to become educated about ocean acidification. Weaver made a connection between Acid Test and James Cameron’s upcoming eco-themed Avatar. Weaver calls Cameron, her director in Alien, a great “defender of the oceans” and notes that the landscapes of Avatar are heavily influenced by the sea.

Watch Acid Test in its entirety below, catch it on Planet Green, or order it on DVD. It’s an exquisitely filmed, eye-opening look at a very real problem that’s managed to fly under the radar and ride backseat to global warming for quite some time now. As Weaver — an actress whose most memorable on-screen characters are engaged in survival against aliens and the paranormal — poignantly says, “the oceans belong to all of us. We need to be their guardians instead of their destroyers.” 

Thumbnail photo: ZUMA Press