Changing Planet

Extreme Cave Diving with a Purpose

National Geographic Expeditions Council grantee Kenny Broad has been on hundreds of dives where the visibility is so bad he can’t see his own gauges in front of his face. He is an environmental anthropologist who explores inland underwater caves. It is an extreme working environment where one wrong move can be fatal.

Broad and his team, in collaboration with the National Museum of the Bahamas, began the Blue Holes Project to explore groundwater and submarine caves in the Bahamas. They collect data to help with issues like water management, preserving fossils, and climate change.

“It’s like going in a time machine, because we can find out about the ancient past,” Broad says. “We can take geologic samples, for example, and then study them and try to understand how climate change occurs, so how the ice ages occurred in the past. That allows us to improve the models of future climate, and our understanding of not just what’s going on with global warming, but the larger record of global climate change.”

As exciting as they sound, exploration dives are not pleasure dives. “It’s a pretty good challenge to go into an underwater cave and come out alive,” Broad says. “[Exploration dives] are much higher risk, because you’re not just going in and out—you’re trying to take samples, and pictures, and data.”

Along with multitasking in a challenging environment, the team members know they will probably not be able to see each other or where they are going on their way out. “Imagine turning the lights off in your house,” Broad says, “and putting a blanket over your head and then trying to find your way out.”

In cave diving you have to find your way back out the same way you enter, so there are some golden rules. The first one is to always run a continuous guideline. “That’s basically a piece of nylon line that you run wherever you go, and that’s how you find your way out, because it’s very likely that you’ll come out with zero visibility,” Broad says.

Despite how challenging the working environment is and how bittersweet it is—he’s lost friends and collaborators—Broad is still doing almost 50 cave dives a year. “The bottom line is I love the experience of being in underwater caves, and now I’ve grown to love the entire process of doing science related to underwater caves, so it’s not just about exploration for exploration’s sake,” he says. “It matters that I’m putting together a good project, that not only explores the cave, but also has a meaningful outcome.”

Broad was honored, along with his late friend, Wes Skiles, as 2011 Explorers of the Year.

You can read more about the Blue Holes Project here.

Carolyn Barnwell has been a producer on the Science and Exploration Media team at National Geographic for over five years. She creates content to support the non-profit National Geographic Society including impact initiatives and the important work of explorers and grantees around the globe. She wrote, produced and edited for Nat Geo’s first-ever web series focused on explorers in the field: Expedition Raw and Best Job Ever. She loves yin yoga, wildlife encounters, and eating baked goods while they are still warm from the oven.

About the Blog

Researchers, conservationists, and others share stories, insights and ideas about Our Changing Planet, Wildlife & Wild Spaces, and The Human Journey. More than 50,000 comments have been added to 10,000 posts. Explore the list alongside to dive deeper into some of the most popular categories of the National Geographic Society’s conversation platform Voices.

Opinions are those of the blogger and/or the blogger’s organization, and not necessarily those of the National Geographic Society. Posters of blogs and comments are required to observe National Geographic’s community rules and other terms of service.

Voices director: David Braun (

Social Media