The Robertses in their Chevy Chase backyard: Carter is president and CEO of the World Wildlife Fund; Jackie, director of sustainable technologies for the Environmental Defense Fund. Photo by Skip Brown

Sitting on the screened back porch of his brick colonial in Chevy Chase, Carter Roberts has the abstracted expression of a person who has just overheard a fascinating snippet of conversation.

“That’s a catbird,” he says, nodding toward a stand of tall trees shading the yard. “Just migrated up from Central America.”

OK, so the bird hidden in the foliage didn’t actually tell him that. But Carter, an ardent birder, says he has sighted all but two of the 728 bird species in North America, and he knows most of their songs.

As president and CEO of the World Wildlife Fund (WWF), Carter leads the planet’s largest independent conservation organization; his wife, Jackie Roberts, is director of sustainable technologies for the Environmental Defense Fund (EDF). They’re two of Washington, D.C.’s most powerful and influential environmentalists. But in conversation, they’re friendly and low-key, and they talk about saving the planet without a hint of irony.

Searing personal experience has convinced them it’s an achievable goal. On Sept. 11, 2001, their daughter, Eliza, was diagnosed with a rare form of leukemia and given a 7 percent chance of surviving to her first birthday. The Robertses waged a dramatic and ultimately successful fight to save her—and in so doing, renewed their belief that the Earth, too, can be saved.

The environmental movement, Carter says, “is full of jeremiads—prophecies of doom. But you’ve got to have the conviction that you can write a different ending to the story.”  

At 53, Carter retains the Southern lilt of his youth. His environmentalism is a product of exploring the woods in his native Georgia as a child, he says. He was the type of kid who spent hours turning over logs looking for salamanders, the type of teenager who’d wander out of a noisy party to stargaze.

After graduating from Princeton and Harvard Business School, he got a corporate job in Boston, but spent every spare minute hiking and rock climbing. When volunteering at The Nature Conservancy turned into a job offer in 1989, Carter jumped at it; his business training came in handy as he negotiated land deals for parks in New England.

Jackie grew up in Chevy Chase, an athlete who also loved hiking and the outdoors. Now 51, the fifth-generation Washingtonian graduated from the National Cathedral School in the District, then entered Yale’s class of 1984, where a course in environmental law sparked her interest in conservation as a career. Since the university didn’t have an environmental studies major at the time, she focused on chemical engineering in order to better understand pollution.

Her first job out of college was cleaning up a Superfund site in New Bedford Harbor in Massachusetts for the Environmental Protection Agency. After returning to Yale for an MBA, she worked on the EDF’s landmark project in the early 1990s, in which McDonald’s agreed to replace its Styrofoam containers with biodegradable packaging.

“Jackie could have had a very lucrative career in business,” says Richard Chow, a childhood friend and Yale School of Management classmate. “But she’s always taken the road that’s more challenging, more fundamentally aligned with her values.”

An old girlfriend of Carter’s who also knew Jackie decided that the two would be perfect for each other, since both had MBAs and worked in the environmental field. “Actually, the work that we did was pretty different,” Jackie says. “Mine was technical—the brown part [of environmentalism]—and Carter’s was conservation strategy, the green part.”

In the winter of 1990, Jackie went to Boston on business and Carter proposed that they meet and walk to a science museum. When Jackie readily agreed that the idea sounded like fun, it appeared they might hit it off. They did, and the next weekend Carter traveled to D.C., where Jackie lived, to watch her play ice hockey.

They hadn’t been dating long when tragedy intervened: Jackie’s 19-year-old brother, Christian Prince, a sophomore at Yale, was shot and killed near his college residence by a teenage mugger in February 1991. The suspect was acquitted of the murder charge when a witness retracted his statement. Jackie and her family testified on Capitol Hill in favor of the Brady Handgun Control Act, which would require a waiting period for gun purchases, and Jackie also debated an opponent of the bill on the Today Show. The bill finally became law in 1993.

Carter stood by Jackie throughout the ordeal, and they married on Gibson Island in the Chesapeake Bay in June 1993. When their first son was born in 1998, they named him Christian.

Eventually, the couple settled in D.C., where Jackie continued at the EDF and Carter worked on rain forest projects for The Nature Conservancy in Central and South America.

In July 2001, Jackie gave birth to twins, Eliza and Street. Caring for a toddler and nursing two babies became even more grueling when Eliza was hospitalized repeatedly with high fevers and mysterious infections.

On the night of Sept. 10, Eliza was rushed to Georgetown University Hospital, where her life hung by a thread. The next morning, Carter and Jackie learned that she had myeloid leukemia, a disease that’s particularly deadly in infants. Jackie recalls seeing the smoke rising from the Pentagon as she looked out the hospital window, and feeling that the world was coming to an end.

Added to the grim prognosis was the fact that nobody in the family was a match for bone marrow, meaning that Eliza would have to undergo radiation after a transplant from an unrelated donor. Radiation is dangerous to a baby’s developing brain and can cause severe cognitive deficits down the line, says Dr. Aziza Shad, who was Eliza’s pediatric oncologist.

“Carter and Jackie were heartbroken, obviously,” Shad recalls. “But instead of looking back, playing the blame game and wondering if this or that had caused it, they just moved forward.”

“We were determined,” Carter says, “that Eliza was going to be among the 7 percent” to survive.

Jackie believes that her work helped prepare her for dealing with Eliza’s illness. “I was used to coming up with new solutions to things, and we knew that Eliza’s cure wasn’t going to be in a textbook or on the Internet,” she says. “We’d have to figure out who the experts were, look at numbers and data and see connections.”

The couple called pediatric oncologists around the country, and were touched when many took the time to call back. “But everybody had a different opinion about what we should do,” Jackie says.

While she shuttled between home and hospital, still nursing both twins, Carter flew to visit various cancer treatment centers. A young doctor named John Wagner, who had conducted a small study at the University of Minnesota in Minneapolis, gave them hope. His protocol involved a new combination of chemotherapy with an umbilical cord blood transplant, which would replace bone marrow and reduce the risk of relapse. Late in 2001, Wagner’s results hadn’t yet been published, “but he let me look at them on the computer,” Carter recalls.

The slight bump in the cure rate induced Carter and Jackie to move the entire family to Minneapolis for five months while Eliza underwent the experimental treatment. “I said, ‘I know that I could be wrong—it doesn’t always work out,’ ” says Wagner, who is now an internationally recognized expert in the field of stem cells and umbilical cord blood transplant. (His work with another family to select an embryo whose cord blood would save an ailing sibling inspired the 2004 Jodi Picoult novel, My Sister’s Keeper.)

Eliza was a year and a half old when a blood test showed no sign of disease. “I said to Dr. Wagner, ‘When will we be out of the woods?’ ” Carter recalls. “And he said, ‘Today.’ So we stopped at a pastry shop and bought a big cake and celebrated.”  

Today, at 12, Eliza is in good health, a rising sixth-grader at Sidwell Friends School with a keen interest in fashion design. Though she has no memory of her illness, the treatment she underwent has become standard, and the survival rate from the disease is now 60 to 70 percent.

“Some people would rather have taken a more conservative approach, and I understood parents who wouldn’t have wanted to try something brand new,” Wagner says. “But [the Robertses and I] had a similar mindset: We don’t want to accept the way things are now—we want to find something better, to go for it all.”