Most scientists find a topic that interests them and keep digging deeper and deeper into the details. But Ken Caldeira takes the opposite approach in search for solutions to climate change. He goes after the big questions, and leaves the details to others.
We caught up with Caldeira on Australia's Great Barrier Reef, where he was conducting an experiment to measure how coral reefs are coping with increasing acidity in the world's oceans. People are causing this change by burning fossil fuels and putting carbon dioxide into the air. From there, it dissolves into the oceans, and makes them more acidic.
As a result, the world's coral reefs are in trouble. In a matter of decades, ocean water could become so corrosive that reefs may start dissolving faster than the coral can grow.
Caldeira works for the Carnegie Institution for Science, and he's based on the Stanford University campus. But throughout February, his base of operations was One Tree Island, Australia.
He spent many a day out on the reef, wearing a floppy sun hat, tattered shorts and a head-to-toe "rash guard" to block the intense sunlight. He and his team were pumping antacid onto a stretch of the reef to see if neutralizing some of the increased acidity would help the coral grow faster.
Nobody has ever tried this before. And Caldeira readily acknowledges that he may not get a clear answer himself. Over the course of one hourlong dose of antacid, he's hoping to measure changes in the amount of reef-building calcium carbonate the corals absorb. (See related story for more details.)
Caldeira has license to do this because he works at an unusual place. The Carnegie Institution for Science was endowed by industrialist Andrew Carnegie more than a century ago, so Caldeira worries less about money than other scientists do.
"My job offer letter said 'make important scientific discoveries,' " Caldeira says. "And they basically give me some resources and leave me alone to make important scientific discoveries."
This seems to have worked. More than 12,000 papers in the scientific literature refer to papers that Caldeira has written or co-authored.
Ken Caldeira of the Carnegie Institution for Science takes a water sample during his experiment on part of the Great Barrier Reef. The water is slightly pink because his team is using a dye to trace an acid-neutralizing chemical as it flows across the reef.
Science wouldn't really work if everyone tried to go after the flashy findings and not fret about chasing down all the details. But big-picture thinkers like Caldeira also help drive the field.
The reef expedition was a relatively rare foray; over the years, most of his work has been at a computer screen. He has calculated what it would take to cool the planet by spraying reflective particles into the atmosphere. He has wondered what would happen to global temperatures if all the trees near the Arctic were cut down. He has calculated just how much clean energy generation would be needed to replace all the fossil fuels we're using.
But for all that, he loves being out on a reef, doing firsthand research and taking risks on experiments that may simply not have enough power to detect the small changes he's looking for.
"This is how the science gets pushed forward, by people taking risks," he says. "And maybe we'll get lucky and it will work, and maybe it won't."
In a world where science is often driven by a researcher's ability to get government grants, taking a risk like this is a luxury.
But when Caldeira steps back to look at the big picture, it leaves room for some startling insights. For example, it might seem that our vast skies have an endless ability to hold the billions of tons of carbon dioxide we produce every year.
But here's how Caldeira visualizes it: "If you were to compress the entire atmosphere so it was the density of water, it would only be 30 feet deep, so all the stuff we're throwing into the atmosphere, it's like we're throwing it into an ocean that's only 30 feet deep." More