MIAMI—The water rose quickly. At noon on a brilliantly sunny day here, several blocks from the beach, a lake of salt water suddenly appeared in the street, filtered up from the porous limestone that resides underneath the whole county of Miami-Dade. On the corner of 79th Street and 10th Avenue in the Shorecrest neighborhood, people wandered outside their apartment buildings to stare at the rising water, sloshing through in rain boots to take out their trash.

“It’s been like this for a few days now, rising and then receding and then rising again,” says Jessica Benitez, a resident who moved to Miami from her native Venezuela about a month and a half ago. She says she didn’t know these apartments would flood before she moved into them, and she still doesn’t know how to predict when the water is going to rise. She got home from the store a few days ago to find her street completely flooded, and she tied plastic bags around her feet to get to her door. “[The city] has never told us anything. The water just sits there. It’s like there are no drains, and I don’t understand why,” she says.

She’s not the only one who feels that way. This is just one neighborhood of many in Miami-Dade dealing with the effects of Florida’s King Tide last week, the highest tide of the year. Coastal neighborhoods are hardest hit, but the flooding also reaches farther inland, to less affluent communities. It’s here where the consequences of climate change and sea-level rise could in fact be most grave, says Nicole Hernandez Hammer, a climate researcher with the Union of Concerned Scientists. Middle- and low-income households tend to be less resilient to shocks such as flooding, and they also run the highest risk of being forgotten in the rush to save the millions of dollars in real-estate investments on the waterfront.

“It’s getting worse. When you visit places that weren’t flooding 30 years ago, they’re flooding now,” says Hammer. Today, the Miami area experiences about six of these sunny-day flooding events per year. But the Union of Concerned Scientists projects that by 2045, they’ll be happening 380 times per year. “That’s two times per day in some areas,” she says.

October 12, 2016
Nano-spike catalysts convert carbon dioxide directly into ethanol
ORNL's Yang Song (seated), Dale Hensley (standing left) and Adam Rondinone examine a carbon nanospike sample with a scanning electron microscope. Credit: ORNL

In a new twist to waste-to-fuel technology, scientists at the Department of Energy's Oak Ridge National Laboratory have developed an electrochemical process that uses tiny spikes of carbon and copper to turn carbon dioxide, a greenhouse gas, into ethanol. Their finding, which involves nanofabrication and catalysis science, was serendipitous.

"We discovered somewhat by accident that this material worked," said ORNL's Adam Rondinone, lead author of the team's study published in ChemistrySelect. "We were trying to study the first step of a proposed reaction when we realized that the catalyst was doing the entire reaction on its own."

The team used a catalyst made of carbon, copper and nitrogen and applied voltage to trigger a complicated chemical reaction that essentially reverses the combustion process. With the help of the nanotechnology-based catalyst which contains multiple reaction sites, the solution of carbon dioxide dissolved in water turned into ethanol with a yield of 63 percent. Typically, this type of electrochemical reaction results in a mix of several different products in small amounts.

"We're taking carbon dioxide, a waste product of combustion, and we're pushing that combustion reaction backwards with very high selectivity to a useful fuel," Rondinone said. "Ethanol was a surprise—it's extremely difficult to go straight from carbon dioxide to ethanol with a single catalyst."