Luke Runyon / KUNC/LightHawk

LAGUNA GRANDE, BAJA CALIFORNIA, MEXICO — It’s mid-morning in the Sonoran desert and already the temperature is rising.

Karen Schlatter suggests we find some shade, a relatively easy task at Laguna Grande, a restoration site along the Colorado River’s historic channel in Mexico. It’s managed by the Sonoran Institute, where Schlatter is associate director of the binational environmental group’s Colorado River Delta program.

Luke Runyon / KUNC

CIÉNEGA DE SANTA CLARA, MEXICO — Juan Butrón-Méndez navigates a small metal motorboat through a maze of tall reeds here in the Mexican state of Sonora. It’s nearing sunset, and the sky is turning shades of light blue and purple.

The air smells of wet earth, an unfamiliar scent in the desert.

Luke Runyon / KUNC/LightHawk

SAN LUIS RIO COLORADO, MEXICO — From inside a small airplane, tracing the Colorado River along the Arizona-California border, it’s easy to see how it happened.

As the river bends and weaves through the American Southwest, its contents are slowly drained. Concrete canals send water to millions of people in Phoenix and Tucson, Los Angeles and San Diego. Farms, ribbons of green contrasted against the desert’s shades of brown, line the waterway.

Updated at 3:08 p.m ET

Frustrated by the large number of Central Americans who have been entering the country from Mexico, President Trump doubled down on his threat to close the Southern U.S. border.

"I'm ready to close it," Trump said Tuesday. "If we don't make a deal with Congress, the border is going to be closed, 100 percent."

Luke Runyon / KUNC

2018 wasn't the worst winter on record for the southern Rocky Mountain region, but it was close to it.

“It was an extreme year on the dry side, widespread across the Colorado River Basin,” says Greg Smith, a hydrologist at the Colorado Basin River Forecast Center (CBRFC) in Salt Lake City.

Pete McBride / U.S. Geological Survey

In 2014, the Colorado River did something it hadn’t done in decades. For a few short weeks that spring, the overdrawn, overallocated river reached the Pacific Ocean.

Instead of diverting the river’s last bit of water toward farm fields, the final dam on the Colorado River at the Mexican border lifted, and water inundated nearly 100 miles of the dry riverbed. It was called the pulse flow, meant to mimic a spring flood.

Courtesy Sarukhan and Associates

On this episode of Platform Americas: a conversation with Arturo Sarukhan, a former ambassador to the U.S. from Mexico. He warns that the U.S. neglects its souring relationship with Mexico at the peril of both countries. Then we chat with Tijuana-born, punk-turned-pop singer Ceci Bastida in her L.A. studio. 

Courtesy U.S. Geological Survey

In the spring of 2014, a rare moment happened on the lowest stretches of the Colorado River. Instead of its last few drops being diverted at a dam near the U.S.-Mexico border, it flowed through its banks.

“There was a remarkable amount of excitement and energy in the air,” says James Leenhouts, a U.S. Geological Survey hydrologist who runs the agency’s Arizona Water Science Center and was present for the moment. “One of the most remarkable impacts of the flow was the human impact.”

In communities where the river hadn’t flowed for nearly two decades, impromptu festivals broke out, children waded into the water and mariachi bands set up to entertain the crowds. As the water settled into the valley it was clear the “experimental pulse flow” made a profound cultural imprint on the region the Colorado River once regularly flooded.

Farms and ranches throughout the country won’t see their labor shortages solved by a renegotiation of the North American Free Trade Agreement (NAFTA).

In a call with reporters while visiting Mexico ahead of the trade talks, U.S. Agriculture Secretary Sonny Perdue said labor issues likely wouldn’t be addressed during formal negotiations among the United States, Mexico and Canada, set to begin August 16th.

Sandy and Chuck Harris / Creative Commons License

Monarch butterflies are disappearing. Scientists agree that in the last 20 years, populations of the black and orange insect have been in precipitous decline. But there's much less certainty on what’s causing them to vanish.

As each new scientific paper on monarch decline is published, the image becomes slightly less opaque. So far, potential culprits include disease, climate change, drought, deforestation, and sparse nectar plants. Blame has been cast on everyone from loggers to farmers to suburban developers.

In the battle to save the migratory monarch, advocates have zeroed in on a simple, leafy weed.