In Organ Pipe Cactus National Monument, Arizona, you can find more than 30 species of cactus, including the saguaro, desert giants that tower over the landscape and live for centuries. Desert specialists like endangered Sonoran pronghorn and Sonoyta mud turtles thrive there on just a few inches of rain per year.
This UNESCO Biosphere Reserve lies right on the United States-Mexico Border, previously demarcated only by a short three-foot-tall fence running through the wilderness, one that allowed animals to move freely. But in early 2020 construction began on President Trump’s signature project: a 30-foot-tall wall of steel and concrete.
Now that wall is almost entirely complete, along all 30 miles of the reserve.
Organ Pipe is not alone. The border wall is going up quickly. Nearly 400 miles have been completed in the last two years, mostly in California, Arizona, and New Mexico—the wall now shadows the majority of the border outside Texas. Another 330 more miles are under construction.
And yet, the wall’s massive size, environmental impact, and quickly expanding footprint has not received the public attention one might expect—in part because politics has obscured the reality of what’s happening on the border.
10 Empire State buildings
By some measures, the border wall is the biggest public works project in decades. Contractors for Customs and Border Protection (CBP) have put up walls containing nearly 600,000 tons of steel. That’s enough for 10 Empire State Buildings. Another 800,000 tons of concrete form the fence’s base.
With $15 billion secured so far to fund it, it will cost approximately twice what the Panama Canal cost to build in the early 1900s, in today’s dollars. With that money, you could build and launch three Hubble Space Telescopes; you could pay a generous salary for more than 200,000 public high school teachers—which is, incidentally, about how many there are in all four border states.
Nevertheless, some prominent journalists and political opponents of Trump have noted that the vast majority of the border wall constructed so far is “replacement,” as if to suggest the wall does not represent a substantial change. But that’s false. Almost all of this “replacement” wall is 30-foot fencing made of steel posts, the majority of it replacing short barbed-wire fencing and vehicle barriers a few feet high, according to CBP.
“Every mile of border wall system construction is new—whether we’re constructing in a place where previously no barriers existed or replacing a five-foot steel vehicle barrier with an 18- or 30-foot steel bollard wall complemented with roads and technology,” says CBP spokesperson Matthew Dyman.
Downplaying the scale of what’s been built is counterproductive and illogical, says Laiken Jordahl, an activist with the Center for Biological Diversity, an environmental group. Jordahl points out that most Americans—around 60 percent—don’t support more wall construction.
One reason for a lack of public awareness is that border wall construction is taking place in wilderness areas, explains Myles Traphagen, a conservation scientist with Wildlands Network, a nonpartisan environmental group dedicated to preserving wildlife corridors. The wall traverses places most people don’t go, and CBP often doesn’t allow people near construction crews, he says.
“It's out of sight, out of mind,” Traphagen says. With construction on remote public and various trial lands, “There’s no core constituency opposing this.”
What’s the impact?
All this wall construction will have a significant environmental impact. Much is unknown, in part because Department of Homeland Security chief Chad Wolf has waived scores of laws—including the Endangered Species Act—that would require extensive mitigation and research of likely effects. This would normally be illegal, but it is permitted under the 2005 Real ID Act, which allows the agency to not comply with almost any law in the process of building the border wall.
The first obvious problem the wall creates is that it blocks the movement of wildlife. The fencing prevents animals from foraging and finding food, migrating, and spreading their genes, which could lead to regional extinctions of various species, says Aaron Flesch, a researcher at the University of Arizona who’s studied the impact of walls on animal movement. (Read more: Border wall construction expands, despite pandemic, imperiling jaguars and other animals.)
Already, Traphagen has seen the 30-foot wall have an effect on wildlife abundance and movement at San Bernardino National Wildlife Refuge in southeastern Arizona, where his organization has dozens of camera traps.
“The numbers of javelina have really gone down,” he says. The cameras also show that mountain lions have drastically altered their movement patterns. He suspects “they want to cross to a former place they use to hunt [in Mexico], but they can’t.”
Traphagen says the wall won’t just affect individual locales like San Bernardino, but could change migration and gene flow at a continental scale. A complete border wall could “alter the evolutionary history of North America forever,” he says.
Then there’s the light pollution. CBP’s Dyman says about 90 percent of the new fencing will have lights, some of which will be on at all times. Lighting up some of the most biodiverse places in the United States could hurt insects, birds, bats, and other animals by disrupting their nighttime activity, says Kevin Dahl of the National Parks Conservation Association.
Also, massive amounts of water go into making cement for the fence’s base. CBP doesn’t currently measure water use, Dyman says. But past estimates by the agency suggest that wall construction near Organ Pipe used up to 710,000 gallons of water per mile. That could endanger precious water sources like Quitobaquito Springs in Organ Pipe, where flow hit an all-time low this summer. (Read more about the sacred Arizona spring drying up as border wall construction continues.)
The water usage has also led to other problems like lowered water tables at the San Bernardino refuge, home to four species of endangered or threatened fish. To protect the fish habitat, the refuge had to take “life support” actions to manage the water shortage and allow several ponds to go dry, staff emails reveal. The refuge manager referred to the wall’s water usage as the “greatest threat to endangered species in the Southwest region.”
President Trump hopes to complete 450 miles of wall by the end of this year. Even if Joe Biden wins the presidency in Tuesday’s election, construction is expected to continue at least into January.
Some impacts of the wall are irreversible—particularly the draining of desert aquifers, a desecration and a grave misuse of a sacred resource, says Tohono O’odham tribal elder Ophelia Rivas. Some important aquifers in the Sonoran desert could take centuries to reach the levels of just a few years ago, hydrologists say.
But other effects are easier to address. Biden has said he would immediately halt construction, and many have mused about how to best remediate the damage. Certain sections could be torn down, although nobody knows how likely this is, or more spacious wildlife passages could perhaps be added. But making change will be tricky.
“While ending construction is easy to say, it might not be so easy, because [Biden] will have to consider the phase of construction, gaps in the wall that could be exploited and the termination costs for existing contracts, which can come with a high price tag for taxpayers,” Scott Amey, general counsel of the Project on Government Oversight, told ProPublica. Biden might have to complete “certain portions of the wall whether he likes it or not.”
But none of that is certain yet—especially with an election looming.