Border Walls & Climate Change

Alexis Tomaino

Scientists now estimate that “half of all life” is “on the move” in direct response to anthropogenic climate change.  Yet at the very moment when ecological corridors for animal migrations should be safeguarded and prospectively secured because of climate change, more nations are constructing international barriers as a national security tool to impede human migration. Walls erected along international boundaries in the name of national security have unintended but significant consequences for biodiversity: they reduce the area, quality, and connectivity of plant and animal habitats.  And they block the ability of species to migrate and relocate to more suitable habitats.

            Since 1945, the number of large-scale, transnational border walls has increased from seven to 77, most built for the sole purpose of blocking human migration. This is a global crisis: in Africa, a barrier between Somalia and Kenya, made of barbed wire, concrete, and posts is nearing completion and a 1,700-mile sand wall fortified and surrounded by millions of land mines was built by Morocco along disputed, ungoverned territory on its border with Western Sahara. In Asia, Chinese President Xi Jinping has called for an iron wall around the Xinjiang region. In Central America, Ecuador has erected concrete panels along the Peruvian border.  In Europe, a mile-long wall exists at Calais, France funded by the United Kingdom to prevent migrants from accessing the Channel Tunnel and the Baltic States are raising a fence along their eastern frontier. And, in North America, the United States President Donald Trump has pledged to construct a “great wall” (the “Trump Wall”) along the 1,933 mile-long southern border between the United States and Mexico (the “Border”)—and in the process bisect a continent—in response to what he called a national security threat of human migration. 

            Although the construction of Trump Wall has been debated for a variety of reasons including illegal diversion of funds earmarked by Congress to fund the wall, largely absent from such discussions is a meaningful analysis of the devastating impact of such a wall on species’ climate change adaptation.  The border wall not only divides communities where millions of people live, it also cuts through the habitats of more than 1,500 wildlife species, disrupting a fragile and unique web of life in the borderlands. Aside from the physical wall, construction vehicle disturbance as well as lighting and noise pollution will wreak havoc on wildlife and sensitive habitat. Two animals—the ocelot (Leopardus pardalis) and Sonoran pronghorn (Antilocapra americana sonoriensis)— help bring this abstract problem into focus.  What’s undeniable is that the 654 miles of walls and fences already along the Border have cut off, isolated, and reduced populations of these amazing animals. 

A cat with its mouth open

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            “Drive slowly. Ocelots” signs still pepper the campus of the University of Texas at Rio Grande Valley, located just twenty miles from the Border, harkening to the days when these small, spotted and striped felines roamed broadly throughout the Southwest.  But any actual sighting of ocelots now is a rarity.  Biologists estimate that fewer than 50 remain in the U.S.  Because of these small populations, the Trump Wall would, inter alia, weaken these species’ genetic health by blocking access to suitable mates in Mexico.  Populations with low genetic diversity are poorly suited to adapt to changing environmental conditions, shrinking habitats or new diseases.  Thus, without a concerted relocation plan, the ocelot would become extirpated in the U.S. because the Trump Wall result in the loss of connectivity with other ocelots.  

A herd of zebra standing on top of a dry grass field

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            Known as the “prairie ghost,” the Sonoran Pronghorn is a small antelope with a reddish-brown coat, white belly, and white and black face with shiny black horns.  These animals are the fastest land animal in North America. Only 400 Sonoran Pronghorn are estimated to remain in the wild with only 160 left in the United States.  In addition to weakening these species’ genetic health by blocking access to suitable mates in Mexico, Sonoran Pronghorn move nomadically in response to changing forage conditions and water availability as a result of sporadic rainfall and are uniquely susceptible to drought conditions that are expected to increase as a result of climate change.  Indeed, the U.S. Fish and Wildlife Service recommends in its 2015 Draft Recovery Plan for Sonoran Pronghorn that the ability to migrate to water sources be preserved.  Because they require large expanses of contiguous habitat to persist in the harsh desert environment, the Trump Wall would almost certainly result in the extinction of the Sonoran Pronghorn.

            The inherent conflict between the use of a Border wall as a “national security” tool to control human migration and the need to protect ecological migration corridors along the Border for species survival and ecosystem health in light of climate change must be resolved in favor of the animals.  Time is of the essence.  The Border is not yet completely walled-off and vital migration corridors still remain.  But to add insult to injury, many of these critical areas are on federal land which makes them the easiest to construct upon because the land is already under federal control.  For example, the Lower Rio Grande Valley includes protected areas home to a vast array of wildlife including endangered and threatened species with ranges not restricted to one country.  Indeed, the primary wildlife conservation strategy has been to link habitat patches that are isolated due to intense agriculture, urbanization, and security fencing, in order to create and maintain a more continuous wildlife corridor for the species that migrate and move among habitat areas. In south Texas alone, the federal government has spent over $80 million in taxpayer money to support piecemeal aggregation of the refuge which today exceeds 90,000 acres. These federal efforts to conserve the rich and diverse biology are imminently threatened by the proposed Border wall. And the eyes of the world are upon us.  The United States should cease construction of the Border Wall and commence a prioritization of animal migration corridors in light of climate change.  If we do not, we have no ability to speak out when others perpetuate the same mistake.

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