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Honorable Joseph R. Biden, Jr.
President of the United States
The White House
1600 Pennsylvania Avenue, NW, 1st Floor, West Wing
Washington, DC 20500

Secretary Alejandro Mayorkas 
US Department of Homeland Security 
3801 Nebraska Avenue NW 
Washington, DC 20016

Dear President Biden and Secretary Mayorkas,

Climate change should prompt the Department of Homeland Security (DHS) to revise its policies relating to human mobility in many respects, including by urgently addressing the responsibility of the United States to those who move in the context of adverse climate change impacts. The undersigned 68 human, civil, immigration, and environmental rights organizations, write to urge DHS to plan for extreme heat as a crucial element of this administration’s approach to climate change and the border.

In particular, this summer’s historic incidences of extreme heat further underscore the cruelty of the ‘prevention through deterrence’ paradigm and increase the urgency of adopting a climate-informed approach to policies affecting border communities, migrants, and asylum seekers. DHS should plan now for continued extreme heat events by ending reliance on the deterrence paradigm and transforming border operations to prioritize life-saving humanitarian actions.

The Harms of “Prevention through Deterrence”

In late August, US Customs and Border Protection (CBP) agents found a two-year old boy alive next to his mother and 10-year-old sister’s dead bodies in the desert west of Yuma, AZ. The Yuma County medical examiner determined the deaths were heat-related. The high on the day the bodies were recovered was 119 degrees.[1]

Our organizations and many others have long noted the harms of the United States’ “prevention-through-deterrence” enforcement strategy, which includes policies that limit the entry of asylum seekers and migrants at ports of entry and concentrate enforcement in populated areas to force border-crossers into “hostile terrain.”[2] As former Immigration and Naturalization Service Commissioner Doris Meissner told Congress in 2013, deterrence has forced migrants “across increasingly difficult terrain and dangerous, historically isolated desert areas, especially in Arizona.”[3]

Migrants encounter multiple life-threatening dangers in the rough terrain of the border region. Extreme heat is among the most deadly. One study based on coroners’ reports of migrant deaths estimated that deaths due to environmental heat exposure represent approximately 73 percent of deaths of migrants crossing between ports of entry, followed by vehicle crashes (eight percent) and drownings (six percent).[4]

According to the government’s own data, 7,505 people died crossing the US-Mexico border in the 20-year period between 1998 and 2018, but there are indications that the true number is far higher.[5] In the past year, the death toll as measured by the number of human remains recovered, has been on the rise. In Arizona, the nonprofit Humane Borders and the Pima County Medical Examiner’s office found the remains of 43 migrants in June and the remains of a total of 127 people during the first half of 2021, an increase over the same period in 2020.[6] The Brooks County Sheriff’s Department in Texas reported 50 migrant deaths in the first six months of 2021, more than in all of last year.[7] In the Big Bend area of Texas, 32 migrants had perished by July of this year, more than four times than the previous year.[8] And in the eastern California deserts, Border Patrol reported a 185 percent increase in the number of rescues it performed this year over last and that 31 border crossers have lost their lives in the area since October 2020.[9]

The people impacted by border policies that force people to cross through rough terrain are not only new arrivals, but also people who have been deported from the United States without proper consideration of their deep ties to home and family, and who are seeking to reunite with family. Homero Roman has been missing since 2015 after crossing the border from Mexico into the harsh terrain of Brooks County, Texas, to reunite with his family.[10] Homero’s parents had brought him to the US as a child, and he grew up in Texas. After a traffic stop, US authorities deported him to Mexico, a country he had not lived in or visited for more than two decades. Homero is just one of hundreds of people who disappeared into the expansive brush of Brooks County over the past decade, pushed into harsh terrain while seeking to avoid an interior CBP checkpoint.[11]

These policies prompted the American Public Health Association to characterize deaths on the border as a “public health crisis,” calling instead for humane immigration policies that “target the social and economic underpinnings of migration.”[12]  

Border Patrol “rescue” operations are a flawed and insufficient response to threats to life posed by these policies, which are exacerbated if agents destroy life-saving water and food supplies.[13] Based on a statistical, spatial analysis of 415 acts of destruction or damage to humanitarian water drop sites, the organization No More Deaths concluded that the Border Patrol was likely consistently responsible for destroying life-saving water caches in Arizona borderlands.[14] The organization also cites anecdotal evidence of US Border Patrol agents destroying and confiscating humanitarian supplies, including multiple eyewitness accounts of agents pouring out or destroying water supplies and four separate occasions when this destruction was caught on video.

In addition, current US law and policies permit criminal prosecution of the provision of humanitarian aid to migrants and asylum seekers at the border.[15] In just one example, Dr. Scott Warren was prosecuted in 2018 for alleged crimes of harboring and conspiracy to transport two migrants, simply for providing them with water, food, and medical assistance in the desert town of Ajo, Arizona, where he lives. Although Dr. Warren was ultimately exonerated, the Biden administration has not formally adopted a policy of applying a humanitarian exemption from criminal prosecution related to smuggling and harboring charges.

Enforcement operations at the border that include outdoor detention may also raise increased risks in the context of extreme heat. The ACLU has recently raised concerns that families with small children are being held for several days outdoors at the Border Patrol’s “Temporary Outdoor Processing Site” (TOPS) under the Anzalduas Bridge in South Texas, with temperatures in the 90s and no basic temperature controls.[16]

The Growing Impacts of Extreme Heat

This year, as deaths appear to be on the rise, areas along the US-Mexico border have already experienced record-high temperatures.[17] With moderate action to reduce greenhouse gas emissions, by midcentury the 23 US counties along the Mexico border could see an annual average of 60 days with a heat index above 100°F in just a few decades, up from an average of 28 days 1971 to 2000.[18]

The Southwest is one of the fastest warming regions of the country,[19] and heat waves have gotten longer, more intense, and more frequent in the region and nationwide.[20] With increases in daily high temperatures also come increases in record-breaking night-time lows, which compound health impacts by making it more difficult for the human body to recover from exposure to extreme heat.[21]

Extreme heat poses a range of health threats, from minor illnesses such as heat cramps to potentially lethal conditions such as heat stroke or heat-related heart attacks and kidney disease.[22] Increases in heat are linked to increased deaths even at temperatures below heat emergency thresholds, and heat can worsen illnesses, for example cardiovascular and respiratory conditions.[23] Older people, pregnant people, people with disabilities, and children are especially “at-risk” groups for heat illness.[24] High heat exposure during pregnancy is a risk factor for stillbirth and preterm birth.[25] Even with life-saving medical treatment, severe heat-related illnesses can cause long-term organ damage and disability.[26] High humidity further compounds the health-harming effects of heat, but in areas with low humidity, such as along some parts of the US-Mexico border, even short exposures to temperatures above 104°F (40°C) can cause extreme heat stress.[27] Because of the existing concentration of climate-warming pollution in the atmosphere, these threats are expected to grow even if the world ambitiously and urgently acts to limit further emissions.[28]

Inadequate responses to extreme heat also affect border communities, including those who cross the southern border for work, school, and family visits. A lack of appropriate conditions at ports of entry endangers all people, and especially vulnerable individuals such as older adults, pregnant people, people with disabilities, and children. Responses to extreme heat in the border region, including access to cooling shelters and water, should be nondiscriminatory and accessible regardless of migration status.

Preparing for migration in a changing climate means moving away from the deterrence paradigm and problematic “Do Not Come” messaging, which ignores the lived realities of people fleeing for their lives and their right to seek safety.[29] Instead, the US strategy to address migration in the context of climate change should be rooted in human rights and humanitarian protection. Considering the likelihood of increasing extreme temperatures at the border, humane and rights-respecting migration and border policies, the Department of Homeland Security should:

In general:

  • End the use of the “prevention through deterrence” strategy of border enforcement, which puts border crossers in jeopardy and will only get worse with heat.
  • Ensure CBP adopts longer-term climate adaptation planning and implementation, including a heat action plan focusing on at-risk populations.
  • Develop and implement an enforcement guideline memo that instructs CBP agents not to refer for prosecution persons who provide humanitarian assistance and other voluntary support to migrants in need.
  • Halt any intimidation, harassment, or stigmatization and criminal prosecution of humanitarian aid volunteers who are providing life-saving assistance to people in need.
  • Create an independent, non-enforcement-related border region rescue team with staff available 24 hours each day in every border sector to coordinate, manage, and perform rescues.
  • Implement guidelines for identification and repatriation of deceased migrants in the borderlands.

At ports of entry:

  • Cease putting migrants at risk in hazardous crossings by ensuring that ports of entry are capacitated to offer full access to asylum at ports of entry, starting with an immediate rescission of the Title 42 expulsion order in its entirety.
  • Build sufficient processing capacity at ports to reduce or eliminate waitlists or similar obstacles that push asylum seekers into dangerous conditions in migrant camps on the Mexican side of the border or to enter via alternate, more dangerous routes.
  • Train all CBP personnel who interact with border crossers and border communities on how to identify, address and triage the symptoms of heat-related illnesses.[30] The National Integrated Heat Health Information System[31] and Global Heat Health Information Network[32] would be valuable sources of guidance to CBP.
  • Designate special crossing lanes for pregnant people, older people, people with disabilities, children, or others with an increased risk of heat-related illness during extraordinary wait times at ports of entry. Ensure adequate shade, water, and benches for all.
  • Establish water cooling stations at ports of entry and implement emergency first aid plans for people entering a port of entry and experiencing a heat-related emergency.

Between ports of entry:

  • Establish additional water and cooling stations between ports of entry.
  • Support borderlands emergency response systems of adequate scope that are separate from immigration enforcement.
  • Develop emergency first aid plans for migrants crossing between ports of entry experiencing heat emergencies and ensure border agents are trained in emergency medical response.
  • Hold accountable US agents who destroy water stores or humanitarian supplies.

Implementing these recommendations would help prevent unnecessary loss of life in the borderlands. More importantly, by creating a more welcoming, better managed border and doing away with “prevention through deterrence” tactics, DHS can encourage a greater proportion of border crossers to come to ports of entry to apply for immigration relief and discourage people from putting their lives at risk when seeking safety or wanting to reunite with their family members in the United States. We thank you for your attention to these urgent issues and welcome further engagement. Please don’t hesitate to reach out to Clara Long at Human Rights Watch ( and Juanita Constible at the Natural Resources Defense Council (


ACLU of San Diego & Imperial Counties

Al Otro Lado

Alianza Americas

Alianza Nacional de Campesinas

Alliance of Nurses for Healthy Environments

Alliance San Diego

American Friends Service Committee

Amnesty International USA

Arizona Justice For Our Neighbors

Asian Pacific American Labor Alliance - AFLCIO (San Diego Chapter)

Association of Farmworker Opportunity Programs

Bellevue Program for Survivors of Torture


Borderlands for Equity

Casa Familiar

Catholic Legal Immigration Network, Inc.

Center for Biological Diversity

Center for Gender & Refugee Studies

Center for Justice & Reconciliation at Point Loma Nazarene University

Church World Service

Climate Refugees

Coalición de Derechos Humanos

CRLA Foundation

Disciples Refugee & Immigration Ministries

Earth Action, Inc

Employee Rights Center

Episcopal Farmworker Ministry

Espacio Migrante

Fellowship Southwest

Florence Immigrant & Refugee Rights Project

Food Empowerment Project

Frontera de Cristo

Haitian Bridge Alliance

Hispanic Federation

Hope Border Institute

Indivisible San Diego Persist

Karen Organization of San Diego

Kino Border Initiative

Latin America Working Group (LAWG)

Medical Society Consortium on Climate and Health

* Not all members endorsed this letter

Medical Students for a Sustainable Future

Migrant Clinicians Network

Mississippi Center for Justice

Multicultural Efforts to end Sexual Assault (MESA)

National Environmental Health Association

National Environmental Health Association

National Immigrant Justice Center

Natural Resources Defense Council

No More Deaths / No Más Muertes

Oxfam America

Philadelphia Area Project on Occupational Safety and Health

Physicians for Human Rights

Physicians for Social Responsibility AZ Chapter

Progressive Democrats of America, Tucson, AZ Chapter

Project Lifeline

Rocky Mountain Immigrant Advocacy Network

San Diego Immigrant Rights Consortium

Southbay People Power

Southern Border Communities Coalition

Student Action with Farmworkers

The Sidewalk School

Union of Concerned Scientists

Unitarian Universalist Refugee and Immigrant Services and Education


Universidad Popular

Washington Office on Latin America

Witness at the Border

Women's Refugee Commission






[1] L. Gomez, “2-Year-old Boy Found Alive Next to his Migrant Mother’s Dead Body near Yuma,” Tucson Sentinel, September 2, 2021, (accessed September 14, 2021).  

[2] Amnesty International, In Hostile Terrain: Human Rights Violations in Immigration Enforcement in the US Southwest (2012), (accessed September 14, 2021).

[3] D. Meissner, “Border Security: Measuring the Progress and Addressing the Challenges,” Testimony before the Committee on Homeland Security and Governmental Affairs, US Senate, March 14, 2013, (accessed September 14, 2021).

[4] S. Sapkota et al., “Unauthorized Border Crossings and Migrant Deaths: Arizona, New Mexico, and El Paso, Texas, 2002–2003,” American Journal of Public Health 96, 7 (2006): 1284, (accessed September 14, 2021).

[5] US Border Patrol, Southwest Border Deaths by Fiscal Year (March 2019), (accessed September 14, 2021).

[6] S. Betancourt, “Forty-three bodies found in Arizona borderland amid brutal heat,” Guardian, July 12, 2021, (accessed September 14, 2021).

[7] “Growing Number of Migrants Dying After Crossing U.S.-Mexico Border, Report Says,” KENS5, July 15, 2021, (accessed September 14, 2021); M. Gibson, “There's an increase in immigrant bodies found in Brooks County,” KIII-TV, June 4, 2021, (accessed September 14, 2021).

[8] J. Resendiz, “Border Patrol deploys rescue beacons in wake of 32 migrant deaths in Big Bend region of Texas,” Border Report, July 24, 2021, (accessed September 14, 2021).

[9] S. Rivera, “Border Patrol reports 31 migrant deaths so far this year in California wilderness,” Border Report, July 23, 2021, (accessed September 14, 2021).

[10] C. Cardenas, “Every Year, Hundreds of Migrants Die or Go Missing in Brooks County. A New Documentary Tells Two Families’ Stories,” Texas Monthly, November 6, 2020, (accessed September 14, 2021).

[11] N. Miroff, “Huge border influx brings fears of grim summer for migrant deaths,” Washington Post, June 3, 2021, (accessed September 14, 2021); Sarah Betancourt, “Forty-three bodies found in Arizona borderland amid brutal heat,” Guardian, July 12, 2021, (accessed September 14, 2021).

[12] American Public Health Association, “Border Crossing Deaths: A Public Health Crisis Along the US–Mexico Border,” November 10, 2009, (accessed September 14, 2021); see also Kathryn Hampton, MSt, “Zero Protection: How U.S. Border Enforcement Harms Migrant Safety and Health,” Physicians for Human Rights, January 10, 2019, (accessed September 14, 2021).

[13] Abuse Documentation Working Group, “Left to Die: Border Patrol, Search and Rescue, and the Crisis of Disappearance,” part 3 in Disappeared: How the U.S. Border Enforcement Agencies are Fueling a Missing Persons Crisis (La Coalición de Derechos Humanos and No More Deaths, 2016), (accessed September 14, 2021); Samuel M. Keimet et al., “Wilderness Rescue and Border Enforcement Along the Arizona Mexico Border – The Border Patrol Search, Trauma and Rescue Unit,” Wilderness and Environmental Medicine, 20, 1 (2009): 39-41, (accessed September 14, 2021).

[14] Abuse Documentation Working Group, “No More Deaths, Interference with Humanitarian Aid: Death and Disappearance,” part 2 in Disappeared: How the U.S. Border Enforcement Agencies are Fueling a Missing Persons Crisis (La Coalición de Derechos Humanos and No More Deaths, 2016), (accessed September 14, 2021).

[15] Amnesty International, ‘Saving Lives is Not a Crime’: Politically Motivated Legal Harassment of Migrant Human Rights Defenders by the USA (2019), (accessed September 14, 2021).

[16] S. Drake and K. Huddleston, “Border Patrol Must Stop Holding People in an Inhumane Outdoor Pen Under a Highway in South Texas,” American Civil Liberties Union, August 9, 2021, (accessed September 14, 2021).

[17] A. Marksz, “Migrant deaths in the desert at record levels as heat wave pounds West,” KOLD News 13, July 15, 2021, (accessed September 14, 2021).

[18] Calculated using the ‘Historical’ and ‘Slow Action’ (RCP 4.5) columns in Union of Concerned Scientists Killer Heat Data (2019), (accessed September 14, 2021).

[19] US Environmental Protection Agency, “Climate Change Indicators: U.S. and Global Temperature,” updated July 21, 2021, (accessed September 14, 2021).

[20] S. E. Perkins-Kirkpatrick and S. C. Lewis, “Increasing Trends in Regional Heatwaves,” Nature Communications 11, no. 1 (December 2020): 3357, (accessed September 14, 2021).

[21] K. Pierre-Louis et al., “Nights Are Warming Faster Than Days. Here’s Why That’s Dangerous.” New York Times, July 11, 2018, (accessed September 14, 2021).

[22] M. C. Sarofim et al., “Temperature-Related Death and Illness. The Impacts of Climate Change on Human Health in the United States: A Scientific Assessment,” in The Impacts of Climate Change on Human Health in the United States: A Scientific Assessment (U.S. Global Change Research Program, 2016), (accessed September 14, 2021).

[23] “Chapter 14: Human Health” in Fourth National Climate Assessment, US Global Change Research Program, 2018, (accessed September 14, 2021).

[24] Environmental Protection Agency and Centers for Disease Control, “Climate Change and Extreme Heat: What You Can Do to Prepare,” October 2016, (accessed September 14, 2021); S. Harrington, “How Extreme Weather Threatens People with Disabilities,” Scientific American, September 18, 2019, (accessed September 14, 2021).

[25] M. Chersich et al., “Associations between high temperatures in pregnancy and risk of preterm birth, low birth weight, and stillbirths: systematic review and meta-analysis,” BMJ 371 (2020), (accessed September 14, 2021); Bruce Bekkar, MD, Susan Pacheco, MD; R. Basu, PhD, et al., “Association of Air Pollution and Heat Exposure With Preterm Birth, Low Birth Weight, and Stillbirth in the USA Systematic Review” Journal of the American Medical Association Network Open 3, no. 6 (2020), doi:10.1001/jamanetworkopen.2020.8243 (accessed September 14, 2021); Human Rights Watch, “Climate Crisis A Rising Threat to Maternal Health in the US,” May 6, 2021, (accessed September 14, 2021).

[26] Mayo Clinic, “Heatstroke,” (accessed September 14, 2021).

[27] S. Asseng et al., “The Upper Temperature Thresholds of Life,” The Lancet Planetary Health 5, no. 6 (June 2021): e378–85, (accessed September 14, 2021).

[28] R. A. Myles et al., “Global Warming of 1.5 Degrees C: Summary for Policymakers” (Intergovernmental Panel on Climate Change, 2018), (accessed September 14, 2021); “America in 2090: The Impact of Extreme Heat, in Maps,” New York Times, July 21, 2021, (accessed September 14, 2021); K. L. Ebi et al., “Burning Embers: Synthesis of the Health Risks of Climate Change,” Environmental Research Letters, March 1, 2021, (accessed September 14, 2021).

[29] Human Rights Watch, “Biden Tells Central American Asylum Seekers to Stay Home,” July 23, 2021, (accessed September 14, 2021); P. Alvarez, “US is running more than 30,000 radio ads a month to deter migration from Central America,” CNN, July 15, 2021, (accessed September 14, 2021).

[30] Occupational Safety and Health Administration, “Prevent Heat Illness at Work,” 2021, (accessed September 14, 2021).

[31] National Integrated Heat Health Information System, (accessed September 14, 2021).

[32] Global Heat Health Information Network, (accessed September 14, 2021).

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