WASHINGTON — Centuries of land loss and forced relocation have left Native Americans significantly more exposed to the effects of climate change, new data show, adding to the debate over how to address climate change and racial inequity in the United States.
The findings, which took seven years to compile and were published Thursday in the journal Science, mark the first time that researchers have been able to quantify on a large scale what Native Americans have long believed to be true: That European settlers, and later the United States government, pushed Indigenous peoples onto marginal lands.
“Historic land dispossession is a huge factor contributing to extreme climate change vulnerability for tribes,” said Kyle Whyte, one of the study’s authors, who is a University of Michigan professor and a member of the Citizen Potawatomi Nation.
The new data comes as the United States suffers through increasingly severe heat waves, drought, wildfires and other disasters made worse by a warming planet. By demonstrating that government actions have made Native Americans more exposed to climate change, the authors argue, the data strengthens the case for trying to make up for that damage, however imperfectly.
“This is not just a story of the past harms,” said Justin Farrell, a Yale University professor and another of the study’s authors. “We have to think about ways to recompense for this history.”
To measure the effects of forced migration on climate exposure, the authors assembled a database showing the historical land bases and land loss of 380 individual tribes, based on data from tribal nations’ own records, land cession treaties and other federal archives. Most of the data spanned the period from the 1500s to the 1800s.
The authors then compared the amount of land tribes used to have with each tribe’s present-day reservations. In total, the amount of land shrank by 98.9 percent. In many cases, no comparison was possible: Of the 380 tribes they examined, 160 have no federally or state-recognized land base today.
But for the remaining 220 tribes, the authors found that their present-day lands, on average, are just 2.6 percent the size of their historical lands — an average reduction of 83,131 square miles.
In addition to occupying far less land, most tribes were pushed far from their historical lands. The average distance between historical and current lands was 239 kilometers (149 miles); one tribe, the Kickapoo, moved 1,366 kilometers (849 miles).
More days of extreme heat
Not only were tribes pushed onto smaller lands far from their original territory; those lands also have less hospitable climates.
The authors measured exposure to extreme heat by tabulating the average annual number of days above 100 degrees Fahrenheit between 1971 and 2000 across each tribe’s present-day lands, and then doing the same for historical lands.
They found that overall, present lands experience two additional days of extreme heat each year. But for some tribes, the difference is far greater.
The Mojave tribe, whose current land is along the Colorado River, experiences an average of 117 days above 100 degrees or 62 more than on its historical lands.
The Hopi reservation, in Northeast Arizona, recorded 57 days above 100 degrees on average, compared with just two days on their historical lands, which included higher ground. The Chemehuevi, along the California and Arizona border, experienced an average of 84 days of extreme heat each year, 29 days more than on their historical lands, which likewise included higher ground.
More extreme heat means higher electricity costs, according to Brian McDonald, secretary treasurer for the Chemehuevi Indian Tribe. He said those higher costs are especially challenging because many residents have low incomes.
Extreme heat increases the incentives for tribal members to leave their reservation and relocate to cities, where there’s more access to air-conditioned spaces and more transportation options to get to those places, according to Nikki Cooley, co-manager of the Tribes & Climate Change Program at Northern Arizona University.
“In the past, we used to go to the high country, where we had our summer camps. That’s where we would cool off,” said Ms. Cooley, who is a citizen of the Diné (Navajo) Nation. “We don’t have that, because all of the high-elevation communities are off the reservation.”
‘You’re disconnecting their umbilical cord’
As heat pushes tribal members away from their communities, the result is the further erosion of Indigenous culture and language, Ms. Cooley said.
“You’re disconnecting their umbilical cord — their tie to the land, and to the elders, who most likely will not be moving with them to these urban locations,” she said.
The authors looked at the difference in other types of climate vulnerability. They found that another change was rainfall: Across all 220 tribes, average annual precipitation was almost one-quarter lower on current-day lands than on historical ones.
Among the tribes who receive less rainfall is the Pueblo of Laguna, whose current lands are west of Albuquerque. According to the new data, the average annual precipitation on the tribe’s current land is about half of what its historical lands receive.
The tribe’s members include Deb Haaland, whom President Biden appointed as the first Native American to lead the Interior Department, which has responsibility for tribal lands.
Secretary Haaland’s office declined a request for an interview about the steps her agency has taken to make tribal nations more resilient against the effects of climate change.
Representative Teresa Leger Fernández, a Democrat from New Mexico and chair of the House Subcommittee for Indigenous Peoples of the United States, praised the infrastructure bill that Mr. Biden has pushed, which includes $216 million for climate resilience and adaptation for tribal nations.
More than half of that money, $130 million, would go toward “community relocation” — helping Indigenous Americans leave dangerous areas.
“That is not enough. But it is more than we have ever received,” Ms. Leger Fernandez said in an interview. She said the government should pursue other options, including helping to transfer more land back to tribal nations that previously occupied that land — including land now held by the federal government, or using federal money to purchase private land from willing sellers.
“Be aware, and be educated, about the hard history of our nation,” Ms. Leger Fernandez said. “I think all of those options are on the table.”
Paul Berne Burow, another of the paper’s authors and a doctoral student at Yale, said giving land back should be seen as a form of reparation, and also a way to make tribal nations more resilient to a changing climate.
“There are really meaningful, deep connections that people have to place,” Mr. Burow said. “Returning dispossessed lands is one of the best things that can be done to begin to address these inequalities.”