(CN) — Communities in the Caribbean and on islands off the coast of West Africa must adopt the nomadic, less stationary modes of living their ancestors embraced if they are to survive dangers that come with rising sea levels, according to a study released Monday.
The islands examined in the study have varying degrees of elevation, but those with lower elevation levels face more urgent threats since even a small increase in sea levels could bring catastrophic floods.
To protect communities from damage caused by sea-level rise, islands must embrace indigenous understandings about climate change and ancient methods for adapting lifestyles to ever-changing environments, according to Kristina Douglass, assistant professor of anthropology at Penn State.
"I'm working in a place – Madagascar – where communities around me are sensing, in the span of a few years, that they are seeing climate change," Douglass said in a statement. "They have seen climate events take out entire reefs."
Douglass and other researchers combed through archaeological records of communities in the Caribbean and the islands in the southwestern Indian Ocean off the east coast of Africa from Kenya to Mozambique.
Researchers found that contemporary agricultural practices and the legacy of colonization led to community planning that increased vulnerability to climate change over time, according to the study published Monday in Proceedings of the National Academy of Sciences.
"If we look back, we see that all the communities have been displaced into marginal land," said Douglass. "If they don't see this, they won't be able to find a solution. They have to consider that around the Caribbean and off of Africa there are historical factors that contribute to the problem."
The southwestern Indian Ocean islands, or SWIO, were settled only 2,000 years ago by continental Africans while indigenous Native American groups arrived in the Caribbean islands nearly 6,000 years ago.
In the last millennium, rampant colonization devastated communities and natural environments in both sets of islands, propping up economies built using mass enslavement and marginalization of indigenous groups.
Diseases introduced to Caribbean communities decimated native people and largely replaced them with colonists and enslaved Africans.
Colonization also shifted modes of living on the islands from nomadic to stationary, with colonists pushing visions of more sedentary lifestyles rooted near fields, pastures and fishing areas, the study said.
In the past, when sea levels rose, Caribbean communities that noticed coastal water sources becoming salty would leave the coast and move inland to higher ground, researchers said.
During storm surges, communities survived because they recognized risks and vacated the flood zones, researchers said.
"For some islands, archaeological and paleoecological research offer an important record of pre-colonial climate change and its interplay with human lives and landscapes," the study says. "The archaeological record suggests strategies and mechanisms that can inform discussions of resilience in the face of climate change."
In the tropical SWIO islands, rainfall levels vary depending on ocean temperatures and the El Niño/Southern Oscillation.
In southern Madagascar, the legacy of colonization – coupled with unstable rain patterns – has made communities vulnerable to food insecurity, researchers said. In 2016, a significant dip in rainfall caused widespread famine due to crop failures.
"Being nomadic is a way to deal with highly unreliable climate," said Douglass. "But encouraging sedentary lifestyles made it easier to manage local people."
In past times, indigenous communities used the prickly pear cactus – native to the Americas – as a defensive tool against intruders but also as a water source for cattle, people and surrounding wildlife, the study said.
In Madagascar, the Malagasy pastoralists adapted the non-native plant for communities’ defenses against various climate events. But the plant populations and their water reservoirs were decimated in the 1930s by French colonists who released parasitic cochineal larvae that destroyed the cactus barriers built by islands’ original inhabitants.
During ensuing droughts, famine spread across the islands after colonists forced people to build irrigation systems to cultivate cash crops and improve grasslands, researchers said.
But Douglass said the modernization of communities came not only from colonists but from islanders as well.
"There is a globalizing influence shaping people to the ideal of what seems to be modern," said Douglass.
Threats to the environment that come with pollution, consumption and waste are increasing as inhabitants chide traditional practices, for example by choosing disposable diapers over cloth ones even as space for landfills becomes scarce, Douglass said.
Tourism, a vital player in islands’ economies, has also increased pressures around land use, waste management and environmental degradation, the study said. Housing construction on the islands, and the impact it has on environments, was also examined in the study.
While traditional housing was relatively inexpensive to build – and had less of an impact on the environment – some islanders have opted to construct more expensive, modern housing models that require more labor and certain resources that are unsustainable.
"The desire to be modern, the elite status connected to things from overseas is real," said Douglass. "We need ways to shape views on what is a good house."
Researchers said preserving indigenous practices, native languages and islander communities is vital to ensuring ancient methods are applied to contemporary life.
Jago Cooper, curator of the Americas, British Museum co-wrote the study.
Researchers did not immediately respond to a request for comment.
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