The islands of Sicily were initially one landmass, according to a recent study published in the journal Science Advances — which shows how when sea levels rise, human populations typically adapt to changes rather than simply abandon them, as common sense might suggest.
Isles of Sicily once giant single landmass before sea-level rise divided it
The average sea level is rising roughly 0.14 inches/year (3.6 mm/year) — an unprecedented rate of rise for millennia, according to the study. But the distribution of this rise in terms of volume isn't the same worldwide. This means some regions will see a greater rise in sea-level than the average, which makes them especially vulnerable to the hazards of submersion.
The climate crisis combined with a continuing rise in sea level will mean the high-end outliers of worldwide flooding will be extreme — since some areas inevitably see worse weather than others.
Despite projected global and regional sea-level changes becoming more constrained, no one can fully predict how cultural and behavioral norms may shift. Future coastal flood risk to human populations — combined with projected migration patterns are typically based on environmental thresholds — ones lacking a defined limit of adaptation driven via culture and the perception of risk in human societies.
Climate crisis could drive technological advancement
During prehistoric sea-level rise, catastrophic flooding is associated with a rapid migration on a massive scale — but this commonsense perception of natural disaster and societal response is overly simplified, according to the authors of the study.
In modern society, the event of a catastrophic sea-level rise will be more complex, involving interactions between climate drivers, the subsequent changes in the local environment, and the way humans ultimately react. In the new study, the researchers focused on past changes and human responses that happened amid the submergence of populated coasts as the sea level rose.
In the last 11,700 years (also called the Holocene), cultural transitions typically spread through whole societies with substantial advances in technology. But these transitions are typically joined by (and are perhaps related to) climate and environmental shifts, including sea-level rise, notes the study.
Rising sea-levels pose numerous dangers to society
The rate of global sea-level rise amid the Early Holocene was equal to or greater than present-day rates — and superimpose onto the shift from Mesolithic hunter-gatherers to the farming-based lifestyle of the Neolithic era. This is because of the rapid disintegration of ice sheets across Scandinavia and North America.
The subsequent migration of coastal communities amid sea-level rise could have created a need for society to transition into a Neolithic standard throughout Europe. Additionally, rising sea levels could have provided new opportunities for humans to migrate throughout northwest Europe via expanding seaways.
However, rising sea levels are a double-edged blade. While benefits and motivation for technological advancement exist, numerous threats arise — including coastal erosion, habitat endangerment, land loss, flooding, and a loss of crucial resources — placing coastal society in danger.
Humans typically adapt rather than flee effects of rising sea level
Taken together, these threats make island communities especially vulnerable to the effects of the climate crisis — because of the scale of changes happening in an isolated location.
The scientists in the recent study combined pollen and charcoal data from 17 sediment cores using optically stimulated luminescence and radiocarbon — in addition to population dynamics gathered and inferred from regional archeology. As a whole, they showed how prehistoric populations in the area of Sicily (especially during the Bronze Age) adapted to — instead of abandoned — new island distributions amid a period of gradual sea-level rise and major shifts in culture.
So while we trade climate crisis memes about Brooklyn and San Francisco sinking into the sea with apocalyptic undertones — this latest study shows how despite the substantial chaos and danger of shifts in sea-level, human populations are more likely to adapt than simply flee a region — a scenario reconstructed in a brilliant work of speculative fiction called "New York 2140" by author Kim Stanley Robinson — wherein Manhattan has transformed into a Venice-like sci-fi metropolis, with impressive new vehicles and technology.