What happens if sea levels rise 1 meter
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Impacts of a 1-Meter Sea-Level Rise
Coastal Groundwater Hazards and Infrastructure Risks
A 1-meter rise in sea levels will significantly impact coastal groundwater systems, particularly in regions like California. This rise will elevate coastal water tables, leading to groundwater hazards that threaten infrastructure and ecosystem resilience. In California, areas flooded from below are predicted to expand 50-130 meters inland, with low-lying communities such as those around San Francisco Bay being most at risk. The extent of flooding is highly dependent on coastal topography and drainage capacity, with long-term rising water tables intercepting low-elevation drainage features, thereby limiting the extent of shoaling in approximately 70% of California’s coastal water tables.
Threats to Coastal Wetlands
Coastal wetlands are particularly vulnerable to a 1-meter sea-level rise. It is estimated that around 64% of freshwater marshes, 66% of coastal wetlands from the Global Lakes and Wetlands Database, and 61% of brackish/saline wetlands are at risk of submersion. This loss will be most pronounced in regions like East Asia and the Pacific, and the Middle East and North Africa, with countries such as China, Vietnam, Libya, and Egypt bearing the brunt of these impacts. The economic value of the goods and services produced by these at-risk wetlands is estimated to be approximately $630 million per year.
Population and Housing Vulnerability
A 1-meter rise in sea levels will also pose significant risks to populations and housing in low-lying coastal areas. In the contiguous United States, it is estimated that 3.7 million people live on land within 1 meter of high tide. States like Florida, Louisiana, California, New York, and New Jersey have the largest populations living below this line. Over 10% of the population in 544 municipalities and 38 counties live below this threshold, indicating widespread vulnerability across various communities.
Economic and Environmental Costs
The economic and environmental costs of a 1-meter sea-level rise are substantial. In the United States, thousands of square miles of land could be lost, particularly in low-lying areas such as the Mississippi Delta. Storm damage, already estimated at over $3 billion per year nationwide, could increase, especially along the well-developed and low-lying Atlantic coast. Additionally, rising sea levels will increase the salinity of marshes, estuaries, and aquifers, disrupting marine life and potentially threatening drinking water supplies.
Global Population Exposure
Globally, the number of people living on land below projected high tide lines for 2100 is expected to increase significantly. Currently, 190 million people occupy such land, and this number could rise to 630 million under high emissions scenarios. Accurate estimates of global mean sea-level rise are crucial, as new digital elevation models suggest that previous estimates have significantly underestimated the number of people at risk.
Conclusion
A 1-meter rise in sea levels will have profound impacts on coastal regions worldwide, affecting groundwater systems, wetlands, populations, and economies. The extent of these impacts will vary based on local topography, drainage capacity, and regional vulnerabilities. Proactive measures and strategic planning are essential to mitigate these risks and adapt to the changing coastal landscape.
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