Editorial | Take heed to rising sea levels

The risk of rising seas gobbling up more of Jamaica may be closer than previously thought, which should further concentrate the minds of policymakers who deal with these problems.

A study by Wageningen University in the Netherlands, recently published in scientific magazine Nature, concluded that more than 99 per cent of previous analyses used incomplete or inaccurate methods when assessing sea-level risks. They estimate that the planet has already locked into about six inches of global sea level rise by 2050, higher than hitherto assumed.

The study suggests that it’s a far more frequent problem in the Global South, the Pacific and Southeast Asia, and less so in Europe and along Atlantic coasts.

The findings suggest that, if sea level rises by about three feet, it would put 37 per cent more land under water than currently assumed, affecting up to 132 million people across the world.

In others, including coastal zones in Southeast Asia, the discrepancy can be as much as a metre-and-a-half, the researchers say.

GOT NUMBERS WRONG

The researchers at Wageningen say previous studies got the numbers wrong because, rather than using coastal data, they relied on a decade-old simplified “geoid model”, which shows average sea level based on gravity and the Earth’s rotation, not accounting for factors like tides, current and water temperature.

“If you want to know the elevation of your land relative to sea level, you have to convert the different data sets to a common reference frame first. Then you can correctly determine the relative height between the two,” Philip Minderhoud, the senior author of the research and an associate professor at Wageningen University & Research, in the Netherlands, said.

Based on the findings, tens of millions of people are in danger of being flooded out, forcing countries to think about, and spending more on, coastal defences. Indeed, Jamaica has a good sense, and recent evidence of what higher sea levels, when compounded by extreme weather events, could mean.

Last October, when Category 5 Hurricane Melissa, with 185 mph sustained winds pounded the island, its estimated seven to 11 feet-high storm surges devastated coastal communities in the west of the island, leaving billions of dollars in damage to homes and infrastructure and crippled economic activity.

If nothing else, what the report by Professor Minderhoud and his colleagues calls for is an urgent re-evaluation of existing coastal impact assessments and the implications for climate finance and coastal adaptation.

POSE A THREAT

Already, the National Environment and Planning Agency (NEPA) estimates that, over the past 60 years, several places along the Jamaican coast have lost 100 metres or more of beach. Further, and faster than anticipated, rises in sea levels pose a threat to the coastal ecosystems, including mangroves, wetlands and low-lying forests. Further, saltwater infiltration will intensify as storm surges to penetrate further inland.

While it should be happening anyway, the Wageningen study is a call for strengthening conservation policy; investment in ecological monitoring; restoration of degraded coastal habitats; and stronger enforcement of environmental protections. Indeed, coastal development must be balanced with environmental safeguards to ensure that natural buffers are not removed in pursuit of short-term gains.

It is also a warning that climate risks may be advancing faster than expected. When sea-level measurements reveal that the baseline itself has been underestimated, it suggests that the margin for delay has narrowed.

“Now that we have discovered this blind spot, the scientific community can make more accurate assessments for coastal areas and cities around the world. This will help, for example, to determine which areas are most vulnerable to future sea level rise, and where coastal adaptation strategies are most urgently needed,” the report said.

Jamaican policymakers should take heed.