There is bad news from the oceans

Well, ‘Dead Men Tell No Tales’. Let’s talk about the living and what’s in store for them. Running now: A Tale of Intruding Waves.

Well, two studies, out in the past few days, flag some bad news for humans, indicating that the sea level is rising alarmingly across the globe and could jeopardise millions of lives in vulnerable regions.

First off, a research published in science journal Nature says coastal flooding will become more, and dangerously, common now thanks to sea-level rise. Next, a paper in the Proceedings of the National Academy of Sciences (PNAS) says that the rate of rising seas is itself increasing alarming.

In the Nature study, scientists have estimated that even small amounts of sea-level rise, at 5-10 cm, can double the frequency of what science calls extreme water level events. And, mind you, this is no distant dystopian scenario; it is likely to hit us as early as 2030. Analyses show that the sea level is rising at 3-4mm a year and the pace will go up due to ocean warming and ice melt on land — up to as much as between 0.3 to 2 metres by the end of this century.

Coastal flooding is an immediate fallout of this. Also in the package are more beach erosion, groundwater loss, changes in wave movements, and passive inundation of low-lying coastal areas due to high tide. Millions of people living in these regions will lose property and jobs and will have to migrate, which will pose bigger challenges to urbanisation. The UN estimates that 40 per cent of the world’s population lives within 100 km from a coast. And Asia has the highest coastal population. China, India, Bangladesh, Indonesia and Vietnam will be the most exposed.

You heard me. The analysis of water-level observations shows the tropical region of the world is more vulnerable. Countries such as India will see more floods and erratic rains. Some 20 big tropical cities face “a dire future” in the face of coastal flooding, according to the study. The list includes Mumbai and Kochi.

The PNAS analysis shows our oceans are rising nearly three times as rapidly as they were in most of the 20th century. This clearly shows that a much-feared trend of not just sea level rise, but its acceleration, is now under way, says Sönke Dangendorf, a researcher with the University of Siegen in Germany who led the study along with scientists at institutions in Spain, France, Norway and the Netherlands.

Granted, the paper isn’t the first to spot the trend, but it finds a bigger rate of increase than in past studies. The paper concludes that before 1990, oceans were rising at about 1.1 mm a year, or just 0.43 inches per decade. From 1993 through 2012, though, it finds that they rose at 3.1 mm a year, or 1.22 inches per decade.

The cause, according to Dangendorf, is that sea-level rise throughout much of the 20th century was driven by the melting of land-based glaciers and the expansion of seawater as it warms, but sea level rise in the 21st century has now, added in major contributions from the ice sheets of Greenland and Antarctica.

The study cobbled up a sea level record for the 20th century, tracking years where satellite records were absent. It came up with a relatively small rate of sea level rise from 1900 through 1990, followed by a much faster one afterward. And the results, obviously, tell us we need to act and we need to act now. It may not be apocalypse now, but it’s going to be here real soon.

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