00:00Did you know that China's coastal cities are sinking and the sea levels are rising at record
00:05speeds? Well, a team of scientists led by Rutgers University has uncovered the truth.
00:10Sea levels today are climbing faster than at any time in the past 4,000 years.
00:15Their big finding? Well, China's coastal cities are at some of the highest risk in the world.
00:21And this is not just a headline scare, but it is backed by thousands of geological records.
00:26The researchers dug deep. They analysed ancient coral reefs. They studied mangrove formations.
00:33These natural time capsules hold evidence of how high the seas once reached. With that data,
00:39scientists reconstructed ocean changes going back almost 12,000 years.
00:44So how fast are the waters rising? Well, according to this study published in the journal Nature,
00:49global sea levels have gone up by around 1.5 milliliters each year since 1900.
00:54Now, that may sound small, but it is the fastest average rise in any century-long period over the
01:00last four millennia. It is a big leap for a system that's usually slow to change.
01:05Now, the lead researcher, Yucheng Lin, explains what is exactly behind this speed.
01:11Well, two major forces are at play. Thermal expansion and melting ice.
01:16When the planet heats up, the oceans absorb that heat and water expands.
01:19But that's not all. Melting glaciers and ice sheets, especially in Greenland and Antarctica,
01:25dump huge amounts of water into the oceans. More heat, more water, more risk for everyone
01:31on the coast. So for China, the threat is doubled. Many of its biggest cities, for example, Shanghai,
01:38Xinjiang and Hong Kong sit on soft sinking sediment. Deltas made of waterlogged land are naturally
01:45unstable. But human activity is making it even more worse. Extracting groundwater for daily use
01:52speeds up the sinking process. Subsidance, the slow sinking of the earth, happens from both natural
01:57and man-made causes. Now, in Shanghai, some areas dropped more than one meter in the last century.
02:04That's far faster than the pace of global sea level rise. And every centimeter higher the ocean goes,
02:10the risk of flooding spikes for these vital urban and industrial areas. Why does it matter outside China?
02:17Well, these delta regions aren't just local. They're also crucial part of the global supply chain.
02:23So whenever the manufacturing hubs face flooding, international commerce also feels the shock.
02:29So these regions are flat and fertile, perfect for development, but highly exposed to any change in water levels.
02:37So what is being done about this big problem? Well, the news is not all grim. Cities like Shanghai have
02:43slowed the subsidence by controlling groundwater extraction. They are re-injecting fresh water
02:49and stepping up regulations. Scientists have mapped the most vulnerable zones, giving city planners the
02:56tools they need to protect people and businesses. So this study reaches far beyond China. Other major cities
03:03like New York, Jakarta, Manila, all are built on similar low-lying land. They face the same threats.
03:10Experts remind us that while deltas are great for farming, fishing and building cities, they're also
03:17especially prone to sinking when human demand outpaces nature's balance. One more thing is that the
03:23Rutgers-led team used a smart technology too. Their software helps model environmental changes across
03:29millennia. That's vital for seeing the bigger picture. The study got support from the National Science
03:35Foundation and NASA, giving it global credibility. So the bottom line is this. Science tells us that China's
03:42coastal cities and many others worldwide must adapt fast. Sea level rise is no longer a distant future threat.
03:49It's happening now and for many, it's a matter of survival.
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