The Oceans Are Warming, Expanding, and Becoming Dangerously Acidic

נשלח 11 באוק׳ 2014, 8:02 על ידי Sustainability Org   [ עודכן 11 באוק׳ 2014, 8:02 ]
Brian Merchant, 10/10/2014

We already know that climate change is warmingacidifying, and expanding the oceans. We just didn't know how fast, or how drastically. We still don't, exactly, but we know this: Things are looking as grim below the ever-rising waves as they are above.

This week brought an onslaught of bad news for the planet's oceans—no fewer than four major scientific studies and reports were released detailing the deleterious effect humanity's relentless carbon habit is having on the marine world. 

Every time I sat down to write about one of them, it seemed, another one was already making headlines (in the tiny, 'green' corner of the internet where people read about things like the impending collapse of vast ecosystems, anyway). So our oceans haven't exactly turned into hot acid baths—but they're a lot closer to that than they used to be.

Warmer

First, the heat:  Two landmark studies revealed that the oceans are warming up to twice as fast as we previously thought—which is a big deal, because oceans absorb some 90 percent of the heat generated by human activity. The 'missing' warming comes from the world's southern oceans, which had never received a proper comprehensive survey—shipping vessels had already collected plenty of data in northern oceans. 

To fill the void, scientists floated hundreds of ocean-faring drones called Argos, which bob and dive beneath the surface to take measurements, around the globe. Their measurements indicate that in total, the globe's oceans are sucking down 24 to 58 percent more energy than was previously on the books. 

As the authors of the Nature Climate Change study note, their findings "have important implications for sea level, the planetary energy budget and climate sensitivity assessments." (The second study, published in the same journal, found that the warming was primarily confined to shallow waters, and that deep sea temperatures seemed largely stable.)

So oceans—the shallower parts, anyway—will not only be warmer, which will impact marine life in unknown ways, but climate change as a whole is likely happening faster than was suspected before. It also means we can probably expect sea levels to rise more rapidly, as water expands as it warms.



Higher

Meanwhile, another report found that those higher sea levels will bring severe impacts—like more frequent floods—to coastal cities. High tides will be even higher, after all, and increasingly they will be so high that they will flood entire neighborhoods. The study, "Encroaching Tides," compiled by the Union of Concerned Scientists, assessed the likely impact of tidal flooding on cities effected by rising sea levels. 

"By 2045, many coastal communities are expected to see roughly one foot of sea level rise," it concluded. "The resulting increases in tidal flooding will be substantial and nearly universal in the 52 communities analyzed."

Researchers with the UCS told Climate Central that tidal flooding was likely to become "the new normal," and stood to ruin infrastructure, threaten homes, and disrupt transit lines.

Never turn your back on the ocean

The cities that UCS examined were all in the US, but similar effects can be expected worldwide. Sometimes, as in low-lying coastal nations like Bangladesh, where citizens have far fewer resources than Americans to cope, they will be much worse. 

"A growing proportion of these floods would be extensive, and as floods reach farther into communities, they would also last longer," the authors continued. "Flood-prone areas in five of the mid-Atlantic communities studied could be inundated more than 10 percent of the time."

Coastal dwellers, many of whom live where they do because they enjoy or need the bounty and beauty of the ocean, are going to be seeing a lot more of it than they might like.

More Acidic

I've saved the most disturbing oceanic detriment for last: a major review of hundreds of studies has confirmed that the ocean's acidity has increased 26 percent since pre-industrial times. 

The Convention on Biological Diversity, which met this week in South Korea, concluded as much in an extensive 102-page report detailing the latest findings on ocean acidification.

"In the past 200 years, it is estimated that the ocean has absorbed more than a quarter of the carbon dioxide released by human activity, increasing ocean acidity by a similar proportion," the authors wrote. "It is now nearly inevitable that within 50 to 100 years, continued anthropogenic carbon dioxide emissions will further increase ocean acidity to levels that will have widespread impacts, mostly deleterious, on marine organisms and ecosystems, and the goods and services they provide."

The ocean's acidity has increased 26 percent since pre-industrial times

Sea creatures with calcium-based shells are already having trouble growing them in parts of the world, and coral reefs are already facing a rapid decline.

The scientists tried to put a price tag on the economic damage that the phenomenon would inflict, and the total was, predictably, depressing: The authors estimate acidification will cost "$1 trillion annually by 2100," and will pose a direct threat to those who rely on seafood for nutrition or income.  

Taken together, it's hard to overstate the significance of these findings—the next generation will come to grips with an ocean entirely different in character. Already a violent force, it will invariably seem more hostile; more prone to flooding city streets, to  dissolving sea creatures whole, to swallowing low-lying land masses. 

It will be an ocean home to dying coral reefs and fearsome tidal surges, one that will probably feed plenty more hurricanes like Sandy, and leave plenty more physical and psychological scarring across the populace that must cope with it.

One of the most memorable and allegory-friendly bits of advice my father gave me when I was young applies here: "Never turn your back on the ocean." Now, it seems we have no choice.

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