Humans are Making Oceans Warmer, Deeper, and Life Threatening

• Edwin S. Rubenstein
• December 17, 2019
• Forum Papers
• Forum Paper
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HUMANS ARE MAKING OCEANS WARMER, DEEPER, AND LIFE THREATENING

An NPG Forum Paper
by Edwin S. Rubenstein

Without oceans, climate change would be much worse. The oceans directly absorb about a quarter of the CO2 humans spew into the atmosphere. They also take over 90% of the heat from global warming, acting as a buffer against even greater warming. But the oceans themselves are in trouble from climate change, as the latest report from the UN’s Intergovernmental Panel on Climate Change (IPCC) clearly shows.

“The ocean has been acting like a sponge, absorbing heat and carbon dioxide to regulate global temperatures, but it can’t keep up,” IPCC vice chair Ko Barrett said at a press conference. “The world’s oceans…have been taking the heat of climate change for decades. The consequences for nature and humanity are sweeping and severe.”

 “Global warming is really ocean warming,” Josh Willis, a NASA oceanographer who had no role in the UN report, adds.

The new report is a follow-up to an earlier UN report, reviewed in our Forum Paper of a few months ago, on how climate change impacts the land. That report assessed the seeming inability of reforestation, renewable energy, and other terrestrial mitigation strategies to curb greenhouse gas emissions. 

This report is no more cheerful than that one. In fact, it is even scarier: 

It concludes that a potentially disastrous rise in global sea levels is inevitable. 

In the “best case” scenario, where humans hold warming to 2.7 degrees Fahrenheit above pre-Industrial Revolution temperatures, sea levels will likely rise between one and two feet by century’s end. (This is already over optimistic: most models see temperature rising beyond this level by mid-century.) 

But if emissions continue to rise at the high rates actually experienced in recent decades, the IPCC found sea levels would rise from two to over three and a half feet. That’s because Earth’s most massive ice sheets, on Antarctica and Greenland, “are projected to lose mass at an increasing rate throughout the 21st century and beyond,” the study says.

Ten percent of the world’s population lives in coastal areas that are less than 33 feet above sea level. 

Two thirds of the world’s cities with over five million people are located in low-lying areas where catastrophic flooding is deemed likely. Not all of them are poor and remote: Miami has been listed as “the number-one most vulnerable city worldwide” in terms of potential damage to property from storm-related flooding and sea-level rise.

Miami’s fate, as seen by scientists at Climate Central, a nonprofit organization, is described like this: 

“Few other cities in the world have as much to lose from rising sea levels as Miami, and the alarm bells sound ever louder with each successive “king tide” that overwhelms coastal defenses and sends knee-deep seawater coursing through downtown streets. 

“Locals consider this the “new normal” in the biggest city of Florida’s largest metropolitan area, which would simply cease to exist with a 3C temperature rise. Even at 2C, forecasts show almost the entire bottom third of Florida – the area south of Lake Okeechobee currently home to more than 7 million people – submerged, with grim projections for the rest of the state in a little more than half a century…”

Climate Central’s scenarios are based on digital mapping of the Miami metro area’s population and land elevation, and temperature projections based on University of Washington emissions modeling and UN warming estimates…

Continue reading the full Forum paper by clicking here.