If Sea Levels Keep Rising, a Lot of Us Will Be Swimming to Work

The 20th anniversary of Earth Day in 1990 was momentous for me for a simple reason: My second book, Saving the Earth, A Citizen’s Guide to Environmental Action, was published on that day.

It was one of a handful of books that came out that spring—including Bill McKibben’s groundbreakingEnd of Nature—that attempted to draw attention to a handful of environmental concerns that we all saw at the time as being grave, though not very well understood.

Climate change was one of those concerns. “Global warming” was a phrase just starting to be heard, in large part due to the June 23, 1988 testimony of NASA scientist James Hansen before the Senate Committee on Energy and Natural Resources in which he explained how and why the Earth was heating up. Hansen, of course, quit his job at NASA just a few weeks ago to allow himself more free time to remind people that the risks he warned about more than two decades ago are still very relevant.

Every Earth Day, I pull Saving the Earth off the shelf and page through it to remind myself how we’re doing. The book highlights 14 different environmental issues—the causes, effects and solutions—and I have to say each year I find myself disappointed that we still aren’t doing more on the solutions front.

Addressing contributors to climate change is one of our biggest failures. (I just read that SUVs are becoming ever more popular in China, and that by 2030 the Chinese will be buying 30 million cars a year, twice as many gas-guzzlers as the U.S. buys today.)

My specific penchant these days is focused on the impacts of climate change on the ocean; I am most curious and concerned about how we, as a global population, are doing about rising sea levels.

Over the past century, the burning of fossil fuels and other human and natural activities has released enormous amounts of heat-trapping gases into the atmosphere. These emissions have caused the Earth's surface temperature to rise, and the oceans absorb about 80 percent of this additional heat.

Thanks to core samples, tide gauge readings, and, most recently, satellite measurements over the past century, we know that the Global Mean Sea Level (GMSL) has risen by four to eight inches. However, the annual rate of rise over the past 20 years has been 0.13 inches a year, roughly twice the average speed of the preceding 80 years.

Most predictions say the warming of the planet will continue and likely will accelerate. Sea levels will continue to rise as well, but predicting the amount is an inexact science. A recent study says we can expect the oceans to rise between 2.5 and 6.5 feet by 2100, enough to swamp many of the cities along the U.S. East Coast. More dire estimates, including a complete meltdown of the Greenland ice sheet, push sea level rise to 23 feet, enough to submerge London and Los Angeles.

As we saw with superstorm Sandy—where extremely severe weather was combined with a very high tide, on top of sea levels that have risen six to nine inches over the past century—even a little bit of sea-level rise around the world has the potential to cause hundreds of billions of dollars of damages and the displacement of millions of people.

We know what causes rising sea levels:

—Thermal expansion: When water heats up, it expands. About half of the past century's rise in sea level is attributable to warmer oceans simply occupying more space.

—Melting of glaciers and polar ice caps: Large ice formations, like glaciers and the polar ice caps, naturally melt back a bit each summer. But in the winter, snows, made primarily from evaporated seawater, are generally sufficient to balance out the melting. Recently, though, persistently higher temperatures caused by global warming have led to greater-than-average summer melting as well as diminished snowfall due to later winters and earlier springs. This imbalance results in a significant net gain in runoff versus evaporation for the ocean, causing sea levels to rise.

—Ice loss from Greenland and West Antarctica: As with glaciers and the ice caps, increased heat is causing the massive ice sheets that cover Greenland and Antarctica to melt at an accelerated pace. Scientists also believe melt water from above and seawater from below is seeping beneath Greenland's and West Antarctica's ice sheets, effectively lubricating ice streams and causing them to move more quickly into the sea. Moreover, higher sea temperatures are causing the massive ice shelves that extend out from Antarctica to melt from below, weaken, and break off.

—We also know the effects: When sea levels rise rapidly, as they have been doing, even a small increase can have devastating effects on coastal habitats. As seawater reaches farther inland, it can cause destructive erosion, flooding of wetlands, contamination of aquifers and agricultural soils, and lost habitat for fish, birds, and plants. When large storms hit land, higher sea levels mean bigger, more powerful storm surges that can strip away everything in their path.

—In addition, hundreds of millions of people live in areas that will become increasingly vulnerable to flooding. Higher sea levels would force them to abandon their homes and relocate. Low-lying islands could be submerged completely.

As for solutions, we now have plenty of data on how to fix the problem, though clearly we are not very good listeners since the problem continues to grow.

The simplest solution remains simply to burn fewer fossil fuels. A new study by the Scripps Institution for Oceanography, NCAR, and Climate Central, says curbing emissions of certain pollutants can help prevent the sea level rise.

The study highlights that by reducing emissions of four specific pollutants—methane, tropospheric ozone, hydrofluorocarbons and black carbon—we could possibly prevent the rate of sea level rise by approximately 25 to 50 percent.

Which means less fracking, cutting back on motor vehicle exhaust, industrial emissions and chemical solvents, including windshield washer fluid, creating fewer CFCs and cutting back on anything that creates smoke or soot.

Sounds simple, right?

Check back on Earth Day 2014 to see how we’re doing.


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