Levees Not War

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National Assessment Finds Climate Change “Has Moved Firmly into the Present”

The effects of human-induced climate change are being felt in every corner of the United States. . . . If greenhouse gases like carbon dioxide and methane continue to escalate at a rapid pace, [scientists] said, the warming could conceivably exceed 10 degrees by the end of this century.

—“U.S. Climate Has Already Changed, Study Finds, Citing Heat and Floods,” New York Times (5/7/14)

Melting of West Antarctic Ice Sheet “Has Passed Point of No Return”

Scientists say that the melting will continue as long as the heat-trapping carbon dioxide in the atmosphere increases. Even if carbon dioxide and temperatures stabilize, the melting and shifting of glaciers will continue for decades or centuries as they adjust to the new equilibrium.

—“The Big Melt Accelerates,” New York Times (5/20/14)

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Two major reports released in recent weeks state emphatically that dramatic changes in climate are under way in the United States and globally, with a 10-degree average temperature rise in the U.S. possible by 2100, and world sea levels likely to rise by 4 to 12 feet or more by the end of the century. Perhaps most ominous of all, according to papers published last week in Science and Geophysical Research Letters, the melting of the West Antarctic Ice Sheet has already “passed a point of no return,” which will lead to alarming sea level rises that will imperil—or render uninhabitable—coastal and low-lying cities around the planet: New Orleans, New York, Miami, Boston, Venice, Shanghai, Mumbai . . .

A good summary by NASA of the Science and Geophysical Research Letters papers’ findings, along with an explanatory video, can be found here.

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More Intense, Frequent Extreme Weather Projected for U.S.

The National Climate Assessment, released by the White House on May 6, was conducted by a team of more than 300 experts guided by a 60-member Federal Advisory Committee and reviewed by the National Academy of Sciences. Among the Assessment’s many noteworthy findings: “The intensity, frequency, and duration of North Atlantic hurricanes, as well as the frequency of the strongest hurricanes, have all increased since the early 1980s. Hurricane intensity and rainfall are projected to increase as the climate continues to warm.”

The Assessment also projects increases in extreme weather generally, both in intensity and frequency: heat waves, droughts, wildfires, along with (in other places) excessive rainfall, flooding, tornadoes “and other severe thunderstorm phenomena,” etc.:

The number of extremely hot days is projected to continue to increase over much of the United States, especially by late century. Summer temperatures are projected to continue rising, and a reduction of soil moisture, which exacerbates heat waves, is projected for much of the western and central U.S. in summer.

In a good summary of 12 points the Obama administration wants the American public to understand from the Climate Assessment, Grist.org includes one point (among others) that this blog takes very seriously: “Infrastructure is being damaged by sea level rise, heavy downpours, and extreme heat; damages are projected to increase with continued climate change.” (See Further Reading below.)

The Climate Assessment’s findings on sea level rise make for chilling reading:

The oceans are absorbing over 90% of the increased atmospheric heat associated with emissions from human activity. Like mercury in a thermometer, water expands as it warms up (this is referred to as “thermal expansion”) causing sea levels to rise. Melting of glaciers and ice sheets is also contributing to sea level rise at increasing rates.

Recent projections show that for even the lowest emissions scenarios, thermal expansion of ocean waters and the melting of small mountain glaciers will result in 11 inches of sea level rise by 2100, even without any contribution from the ice sheets in Greenland and Antarctica. This suggests that about 1 foot of global sea level rise by 2100 is probably a realistic low end. On the high end, recent work suggests that 4 feet is plausible. . . .  some decision makers may wish to use a wider range of scenarios, from 8 inches to 6.6 feet by 2100.

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When Rachel Maddow broadcast from the French Quarter the Friday night before the Super Bowl (how long ago that feels!), she surely did not imagine she would be back a few months later covering the hugest godawful environmental catastrophe this nation has ever seen. Since the Earth Day Blowout Rachel has been to Venice, Louisiana, down in the Birdfoot, as has her NBC comrade Brian Williams, and on Wednesday she broadcast from the west bank of New Orleans, with the city and the river behind her. Tonight (Thursday) she will broadcast from Grand Isle, Louisiana.

Today’s Lesson: Why Louisiana’s Wetlands Are Important

Rachel visited the Jean Lafitte National Historic Park and Preserve, about 15 miles from the Quarter, and spoke with park official David Muth and Dr. Larry McKinney, research director of the Harte Institute for Gulf of Mexico Studies at Texas A&M–Corpus Christi, about why coastal wetlands are important: not only for all the life within them but also because every 2.7 square miles reduces hurricane storm surge by about a foot. The swamps are a buffer for New Orleans and other human settlements in coastal Louisiana. But because the state is losing about 25 square miles every year, or 50 acres a day—1,900 square miles have disappeared in the past century—the 15-, 20-, and 25-foot storm surges that come with hurricanes grow more catastrophic every year. Parks official David Muth tells Rachel:

Our biggest concern is that as we enter hurricane season, when we have a storm in the Gulf, even if it doesn’t come ashore, it can push enormous amounts of water up into this estuary. And once that happens, then a lot of that oil has the potential to come much farther inland, even into a fresh water swamp like this than we might otherwise have thought possible.

We wrote a few weeks ago in some detail about how the oil slick threatens the vegetation that holds the wetlands together—the sea grass and cypresses whose roots hold the soil together and put the “land” in wetlands—and how the Oilpocalypse thus threatens the long-term survival of the Crescent City, long after it may wipe out the livelihoods of the shrimpers, oystermen, and fishermen along the Gulf Coast. We are grateful to MSNBC for sending Rachel and her crew, and to NBC for keeping environmental reporter Anne Thompson on the scene, and for sending, again and again, Brian Williams, whose affection for New Orleans and Louisiana is evident and, we hope, contagious. Thanks for keeping the spotlight on.

. . . no place in America is safe. Hurricane tidal surges of 10 feet or more could swamp Houston, Charleston, Long Island . . . A tornado in Brooklyn (really), earthquakes not limited to California, an interstate bridge collapsing at rush hour into the Mississippi in Minneapolis (it didn’t take an earthquake) . . . Where will the federal government be when you’re down and out? Northeastern energy grid blackouts, hijacked planes . . . These are matters of survival that concern us all equally, regardless of residence or party affiliation. Without care and maintenance, things fall apart. Without funding, without investment, things fall apart. And the longer our so-called leaders shy away from climate change, the higher the temperature, and so with the sea level.

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