Monday, April 16, 2018

Climate Change: The Water Will Come by Jeff Goodell

Global warming will bring the rise of sea level as melting ice pours into the oceans.  Sea level rise, as well as most other climate change impacts, is often projected to become significant in the distant future.  This detracts from the urgency of the issue and allows deferral of action to an undetermined future time.  However, climate change is already upon us and changes in sea level are already causing problems.  If we are ever to successfully adapt to coming conditions, we must begin now when changes are relatively mild rather than wait until they become catastrophic.  That is the message Jeff Goodell presents in his book The Water Will Come: Rising Seas, Sinking Cities, and the Remaking of the Civilized World.

“….if you live on a coast, what matters more than the height the seas rise is the rate at which they rise.  If the water rises slowly, it’s not such a big deal.  People will have time to elevate roads and buildings and build sea walls.  Or move away.  It is likely to be disruptive, but manageable.”

“Unfortunately, Mother Nature is not always so docile.  In the past, the seas have risen in dramatic pulses that coincide with the sudden collapse of ice sheets.  After the end of the last ice age, there is evidence that the water rose about thirteen feet in a single century.  If that were to occur again, it would be a catastrophe for coastal cities around the world, causing hundreds of millions of people to flee from the coastlines and submerging trillions of dollars of real estate and infrastructure.”

The options available will, of course, depend on the wealth of the affected country, and, as usual, the poor will suffer the most.

“Globally, about 145 million people live three feet or less above the current sea level.  As the waters rise, millions of these people will be displaced, many of them in poor countries, creating generations of climate refugees that will make today’s Syrian war refugee crisis look like a high school drama production.”

What do we know about the rate of sea level rise?  Not much, as it turns out.  What we know for sure is how much water is currently captured in Greenland and Antarctica.

“Antarctica is about seven times bigger than Greenland and contains much more ice.  If the whole continent were to melt (a scenario that would likely take thousands of years), it would raise the Earth’s sea levels by about two hundred feet.  If all of Greenland were to go (a scenario that would take significantly less time), it would raise sea levels about twenty-two feet….Right now melting from Greenland contributes roughly twice as much to current sea-level rise as Antarctica—but that may change in coming decades.”

The situation in Antarctica is particularly complex.  Melting from warmer air is not the main issue.  Rather it is melting from below caused by warmer waters.  The ice sheets extend beyond the land mass and terminate in the sea.  Warming waters could cause these extended ice regions to fracture and break off.  That could trigger instability of the thick ice masses behind causing much more rapid sea rise than expected from a simple melting process.

Even predicting melt rates from a warming atmosphere is fraught with uncertainty.

“In the past twenty years, the Arctic has warmed by more than three degrees Fahrenheit, roughly twice as fast as the global average.  As the ice melts, the region’s albedo, or reflectivity, changes.  Clean, fresh snow is one of the most reflective substances known in nature, reflecting away more than 90 percent of the sunlight that hits it.  But as the ice softens, its structure alters, lowering the reflectivity and absorbing more heat.  As it melts away, more water and more land are exposed, both of which are darker, and both of which absorb still more heat.  This in turns melts more ice, creating a feedback loop that can accelerate quickly.”

Scientists feel most comfortable trying to predict sea level rise out to the end of the current century using their best physical models and incorporating various scenarios for greenhouse gas production.  But they do not feel much confidence in the accuracy of their predictions.

“’We just don’t know what the upper boundary is for how fast this can happen.’  Richard Alley, a geologist at Penn State University who probably understands ice sheet dynamics better than anyone, told me.  ‘We are dealing with an event that no human has ever witnessed before.  We have no analogue for this’.”

Estimates of how high the seas will rise by 2100 are highly uncertain, but there is a definite tend toward higher sea levels.  The last official estimate by the Intergovernmental Panel on Climate Change (IPCC) came out in 2013 predicting a maximum anticipated rise of about 3 feet 2 inches.  Since the data available for that estimate was used, scientists observed an anomalously high ice melt event in Greenland and surprising ice sheet breakups in Antarctica that have raised concerns that the 2013 estimate may be way too conservative.  Unofficial estimates now range from about 3 feet up to as much as 15 feet.  Recall Goodall’s statement that 145 million people live on land that will be submerged by a 3-foot rise.  A 6-foot rise would be much more disruptive.

Much of Goodell’s book deals with interactions with cities and states threatened by rising sea levels.  Many people agree that the seas are rising and will continue to do so.  However, the ones that are planning to protect their cities are those that have already suffered damage from rampaging waters via storm surges such as New York City and Venice, Italy.  These polities have gained permission to invest the resources to protect themselves from future similar surges because it has become clear that the events could occur again.  Building additional protection for future sea rise seems to be a too far off a concern to justify the additional expense. 

Goodell was often presented with this this perspective: “Who cares?  I’ll be dead by then.”  Well, somebody should care.  The year 2100 is within the life span of the very young.  A 30-year-old might expect to live until 2075-2080.  If any of these estimates of sea-level rise are accurate the world will become a much different place during their lifetime.

“….we are not wired to make decisions about barely perceptible threats that gradually accelerate over time.  We’re not so different from the proverbial frog that boils to death in a pot of slowly warming water.”

Goodell provides a final thought.

“The real x-factor here is not the vagaries of climate science, but the complexity of human psychology.  At what point will we take dramatic action to cut carbon dioxide pollution?  Will we spend billions on adaptive infrastructure to prepare cities for rising waters—or will we do nothing until it is too late?  Will we welcome people who flee submerged coastlines and sinking islands—or will we imprison them?”

The interested reader might find the following articles informative:

Global Warming and the Resurrection of Dormant Diseases

Putting Climate Change in Perspective

Ground Zero for Sea-Level Rise: South Florida

Global Warming and the Holocaust’s Warning: It Can Happen Again

Geoengineering, Volcanoes, and Climate Change Experiments

No comments:

Post a Comment

Lets Talk Books And Politics - Blogged