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This blog is expressly directed to readers who do not have strong training or backgrounds in science, with the intent of helping them grasp the underpinnings of this important issue. I'm going to present an ongoing series of posts that will develop various aspects of the science of global warming, its causes and possible methods for minimizing its advance and overcoming at least partially its detrimental effects.

Each post will begin with a capsule summary. It will then proceed with captioned sections to amplify and justify the statements and conclusions of the summary. I'll present images and tables where helpful to develop a point, since "a picture is worth a thousand words".

Friday, April 28, 2017

Sea Level Rise, Due to Human Activity, Imperils Many


Summary. This post discusses three newspaper articles concerning global warming-induced sea level rise, which all appeared in a one-week period about the third week of April, 2017.

Sea level rise is inexorable, already irreversibly “baked in” to the planet’s climate, because melting of ice in the summer season is not restored by new snow and ice in the winter, and because the melted water flows away into the ocean.
Sea level rise is already causing human societal and economic damage around the world.  It will continue unabated, and likely worsen, in future centuries.  To minimize these harms, the world has to minimize greenhouse gas emissions to near zero as soon as possible.  This process would be significantly advanced by adhering to the Paris climate agreement. 
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The Washington Post reported on April 26, 2017 that the rate of sea level rise now foreseen by scientists is considerably higher than published only four years ago by the Intergovernmental Panel on Climate Change (IPCC) in its Fifth Assessment Report.

The Post article reports that the projections are a collaborative effort among 90 scientists, which was subjected to peer review by 28 other scientists.  Climate models based on two scenarios for continued rates of emission of greenhouse gases to the year 2100 were used for the projections.  One is a moderately stringent policy limiting emission rates.  The second is a scenario based on continued unconstrained emission rates comparable to those that reflect today’s fuel use.  The results are shown in the following table, which also includes the 2013 IPCC projections for comparison.

Scenario
Predicted sea level rise by 2100 [2013 IPCC prediction]
Moderately stringent
At least 52 centimeters (1.7 feet) [32 centimeters (1 foot)]
Unconstrained
At least 74 centimeters (2.4 feet) [45 centimeters (1.5 feet)]

The updated estimates take into account the increased rate of melting of the Greenland Ice Sheet and Antarctic ice shelves recently observed, and expansion of the liquid ocean due to its higher temperature, among other contributing sources.

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This article reports that Tasmania, the island south of the Australian mainland, is already suffering the ravages of sea level rise.  The shoreline is being eroded by rising seas, and trees are being uprooted and falling into the sea.  An abandoned shoreline coal mine is being filled in by the sea.  The article states “The ocean is rising in large part…because people the world over have burned so much coal, pumping planet-warming carbon dioxide into the air. Perhaps a new stone marker [referencing a seaside prisoners’ graveyard] ought to be planted above the eroding mine: Cause, Meet Effect.”  A Tasmanian ecologist stated, with some irony, “It’s a smoking gun for sea-level rise causing an acceleration of erosion.  And it’s coal! Mined for burning!”

The article summarizes manifestations of worsening global warming: “In country after country, managers of national parks and other historic sites are realizing that climate change, with its coastal flooding and erosion, rising temperatures and more intense rainstorms, represents a profound risk to the heritage they are trying to preserve.”  It mentions damage to the Statue of Liberty’s foundation by Hurricane Sandy, loss of most of the glaciers in America’s Glacier National Park, damage to Australia’s Great Barrier Reef due to rising ocean temperature (vindicating a 10-year old prediction), among many other examples.
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https://www.nytimes.com/2017/04/20/magazine/how-singapore-is-creating-more-land-for-itself.html?_r=0













Singapore is an independent island city-nation just off the coast of the southern tip of Malaysia.  It is a thriving metropolis, whose economic base is commerce and the financial industry.  The article notes that Singapore has felt the limitations of its small land area for decades.  This has constrained the ways it can develop additional useful real estate as its fortunes continue to grow. 

In recent years this quandary has been worsened by the encroachment of rising sea levels.  Singapore fortunately has the financial resources artificially to expand its land area by robbing it from the sea.  The image above shows one example.  The city sinks massive ocean-resistant caissons (seen above from the air) into the sea bed surrounding its natural land base, forming void rectangular enclosures.  It then imports huge quantities of sand, or of pulverized rock, and fills in the rectangles to provide new land area which, when completed, will form new surface area for development.  The new land is high enough to withstand sea level rise in the coming years.

The article contrasts the case of affluent Singapore with other, more impoverished, island “micro-nations” that are losing the battle against rising seas.  Solomon Islands is a Pacific Ocean nation on six major islands and several hundred smaller islands, with an area of 11,000 sq. mi.  The article notes that five small islands have already disappeared under rising seas.  Kiribati has bought 6,000 acres of land 1,000 miles away in Fiji for resettlement of its people.  The Maldives is considering a similar purchase in Australia.  Some of the people living on the island micro-nations of Tuvulu, the Marshall Islands and Nauru have already departed.

Discussion

Newspaper reports on sea level rise.  The examples cited in the articles above pinpoint the flooding, and consequent damages, to be expected along coastlines all over the world as sea levels continue rising.  Man-made global warming, the main cause for the rising seas, is unequivocally due to humanity’s burning of carbon-containing fuels for energy, emitting the greenhouse gas carbon dioxide into the atmosphere.  (Other man-made greenhouse gases also contribute to warming.) 
The fundamental problem is that carbon dioxide remains resident in the atmosphere for centuries because there are no natural processes that remove it at the speed and on the massive scale needed to balance the excess amounts that we produce.  As a result, warming will continue worsening until emissions are effectively minimized to near zero. 

Polar melting.  As noted in the Summary, the long-term average temperature of air in contact with the Greenland ice sheet and of ocean water in contact with the Antarctic ice shelves is already warm enough to lead to net melting of these ice reservoirs, raising global sea levels.  We cannot go back to a planetary regime having a lower temperature (which might slow or stop melting of the ice) because of the permanence of carbon dioxide in the atmosphere.  Consequently the sea level is projected to increase for centuries.  Projected higher temperatures will worsen this trend.
The “social cost of carbon” is an economic term for a framework that attempts to place direct financial costs, as well as indirect societal costs, on the consequences of carbon dioxide-induced global warming.  This is necessary because direct costs for the use of carbon-containing fossil fuels stop at the point of sale of the fuel.  The costs incurred as consequences of the resulting global warming are not reckoned in the sale price. 

This may be contrasted, for example, by the costs that residents bear to have their household waste removed by tax-supported services, or the charges that they pay for treatment of their waste water.  The separate expense of handling the waste is directly borne by property owners and/or municipal taxpayers.  No analogous cost for waste treatment is built into the cost structures of fossil fuel-derived energy use.  This is the accounting that enters into pricing the social cost of carbon.
Contributions to the social cost of carbon are seen in the journal snippets presented here.  Singapore is fortunate in having the resources to protect itself from sea level encroachment.  The other oceanic island micro-nations mentioned here do not; they face existential threats in the near future. 

In the U. S., coastal communities in Miami and south Florida, as well as Norfolk, Virginia, now suffer fair weather flooding at high tide, due to higher sea levels, that had not occurred previously.  Their cost of carbon lies in the extensive, expensive barriers they are forced to put in place to minimize the flooding.  Likewise, the New York region is planning to construct similar barriers as a defense against the possibility that future storm surges similar to that of Hurricane Sandy could occur.  All these projects were not foreseen in earlier budgeting processes.  The additional expenses for them become unexpected taxpayer burdens at the state and local levels.  They clearly represent social costs of carbon that are not included in the prices paid for fossil fuels at the time of use.
Conclusion

Three simultaneously published newspaper articles have pointed out the present and future harms to humanity due to sea level rise.  The rising level is due to humanity’s burning of fossil fuels, worsening the carbon dioxide-induced greenhouse effect and producing warmer global average temperatures that melt polar ice caps.
We must work together to minimize future increases in the carbon dioxide burden of the atmosphere in order to slow continued sea level rise.  (The world’s temperature is already too high to stop it outright.)  The Paris climate agreement of 2015 is a good start on this path.  All nations of the world should embrace its provisions, and improve the emission limits it has created.  Rejecting the agreement would be at humanity’s peril.

© 2017 Henry Auer
 

2 comments:

  1. Time to shut your blog now, Henry. ..it's all over...we've entered the New Trumpocene.
    http://principia-scientific.org/is-no-greenhouse-effect-possible-from-the-way-that-ipcc-define-it/#comment-11469

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