Cutting Edge Research

Coastal Impact Study:
Nation Under Siege

Introduction

We have only to look at one event in just one city, hurricane Katrina and its impact on New Orleans, to understand what may soon be upon us...

There have been recent and very clear warnings from the US scientific community that we are perilously close to a climate change tipping point and that unless we begin reducing greenhouse gas (GHG) emissions we will soon pass this point with widespread undesirable consequences. Scientists estimate that continued growth of GHG emissions for another 10 years would make it impractical, and most likely impossible, to avert dangerous climate change [1].

With a business-as-usual approach, where fossil-fuel consumption and GHG emissions continue to increase, we will likely see a warming of 2 °C to 3 °C this century with a planetary energy imbalance sufficient to melt enough ice to raise sea level by several meters [2]. During the last interglacial period, 125,000 years ago, when the earth was this warm, sea level was four to six meters higher than today [3].

Because 53 percent of all Americans live in and around coastal cities and towns [4], it is important to understand the point at which sea level rise creates an untenable situation in the US. We have seen and heard much about the catastrophic global consequences of six meters of sea level rise, and the effects of a much smaller rise on low-lying countries, like Bangladesh and island states in the South Pacific. What has not been made clear is the possible timing and effect of smaller increments of sea level rise on the US.

The following study of the US coasts reveals that, beginning with just one meter of sea level rise, our nation will be physically under siege, vulnerable to catastrophic property and infrastructure loss with large population disruptions and economic hardship. We have only to look at one event in just one city, hurricane Katrina and its impact on both New Orleans and our country, to understand what may soon be upon us if firm and immediate action to reduce GHG emissions to acceptable levels is not taken.

The most recent scientific study, issued by 47 scientists from many of our most respected institutions (from NASA on the East Coast to Lawrence Berkeley National Laboratory on the West Coast), indicates that, at approximately 450 parts per million (ppm) carbon dioxide (CO2) in the atmosphere (a greenhouse gas), we will reach a tipping point and trigger “dangerous climate change” with potentially irreversible glacial melt and rapid sea level rise “out of humanity’s control” [5]. We are currently dangerously close to this threshold at 383 ppm, and are now increasing atmospheric concentrations of CO2 at about 2 ppm annually [6].

The one inexpensive fossil fuel in plentiful supply that, if consumed at its present and/or an expanding rate, will push the planet past the 450 ppm threshold, is coal. If we are to avert this tipping point, we will need to call for an immediate halt to the construction of any new conventional coal-fired power plants and the phasing out of existing and aging coal plants over time. If we fail to take this action, there is no doubt we will soon reach the 450 ppm threshold.

1. Hansen, J. et al., “Dangerous human-made interference with climate: a GISS model E study,” Atmos. Chem. Phys., 29 March, 2007: 2298.
2. Hansen, J. et al., “Climate change and trace gasses,” Philosophical Transactions of The Royal Society A., 18 May, 2007.
3. Intergovernmental Panel on Climate Change (IPCC), “Working Group 1: The Physical Basis of Climate Change, Summary for Policymakers,” 2007.
4. Crossett, K. et al., “Population Trends Along the Coastal United States: 1980-2008,” National Oceanic and Atmospheric Administration, 2004.
5. Hansen, J. et al., “Dangerous human-made interference with climate: a GISS model E study,” Atmos. Chem. Phys., 29 March, 2007: 2298.
6. Leslie McCarthy, “Research Finds That Earth's Climate is Approaching 'Dangerous' Point,” NASA, www.nasa.gov/centers/goddard/news/. 		 

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Foreword
Introduction
Sea Level Rise
Visual Imaging
One Meter of Sea Level Rise... and Rising
A Lesson Learned?
Current Trends
Timeline
Fossil Fuels and Climate Change
The Power of Coal
Silver Bullet: Moratorium on Coal
Replacing Coal
The 2030 Challenge
Been There, Done That
Revisiting Katrina
Conclusions
Appendix

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