Sea level rise posed an urgent threat to coastal cities and towns all across the planet. That's what a new study published by Proceedings of the National Academy of Sciences
indicates.
Carbon choices determine US cities committed to futures below sea level pdf
U.S. Cities We Could Lose to the Sea
By Climate Central
Historic carbon emissions have already locked in enough future sea level rise to submerge most of the homes in each of several hundred American towns and cities, according to Climate Central-led research published Monday in Proceedings of the National Academy of Sciences. The animated timeline on this page maps, year by year, how the total number of locked-in cities could climb to more than 1,500, if pollution continues unchecked through the end of the century. It also lays out an alternative timeline based on extreme carbon cuts, leading to fewer than 700 locked-in cities. You can watch threats unfold nationwide or for individual states, and track the potential fate of each municipality. Click on “Start” to begin.
Our research does not project, and this animation does not show, exactly when sea level will reach heights great enough to pose these dangers — likely centuries. Rather, our findings assess when enough carbon pollution will have accumulated, under each scenario, to lock in future sea level rise posing existential threats for each town or city — sea level rise that could submerge land where more than half of today’s population lives.
Authors: Benjamin H. Strauss - Climate Central, Scott Kulp - Climate Central, and Anders Levermann - Potsdam Institute for Climate Impact Research
Journal: Proceedings of the National Academy of Sciences, U.S.A.
Publication Date: 2015
PDF of Full Paper
Abstract
Anthropogenic carbon emissions lock in long-term sea-level rise that greatly exceeds projections for this century, posing profound challenges for coastal development and cultural legacies. Analysis based on previously published relationships linking emissions to warming and warming to rise indicates that unabated carbon emissions up to the year 2100 would commit an eventual global sea-level rise of 4.3–9.9 m. Based on detailed topographic and population data, local high tide lines, and regional long-term sea-level commitment for different carbon emissions and ice sheet stability scenarios, we compute the current population living on endangered land at municipal, state, and national levels within the United States. For unabated climate change, we find that land that is home to more than 20 million people is implicated and is widely distributed among different states and coasts. The total area includes 1,185–1,825 municipalities where land that is home to more than half of the current population would be affected, among them at least 21 cities exceeding 100,000 residents. Under aggressive carbon cuts, more than half of these municipalities would avoid this commitment if the West Antarctic Ice Sheet remains stable. Similarly, more than half of the US population-weighted area under threat could be spared. We provide lists of implicated cities and state populations for different emissions scenarios and with and without a certain collapse of the West Antarctic Ice Sheet. Although past anthropogenic emissions already have caused sea-level commitment that will force coastal cities to adapt, future emissions will determine which areas we can continue to occupy or may have to abandon.
The science behind the map
Carbon pollution casts a long shadow. It is expected to persist in the atmosphere long enough to prolong temperature increases for hundreds and thousands of years, long after we stop burning fossil fuels or clearing forests. Our research first translates cumulative carbon emissions into locked-in long-term global temperature increases, and then translates these into locked-in sea level rise projections.
The sea level projections are based on four separate models for the expansion of ocean water as it warms; melting glaciers; and the decay of Greenland and Antarctic ice sheets. We develop local projections that can vary by several feet from the global average based mainly on changing gravity fields as the polar ice sheets lose mass. (Local projections shown do not factor in the continuation of current land subsidence or uplift. In most places, these might translate to inches per century, but some places, such as southeastern Louisiana, are sinking closer to one foot per century.)
If you haven't looked at those maps please make sure you do. They're starling to see.
Interactive Map Shows 414 U.S. Cities Already Locked Into Catastrophic Sea Level Rise
By Cole Mellino
All of these reports confirm that sea level rise would be devastating for coastal cities in the U.S. To illustrate just how destructive it would be, Climate Central, in conjunction with the PNAS study, created an interactive map showing which U.S. cities we could lose to sea level rise, in what year we will lock in enough future sea level rise to inundate each city and what percentage of the population in each city lives below the locked-in sea level rise.
Check it out:
Antarctic ice shelf collapse and unstoppable sea level rise 'very likely' without tough climate action, say scientists
Warming of 1.5 to 2 degrees Celsius above current levels could lead to "unstoppable" sea level rise that would last for thousands of years, according to a new model of Antarctic ice sheets.
By Anna Salleh
The new model, published today in Nature, shows that such temperatures would result in 80 to 85 per cent loss of major Antarctic ice shelves, something that is possible by the end of the century under existing IPCC scenarios.
Collapse of the ice shelves would trigger a rapid melt of the Antarctic ice sheets, releasing vast amounts of Earth's freshwater stores into the ocean, said the researchers.
By 2100 this would add up to 40 centimetres to sea levels, melt rate would continue to accelerate until 2300, and sea levels would continue to rise after that for thousands of years.
If this doesn't wake up our political and economic elites to the urgency of our predicament very soon, it will be up to us to take grassroots action to change our disastrous trajectory as a society.
Poll Finds Fewer Americans Than Ever Doubt Climate Change Is Happening
At least 70 percent of Americans now believe that global warming during the last 40 years is real and supported by solid evidence, coinciding with the lowest percentage of Americans who doubt climate change, according to a new poll released this week.