TY  - JOUR
A1  - Strauss, Benjamin H.
A1  - Kulp, Scott
A1  - Levermann, Anders
T1  - Carbon choices determine US cities committed to futures below sea level
JF  - Proceedings of the National Academy of Sciences of the United States of America
N2  - 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.
KW  - climate change
KW  - climate impacts
KW  - sea-level rise
Y1  - 2015
U6  - https://doi.org/10.1073/pnas.1511186112
SN  - 0027-8424
VL  - 112
IS  - 44
SP  - 13508
EP  - 13513
PB  - National Acad. of Sciences
CY  - Washington
ER  - 
TY  - JOUR
A1  - Levermann, Anders
A1  - Clark, Peter U.
A1  - Marzeion, Ben
A1  - Milne, Glenn A.
A1  - Pollard, David
A1  - Radic, Valentina
A1  - Robinson, Alexander
T1  - The multimillennial sea-level commitment of global warming
JF  - Proceedings of the National Academy of Sciences of the United States of America
N2  - Global mean sea level has been steadily rising over the last century, is projected to increase by the end of this century, and will continue to rise beyond the year 2100 unless the current global mean temperature trend is reversed. Inertia in the climate and global carbon system, however, causes the global mean temperature to decline slowly even after greenhouse gas emissions have ceased, raising the question of how much sea-level commitment is expected for different levels of global mean temperature increase above preindustrial levels. Although sea-level rise over the last century has been dominated by ocean warming and loss of glaciers, the sensitivity suggested from records of past sea levels indicates important contributions should also be expected from the Greenland and Antarctic Ice Sheets. Uncertainties in the paleo-reconstructions, however, necessitate additional strategies to better constrain the sea-level commitment. Here we combine paleo-evidence with simulations from physical models to estimate the future sea-level commitment on a multimillennial time scale and compute associated regional sea-level patterns. Oceanic thermal expansion and the Antarctic Ice Sheet contribute quasi-linearly, with 0.4 m degrees C-1 and 1.2 m degrees C-1 of warming, respectively. The saturation of the contribution from glaciers is overcompensated by the nonlinear response of the Greenland Ice Sheet. As a consequence we are committed to a sea-level rise of approximately 2.3 m degrees C-1 within the next 2,000 y. Considering the lifetime of anthropogenic greenhouse gases, this imposes the need for fundamental adaptation strategies on multicentennial time scales.
KW  - climate change
KW  - climate impacts
KW  - sea-level change
Y1  - 2013
U6  - https://doi.org/10.1073/pnas.1219414110
SN  - 0027-8424
VL  - 110
IS  - 34
SP  - 13745
EP  - 13750
PB  - National Acad. of Sciences
CY  - Washington
ER  -