TY - CONF
T1 - A global analysis of human habitation on river deltas
AU - Edmonds, Douglas
AU - Caldwell, Rebecca
AU - Baumgardner, Sarah
AU - Paola, Chris
AU - Roy, Samapriya
AU - Nelson, Amelia
AU - Nienhuis, Jaap
N1 - 19th EGU General Assembly, EGU2017, proceedings from the conference held 23-28 April, 2017 in Vienna, Austria.
PY - 2017/4/1
Y1 - 2017/4/1
N2 - River deltas are ideal sites for human habitation because of their
fertile floodplains, easy access to the ocean, and abundant land. But
anthropogenic and natural processes are causing deltas to sink, which
increases the probability of coastal flooding and human exposure to
risk. The full extent of the risk posed to humans is unclear because the
number of people living on river deltas is unknown. Towards this end we
mapped the locations and areas of all deltas in the world (n= 1813).
Using Google Earth we identified all river mouths (≥ 50 m wide) on
marine coastlines that are also connected to an upstream catchment.
Rivers that split into two or more active or relict distributary
channels, end in a depositional protrusion from the shoreline, or do
both, are defined as deltas. The depositional protrusion and
distributary channel network define the geomorphic area of each delta.
We mark the position of the delta apex at the first bifurcation, or for
a single channel delta at the intersection of the regional shoreline and
the main channel. We mark three lateral extents, one on either side of
the main channel at the maximum displacement of the depositional
protrusion or the distributary network, and one on the most basinward
position of the delta. We define delta area as the convex hull around
these extent points and the delta apex. For each delta area polygon we
extract elevation from the Shuttle Radar Topography Mission dataset and
population count in years 2000, 2005, 2010, 2015, and 2020 from Gridded
Population of the World, version 4. In total, deltas cover 0.56% of the
total area of the world yet contain 4.1% of the world's population. The
population on deltas has grown from 237 million in 2000 to projected
values of 322 million in 2020. Deltaic population is growing at 1.59%
per year, which outpaces the world growth rate of 1.11%. Additionally,
population density is increasing with time from 322 people per km2 in
year 2000 to projected values of 422 people per km2 in 2020. Of the 300
million people currently living on deltas, roughly 69% live below 10
meters elevation in the so-called low elevation coastal zone that is
particularly susceptible to coastal flooding. Interestingly, the
population in the low elevation coastal zone is unevenly distributed.
The largest number of people, approximately 24%, live between 4 and 6 m
elevation. This elevation range is also more densely populated at 580
people per km2, which is nearly 12 times the global mean of 47 people
per km2. We consider these estimates to be a minimum given that we
define delta area from the geomorphic footprint.
AB - River deltas are ideal sites for human habitation because of their
fertile floodplains, easy access to the ocean, and abundant land. But
anthropogenic and natural processes are causing deltas to sink, which
increases the probability of coastal flooding and human exposure to
risk. The full extent of the risk posed to humans is unclear because the
number of people living on river deltas is unknown. Towards this end we
mapped the locations and areas of all deltas in the world (n= 1813).
Using Google Earth we identified all river mouths (≥ 50 m wide) on
marine coastlines that are also connected to an upstream catchment.
Rivers that split into two or more active or relict distributary
channels, end in a depositional protrusion from the shoreline, or do
both, are defined as deltas. The depositional protrusion and
distributary channel network define the geomorphic area of each delta.
We mark the position of the delta apex at the first bifurcation, or for
a single channel delta at the intersection of the regional shoreline and
the main channel. We mark three lateral extents, one on either side of
the main channel at the maximum displacement of the depositional
protrusion or the distributary network, and one on the most basinward
position of the delta. We define delta area as the convex hull around
these extent points and the delta apex. For each delta area polygon we
extract elevation from the Shuttle Radar Topography Mission dataset and
population count in years 2000, 2005, 2010, 2015, and 2020 from Gridded
Population of the World, version 4. In total, deltas cover 0.56% of the
total area of the world yet contain 4.1% of the world's population. The
population on deltas has grown from 237 million in 2000 to projected
values of 322 million in 2020. Deltaic population is growing at 1.59%
per year, which outpaces the world growth rate of 1.11%. Additionally,
population density is increasing with time from 322 people per km2 in
year 2000 to projected values of 422 people per km2 in 2020. Of the 300
million people currently living on deltas, roughly 69% live below 10
meters elevation in the so-called low elevation coastal zone that is
particularly susceptible to coastal flooding. Interestingly, the
population in the low elevation coastal zone is unevenly distributed.
The largest number of people, approximately 24%, live between 4 and 6 m
elevation. This elevation range is also more densely populated at 580
people per km2, which is nearly 12 times the global mean of 47 people
per km2. We consider these estimates to be a minimum given that we
define delta area from the geomorphic footprint.
M3 - Abstract
SP - 10832
ER -