Global change in streamflow extremes under climate change over the 21st century
Global warming is expected to intensify the Earth's hydrological cycle and increase flood and drought risks. Changes over the 21st century under two warming scenarios in different percentiles of the probability distribution of streamflow, and particularly of high and low streamflow extremes...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2017-11-01
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| Series: | Hydrology and Earth System Sciences |
| Online Access: | https://www.hydrol-earth-syst-sci.net/21/5863/2017/hess-21-5863-2017.pdf |
| Summary: | Global warming is expected to intensify the Earth's hydrological cycle and
increase flood and drought risks. Changes over the 21st century under two
warming scenarios in different percentiles of the probability distribution
of streamflow, and particularly of high and low streamflow extremes
(95th and 5th percentiles), are analyzed using an ensemble of
bias-corrected global climate model (GCM) fields fed into different global
hydrological models (GHMs) provided by the
Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP) to understand the changes in streamflow
distribution and simultaneous vulnerability to different types of
hydrological risk in different regions. In the multi-model mean under the
Representative Concentration Pathway 8.5 (RCP8.5)
scenario, 37 % of global land areas experience an increase in magnitude of
extremely high streamflow (with an average increase of 24.5 %),
potentially increasing the chance of flooding in those regions. On the other
hand, 43 % of global land areas show a decrease in the magnitude of
extremely low streamflow (average decrease of 51.5 %), potentially
increasing the chance of drought in those regions. About 10 % of the
global land area is projected to face simultaneously increasing high extreme
streamflow and decreasing low extreme streamflow, reflecting the potentially
worsening hazard of both flood and drought; further, these regions tend to
be highly populated parts of the globe, currently holding around 30 % of
the world's population (over 2.1 billion people). In a world more than 4°
warmer by the end of the 21st century compared to the
pre-industrial era (RCP8.5 scenario), changes in magnitude of streamflow
extremes are projected to be about twice as large as in a 2° warmer
world (RCP2.6 scenario). Results also show that inter-GHM uncertainty in
streamflow changes, due to representation of terrestrial hydrology, is
greater than the inter-GCM uncertainty due to simulation of climate change.
Under both forcing scenarios, there is high model agreement for increases
in streamflow of the regions near and above the Arctic Circle, and
consequent increases in the freshwater inflow to the Arctic Ocean, while
subtropical arid areas experience a reduction in streamflow. |
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| ISSN: | 1027-5606 1607-7938 |