 |
| Image & Article courtesy : MIT News |
Economic and population growth on top of climate change could lead to serious
water shortages across a broad swath of Asia by the year 2050, a newly
published study by MIT scientists has found.
The study deploys detailed modeling to produce what the researchers
believe is a full range of scenarios involving water availability and
use in the future. In the paper, the scientists conclude there is a
“high risk of severe water stress” in much of an area that is home to
roughly half the world’s population.
Having run a large number of simulations of future scenarios, the
researchers find that the median amounts of projected growth and climate
change in the next 35 years in Asia would lead to about 1 billion more
people becoming “water-stressed” compared to today.
And while climate change is expected to have serious effects on the
water supply in many parts of the world, the study underscores the
extent to which industrial expansion and population growth may by
themselves exacerbate water-access problems.
“It’s not just a climate change issue,” says Adam Schlosser, a senior
research scientist and deputy director at MIT’s Joint Program on the
Science and Policy of Global Change and a co-author of the study. “We
simply cannot ignore that economic and population growth in society can
have a very strong influence on our demand for resources and how we
manage them. And climate, on top of that, can lead to substantial
magnifications to those stresses.”
The paper, “Projections of Water Stress Based on an Ensemble of
Socioeconomic Growth and Climate Change Scenarios: A Case Study in
Asia,” is being published today in the journal PLOS One. The
lead author is Charles Fant, a researcher at the Joint Program. The
other co-authors are Schlosser; Xiang Gao and Kenneth Strzepek, who are
also researchers at the Joint Program; and John Reilly, a co-director of
the Joint Program who is a senior lecturer at the MIT Sloan School of
Management.
To conduct the study, the scientists built upon an existing model
developed previously at MIT, the Integrated Global Systems Model (IGSM),
which contains probabilistic projections of population growth, economic
expansion, climate, and carbon emissions from human activity. They then
linked the IGSM model to detailed models of water use for a large
portion of Asia encompassing China, India, and many smaller nations.
The scientists then ran an extensive series of repeated projections
using varying conditions. In what they call the “Just Growth” scenario,
they held climate conditions constant and evaluated the effects of
economic and population growth on the water supply. In an alternate
“Just Climate” scenario, the scientists held growth constant and
evaluated climate-change effects alone. And in a “Climate and Growth”
scenario, they studied the impact of rising economic activity, growing
populations, and climate change.
Approaching it this way gave the researchers a “unique ability to
tease out the human [economic] and environmental” factors leading to
water shortages and to assess their relative significance, Schlosser
says.
This kind of modeling also allowed the group to assess some of the
particular factors that affect the different countries in the region to
varying extents.“For China, it looks like industrial growth [has the greatest impact]
as people get wealthier,” says Fant. “In India, population growth has a
huge effect. It varies by region.”
The researchers also emphasize that evaluating the future of any
area’s water supply is not as simple as adding the effects of economic
growth and climate change, and it depends on the networked water supply
into and out of that area. The model uses a network of water basins, and
as Schlosser notes, “What happens upstream affects downstream basins.”
If climate change lowers the amount of rainfall near upstream basins
while the population grows everywhere, then basins farther away from the
initial water shortage would be affected more acutely.
Future research directions
Other scholars who have examined the work say it makes a valuable contribution to the field.
“They’re looking at a really important issue for the world,” says
Channing Arndt, an agricultural economist at the United Nations’ World
Institute for Development Economics Research, who thinks that the basic
finding of the study “makes sense.”
Arndt also believes that the ambitious scope of the study, and the
way it evaluates the effects of climate change as well as economic and
population growth, is a worthwhile approach. “Doing it in this
integrated way is the right way to go about it,” he adds.
The research team is continuing to work on related projects,
including one on the effects of mitigation on water shortages. While
those studies are not finished, the researchers say that changing
water-use practices can have significant effects.
“We are assessing the extent to which climate mitigation and
adaptation practices — such as more efficient irrigation technologies —
can reduce the future risk of nations under high water stress,”
Schlosser says. “Our preliminary findings indicate strong cases for
effective actions and measures to reduce risk.”
The researchers say they will continue to look at ways of fine-tuning
their modeling in order to refine their likelihood estimates of
significant water shortages in the future.
“The emphasis in this work was to consider the whole range of
plausible outcomes,” Schlosser says. “We consider this an important step
in our ability to identify the sources of changing risk and large-scale
solutions to risk reduction.”
source : MIT News
No comments:
Post a Comment