We have discussed this
at length here in this blog and I am completely convinced that all the deserts
can be nicely vegetated with a range of water producing strategies and technologies. On the other hand, I am no fan of
conventional seawater desalination simply because it is not particularly
sustainable. It only make engineers
happy.
The perimeter grow out
needs to be wet and the easiest way to make that all happen is with artificial
reefs and mangrove swamps that then fill the atmosphere with humid air. Then the rest is well planned hydraulics and
nature doing what it does best.
Yet this piece tells us
that many others are worrying this problem and reaching for viable
solutions. That is good.
Should we turn deserts
into carbon-sucking tree plantations?
By John
Upton
To
fight climate change, some scientists think we should vegetate the hell out of
deserts. The latest such idea calls for large plantations of a hardy species of
Central American tree to be planted in near-coastal desert areas and irrigated
with desalinated water.
While
forests soak up carbon dioxide, deserts do comparatively little to help with
climate change. So should these seas of sand be planted and watered out of
existence in a bid to reduce CO2 levels?
Some
say yes. The approach would be like geoengineering,
but rooted in a more natural system. Scientists call it bioengineering or
carbon farming.
The
idea of replacing deserts with forests to help the climate is not brand new. A
few years ago, for example, scientists
proposed planting eucalyptus trees through the Saharan and Australian deserts to
help absorb carbon dioxide.
The
latest suggested approach, which would involve the planting of vast orchards of
Barbados nut trees, technically known as Jatropha curcas trees, was
proposed Wednesday by a group of German researchers in the
journal Earth System Dynamics. They say vegetating the world’s
near-coastal deserts with this species, which can withstand harsh growing
conditions, could provide an alternative to mechanical carbon-sequestration
techniques.
The
researchers crunched some numbers and determined that the carbon-farming costs
would be competitive over 20 years with carbon
capture and storage, an embryonic technology in which a power plant’s
carbon emissions are captured and funneled underground. Carbon farming could be
funded by governments through carbon taxes and through the sale of carbon
allowances.
“Suitably
deployed, these plants could transform unused, barren lands into long-term
carbon sinks,” they write in the paper. “The carbon efficiency of this
bio-ecosystem would compare favourably with all other existing processes
for carbon storage and sequestration, including the cultivation of bio fuels.”
Not
only would the trees soak up CO2 and deposit some of it into the soil, but
their growth could influence rainfall patterns, soil quality, and regional
climates, paving the way for the natural growth of other plants.
Jatropha
curcas can withstand conditions that would make most plants wither, but
they’re not magical. They still need water. The scientists propose desalinating
water from the sea to irrigate the orchards. This is an expensive and
energy-intensive way of obtaining fresh water, but the scientists incorporated
that into their cost estimates.
Oil
from the trees is already used extensively for biofuel, and the scientists say
that after an orchard had been growing for a few years it would produce
nuts and leaves that could be burned to provide some of the power needed for
desalination.
The
idea seems worthy of further investigation — although it wouldn’t be much good
for the tortoises and other wildlife that revel in the world’s deserts.
Here’s
a graphic from the paper that helps explain the proposal:
John
Upton is a science fan and green news boffin who tweets, posts articles to Facebook, and blogs about ecology. He welcomes
reader questions, tips, and incoherent rants: johnupton@gmail.com.
1 comment:
He dude, your government was recently instrumental in killing the greatest desert hydration project in the world. Do a search for "the great man made river". The US with the help of the French paid to have Kadafi overthrown and his project stopped. Why? Follow the money and food trail.
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