Geoscience Reference
In-Depth Information
CO
2
captured from the air with hydrogen
to produce a carbon-neutral transportation
fuel, which would have an advantage over
conventional biofuels because the produc-
tion of the fuel would not require the use
of land which could otherwise be used to
produce food.
There's something admittedly romantic
about the notion of building machines to
pull CO
2
out of the air. It's the stuff of sci-
ence fiction, calling to mind the works of
Jules Verne. The idea also has an advantage
over many other geoengineering schemes
in that there are fewer unpredictable or un-
desirable side effects. For that reason alone
it is worthy of significant investigation.
most likely to be employed, for several
reasons. First of all, its technological and
financial requirements are relatively low:
only ships and a supply of soluble iron ma-
terials are needed. It is also a particularly
attractive option for polluters involved in
carbon emissions trading, which is one of
the ways countries can meet their climate
change mitigation duties under the Kyoto
Protocol. Under the protocol, countries can
use greenhouse gas removal programs such
as reforestation or carbon sinks to meet
their emission reduction requirements.
Thus if ocean fertilization on a large scale
becomes an option for countries looking to
meet emission reduction requirements, it
could be a highly profitable endeavor. At
present, carbon sinks from ocean fertiliza-
tion are not a tradable emissions commod-
ity, but the possibility of huge profits has
already attracted attention from private
companies.
Fertilization is not without its detractors.
In 2008 the United Nations Convention for
Biological Diversity agreed to what the Ger-
man environment minister Sigmar Gabriel
described as a “de facto moratorium.” Del-
egates agreed to refer to the London Con-
vention for guidance on ocean fertilization.
In late 2008 the London Convention stated
that ocean fertilization activities other
than “legitimate scientific research should
not be allowed.” In January 2009 an Indo-
German scientific team sponsored by the
Alfred Wegener Institute and others con-
ducted the lohafex experiment in the
southwest Atlantic despite protests from
seeding the oceans
One of the most extensively studied ideas
is to artificially increase planktonic algal
blooms. The phytoplankton capture car-
bon by photosynthesis, acting like a carbon
sponge. When they die they carry some of
this carbon to the ocean floor. Scientists
have discovered that planktonic blooms
can be induced by introducing limiting nu-
trients, such as phosphate or nitrogen, but
it appears that one of the most effective
ways to create an algal bloom is to fertil-
ize with iron those regions in the sea which
otherwise are abundant in phosphate and
nitrogen. This has been done successfully
a number of times as part of scientific
experiments.
Fertilizing the ocean with iron appears
to be one of the geoengineering schemes
