Geoscience Reference
In-Depth Information
address the mitigation of CO
2
separately from that of other
greenhouse gases;
−
take ocean acidification into account in discussions aiming to
define the acceptable level of CO
2
;
−
−
establish an ocean acidification index concurrent with the
temperature.
Harrould-Kolieb and Herr [HAR 12] recognized that these are
major challenges, but believe, in contrast to Kim [KIM 12], that the
UNFCCC offers a better framework for preparing for the mitigation of
ocean acidification and even proposed that the UNFCCC begins to
exclusively focus on CO
2
emissions in order to increase the chances of
simultaneously addressing climate change and ocean acidification.
5.5.2.
Geoengineering techniques
Geoengineering is the deliberate and large-scale manipulation of the
environment of the planet in order to counter anthropogenic climate
change [THE 09]. There are two groups of techniques: those aiming to
reduce the CO
2
that is already present in the atmosphere (carbon dioxide
removal, CDR) and those aiming to reflect part of the solar radiation
and heat back into space
(solar radiation management, SRM). The
potential effects of these techniques on ocean acidification have been
examined by Williamson and Turley [WIL 12].
CDR techniques include the following: sequestration of the CO
2
in
sub-seafloor storage, ocean fertilization through the supply of
nutrients such as iron and basic products such as bicarbonate,
carbonated minerals, or pulverized calcerous rocks in order to increase
pH and CaCO
3
saturation. Some of these techniques, such as
fertilization, which aims at stimulating phytoplankton growth, and
therefore increasing the biological assimilation of atmospheric CO
2
,
only shift the problem elsewhere. A large-scale fertilization would
cause a sequestration of CO
2
in deep waters following sedimentation
and the decomposition of additional organic matter created at the
surface. This would, therefore, increase the rate at which pH decreases
in deep waters [CAO 10, OSC 10].
