2018-09-18 06:26:52 UTC
limit the effects of global warming through aerosols.
With concern about global warming caused about climate change
continuing to rise and fewer and fewer options to do something
about it, scientists are proposing a radical new solution.
Experts say we should study the next major global volcanic
eruption to learn about spreading aerosols to reflect sunlight
back into space and cool the planet.
Volcanoes spew a huge amount of rock and ash when they blow, and
that mixes with water vapor to form aerosols, which acts as a
giant reflector that keeps light from entering the Earths
atmosphere. During the eruption of Mount Pinatubo in the
Philippines nearly 30 years ago, global temperatures plunge by
nearly a full degree Fahrenheit for about two years.
As a result, scientists believe they can study the effects of
the next volcanic eruption to determine the feasibility of
actions like spreading aerosols in the sky via jet planes or
other methods in order to counteract the effects of global
The following is a statement from a 2007 NASA paper on the
subject of managing solar radiation.
In November of 2006 the NASA Ames Research Center and the
Carnegie Institution of Washington Department of Global Ecology
at Stanford University sponsored an expert workshop on the use
of solar radiation management as a strategy for coping with the
challenge of climate change. The basic concept of managing
Earths radiation budget is to reduce the amount of incoming
solar radiation absorbed by the Earth so as to counterbalance
the heating of the Earth that would otherwise result from the
accumulation of greenhouse gases.
The workshop did not seek to decide whether or under what
circumstances solar radiation management should be deployed or
which strategies or technologies might be best, if it were
deployed. Rather, the workshop focused on defining what kinds of
information might be most valuable in allowing policy makers
more knowledgeably to address the various options for solar
radiation management. The report concludes with an appendix that
describes important environmental science, engineering, and
policy research issues.
The volcanic eruptions of El Chichón and Pinatubo injected
enough sulfate aerosol into the stratosphere to decrease
temperatures in the Northern Hemisphere for 1 to 3 years by
several tenths of a degree Celsius. Repeating the aerosol
injections and optimizing them for cooling could amplify the
impacts on global temperatures. Further research could assess
whether this approach could safely counter the significant
increases in temperature that could occur by 2100 if
anthropogenic greenhouse gas emissions continue unabated.
Research could determine, for example, whether injections of
sulfates or other materials into the stratosphere could diminish
cooling in the Arctic region, an area of seemingly high
vulnerability to climate change.
Workshop participants also considered other approaches to solar
radiation management, such as a plan to raise the reflectivity
of low altitude marine clouds. Work has begun on designing
seagoing hardware capable of producing the upward directed spray
of mixed air and seawater intended to increase cloud
reflectivity. Another proposed approach was to block some
sunlight with an orbiting space sunshade. The inner Lagrange L1
point is in an orbit with the same one-year period as the Earth,
in-line with the sun at a distance where the penumbra shadow
covers, and thus cools, the entire planet. A presentation on
this concept proposed several approaches for overcoming the
various engineering and economic challenges a sunshade presented
although those challenges remain daunting.
These concepts have been the subject of some preliminary
theoretical analysis, but none have been tested in the field
under controlled experimental conditions. Solar radiation
management as climate policy Research into solar radiation
management approaches could develop information related to
effectiveness and unintended consequences. Research could
proceed in a carefully graduated series of theoretical studies
and experiments. If the deployment of such technologies were
ever to comeunder consideration, having generated detailed
knowledge about the consequences of each option could be
extremely valuable. On the other hand, research may show that
solar radiation management strategies would not be feasible for
any of a number of reasons.
Although the workshop did not address the issue of the
circumstances under which solar radiation management should be
deployed, participants views on this matter appeared to span
the gamut including (i) never, (ii) only in the event of an
imminent climate catastrophe, (iii) as part of a transition to a
low-carbon-emission economy, and (iv) in lieu of strong
reductions in greenhouse gas emissions. More importantly, the
discussion illuminated important differences in the economic and
political implications of solar radiation management depending
on whether deployment occurred in the face of imminent climate
emergency or was implemented preemptively well in advance of
crisis conditions. Thus the circumstances under which solar
radiation management might be deployed could have major
implications for its economic and policy implications.