Geoengineering's limitations: technical, social, and ethical
- 19 Dec 2013, 09:30
- Mat Hope
Credit: Satoru Kikuchi
As politicians edge towards agreeing a new
international climate deal in 2015, policymakers are increasingly
considering a broad sweep of policy options to reduce global
greenhouse gas emissions - including techniques to deliberately
'engineer' the climate.
In a special edition of the journal Climatic
Change, researchers have turned their attention to addressing
some fundamental issues surrounding the future of
What is 'geoengineering'?
The journal broadly defines
two types of geoengineering: carbon drawdown and removal (CDR)
and solar radiation management (SRM). In theory, both techniques
could help address some, but not all, of the impacts of climate
CDR involves drawing greenhouse gas emissions out of the
atmosphere and locking them away. For example, carbon capture
and storage (CCS) technology - which can be fitted to power plants
to reduce their emissisons - is a type of CDR. SRM techniques
are a bit different. They involve reflecting sunlight away from the
earth's surface in various ways in an attempt to control the amount
of warming that occurs, without actually affecting emissions. This
can be done by creating
clouds or putting
mirrors in space to reflect sunlight, for instance.
This video has a lot more detail, but it's nine minutes long, so
perhaps grab a cup of tea before clicking:
The Solar Radiation
Management Governance Initiative from Environmental Defense Fund
Geoengineering raises some tricky issues, which the academics
try to address. One key question is whether geoengineering
techniques could do enough to reduce climate impacts on their own,
or if they need to be part of wider efforts to address climate
Three papers try to establish under what circumstances ways of
changing the amount of the sun's light that hits earth would be
Two academics from the Pacific Northwest National Laboratory, Steven
Smith and Phillip Rasch, argue SRM is geoengineering is most
useful if the planet turns out to be very sensitive to carbon
They argue that if
climate sensitivity is high, SRM techniques become more
valuable as an extra way to deal with large amounts of warming. If
climate sensitivity turns out to be low, however, they say
"SRM would not be needed".
That's because temperature rise is only one of the climatic
impacts of increased greenhouse gas emissions. Because SRM doesn't
remove carbon dioxide from the atmosphere, it doesn't address
climate impacts like ocean acidification, meaning other policies
will need to be pursued alongside SRM. These would be sufficient to
address climate change impacts if climate sensitivity is low, the
There are other downsides to relying on SRM, according to two
Netherlands-based scientists, Detlef
van Vuuren and Elke Stehfest. If SRM became central to the
world's climate change mitigiation efforts but had to be halted
quickly, there could be extreme temperature shifts as a
consequence, they say. As such, their research suggests SRM is best
deployed in combination with other policies, as "the risks of
stopping its application seem severe".
Despite the risks and technical challenges, it's clear
geoengineering techniques could - theoretically, at least - play a
role in future climate change mitigation efforts.
But could the world work out how to do it cooperatively? A group
of academics have drawn up five principles which they argue should
guide geoengineering decisions, which they call the
- Geoengineering should be in the public interest, and regulated
to ensure this.
- The public should be involved in deciding whether
geoengineering goes ahead or not - particularly people potentially
affected by the technology.
- Geoengineering research should be transparent, with results
published and made available to the public.
- Independent researchers not involved in the geoengineering
projects should assess the potential impact of schemes.
- Governance structures should be in place before geoengineering
schemes are rolled out.
The scientists hope the principles will help policymakers as
they set about creating institutions to regulate geoengineering.
But deciding how such institutions work is also tricky.
Two researchers from the University of Colorado, Lisa
Dilling and Rachel Hauser, suggest setting up national
geoengineering organisations which ultimately fall under the
umbrella of a single, international organisation - similar to the
International Council for Science (ICSU) or the World
Meteorological Organisation (WMO). That way, international rules
could be rolled out across countries, and enforced by a central
It's not just the practicalities of regulating geoengineering
that need further thought, there's also an ethical aspect to
consider. After all, who has the authority to say whether or not
people should actively manipulate the natural environment?
This consideration needs to be at the core of geoengineering
decisions, says Dale
Jamieson, a philosophy Professor at New York University.
Working out who has the right to declare that geoengineering is
needed is a tricky question, Jamieson argues, because "one person's
emergency is another person's bad day at the office".
Just as fundamentally, how do we decide whether or not
geoengineering is "in the public interest", as the first Oxford
principle says it must be?
Gardiner, a philosophy Professor at the University of
Washington, says geoengineering is not a straight-forward 'public
good' as it's not always clear who it will benefit, or how. He says
"There is nothing magical about technological interventions in the
Earth's basic systems that implies (let alone guarantees) universal
benefit". There is simply too much uncertainty around
geoengineering's impacts for such a sweeping statement to be
assumed to be true, he says.
That's why it's so important to include the public in the early
stages of geoengineering debates, another group of academics led by
University of Montana PhD researcher, Wylie
Carr, argue. Carr's team say "the time is right" for the public
to be engaged on geoengineering issues precisely because large
scale schemes currently seem a long way off.
Ahead of the game
While it's unlikely the skies will be filled with balloons
spraying artificial clouds any time soon, technology is being
developed which allows humans to deliberately manipulate the
With such power comes a responsibility to think
about what the technical, political, and ethical implications might
be. And these academics think that's a job best done right at the