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Geoengineering and Synthetic Biology
Posted August 15, 2017 by Daniela Quaglia
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*Guest post by Devang Mehta*

*This September, as part of their annual symposium, EUSynBioS will
hold an **Open
Discussion* <http://www.eusynbios.org/symposium>* on the topic, “Synthetic
Biology and Environmental Engineering”, at the National Center for
Biotechnology, Madrid, Spain. They will host experts in the field to talk
about the science and the more difficult aspects of public acceptance and
bioethics surrounding geoengineering and synthetic biology. *

Geoengineering is a word that means many things to many people. Formally
defined <http://rsta.royalsocietypublishing.org/content/370/1974/4166.long> as
the “deliberate intervention in the climate system to counteract man-made
global warming”, for some scientists it represents a cheap and effective
way to protect our planet from the ravages of climate change. To others, it
is symptomatic of technological hubris: a grand, doomed plan to control
every aspect of our ecosystem. Dig past the rhetoric though and you find a
science that’s still in its infancy, being developed by scientists around
the globe, almost as a last resort in the (now very possible) event that
on-going efforts to avert climate catastrophe by reducing global emissions
fail.

Current research on geoengineering is focused on either removing carbon
dioxide from the Earth’s atmosphere or reducing global warming by
reflecting more solar radiation away from the planet. Most proposals to
achieve these goals rely on physical engineering solutions, cloud seeding
for instance. A more expansive reading of “geoengineering” though, leads to
several intriguing ideas on using synthetic biology to remedy the effects
of intensive industrialisation/pollution on the environment.

*I. Pale blue dot*

In 1980, the US Supreme Court issued a ruling that changed the status of
living organisms forever. In *Diamond v. Chakrabarty*
<https://supreme.justia.com/cases/federal/us/447/303/case.html> the court
affirmed the right of inventors to patent living organisms that had been
modified for some purpose. In this case, the patent was granted to a
genetically engineered creature called the Superbug. The Superbug was a
strain of *Pseudonomas putida* that could break down crude oil, and was
posited as a tool to deal with oil spills. Since then, there’s been a lot
of work in developing such organisms, spawning a field of science called
bioremediation that seeks to undo the damage human industry causes the
environment.

Now, a group of scientists is advocating the use of such organisms on a
global scale to help mitigate the effects of climate change. Their, very
SciFi-*ish,* ideas include: modifying particular species of bacteria that
exist in harsh environments like deserts and equipping them with water
harvesting capabilities
<https://www.newscientist.com/article/mg23130931-000-lets-harness-synthetic-biology-to-fix-our-broken-planet/>;
releasing entire stretches of DNA into a biosphere and allowing them to
spread, equipping any host creature with water/temperature sensing
capabilities, or releasing bacteria into the oceans that can cause pieces
of plastic to stick to each other
<http://2012.igem.org/Team:University_College_London>, solving the scourge
of microplastic pollution.

“biologists are ever-aware of the conceit involved in predicting biological
futures”

These and other ideas find few takers, though, and carry some real risks.
We would have to be prepared to deal with the fact that any man-made
bacteria released into a particular part of the world might *escape *a
particular ecosystem, potentially wreaking havoc in others. Biological
entities evolve, and evolution might change released modified bacteria in
unpredictable ways.

These are concerns synthetic biologists are tackling head on. In the last
five years, we’ve made tremendous progress in engineering ‘kill-switches’
<http://www.biorxiv.org/content/early/2017/04/21/129445> that could allow
us to precisely control engineered bacteria in natural ecosystems. We’ve
also developed bacteria which have been so extensively engineered
<https://www.nature.com/nature/journal/v518/n7537/full/nature14121.html> that
they cannot interact with other life-forms very well, or cannot reproduce,
hence limiting the potential spread of synthetic DNA. Yet, biologists are
ever-aware of the conceit involved in predicting biological futures and for
the moment these bacteria will remain in Petri dishes in labs around the
world.

*II. The red planet*

The largest concern with biological geo-engineering is the fact that we
might cause dangerously irreversible changes to the only habitable planet
we know of. This is why a group of scientists
<http://rsif.royalsocietypublishing.org/content/12/113/20150803>, including
NASA researchers, are exploring biological options in terraforming Mars.
The hopes are many, ranging from making Mars human-habitable (paving the
way for eventual human colonisation), to using the red planet as a test-bed
for ecosystem engineering whose lessons might then rescue the Earth from
climate catastrophe. Less futuristic scenarios include the possibility of
employing bacteria to harvest resources directly from Mars, or recycling
consumable resources like waste-water, making manned Mars-missions a
cheaper and easier endeavour. Most experts agree though that terraforming,
the process of completely changing Mars’ atmosphere is a process that could
take centuries. A nearer-term option is something called para-terraforming.
Paraterraforming envisions making smaller, enclosed spaces on Mars
habitable for humans. Previous experiments in paraterraforming conducted on
Earth have met with little success; however the prospect of engineering
organisms specifically for terraforming makes this a more feasible
proposition.

Some, however, question the ethics of using Mars as a lab-bench. One
argument is that any human attempt at terraforming Mars might destroy or
alter any remnant, hitherto undiscovered life on the planet. Another, that
seeding Mars with terrestrial life may change a potential independent
development of biological life on the planet in the distant future. These
are minority opinions, however. A view that, in my opinion, holds more
merit suggests that the creation of Mars as a back-up planet might hinder
attempts to mitigate anthropogenic climate change and pollution here on
Earth.

*III. A last resort*

There are two forms of climate change mitigation on the table at the
moment, *passive* and *active.*Passive mitigation uses methods that are
easier to swallow for most, reducing global consumption, stricter pollution
controls, and switching to low-carbon sources of energy. The problem,
however, lies in the fact that passive mitigation alone might not be enough
to limit global warming to the 2°C threshold set by the Paris Agreement.
<https://ec.europa.eu/clima/policies/international/negotiations/paris_en>
Indeed,
experts are highly sceptical
<https://www.carbonbrief.org/two-degree-climate-target-not-possible-without-negative-emissions-scientists-warn>
that
limiting warming to even 4°C is feasible given current trends. And the
difference between a 2°C and 4°C limit is that the latter will result in
massive droughts, flooding on an unprecedented scale and food shortages.

In this scenario, several climate experts have called for more drastic
measures including non-biological geoengineering technologies
cloud-seeding. In fact, some estimates claim
<http://people.earth.yale.edu/sites/default/files/files/Boos/StorelvmoBoosHerger2014.pdf>
that
cloud-seeding on a large enough scale might even bring global temperatures
down to below pre-industrial levels. In this scenario then, would we even
need a biological solution that might carry more risk?

A possible benefit of biological remediation is of course that we might be
able to rescue ecosystems that are on the brink of collapse, something that
physical solutions like cloud seeding might never be able to achieve.
Biological solutions can address biological problems in a manner that
purely physical measures might struggle to. Another aspect of synthetic
biology, the de-extinction
<http://www.sciencemag.org/news/2016/09/should-we-bring-extinct-species-back-dead>
of
extinct species, is something that might supplement the reduction in global
warming with the restoration of lost biospheres.

On the policy front, geoengineering is a topic that is often scoffed at or
neglected in favour of discussions such as emissions reduction. The reasons
for this are legitimate, though, given the current political climate with
the US backing out of climate accords
<https://www.theguardian.com/environment/2017/jun/12/us-opts-out-g7-pledge-paris-climate-accord-irreversible>,
the dream of a 2°C reduction in global warming seems to be growing ever
more distant. Science agencies across the world are waking up to this fact,
and just a couple of months ago China announced the world’s largest
geoengineering research program
<https://www.technologyreview.com/s/608401/china-builds-one-of-the-worlds-largest-geoengineering-research-programs/>.
As of now, geoengineering remains a last resort, and biological measures
even more so.

This isn’t stopping scientists from experimenting with it though, and nor
should it.



About the author: *Devang Mehta, **Devang is currently a PhD student in
Plant Biotechnology and Science & Policy at ETH Zurich. He also serves on
the EUSynBioS Steering Committee as Policy Officer. Follow him on twitter
at **@_devangm* <http://twitter.com/@_devangm>* or check out his blog at *
*www.devang.bio* <http://devang.bio/>*. *

Photos: All photos used under CC0 license.

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