http://www.nature.com/news/climate-tinkerers-thrash-out-a-plan-1.16470

NATURE | NEWS

Climate tinkerers thrash out a plan

Geoengineers meet to work out what research is acceptable.
Quirin Schiermeier

02 December 2014

On 1 December, the United Nations kicked off a summit in Lima that aims to
forge a global deal to reduce greenhouse-gas emissions. Now,
representatives of dozens of scientific societies are gathering in
Washington DC to thrash out a set of principles for researching highly
controversial technologies known as geoengineering. The methods offer ways
to cool the planet should political approaches fail.

“There are a number of risks and unknowns,” says Paul Bertsch, deputy
director of the Land and Water Flagship at the Commonwealth Scientific and
Industrial Research Organisation in Brisbane, Australia, and past chair of
the Council of Scientific Society Presidents, which is convening the
geoengineering meeting. “So we urgently need to develop and implement a
coordinated research plan that begins to address these in a deliberate
way.”Some ideas, such as injecting carbon dioxide into rocks or the depths
of the ocean, are already being tested. Others are more futuristic:
spraying sea water into the air to brighten clouds and reflect more
sunlight back into space; adding sulphate particles to the upper atmosphere
to mimic the natural cooling effect of volcanic ash; and even placing giant
mirrors into orbit to reflect sunlight before it reaches Earth.

Not one, however, has garnered much enthusiasm in environmental or
political spheres. The idea of tinkering with the planet smacks of
scientific hubris, and many are worried about unintended consequences.
Climate scientists are concerned, for example, that adding sulphate to the
stratosphere might reduce rainfall in some regions and worsen ozone
depletion.

On 2–3 December, leaders of societies representing some 1.4 million
scientists, engineers and educators will work out what research is and is
not acceptable given the possible social, ecological and economic effects
of climate engineering. A conference held in 2010 in Asilomar, California,
failed to produce clear guidelines (see Nature 464,656; 2010).Most
scientists say that it is too early to consider large-scale trials,
especially for solar-radiation management, because the techniques have not
yet been adequately tested in controlled settings. However, many maintain
that geoengineering should not be ruled out as a last resort to prevent the
worst effects of global warming.

“The question is when, if at all, should we start doing outdoor
experiments?” says Matthew Watson, a volcanologist at the University of
Bristol, UK, who is overseeing a project to determine how the deliberate
spreading of sun-blocking particles might alter atmospheric chemistry (see
‘UK experiments’). “I don’t particularly ‘like’ geoengineering, but I’m
afraid we do need to think about controlled field trials.”

Matthew Watson, a volcanologist at the University of Bristol, presented the
results of the Stratospheric Particle Injection for Climate Engineering
(SPICE) project. SPICE investigated whether spraying particles into the
atmosphere could reflect sunlight and cool the planet, offsetting global
warming. A planned test of some of the technology was abandoned in 2012
when conflict-of-interest issues emerged over a patent application for the
system. But Watson says that SPICE produced useful insights, such as how a
large-scale project might alter the Sahel region in Africa.

Piers Forster at the University of Leeds, who led the Integrated Assessment
of Geoengineering Proposals project, said that his team’s computer
modelling showed that several techniques to manage the Sun’s radiation
would produce damaging changes in rainfall that could affect 25–65% of the
world’s population.Watson, Forster and the University of Oxford’s Steve
Rayner, who is leader of a third effort called the Climate Geoengineering
Governance project, agreed that their work created many questions.

A method that has already been tested — ocean fertilization — provides a
particularly thorny case study. The idea was to boost ocean uptake of
carbon dioxide by pouring iron into the sea to stimulate the growth of
algal blooms. When the algae die, the captured carbon sinks to the ocean
floor, where it may remain locked away for centuries.

But the approach came under fire when eco-entrepreneurs smelled business
opportunities. Plans by companies in the United States and Australia to
fertilize large swathes of ocean to generate carbon credits that could be
sold on greenhouse-gas-emissions markets were headed off by a 2008
amendment to the London Convention, an international treaty that governs
ocean pollution.

Together with a resolution made under the United Nations Convention on
Biological Diversity a few months earlier, the amendment made it difficult
to conduct trials of ocean fertilization. In 2009, for example, an
international research cruise was stopped en route to the Southern Ocean
over fears that an iron-stimulated algal bloom the team had planned to
encourage there might violate international law.

Meanwhile, another attempt, by an amateur scientist in 2012 off the coast
of British Columbia, led to an international storm of protest and prompted
heated discussions in the Canadian government over the legality of the
experiment.

Such unresolved governance issues mean that little funding is available for
further studies. “We’re caught up in politics,” says Ken Buesseler, an
ocean scientist at Woods Hole Oceanographic Institution in Massachusetts.
“You’d absolutely like to avoid rogue experiments that don’t generate
proper science. But there is every reason to pursue real science in the
field in an open and responsible way.”Meeting discussions are aimed at
creating comprehensive guidelines for the safe conduct of field
experiments, and will feed into a report that the US National Academies
intends to release early next year on the technical feasibility of selected
climate-engineering mechanisms.

Neither ocean fertilization nor any other single activity will solve the
global warming problem, cautions Anya Waite of the Alfred Wegener Institute
in Bremerhaven, Germany, who represents the fields of oceanography and
limnology at this week’s meeting. “But limited ocean-fertilization
experiments are telling us a lot about how biological processes in the
ocean control climate. In terms of new regulations, they should be the
first cab off the ranks.”

Nature 516, 20–21
(04 December 2014)
doi:10.1038/516020a

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