SPICE: Stratospheric Particle Injection for Climate Engineering

Lead Research Organisation: University of Bristol
Department Name: Earth Sciences


Climate change is a major threat to humankind. Observational evidence for warming of the climate system is very strong, based on increased temperatures, sea level rise and widespread melting of snow and ice. Future projections by climate models indicate substantial changes in future decades, much of which is on a regional scale that will severely impact regions of the world that are already under stress.There has been much improved understanding of the serious nature of the global warming problem both by politicians and the general public in recent years. However, there is great concern that efforts to mitigate future change by reduced greenhouse gas (GHG) emissions, including the outcome of the international meeting in Copenhagen 2009, are proceeding too slowly to avoid the risk of dangerous climate change and the possibility of certain 'tipping points' (such as the collapse of the Indian Monsoon of melting of the Artic ice sheet) being reached. This has prompted consideration of intervention by alternative means. Although considered by the majority to be the 'Plan B' that should be avoided if at all possible, there is increased consensus that the benefits, risks, costs and feasibility of this as an option requires consideration.A variety of 'geoengineering' options have been proposed, including solar radiation management (SRM) which involves offsetting the effects of GHG increases by causing the Earth to absorb less radiation from the Sun. Reducing incoming solar radiation by injecting sulphate aerosol into the stratosphere was considered the most rapidly deployable, affordable and effective option by the recent Royal Society report on Geoengineering the Climate. Volcanic eruptions provide evidence that sulphate particle injection leads to reductions in globally-averaged surface temperatures. However, there are concerns that there will be substantial regional impacts, on temperatures, rainfall and other aspects of climate. There are also uncertainties concerning timescales e.g. how rapidly injection might act, how quickly it could be 'turned off' and whether the climate responds differently to continued injection of aerosols compared with the episodic nature of volcanic eruptions.In terms of geo-engineering, the natural volcanic analogue of sulphate particle injection may not be optimum in terms of radiation management, and there may be better candidate particles for injection. Related to this, there are significant issues of cost and feasibility of injecting candidate particles into the stratosphere and the sustainability of particular injection technologies that require much further investigation.The SPICE project will investigate the effectiveness of stratospheric particle injection. It will address the three grand challenges in solar radiation management: 1. How much, of what, needs to be injected where into the atmosphere to effectively and safely manage the climate system? 2. How do we deliver it there? 3. What are the likely impacts? These questions are addressed through 3 coordinated and inter-linked work packages:Evaluating candidate particles: What is the 'perfect' particle, that maximizes solar radiation scattering, minimizes the greenhouse effect and the impact on the stratospheric ozone layer and has minimal impact on climate, weather, ecosystems and human health?Delivery Systems: What are the various options for delivery of particles? What is the feasibility of using a tethered-balloon pipe to inject particles and/or gases into the stratosphere in a more cost-effective and sustainable way than alternative methods?Climate and environmental modelling: What are the most effective locations for injection? How can we best use past volcanic analogues? What are the climate and environmental impacts of stratospheric particles?

Planned Impact

Who will benefit from this research? There are a great number of beneficiaries from this work to include: proximal research communities (those interested in aerosol characterisation, atmospheric dynamics and climate modelling), more distal research communities (fluid dynamics, hazard managers, volcanologists), industry (particularly the materials and engineering sectors) and the public, by having a thorough assessment of a short-lead time geoengineering solution to climatic tipping points. How will they benefit from this research? Academic communities will benefit from a greater understanding of stratospheric aerosols and their impacts and through the testing (and honing) of deliver solutions. The public benefit from being safer, as we delimit and attempt to reduce, uncertainty in solar radiation management. What will be done to ensure that they benefit from this research? Outreach, to academia, industry and particulalry the public is a vital component of this research. We will engage with academic and industry partners, and those outside the project through efficient and transparent data distribution, two project workshops, publications and presentations at international conferences. We will communicate to the public by continued face-to-face public interaction (both PI Watson and Co-I Hunt have spent significant amounts of time in these activities), a web presence and media engagement through the media offices at Bristol, Cambridge, Reading and the Met. Office.


10 25 50

publication icon
Oldham P (2014) Mapping the landscape of climate engineering. in Philosophical transactions. Series A, Mathematical, physical, and engineering sciences

publication icon
Rkiouak L (2014) Optical trapping and Raman spectroscopy of solid particles. in Physical chemistry chemical physics : PCCP

publication icon
Stilgoe J (2016) Geoengineering as Collective Experimentation. in Science and engineering ethics

Description SPICE's key findings include:
Non-sulphate particles require less volume, might reduce side effects.

Two lasers needed to suspend non-spherical particles.

TiO2 and SiO2 have less influence on the N2O5 reactions than SO42-

Direct cost cheaper than mitigation, tethered balloons cheapest, SO2 pumping a challenge

CMIP5 simulations not able to detect Northern Hemisphere winter warming consistently, and the solution is to better model stratospheric dynamics.

N2O5 preserved during injection relative to Pinatubo.

Hemispheric injections promote changes in rainfall, typically drying the opposing hemisphere.
Exploitation Route Our results will be used in two contexts:

(1) Laboratory and modelling results will be used in future work, particularly those looking at ozone chemistry and radiative transfer modelling.

(2) Several books have already been written about the SPICE project. It has, and will continue, to prove an important discussion point in the broader context of geoengineering.
Sectors Education,Energy,Environment,Government, Democracy and Justice,Security and Diplomacy

URL http://www.spice.ac.uk
Description SPICE was a very high profile project, which, given the nature of the subject matter, was not unsurprising. The team strived at all times to be open to debate and criticism and, although intangible , we have set the tenor for the debate around geoegineering through our efforts. We designed a blueprint for safe and acceptable work, and, through our actions have profoundly influenced the debate around geoengineering by finally breaking the taboo. Based on the SPICE experience, we suggested the following guidelines (in addition to standard good practice for academics) for conducting research in climate engineering and other controversial, emerging fields: • Consider the broader social context of the research during the project design phase, and, if necessary, integrate and allocate resources for this • Seek ethical approval, but do not consider this to be a 'carte blanche' for conducting research • Explicitly prescribe and review the management of IP • Continually examine your individual and collective motivations for working in the field and how they impact upon research decisions • Expect cultural differences to exist in multi-disciplinary teams, and develop ways of identifying and resolving these • Engage broadly, but be aware of stakeholder misrepresentation and inflexible, extreme views • Strive for transparency and reflexiveness, at the expense of self-promotion • Adopt a responsible innovation approach, mitigating the costs wherever possible but ultimately acknowledging that this will be challenging These guidelines, along with the Oxford Principles, now suffuse the field and provide a safer working space for academics, NGOs and government to ask hard questions
First Year Of Impact 2011
Sector Communities and Social Services/Policy,Education,Energy,Environment,Government, Democracy and Justice,Security and Diplomacy
Impact Types Cultural,Societal,Policy & public services

Description SPICE project debate
Geographic Reach Multiple continents/international 
Policy Influence Type Influenced training of practitioners or researchers
Impact The SPICE project played out, as it should, in the public domain, under the banner of functional transparency. The decision to postpone then cancel the testbed was not an easy one, but, knowingly opening ourselves up to scrutiny helped improve the regulatory framework (we were the first to undertake any regulation of these types of projects) and vastly increased public understanding of geoengineering.
URL http://geoengineeringourclimate.com/2013/05/14/a-commentary-on-the-oxford-principles-opinion-article...
Title Intellectual property around the tethered balloon system 
Description Upon the discovery of pre-existing patent applications relating to the technology to be investigated during SPICE it was felt that IP from the project needed careful management. The SPICE team developed a collaboration agreement that explicitly put all IP from SPICE in the public domain. 
IP Reference  
Protection Protection not required
Year Protection Granted 2011
Licensed No
Impact This has set a precedent for climate engineering research and our (non-IP) collaboration agreement has been used as a model in a subsequent EU funded project (EUTRACE).
Description SPICE Public Engagement 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact The SPICE project team undertook a wide range of engagement activities. These include

Presentation at three science festivals, including a press conference managed by the Science Media Centre (see URL)
Radio Four discussion (13/12/13 and 26/11/14 (Today Programme))
Numerous local and national radio interviews by the PI/Co-Is
Two public debates in Brighton and Cambridge
Year(s) Of Engagement Activity 2011,2012,2013,2014,2015,2016
URL http://www.cam.ac.uk/research/news/spice-project-announced-at-british-science-festival
Description SRMS2015 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact This was an international workshop and discussion meeting on Solar Radiation Management attended by over 100 academics which culminated with a public panel discussion (which was live streamed) whose panel members were:

Nobel prize winning economist Amytra Sen
Onora O'Neill, Chair of the Equality and Human Rights Commission
Lord Rees, Former President of the Royal Society
Professor David Keith, Harvard University.
Year(s) Of Engagement Activity 2015
URL http://www.srms-cambridge.eng.cam.ac.uk/