[This article was originally published by Yale Environment 360 on June 7 and is used here with permission.]
In May, J Craig Venter announced that his team had successfully developed the first self-replicating cell to be controlled entirely by synthetic DNA. Not artificial life exactly, but certainly something different: a synthetic cell in which humans had intervened deliberately with the express purpose of changing the genetic structure and characteristics of a natural organism.
Humans are lining up comparable purposeful interventions in the functioning of another physical system – not the microscopic system of a bacterium, but the macroscopic planetary system that fashions and delivers all our climates. The range of such potential climate-intervention technologies, from altering how much of the sun’s energy strikes the Earth to removing carbon dioxide from the atmosphere, continues to expand against a backdrop of anxiety that humanity may inadvertently be pushing global climate toward a dangerous state.
These two new ventures – manipulating the biological functions of cells and manipulating the physical functioning of the climate system – may be seen as simply the latest steps in the enduring human project of seeking control over the physical world. Hominid mastery of fire in the Paleolithic brought about radical changes in the possibilities for human life, and the manufacture of antibiotic drugs in the twentieth century opened up a wide range of new medical treatments that have reduced suffering and extended human life. Designing self-replicating cells and re-tuning global climate may therefore appear as inevitable developments in our ingenuity and our ability to manipulate the world around us.
But compared to the questions raised by Venter’s biotechnologies, two categorically different sets of questions arise about climate manipulation: how do we judge the risks of unintended consequences? And who is entitled to initiate the large-scale deployment of a climate-intervention technology – and under what circumstances?
Proponents are suggesting two broad categories of technologies to roll back global warming. The first, solar-radiation management (SRM), calls for altering the solar-radiation budget of the planet, using such technologies as mirrors in space, aerosols in the stratosphere, and cloud whitening over the oceans. And then there are technologies, grouped under the category of carbon-dioxide removal (CDR), that propose to accelerate the removal of carbon dioxide from the atmosphere by fertilising the oceans with iron, extracting CO2 from the atmosphere, or sequestering CO2 by heating biomass in oxygen-free kilns and burying the charcoal underground. (See also chinadialogue’s series on geoengineering here, here, here, here and here).
Such interventions would bring about, if not exactly artificial climates, then certainly synthetic ones. The calls for significant investments in these technologies have grown in boldness and urgency over the last few years. Whether from government agencies or private investors such as Richard Branson or the company Climos, resources are being directed into pursuing something akin to Venter’s vision of synthetically controlled cells, but the “cell” in question here is the planetary climate.
Both genres of climate intervention technologies raise serious ethical questions about the propriety of such manipulations, about their accordance with the collective will of people on Earth and about the unforeseen side effects of such interventions. But the proposition of creating synthetic climates through solar-radiation management (less so with carbon-dioxide removal) introduces a range of additional concerns not shared with microscopic cellular manipulation. These concerns arise from the brute fact that there is only one climate system with which to experiment, and it is the one we live with. If it is planetary-scale manipulation of climate that is desired – and it is – then experimentation has to be conducted on a planetary scale to prove the effectiveness, or not, of the technology.
The first concern is the risk of unintended consequences. Given that it is not possible to conduct large-scale planetary experiments in solar-radiation management before going “live” with the technology, risk assessments have to fall back on using virtual climates generated by computer models. The Earth system models currently used to explore the possible future effects of rising atmospheric concentrations of greenhouse gases are the same ones that have to be used to explore the simulated consequences of a variety of solar-radiation interventions.
Using aerosols to offset the additional planetary heating caused by greenhouse gases is a relatively straightforward theoretical calculation; it is a case of simple planetary budgeting. Much harder is to know what this “re-balancing” of the global heat budget will do to atmospheric and ocean dynamics around the world. These are the dynamics that make weather happen at particular times and in particular places and which – through various combinations of rain, wind, temperature and humidity – shape ecological processes and human social practices. The dangers and opportunities associated with climate occur through these local weather phenomena, not through an abstract index of global temperature.
If the goal of climate engineering is simply to reset the global temperature dial at its nineteenth or late-twentieth century register, that might be possible to do. But in the process of doing so, significant perturbations to regional climate conditions, and inter-annual variability around those conditions, are likely to be introduced. Even if changes in the frequency and intensity of storms and precipitation were to be a zero-sum game globally, the distributional effects of such changes will create winners and losers. Such phenomena as El Niño, the Asian monsoon and the Arctic Oscillation will not remain unaffected. And given the far-from-adequate ability of Earth system models to simulate the regional-scale dynamics of the hydrological system, no one should be confident that the full risks of solar-radiation management interventions will be revealed and quantified.
Which brings us to the second question that sets apart the project to fashion a synthetic climate from the project to create synthetic self-replicating cells: under what future scenario could one imagine full-scale deployment of solar-radiation management taking place? Many commentators have drawn attention to the multi-layered issues of financing, ethics, governance, geopolitics and public opinion that surround most of these solar-radiation intervention technologies. These were very much to the fore at the Asilomar International Conference on Climate Intervention Technologies in California earlier this year.
And yet a number of senior and significant voices in the scientific academy and policy community continue to speak of the urgency with which solar-radiation management research should be pursued. They offer these putative control technologies as another option in the portfolio of climate-management strategies, with climate manipulation joining climate-change mitigation and climate adaptation in a trinity of strategies available for policymakers. At the very least, it is argued, solar-radiation management should be available as a backstop technology if the world finds itself in a climate emergency when a dangerous tipping point needs to be avoided.
But can we imagine a possible scenario under which the decision to proceed to full deployment of solar-radiation management might be made? Let us assume the injection of aerosols into the stratosphere had been placed at the top of the list of climate-intervention technologies. Let us also assume that the basic operational mechanics of getting aerosols into the optimal layers of the stratosphere for maximum solar shielding had been figured out. One possible scenario might look something like this:
It is January 2028 and the United Kingdom, one of the permanent members of the UN Security Council, puts forward a formal resolution to start the systematic injection of sulphate aerosols into the stratosphere. The UK’s argument is that, with Arctic sea-ice extent the previous summer having shrunk to just 25% of its late-twentieth century value, with monitors in Canadian permafrost identifying increased rates of methane release, and with the explosion at a nuclear reactor in China two years earlier leading to a moratorium on all new nuclear power plant construction, such direct climate-remediation measures are called for.
The Intergovernmental Panel on Climate Change (IPCC) provides a report for the Security Council on the regional climatic risks of such intervention. Based on the best Earth system models, the IPCC offers probabilistic predictions of the 10-year mean changes in regional rainfall around the world that would result from sustained aerosol injection.
The 15 members of the Security Council argue over the evidence. In particular, they spend much time weighing the probabilities that the Asian monsoon might be weakened as a result. Security Council members also argue about how long the initial aerosol injection should continue – for one year, three years or five years. Against a background of vociferous, and at times violent, globally-coordinated public campaigns (both in favour of and against such intervention), the Security Council votes 11 to two in favour, with two abstentions. The deployment will proceed for a one-year period, after which a full evaluation will be conducted.
Over the following months, protestors attempt to sabotage some of the planes being used to inject aerosols, and direct-action groups affiliated with HOME (Hands Off Mother Earth) send up their own aircraft in symbolic efforts to scrub the aerosols from the stratosphere. After one year the deployment is temporarily halted and climate data are evaluated.
Global temperature has indeed fallen from the previous 10-year mean of 15.23 degrees Celsius (the 1961-1990 average was 14 degrees) to just 14.57 degrees Celsius, the coolest year on the planet since 2014. But regional climate anomalies have been large and variable. Of most concern was a failure of the Asian monsoon, at the cost of US$50 billion (339 billion yuan) to the Indian economy, and the most intense cyclone season in the South China Sea for 20 years.
India – one of the rotating members of the Security Council – and China now trigger an emergency debate calling for a permanent ban on deployment of aerosol-injection technologies. The IPCC argues that one year’s data prove nothing about the efficacy or impact of solar-radiation management. But against a background of further global protests, led by the new popular civic movements in China and India, the Security Council now splits five votes to five, with five abstentions. Turmoil ensues as two Canadian billionaires unilaterally continue aerosol injection.
Of course, one could create a hundred other scenarios under which the story of solar-radiation management may unfold. But I use this one to draw attention to the profound political obstacles and humanitarian risks that shadow attempts to engineer the climate through solar-radiation management. The organisation HOME already exists, seeking to mobilise people everywhere to tell climate engineers to proceed no further with climate manipulation.
The technical body supporting the work of the UN Convention on Biological Diversity has recently proposed a draft text along the following lines: “No climate-related geo-engineering activities [should] take place until there is an adequate scientific basis on which to justify such activities and appropriate consideration of the associated risks for the environment and biodiversity and associated social, economic and cultural impacts.” [Emphasis added.]
Words such as “adequate” and “appropriate” offer new grounds for contention in an already argumentative world. If the politics of climate-mitigation policy under the guise of the Kyoto Protocol have proved intractable, just wait until we see the geopolitics surrounding the negotiation of the first protocol on engineering synthetic climates. In the name of saving the planet from inadvertent greenhouse-gas exacerbated climate change, climate engineers may simply be offering us one Promethean fire to offset the effects of another.
Mike Hulme is professor of climate change at Britain’s University of East Anglia.