Guest post – Bob Olson, Senior Fellow, Institute for Alternative Futures – A Venture Into Geoengineering


Tuesday, Apr. 08, 2014

A friend at the Woodrow Wilson International Center for Scholars, David Rejeski, asked me if I would be willing to write a report on geoengineering. He asked me, not because I had any special expertise in the subject, but because I didn’t. He wanted someone without any obvious biases to take a fresh look at the subject.

My first reaction was to feel like I did have a bias. I had encountered the concept of geoengineering back in 1979 or 1980 when I was working in the Energy Group at the Congressional Office of Technology Assessment. I found the idea “very scary,” to put it mildly. But now I was finding the climate situation “very scary” as well, so I decided I was “fair and balanced” enough to take on the project.

I came out of that experience, and some other work it led to, believing more strongly than ever that the first priority – and second and third priority – is to radically increase the efficiency of energy use, rapidly phase out fossil fuels, and replace them with renewables. I also came out of the experience with my “very scary” reaction to geoengineering still in place.

Here are five of my major concerns.

Unintended Negative Consequences   There are too many gaps and uncertainties in our understanding of geophysical and ecological systems for us to be confident we can safely engineer the global climate. Greater understanding could reduce the risks, but the climate system may be inherently too complex – and therefore the possibility of unanticipated harmful side effects too large – for us to ever consider geoengineering very safe.

Danger of Undermining Emissions Mitigation Efforts   If politicians are led to believe that a low-cost technological fix can reduce or eliminate the need for politically difficult actions such as increasing the cost of carbon by cap and trade schemes or taxation, going against the wishes of powerful fossil energy corporations, and getting countries all around the world to agree on climate goals, it is likely to undermine their resolve to deal with the underlying cause of the problem by reducing greenhouse gas emissions.

Risk of Sudden Catastrophic Warming   This concern stems directly from the possibility that the prospect of successful geoengineering would make emissions reductions seem less urgent, allowing more and more carbon dioxide to build up in the atmosphere over the century ahead. The danger then becomes that if the geoengineering effort should ever falter, a century’s worth of warming could hit us all at once, far too rapidly for human society and other plant and animal species to adapt. Large build-ups of carbon dioxide would last thousands of years in the atmosphere. This means that any geoengineering initiatives that allow such build-ups to occur would need to have internationally sanctioned control that is ultra-reliable and proof against mechanical failures, human error, economic depressions and funding failures, wars, terrorism, natural disasters and simple apathy across many centuries.

Equity Issues   Past experience with volcanic eruptions that throw material into the stratosphere, blocking a fraction of sunlight from reaching the Earth’s surface, shows that the cooling effect they produce is also typically accompanied by reduced precipitation in some areas, increasing the incidence of drought. Recent modeling efforts indicate, unsurprisingly, that geoengineering methods that are essentially “artificial volcanoes,” blocking a small amount of sunlight, would have the same effect. Even if conditions improve in some areas, other areas might suffer.

Commercial Interests Overriding the Public Interest   Dozens of patent applications have already been filed for different geoengineering technologies. What can stop the drive for shareholder profits from leading to inappropriate geoengineering deployments? Would companies undermine mitigation efforts by influencing governments to allow geoengineering technologies to qualify for carbon credits or to meet emissions reduction targets? Questions like these have not yet received nearly the attention they deserve.

Despite these and other concerns, I also came to the view that geoengineering has got to be assessed. We can’t just ignore it.

Despite these and other concerns, I also came to the view that geoengineering has got to be assessed. We can’t just ignore it. One reason for this view is that I came to see there are more varieties of geoengineering and more scenarios of how it might be used than I had appreciated before, so that a flat out rejection of “geoengineering” now strikes me as too sweeping and simplistic.

For example, from whatever peak concentration of carbon dioxide we eventually reach in the atmosphere, it will take about a thousand years for it to decrease by half, and then another thousand years to fall by half again. That means it could take longer than human civilization has been around to get CO2 back to the preindustrial level. However there are many technologies for removing carbon dioxide from the atmosphere. A few, like ocean fertilization, appear ecologically disruptive, but most of them aren’t. They haven’t been given much attention because they’re so slow acting that they can’t have much impact in the short run. But if we could use them to speed up the decline of carbon dioxide concentrations by several thousand years, might we not want to at least consider doing that?

Then there are technologies I referred to as “Soft Geoengineering” in an article I did for Environment magazine (pay-walled). They are things that can be done locally that at first glance appear to be environmentally benign and have multiple benefits beyond impacts on climate. For example, making roofs and paved areas brighter in urban areas would have a very slight global cooling impact, but would also make urban areas more comfortable, reducing the “urban heat island” effect, and save tens of billions of dollars every year in air conditioning costs.

We could brighten water in reservoirs by injecting highly reflective “microbubbles.” By one estimate, putting a “cloud” of microbubbles into a small reservoir would have the reflective impact of 10,000 white roofs. The microbubbles would also sharply reduce reservoir evaporation, which is already a significant issue and will become a bigger one as climate change continues. California loses over 10% of its irrigation supply to evaporation and some countries in the Middle East lose over 50%.

There are no obvious limits to how much carbon can be stored by building more topsoil biomass. Current farming methods erode and degrade topsoil, but we could reverse that by adopting methods that are less disturbing to the soil and plant roots and by more use of cover crops or “green manures” that add organic matter to the soil, increase soil fertility and water retention, and reduce pests and diseases.

Some opponents of geoengineering dismiss such soft geoengineering ideas as being like “soft drugs”: they trap you into thinking that geoengineering can be good for you so you’re more likely to feel favorably toward trying “hard geoengineering” and get hooked on it. There are grains of truth in that view, but I think it’s just too dogmatic. I believe ideas like these deserve more research and would make sense to pursue if they truly prove environmentally benign and cost effective.

David Keith, who is emerging as the leading advocate of using stratospheric aerosols, urges that we consider a scenario that involves using that technology relatively soon, starting a generation from now. He advocates going full speed ahead with energy efficiency and renewables, but also slowly phasing in some use of stratospheric aerosols to moderate climate impacts, watching carefully for any negative effects. He argues that doing this can moderate the serious impacts and risks of climate change, halt or reverse the loss of Arctic ice, prevent massive methane releases from melting permafrost, reduce the decline in precipitation that climate change itself will cause in some areas, and reduce the crop losses predicted from climate change, especially in the hottest and poorest regions. I’m not sold on Keith’s argument, but I’m willing to entertain the possibility that at some point, as we learn more about both climate change and geoengineering, I might give it a second look.

Finally, there’s the “climate catastrophe” scenario where we find ourselves having passed some critical tipping point where climate change is accelerating out of control. If it ever comes to a situation where geoengineering appears to be the only recourse to a global climate catastrophe, decision makers will almost certainly choose to do geoengineering. They should not be put in the position of either letting dangerous climate change occur or deploying unstudied and untested technologies at full scale. We should at least do enough research on some of the key geoengineering technologies to know whether using them would be a disastrous mistake – whether, for example,using stratospheric aerosols would quickly degrade the stratospheric ozone layer.

So, all in all, I emerged from my research effort willing to advocate a certain amount of research on geoengineering, while also believing that for now and the foreseeable future there should be a moratorium on large scale testing. Above all, let’s get on with the transition to energy efficiency and renewables. We need a societal mobilization and technological transformation at a speed and scale that has few if any peacetime precedents. Engage!


Bob Olson is a Senior Fellow at the Institute for Alternative Futures.  The report he authored for the Wilson Center, “Geoengineering for Decision Makers,” can be found here.  Video and papers from the 2012 “Considering Soft Geoengineering” conference based on this work can be found here.






The Washington Geoengineering Consortium does not necessarily endorse the ideas contained in this or any other guest post. Our aim is to provide a space for the expression of a range of perspectives on geoengineering.