With levels of greenhouse gases soaring and the scientific consensus clearly showing that mankind has a significant impact on our climate, it’s clear that something needs to be done.

But nations have repeatedly failed to come to an agreement on how to significantly curb emissions or make any meaningful changes to their carbon footprints, due to the economic and political challenges that drastic changes can raise.

Due to this, some have called for a more radical approach to the climate problem – climate engineering.

The hope is that we will be able to use technology to undo some of the damaging effects of climate change and rising temperatures.

However, with the science behind climate engineering currently remaining untested and still in its early stages, many are also concerned at its possible side effects, or how it could be used to distract from the issue of curbing emissions.

What is climate engineering?

Stefan Schäfer co-leads the research group on climate engineering at the Institute for Advanced Sustainability Studies (IASS), and served as the chair of the conference steering committee for the Climate Engineering Conference 2014.

The IASS examines the impacts, uncertainties and risks of climate engineering techniques, but is not developing or supporting implementation of any techniques.

He defines the umbrella term of climate engineering as “a large set of very different approaches, techniques and proposals that operate on very different timescales and with very different resource requirements, and would require vastly different logistical and material infrastructure” but all of which are designed to change our climate.

“A lot of exaggerated claims are being made about SRM on both ends of the spectrum” Stefan Schäfer

“The general distinction people make is between removing greenhouse gases from the atmosphere (usually referred to as Carbon Dioxide Removal (CDR)) and reflecting solar radiation away from the Earth (Solar Radiation Management (SRM)).”

CDR includes various techniques, from carbon capture through biomass, artificial trees and chemicals like calcium oxide or sodium hydroxide.

However, CDR techniques are slow to act and have an impact, and therefore require long term political support, as well as often require large scale engineering efforts.

SRM “is referred to as a set of high leverage, fast acting, potentially cheap technique that could, over a short timescale, reduce global average temperatures and so reduce some of the effects of climate change.”

The two most discussed approaches in SRM “are to either introduce aerosols into the stratosphere to reflect a small part of the incoming sunlight, or to brighten clouds,” says Schäfer.

In each case, the reduction in solar energy in the atmosphere helps cool the planet in the short term. However, while it could theoretically help solve the temperature-based problems of climate change, major issues like the acidification of the oceans would remain a growing concern.

According to Schäfer, we can’t say just yet which of the SRM techniques is the most promising, or if they are viable. “It’s something that scientists are researching, with some wanting to intensify the research effort.”

“A lot of exaggerated claims are being made about SRM on both ends of the spectrum, with some invoking catastrophism and others possibly neglecting potentially serious risks and concerns. One of our goals is to provide a platform for scientifically supported discussions, so that such claims can be scrutinized and dialogue can emerge.”

Climate engineering has been a source of much discussion in the scientific community for decades, but, at this stage, there isn’t much movement “towards providing some kind of implementation capacity, as they’re all at a hypothetical stage, a conceptual stage.”

But, as the prospect of climate engineering has “moved into political discussions, especially at the international level, it’s really important to have these discussions early on” to provide support for making decisions on where research should continue.

“But I don’t think that a roadmap to implementation is being developed anywhere,” states Schäfer. These are all concepts that people are talking about, at this stage there’s no way to even confidently say that something will be possible to do in the future. It’s all very exploratory, very early.”

In Schäfer’s view, with the current state of climate engineering and the lack of political will around it, “the likeliness that we will see large, or even small, outdoor experimentation on especially the SRM methods in Europe soon is quite small.”

However, while being unable to perform some experiments does obviously impact the rate of research, “there are a lot of things that can still be learned from modelling studies. Climate impact modelling has not been done to a large degree on SRM, so that area could really benefit from more research.”

“With preventing testing, are we concerned about the damage the test could cause, or the creation of dangerous knowledge? Ken Caldeira

Ken Caldeira, an atmospheric scientist at the Carnegie Institution who in 2007 was the principal contributor to an IPCC team that won a Nobel Peace Prize, is sceptical about how much further we can go with just models.

“I’m not saying it’s been exhausted, but a lot of that low hanging fruit of what you could do running a computer model is kind of starting to get exhausted. To get much further than we are today, you would have to do some experiments outdoors, and this is obviously controversial.”

The problem, he says, is that “the world is a lot more complicated than our models, and one thing you can be sure is that things will happen that you didn’t anticipate. Models can form the basis for rational expectation, but you shouldn’t really treat it as a prediction of what will actually happen.”

Caldeira also questions why we have certain safeguards on climate engineering tests: “With preventing testing, are we concerned about the damage the test could cause, or the creation of dangerous knowledge? I think it’s appropriate to have regulatory safeguards to prevent environmental damage, but the idea that knowledge itself is dangerous? I don’t like that framing.”

But one way Schäfer highlights that we could improve our knowledge would be to establish “a research infrastructure that could observe, for example, natural events that are in some aspects analogous to processes that would also happen in SRM deployment scenarios, like volcanic eruptions.”

In 1991, Philippine island volcano Mount Pinatubo erupted, causing millions of tonnes of sulphur dioxide mixed with water droplets to cover the Earth’s atmosphere, reducing the amount of sunlight that reached the planet over the next two years to be reduced by over ten percent.

In a single year, global temperatures dropped by almost three quarters of a degree Celsius, but at the same time there were floods and droughts in various continents. Studying this eruption, as well as others, is seen by many in the field of climate engineering as a way to analyse the impact of SRM techniques without physical experiments.

Political tool

But while there are fears about the unintended consequences of engineering our climate, that is not why many scientists are anxious about working in the field. Instead, many are concerned that it could be used as a political tool to divert attention and resources away from reducing greenhouse gases.

Schäfer believes that this “is probably the largest worry in the academic community right now, that investing into climate engineering research or even discussing the possibility that climate engineering will emerge as a response to some aspects of climate change in the future, will syphon resources away from efforts to reduce greenhouse gas emissions.”

Caldeira, however, has a different view: “There’s a certain empirical question over whether solar geoengineering causes people to want to do more or less about emissions, and the data is pretty thin. I believe that it can actually help, that if people think that we’re desperate enough to try such extreme measures, maybe they should be worried about climate change.”

Additionally, promoting climate engineering requires you to believe that change is happening. “A lot of right wing climate change deniers who don’t agree with climate change like the idea of geoengineering. So that means they’re having to say that there is some risk, some reason for it.”

Aggressive climate engineering

Another concern with climate engineering that many raise is how it could be either used by governments as a weapon, or how it could cause escalating tensions between nations.

Atmospheric scientist Dr. Mark Lawrence, scientific director of IASS, doesn’t believe that direct weaponisation is terribly likely. Not only have 85 countries signed the U.N. Convention prohibiting using the weather as a weapon (and climate is the long-term average of the weather), but the science behind it isn’t ready yet.

“The weaponisation possibility is only there if a climate engineering intervention can be targeted to affect one region and not affect other regions, or at least not affect one’s home region. That would be quite complicated, and the knowledge for that does not yet exist.”

“Climate modifications would also have to last for a long period of time to really be affecting the climate. For example, you could possibly make it rain really hard to cause a flash flood as a form of weather modification, but you would have to change the rainfall for decades to really call it climate modification.”

However, what is a much greater possibility is nations using climate engineering as a threat, or for their own benefit when it could have an adverse impact on other parts of the world.

“It has been speculated that some of the small island states, for instance, could threaten to implement some form of SRM if the larger nations don’t get their act in gear and start reducing CO2. That’s one version that’s like a Cold War scenario.”

“The other possibility is that international conflicts could arise over an implementation of climate engineering, especially SRM. If there was a coalition of the willing, say North American countries, that decides that they are going to implement something that is tuned to their benefit, then it is probably not going to be tuned to the benefit of the rest of the world. So there’s the real concern – if anything is implemented that’s short of a real international consensus regarding the implementation, then it could very well lead to international hostilities.”

At best, climate engineering can alleviate some issues, but not solve the problem.

In Lawrence’s view, climate engineering is “a difficult topic that tends to polarise people very quickly, and that leads to a discussion that is often mainly based on underlying values and principles, which people don’t bring out very clearly, but which strongly influence the way they see and interpret what very little evidence there is.”

“Our information is paltry. With those uncertainties, it’s difficult to make decisions in the first place. But when the issue is something that touches on people’s sense of morality, then the ethical associations very quickly tends to politicise the discourse.”

The future

No country has shown itself to be openly interested in climate engineering, Lawrence says “I don’t think any country at a high level of government is currently going to step forward and say outright that they’re going to put forward any form of climate engineering.”

In the US, Caldeira notes that the issue has become politicised. “The problem is, if a politician who has voted for geoengineering research is on the campaign trail, the opponent will say that they’re ‘in favour of injecting chemicals into the sky’, when they just want to research it. If there wasn’t this political overlay, I think there’d be a research program in the US in this area.”

However there have been small signs of interest from some nations: leaked documents from 2013 showed that Russia had pushed to include support for climate engineering in the UN climate report, while Yuri Izrael, who was an adviser to Russian President Vladimir Putin, conducted a 2009 experiment to spray particles from a helicopter as a very simple SRM test.

China is also seen by some as a potential leader in climate engineering, with the country listing geoengineering among its Earth science research priorities in 2012, and using a barrage of 1,110 rockets filled with silver iodide to stop rain ruining the 2008 Olympics.

Nevertheless, while some countries and groups may push forward with climate engineering, Schäfer believes that “it’s extremely important to always highlight that the most important and crucial thing to focus on now is to reduce greenhouse gas emissions to prevent future climate change.”

There is no quick fix, no ultimate cure. At best, climate engineering can alleviate some issues, but not solve the problem.

Featured image by L.Pettet, iStock