Plan B?

As this term draw to a close, the question still remains: Is geoengineering a plan b for climate change?

Before I started this blog, I had a rough idea what geoengineering was, but without detailed knowledge on particular methods. In the course of the last three month I read and wrote about cloud seeding by spaying seawater, planting trees, stratospheric sulphur injections, ocean fertilisation and space sunshades. These are all very different methods with different side effects. However, they have two thing in common: The aim to change the environment and the climate on a global scale. Moreover, further research is needed, to be certain what impacts these methods will have. I am not sure we will ever know these impacts for sure if we do not try it out. But is that the best way? How much risk are we willing to take? It is obvious, that geoengineering alone cannot be the solution of our problems. We need to reduce our greenhouse gas emissions on any account. There is no way around that! Something has to be done, but I think we should be very cautious with those methods that hold the greatest uncertainties.

What do you think? Is there a particular method you think could work or is geoengineering not the right way to deal with our problems? I personally think, some of the less radical methods (e.g. seawater spraying to form clouds) could help to mitigate climate change, but first we really do need to know a little bit more about the consequences. However, on a long term only reducing emissions will help, there is no way around that!

Was Durban a success?

'Q&A: Why Durban is different to climate change agreements of the past'

The Guardian published a nice article on the outcome of the Durban climate change conference, in the form of questions and answers on what happend before, what the participants agreed on and what will happen next. It gives a short overview over a really sensitive issue.

In a last minute compromise, the participants agreed on setting up a new agreement on cutting down greenhouse gas emissions. For the first time developed as well as developing countries are included. The agreement is supposed to come into force in 2020. Furthermore this agreement should also be legally binding, making it more difficult for governments to just 'wriggle out' of the treaty. However, the exact goals of how far emission will be reduced are not yet clear and further negotiations will take place until 2015. Therefore it remains to be seen how efficient this agreement will really be.

Read this article online:
http://www.guardian.co.uk/environment/2011/dec/11/durban-questions-and-answers

The Guardian also has several other articles on the conference in Durban:
http://www.guardian.co.uk/environment/durban-climate-change-conference-2011

And this is the official website of COP17/CPM7 in Durban:
http://www.cop17-cmp7durban.com/

Are space sunshades the solution?

Another suggested way to mitigate global warming is using small spacecrafts, placed between Earth and sun as a ‘sunshade for the earth’. This method is analysed in an article by Roger Angel (2006). The idea comes from observations of great volcanic events, after which particles in the atmosphere lead to a cooling effect by scattering and reflecting sunlight. The same idea was used for the sulphur injections, which I described before. However, shielding the earth with space sunshades does not have the same negative side effects for the environment that sulphur has. 

The proposed location for the sunshade is near the Earth-sun inner Lagrange point (L1), which is a point between sun and Earth where theoretically gravity alone makes sure the sunshade remains stationary. The penumbra of the sunshade would cover the whole Earth in this position. However, little spacecrafts rather than just particles are necessary to stay in one formation.

The advantage of this technology is, that neither ocean nor atmosphere is modified, which makes this method more environmentally friendly. Furthermore Angel (2006) argues, that the results are easier to predict than the results for other methods, as only one factor (solar radiation) is changed.

The downside is, that it requires a sunshade at a really large scale, which is not only difficult to achieve technically but is also very expensive.

(source: Angel 2006: 17184)

 The idea is to launch many individual ‘flyers’ (Angel 2006) from the Earth. This way there is no need for a single large sunshade. Still there is a very high cost for transportation. Angel (2006) estimates it to be $50/kg. The whole project would have a cost of 1 trillion $, with a cost average of 100 billion/year (‘0.2% of current world gross domestic product’ Angel 2006: 17189). Also it is not enough to just bring the flyers away from the atmosphere. Additional energy is needed to reach the final location. An optimistic goal is that the flyers will stay in place for approximately 50 years, if the technology is improved further and works as ideal as it is hoped. After this they have to be replaces, but a life period for several decades would be a great achievement compared to other techniques. Angel (2006) further suggests that 20 launchers are needed, each launching 20 million flyers, one every 5 minutes. Launching the flyers obviously requires energy, but the positive effect they have once they reach their destination outweighs this negative on climate.

To sum it up, a cloud of small sunshade has the potential to mitigate the current trend of global warming by scattering incoming solar radiation. The environmental impacts, apart from the energy that is needed to produce and launch the flyers, are by far smaller than the impacts of e.g. ocean fertilization or sulphur injections, which makes the idea even more interesting.

However, this is one of the methods with the highest technological level and very high costs. Even if the costs can be reduced to the goal of 50$/kg with more research, the method is still more expensive than most other geoengineering ideas. Therefore I think, that even if the methods works good in theory, the high costs could be the reason why governments might not want to use it. Another question is, how big are the cost if we do nothing? Adaptation to climate change later might be even more expensive, than trying to mitigate it now. So, shouldn’t we make an efforts to raise the money for geoengineering now, rather than paying for the consequences later?

Literature:

Angel, R. (2006) ‘Feasibility of cooling the Earth with a cloud of small spacecraft near the inner Lagrange point (L1)’ PNAS, 103, 46, 17184-17189.
available online: http://www.pnas.org/content/103/46/17184.full.pdf

Ocean Iron Fertilisation

Today’s article deals with another geoengineering method: Ocean fertilization. These methods try to enhance the sequestration of CO₂, by releasing specific nutrients, especially iron into the oceans on a large-scale. The article by Cullen and Boyd (2008) investigates the consequences of ocean iron fertilisation (OIF). As this is another large-scale method, it also has large-scale consequences that have to be considered.

Studies have shown that fertilisation in HNLC regions (high-nitrate and low-chlorophyll, approximately 30% of the world’s oceans) could sequester 0.5 Gt of carbon per year. An even better rate could be achieved in oligotrophic waters by stimulating primary productivity of phytoplankton. However, using OIF leads to large-scale changes in ocean chemistry and the ocean ecosystem. The changes also occur over a long period of time, as the OIF is supposed to work in a scale of at least a hundred years.

The application of iron to the ocean directly leads to an increase in phytoplankton and thereby to an increased production of organic matter, which then sinks into deeper ocean levels. It is important that the sequestered CO₂ remains in the ocean over a longer period of time, which means it has to stay in depth below the zone where winter mixing occurs. Only the CO₂ that reaches deep waters can be seen as sequestered. However, a certain part will not reach this depth and can still affect the surface layer with increased availability of nutrients, inorganic C and an oxygen deficiency. Therefore processes in mid-depth water still need to be studies in more detail.

As a side effect the production of DMS (dimethylsulfite), which is a source of atmospheric sulfur, can be enhanced. As discussed in a previous post, sulfur can lead to cloud formation and thereby enhance albedo, which is another positive effect in terms of climate change mitigation.

With the increased availability of iron more of the macronutrients in the surface layer of the ocean can be used. This in turn leads to a change in the nutrient composition, which can later on lead to a limitation of further primary production. This again can have impacts e.g. on fishing resources.

As another downstream effect OIF could release N₂O and methane, which are even more potent greenhouse gases than CO₂.

Changes in source water in coastal areas can either have positive or negative effects. One positive effect is that the increased nutrient availability can lead to increased primary production. On the other hand, coastal hypoxia can increase or become more frequent, which has already been witnessed in previous OIF experiments. Cullen and Boyd (2008) further suggest, that all changes go on gradually, increasing with repeated fertilisation processes. However, the expected changes can so far not be quantified and we still rely on estimated values. Further research is still needed, before OIF can be seen as a promising and secure geoengineering method. The problem with predictions is the time scale, as experiments today can not show us the impact if iron fertilisation in 100 years. Furthermore there are likely to be other unpredictable effects, which result from the modification of the ocean system. The articles stresses the point, that currently uncertainties are still too high to make sell carbon offset, as it was also suggested. However, Cullen and Boyd (2008) see OIF as a promising method, which on the other hand bears risks.

I think they have a point. From what I have read, ocean fertilisation sounds as a promising option at first sight. However, in my opinion the uncertainties about side effects and long-term ecological consequences are still too high to modify the ocean system on such a large scale. It may be frustrating to repeat this with almost every suggested technique, but again further research is necessary to make a decision about the use of OIF.

Literature:

Cullen, J.J., Boyd, P.W. (2008) ‘Predicting and verifying the intended and unintended consequences of large-scale ocean iron fertilization’ Marine Ecology Progress Series, 364, 259-301.

Available online: http://www.int-res.com/abstracts/meps/v364/p295-301/

How to protect the planet

A little off-topic maybe, but here is a little cartoon about 'the perfect way to protect our planet'...

source: (http://www.haroldsplanet.com/daily/images/80_protect_planet.gif)

Should that make us think...?

Need for further research

"Geoengineering techniques need more study, says science coalition"

"The Solar Radiation Management Governance Initiative says geoengineering could be 'plan B' for climate change"

The guardian published an article about geoengineering on thurday this week. It states that geoengineering is not science fiction and could indeed be a way to combat climate change in future. However, it is still a 'risky business' and there is need for further research. In addition working together internationally and reducing political borders is essential for successful geoengineering.

Read the full article here:

http://www.guardian.co.uk/environment/2011/dec/01/geoengineering-techniques-study-science-coalition?newsfeed=true

Addicted to fossil fuels

(source: http://www.loleegreen.com/wp-content/uploads/2009/06/live-and-learn-or-vice-versa.gif)