How might geoengineering affect our terrestrial biosphere?

Climate stabilisation schemes for example the SPICE project will have a profound affect on terrestrial biosphere. If this scheme works in the way that its proponents claim then we should all benefit from decreased solar radiation. However, CO2 will continue to increase nonetheless (causing CO2 fertilisation). However, what impacts will these changes have on Net Primary Production (NPP) and biomass?

Govindasamy et al. (2002) attempted to model these changes and yielded some staggering results. They judged that with a predicted decrease of 1.8% of solar fluxes then NPP would decrease by around 2.4%. However, with a model where CO2 reaches double that of the present level, NPP increases by around 76%. However, as noted by Schimel (1998), changes in nitrogen availability are crucial to the carbon cycle as they affect nutrient levels in the soil. Consequently, these nutrient levels (which are unaccounted for in the model) might in fact limit the NPP increases calculated.

The model used in this paper acts give an estimate and should be used more to give qualitative projections on future changes in the terrestrial biosphere. The authors admit that although they have produced quantitative data, it should be treated with caution. They have used a very simple ocean model and have prescribed the levels of CO2. With more in depth models and taking climate feedbacks into account, different results will likely be calculated.

                                                                                                  Govindasamy et al. (2002)

Although this might appear to produce very positive affects on the terrestrial biosphere, we still must remind ourselves of the uncertainties that exist regarding geoengineering, many of which have been discussed in past posts

A few words from a very influential man

I’ve recently found myself engrossed in a series of televised lectures from TED conferences (Technology, Entertainment and Design). They have some of the most inspiring and intelligent speakers from Bill Clinton to Steve Jobs and if this is all news to you then i couldn’t recommend it more! (they are all on youtube and only about 20mins long) (TED, 2011)

Although slightly off topic for this blog, I really thought that it might be of great interest to anyone with a passion towards solving climate change to listen to Bill Gates speak on climate change in 2010 (Innovating to zero). He mainly discusses a form of renewable energy known as ‘Terra Power’ (TerraPower, 2011) This is the process of using depleted uranium (what we would know as radioactive waste) as a substitute to the current fuel, enriched uranium. Basically, a complicated form of recycling.......how can that be bad!?  It sounds good in principle but we all know what happened at Fukushima and Chernobyl and the further 33 serious cases since 1952 (The Guardian, 2011). Anyway, i’ll let you make your own minds up on that issue!

Gates briefly mentions geoengineering 24 minutes in and I thought it would be very useful to look at the view of a non-academic. He shares the same views that Schelling talks of relating to a preference for dealing with the cause rather than the symptoms. However, Gates uses an interesting analogy for geoengineeering (Schelling, 1996)

Burning fossil fuels____________Climate change_____________Geoengineering

Over-eating__________________Heart attack________________Surgery

Geoengineering, like heart surgery is a useful insurance policy. But, Gates worries that if we know it is possible, will we neglect to get to the source of the problem and try to fix our polluting ways?

However, he does state that it would be very unwise not to at least research geoengineering as it would be useful to have in the back pocket.

I have posted the video below and i would strongly suggest giving it a watch:

Also, on a very unrelated note, might I suggest watching the TED talk that I have linked.....this one of my favourites!

The politics of geoengineering

As I have already stressed over the course of this blog, geoengineering is a very controversial topic. However, what exactly is geoengineering?.....if you’ve read my first two posts then you probably think that you have this all covered. However, is it more complicated that it at first might seem?

Might I remind you of the definition of geoengineering provided by the National Academy of Sciences

“options that would involve large-scale engineering of our environment in order to combat or counteract the effects of changes in atmospheric chemistry”

Now let me ask you this:

1. If we actively try to reduce fossil fuel emissions, is this geoengineering?
2. Afforestation, a means of geoengineering?

Don’t panic if you don’t know the answer! Neither is right or wrong and this is where the problem lies. I have recently read an article entitled ‘The economic diplomacy of geoengineering’ (Schelling, 1996) that discusses this in a little more detail. 

A number of intriguing scenarios are set out for example:

The construction of a shipping canal between the Gulf of Mexico and the Pacific Ocean

• This would not be classed as geoengineering - it would have ‘geo’ side effects though. Species would interact with those which previously had been 10,000 miles apart.
• However, if this was done intentionally then it would almost certainly be classed as geoengineering

If we learn how to increase snowfall in the:

• Rockies to increase water supply to Colarado and improve skiing this is not geoengineering
• If we do it in the Arctic to store water and counteract sea level rise then this is geoengineering

These contradictions just shouldn’t exist!

What struck me the most in this article is the point that Schelling makes about ‘people having a preference for dealing with causes rather than the symptoms’. He suggests that people would prefer to produce less CO2 rather than remove it. Afforestation for this reason should, but is not referred to as geoengineering. It is rather seen as more natural even though it is not significantly different from ocean fertilisation.

Geoengineering is also a political nightmare! It is so large scale that it transcends national boundaries and as a result.....who should pay? can we all afford to pay the same? Do we all reap the same rewards? To what extent should we geoengineer? When it comes to afforestation for example.....England will find it much more difficult to offset carbon than Siberia where there is plenty of space to plant trees. England should surely be allowed to offset their carbon through planting trees wherever land is cheapest......shouldn’t they? It is these unanswered questions that haunt world leaders and will continue to do so for the time being.

A significant obstacle lies in the question, who reaps the benefits? If we can stop a hurricane from striking the Phillipines then it would appear obvious that we should! Simple

.....BUT......

the south of China would suffer from decreased rainfall! Now a little more Complicated!

Anyway, I hope this post gives you a little insight into the political complexities that surround geoengineering.

Ozone levels as of November 2011

A false colour composite from NASA's Aura satellite showing the significant holes in the polar ozone

Geoengineering and ozone depletion

My last post suggests that there is large support for geoengineering schemes......but do the public really know the ins and outs of the matter? Much of the research that scientists have been carrying out is never seen by the average man on the street. Often only the benefits seem to be published outside of academic journals. My support for geoengineering schemes has diminished since I've started seriously looking into the matter. I recently found an article in science which strongly argues against Stratospheric Particle Injection as a valid geoengineering technique (Tilmes at al., 2008). It does however, at no point in this article discuss whether SRM would work but instead focuses on a significant negative impact - Polar ozone depletion. This post will offer a small summary however, this is a very short and punchy article which I would well recommend a read.

The depletion of the ozone results from two main factors:  

1. Anthropogenic halogen loading in the atmosphere
2. Activation of Chlorine

The most significant depletions of ozone have occurred over the Arctic regions. However, it’s not all bad news, we have already started a recovery!! Halogen loading has started to decline as the world is becoming more and more aware of the impacts. This has lead to the prediction that by 2070 levels will have returned to that of 1980. However, this article concludes by quantifying the delay in this recovery if stratospheric particle injection is put into action. Depending on the extent of the vertical expansion of the ozone hole, a recovery will be delayed by between 30 and 70 years.

The graph below results from a model based on two separate geoengineering scenarios. First, using ‘small’ aerosols and second,with ‘large’ aerosols.

Before looking at this graph it is vital to notice the presence of the background levels of particles. These have naturally (in this case without geoengineering) increased until 2000, resulting in the activation of stratospheric choline particles but then levels are shown to quickly recover over the next 70 years. However, with the introduction of geoengineering (especially using smaller particles) we very quickly backtrack and significant volumes of chlorine are ‘activated’ forming reactive radicles which significantly increases ozone depletion.

In conclusion, this article is the first to quantify the effects of this form of geoengineering on polar ozone depletion. It proposes that it could be hugely damaging and in fact, a step back in our fight against climate change. It highlights the uncertainties that arise on the ideal aerosol sizes and also suggests that the ozone loss from future volcanic eruptions will be exacerbated by the pre-existing levels of ‘artificial’ particles in the stratosphere. I for one am not so confident on geoengineering as I once was!!

Do the public support geoengineering?

Megan Smith, author of the acclaimed blog entitled ‘Feasting on Fossil Fuels’, recently sent me an extremely informative article which investigates the current public opinion on geoengineering (Mercer et al., 2011).

The article, which appeared in the Journal of Environmental Research Letters is centered around a recent survey consisting of 18 questions regarding geoengineering techniques and in particular, SRM. However, the results did not really surprise me.  Around 72% of respondents supported further research into SRA but most believed that this method alone would not be sufficient to counteract the present changes to climate.

However, geoengineering is not without its critics! It is often seen as an easy way out and merely a temporary solution. The risks are also not fully known, with groups like EcoNexus arguing that even at a micro scale, harmful effects might ensue. The previously mentioned postponing of the SPICE project is evidence for the significant pressure that opponents are exerting on both the government and research groups. 

I would be very interested in hearing other peoples views on the matter so please do leave a comment and take the poll 

SPICE - Solar Radiation Management

Stratospheric Particle Injection for Climate Engineering (SPICE) is a project which aims to mimic the effects that volcanoes have on climate. Large volcanic eruptions have unequivocally been proven to reduce temperatures across the whole of the globe (Robock, 2000).

Recent evidence for this lies with eruptions such as Mt Pinatubo in the Philippines. After a substantial eruption in 1991, considerable amounts of tephra and 20 million tonnes of sulphur dioxide were ejected into the stratosphere. This gas is quickly converted to sulfuric acid aerosols which act in a similar way to ozone by absorbing short wave radiation from the sun. Although difficult to conclusively measure, Gobal Circulation Models suggest that temperatures decreased by between 0.2-0.5°C during the following two years (NASA)

The SPICE project aims to test the feasibility of using water as a substitute to SO₂. Due to the great uncertainties in the effects of adding vast volumes of water vapour to the atmosphere, experiments will take place first at a relatively small scale. Water will be drawn up a pipe from the sea to a helium balloon acting as a platform at an altitude of between 10-20km. It will then be introduced into the troposphere (Natural Environmental Research Council)

But will it work...? At the moment this technique is seen to be the one with the most promise. It is by far the most economically viable as, past the stage of research and development, the platform and the water will cost relatively little (especially compared to the use of millions of tonnes of iron needed in the previously discussed ocean fertilisation). However, although this process is known to work naturally after volcanic eruptions, concerns lie with the lack of knowledge as to the effects that will occur through a constant rate of injection compared to the natural episodic injections.

What is not known is the extent of the temperature change that will occur and also for how long it will last. These are significant knowledge gaps that, fingers crossed, the upcoming experiments should help to shed light on. A further worry lies with the regional changes that might occur with other climate factors, not just temperature. Will rainfall be affected for example? Another issue is that Solar Radiation Management has no effect on atmospheric CO₂ levels and therefore will do nothing to halt ocean acidification (The Royal Society report)

The first SPICE experiment was due to be undertaken last month but has been indefinitely postponed due to pressure by the UK population and an advisory panel. In my opinion, research is crucial and this might just be part of the answer that we’ve all been looking for!