Final thoughts....

Over the course of several weeks, I have tried to unpack the term ‘Geoengineering’ and understand its potential as well as its flaws. A variety of Geoengineering options have been presented and ideas/issues surrounding this field have been highlighted. So after all this research, what is to be learned?

Firstly, it is not enough! More research is needed. Figure 1 shows the number of research papers published on Geoengineering per year. According to the Economist, this is just more than 50 papers for 2010. While this may sound like a large amount, this blog has addressed at least 8 different geoengineering options, and there are still more to consider. Therefore, when these 50 papers are stretched over the wide variety of Geoengineering proposals, this indicates that there is very little depth in this field. And this was definitely found when conducting research....there were a lot of great ideas, the basic science was put forward but there was little information on testing and the full impacts of each proposal. Lawrence (2006) found that although you could find a large number or proposals, it takes a great effort to determine the unintended consequences of each option. Many academics agree that research into Geoengineering is still in its infancy (Victor et al, 2009).

However, when comparing the available Geoengineering options and evaluating their potential to offset C02 emissions, it was found that some options could be viable. By simply adopting better forest management, investing into afforestation, disposing of waste differently to produce biochar, and fitting large industrial plants with the technology to capture and store carbon, this could make a significant contribution to reducing emissions. These are activities that could be easily incorporated into society, and could be extremely useful in buying us more time to invest in more long-term solutions.

Figure 1:

Personally, I have found that through learning more about the variety of Geoengineering options available, I have broken down those pre-conceptions I had about the field. I originally viewed Geoengineering as a radical, destructive, field of ideas that could make things worse. And although there are risks, some options should be prioritised and heavily considered.

However, what the research does show is that despite the growing interest in Geoengineering, all the academics interested in this field explicitly state that there is no replacement for cutting emissions. Geoengineering will never be the answer to all the world’s problems. It doesn’t solve the problem of Ocean Acidification and many of the options, with the exception of sun shades and stratospheric aerosols, are unable to fully offset C02 emissions unless strong mitigation occurs. Therefore, if the international community doesn’t put all its efforts into curbing emissions then we will be faced with too worrying futures: One future may involve extreme temperatures, higher sea levels and a greater frequency of climatic events such as hurricanes, storms. While the other future may see the use of stratospheric aerosols, that were used as a last resort to prevent the climate system from destabilising. This future will have a very different climate, may have a lot more pollution, a depleted ozone, and could look very different to today...but the biggest worry is that we may never really be able to predict what this future could look like....

........taking this perspective, I feel the answer to the poll question that I asked right at the beginning of the this investigation, is clear: NO we should not abandon measures of mitigation, however, as a last resort we should make small investments into a handful of geoengineering options in order to give us more time to adapt and invest in long-term solutions....but this is just my opinion...I have tried to give you all the facts...what do you think?

Are we playing God?

Let us go back to the definition of Geoengineering: ‘the intentional modification of the earth’s climate system’. Humans/people have been modifying the environment for years...some deliberate e.g. deliberate fires/building of dams, while some not intentionally e.g. the global-scale transformation that has occurred since the 1850s (Schneider, 1996). Some scientists believe that humans have impacted the earth to such a significant extent that a new geological era should be created, specifically acknowledging the impact that humans have had on the Earth’s ecosystems: the Anthropocene (Crutzen, 2002).

The man who first coined the word ‘Anthropocene’ in 2000, nobel prize winner Paul Crutzen, is also the man who has written numerous papers on the Geoengineering proposal whereby sulphur is injected into the atmosphere. Crutzen believes that we are not doing enough to mitigate GHG emissions, so much so that we need an escape/back up plan; in his mind this is Geoengineering.

So people like Paul Crutzen, may argue that we have already modified the earth; that we have already ‘chosen’ to geoengineer our climate system through the use of fossil fules, so what is the matter with a little more modification? And when scanning the literature and learning about the variety of Geoengineering proposals, I found myself thinking...we are just replicating and enhancing natural processes anyway, aren’t we?

But what makes the topic of Geoengineering so politically radioactive? Is it just the fact that it may dampen efforts to cut emissions? Or is there a moral/ethical aspect as it means we are intentionally modifying nature to suit our needs? By adopting a future of Geoengineering are we saying that we know everything about the climate and how the system works? Are we being too arrogant to think that we have complete control over nature? Society used to hold this view...it led to the building of dams, the modifications of rivers, the building of vast sea walls...the list goes on...but many of these large projects ended in failure. We only have to look at the Aral sea, the Yangtze River or the government’s response to rising sea levels to see this. Would Geoengineering be any different?

I personally feel that many people are resistant to fully acknowledge and consider Geoengineering as a viable solution to climate change as they know that it is still an area that scientists know very little about. We are not ready to say that we know enough about climate to allow us to control and modify it. However, if other scientific risky endeavours, such as genetic engineering and high-energy particle accelerators, have been researched in the past, I think it is now vital to conduct further research into the Geoengineering field (Victor et al, 2009). If anything, it could give us a better understanding of how the climate system works. So I think it is time to take Geoengineering out of the closet in order to better control the experiments and to ensure that all the negative consequences of each option are prevented...otherwise this field really is going to continue to be a ticking timebomb!

Any winning contenders?

This blog has considered a wide variety of Geoengineering options....so what is the verdict? Are any of them a viable option for solving climate change?

Let us firstly look purely at the potential of each option: To compare Geoengineering options, the potential of each proposal to cool the climate is quantified in terms of radiative forcing (RF). RF describes any imbalance in the Earth’s radiation budget that could be caused by human intervention or natural processes. Once a RF is applied, then the Earth’s radiation budget will usually adjust itself and this will be seen through changes in global temperatures. IPCC (2007) states that the present anthropogenic RF is equal to 1.6 Wmˉ². This is the target that many Geoengineering proposals have adopted to counteract. Are any successful? However, what if mitigation continues to be unsuccessful? Lenton and Vaughan (2009) postulate that without mitigation, anthropogenic C02 forcing could reach approximately 7 Wmˉ² by the end of the century. And even with strong mitigation, anthropogenic RF may still exceed 3 Wmˉ². Therefore, which Geoengineering option/options could counteract this?

Placing sun-shades in space ad increasing planetary albedo through the injection of aerosols into the stratosphere are the only two options with the potential to counteract >3 Wmˉ². Moreover, these options could even be scaled up to counteract further anthropogenic RF. The RF potential of enhancing cloud albedo could also achieve 3 Wmˉ² globally, but the effects would be regional and patchy. This is also true for injecting aerosols, depending on when the aerosols are injected. These shortwave measures appear to have the most potential to roughly cancel the anthropogenic C02 RF, as long as strong mitigation measures are also implemented. The remaining measures such as enhancement of the albedo of deserts, urban areas, crops, grasslands etc, could be used in combination and could achieve a partial cancellation of the anthropogenic C02 RF.

Long-wave measures that influence the carbon cycle through the capture of CO2, either by plants, biochar or chemical means, could be used in conjunction to achieve a RF of approximately 2.5 Wmˉ². These options appear to be much more effective compared to ocean fertilisation, where tests have shown that this option only has a RF of 0.23 Wmˉ² (Lenton and Vaughan, 2009).

Figure 1:

So from looking purely from a Geoengineering potential perspective, air capture and storage, the use of sun-shades and stratospheric aerosols, appear to be the options that would induce the greatest radiative forcing...this can be seen in Figure 1. However, what about the risks....While the use of sun-shades and injections of aerosols may have the most potential, they are also the most risky. If deployment is suddenly stopped then rapid warming could occur (Wigley, 2006) (see post: ‘Geoengineering Projects – are they viable of just plain crazy!’). However, carbon cycle engineering carries less risk associated with failure. Therefore, in my opinion, air capture and storage along with afforestation and the use of biochar appears to be the best option. Compared to the remaining Geoengineering proposals, these options are the least risky, and when used in combination could be equally successful as the short-wave options. Moreover, they have the support from the IPCC and afforestion and bio char could also provide other benefits to society not just carbon sequestration. However, their effectiveness is over a long time scale. Furthermore, these options could only counteract 3 Wmˉ² of the anthropogenic C02 RF, what happens if society fails to mitigate emissions? What about the remaining 4 Wmˉ²? This is why many academics are emphasising the need to investigate the option of stratospheric aerosols (Lawrence, 2006; Schneider, 1996; Lenton and Vaughan, 2009; Victor, et al., 2009; Govindasamy and Caldeira, 2000; Matthews and Caldeira, 2007). Even though this option does have a significant risk element, it may be society’s last resort if rapid climate change occurs. The question is, is there any harm in having an insurance policy? Does it mean we will go out and take more risks if we do?

Geoengineering: Ticking timebomb

Hi everybody,

Today I am going to explain my reasoning behind the dramatic title of this blog. When first conducting research into this field I found that many of the academic papers I came across were titled in an equally dramatic manner, the majority of which with rhetorical questions  such as:

•          ‘The Geoengineering Dilemma: To Speak or Not to Speak’ (Lawrence, 2006)
•           ‘Geoengineering climate change: Treating the symptom over the cause’ (Kiehl, 2006)
•           ‘The Geoengineering Option: A Last Resort Against Global Warming’ (Victor, et al., 2009)
•           ‘Geoengineering: Could – Or Should- We do It?’(Schneider, 1996)

This was the first reason for the dramatic title, as right from the onset, even before reading the papers, it can be seen that the topic of Geoengineering is controversial, debatable and is surrounded by ethical and moral issues. Further reading then lead to the creation of the title for this blog as it became apparent that the prospect of Geoengineering could be compared to a ticking timebomb in so many ways: 

1. Even discussing it could have catastrophic impacts as it could cause people to question whether or not they should cut emissions if there are alternate solutions. Therefore even discussing Geoengineering options could give politicians, companies and people an excuse to carry on living their life without fear of the repercussions (Victor, et al., 2009).
2.  Deployment – this has been briefly touched upon in previous posts. Many of the options e.g. ocean fertilisation, enhancing the cloud albedo, injecting aerosols into the atmosphere – these could be carried out by individual countries or even private companies. Therefore, unlike cutting emissions, it does not require a collective effort to be deployed. If one government was to decide they no longer want to cut emissions and that they would prefer to adopt a less costly approach e.g. injecting aerosols (see last post) then they could do so. However, the impacts that this may have are still heavily unknown! (Victor, et al., 2009).
3. It is difficult to police – if a government or private company was to adopt a geoengineering approach e.g. injecting aerosols or enhancing cloud albedo, then it would be difficult to determine who initiated the action (Schneider, 1996).
4.  What is the boundary– unlike testing in other scientific fields that are deemed risky e.g. GM foods or nuclear weapons or nuclear power, although some of the impacts of these activities may be difficult to localise, it is still easier compared to Geoengineering approaches. Where is the line? At what point or amount does injecting aerosols into the atmosphere move from being an experiment, to significantly altering the climate of a region? Ocean fertilisation is easy to limit, but approaches that involve the atmosphere such as injecting aerosols or enhancing cloud albedo, become difficult to limit (Lawrence, 2006).

All of these factors make the Geoengineering field a very dynamic; one that as climate change continues, this field will gain more and more attention. However, to ensure that the negative consequences of Geoengineering do not occur (that the bomb doesn’t go off), a governing body is needed to monitor and regulate all Geoengineering activity. Currently, different projects have captured the attention of different bodies such as the IPCC, US Department of Energy, NASA, UNFCCC, Natural Environment Research Council (NERC) and the Royal Society. This shows that a variety of bodies are interested in Geoengineering, but due to its global nature, an overarching body is required to ensure that the symptom to climate change does not turn out to be worse than the cure.

The Economics behind Geoengineering

Let’s look at the idea of injecting aerosols into space more closely...(Previous posts go into the science, today we will be looking at the cost because as we know money matters!). One of the reasons why research into Geoengineering approaches is on the rise is due to the financial cost of cutting GHG emissions. Could Geoengineering approaches be more cost effective?

David Keith, from the University of Calgary, commissioned a study using a company that makes high-altitude drones. The study showed that small airlines could be newly designed in order to be capable at flying at altitudes of 20-25km and distributing tens of thousands of sulphuric acid vapour. It is estimated that approximately 80 such planes would be required every year to inject the vapour into the atmosphere and cool the Earth by a degree or two. This goal could never be achieved by purely cutting GHG emissions. The planes would have an operational lifetime of 20 years, and would cost approximately one or two billion dollars (Economist, 2010).

The study conducted may be deemed as a breakthrough for such Geoengineering projects...as it proposes that a couple of billion dollars a year spent on sulphur would be enough to offset the warming. If comparing this option with the option of moving to low-carbon energy sources, which would require hundreds of billions of dollars.....then for any politician it’s an easy choice to make! It maybe so easy that the potential risks of the approach could be entirely forgotten!

Locking away the carbon

The IPCC has acknowledged that along with other mitigation options, Carbon Capture and Storage (CCS) could make significant reductions to GHG emissions. Geological storage is the preferred option as there are still large amounts of uncertainty regarding storing CO2 in deep oceans.

Carbon capture firstly involves capturing the CO2 directly from emission sources e.g. power plants and large industrial plants. The C02 is then dehydrated, compressed and transported and then finally injected into a reservoir. The capture and transportation is relatively easy, it is the storage part that is providing an obstacle and is causing concern.

Underground C02 of any kind must take place in sedimentary rock. Figure 1 shows the sedimentary basins of the world where CO2 could potentially be stored. C02 must also be stored deeper than 800m below the surface. Oil fields, gas fields and saline formations have been proposed as storage sites (Marchetti, 1977). Approximately 30 to 50 million metric tonnes of CO₂ are injected annually in the United States into declining oil fields. Both the report from the IPCC and House, et al. (2006) conclude the storage capacity for C02 is expected to exceed available fossil fuel reservoirs. Lenton and Vaughan (2009) postulate that in the long-term, carbon capture and storage could potentially sequester >1000 PgC.

Out of all the Geoengineering options discussed, the option of CCS appears to be the most researched, tested, implemented and supported. The backing and investigation by the IPCC has provided confidence in this option. In 2008, a German Power Plant run by Vattenfall conducted a pilot study through creating a CCS power plant. It was found that this plant reduced emissions of C02 by 80-90% compared to a power plant without CCS (IPCC, 2005). However, as with all of the other Geoengineering options discussed, there are downsides....firstly, capturing and compressing CO2 requires large amounts of energy. The amount of fuel required to operate a CCS plant would need to increase by 25-40% (IPCC, 2005). Secondly, there are numerous health and safety risks regarding storage, and many long-term uncertainties. For example, a big uncertainty regarding the use of deep oceans for C02 storage is the impact that this may have on ocean acidification.

Compared to many of the Geoengineering options investigated, CCS is the first one that I feel confident about. But is this because it has the backing of the IPCC? Compared to the other options were a few academics are leading the research, the IPCC appears to be taking point, bringing a variety of academics together to discuss and research CCS...so maybe Geoengineering is not all bad news!

Biochar? A silver bullet?

Biochar is created through the slow decomposition of organic matter at high temperatures in the absence of oxygen. Normally the organic matter would decompose rapidly after the vegetation/plant matter dies, releasing CO2, however, instead of allowing the plant matter to decompose, the process of pyrolysis can be used to sequester the carbon.

The use of biochar for carbon sequestration is a novel idea (I had never heard of it until I conducted this investigation!) Biochar can draw carbon from the atmosphere, locking it away for thousands of years, making it a long-term carbon sink (Winsley, 2007). Global analysis reveals that approximately 12% of terrestrial carbon emissions could be offset by biochar (Lehmann, et al., 2006). Moreover, by burying the biochar in the soil, this increases the fertility of the soil. Consequently, as with afforestation, the creation of biochar is another option that many land owners and farmers are pursuing as biochar can also be used to earn carbon credits. However, the disadvantage of biochar is that involves burning vast areas of natural habitats and ecosystems. If biochar was heavily integrated into the carbon markets then what would this mean for our natural ecosystems?

When the idea of biochar first came about, many referred to it as the ‘silver bullet’, seeing it as a method to utilise waste in a way that allows society to offset emissions. However, the extent to which emissions are offset is limited. Lenton and Vaughan (2009) suggest that by the 2060s a saturation point will achieved if biochar is fully adopted as a way to sequester carbon. Therefore, this shows that this option is difficult to scale up to a level that will make a significant impact to carbon emissions.

Overall, research shows that biochar can store large amounts of carbon, it is stable and can last a very longtime, so it can even be termed as a ‘permanent’ carbon sink. However, what worries me is the conflicting results found regarding the impact that biochar may have only soil. Some scientists argues that is beneficial and increases the productivity of soil, while others argue that it increases the pH of soil and could be damaging (see video showing experiment with biochar). There is concern that companies may start to heavily invest in biochar through conducting pyrolysis on an industrial scale in order to gain carbon credits. Before this happens we need to ensure we know the effects that biochar will have on our soils; especially since that once it is mixed with the soils, it will be there for a very long time...

Trying the greener option!

While this blog has explored a variety of radical and alternative options, I thought it was time to take a look at a more conservative and greener option: Afforestation. This process, of establishing forests in regions that were not previously forests, sequesters carbon in the biomass of trees. While oceans are considered to be large carbon sinks, forests are also capable of storing relatively large amounts of terrestrial carbon: Occupying one third of the earth, forest vegetation and soils contain approximately 60% of the total terrestrial carbon (Winjum, et al., 1992).

Forest management for carbon sequestration is a low cost, low technology option, which may not stop climate change but will help to mitigate global climate change while more long-term solutions are adopted. It is now being incorporated into policies in the US as forests are now being considered as a source of offsets in carbon markets. Forest management for carbon sequestration also provides an opportunity for land owners to gain a new source of income (Charnley, et al., 2010).

Moore, et al. (2010) argues that that out of the variety of Geoengineering options available, afforestation and forest management is the least risky and most desirable. Chemical carbon capture from air would require an energy source, while ocean fertilisation is less likely to be as effective as terrestrial carbon capture methods and will also be more risky. It is predicted that through the afforestation of regions, CO2 can be reduced by 45ppm by 2060. This may appear minimal but there are numerous other benefits of afforestation e.g. increases in ecosystem richness, water management and providing social amenities. Moreover, the incorporation of afforestation into the carbon markets has yet to be achieved as there are still several questions that need to be answered: What is the management technique that will ensure maximum carbon sequestration? Does this forest management conflict with other aims of forested regions? How do we ensure that all land owners follow the same management practices?

Overall, this option is by far the most safe and the most ‘green’. Consequently, it fits in with many government’s ‘no regrets’ approach to climate change. And despite the fact that it doesn’t reduce C02 emissions significantly, in comparison to other Geoengineering options, afforestation would make the world a much ‘greener’ place...so what is wrong with that?

Other ways to enhance the Earth’s Albedo...

Hi all,

The last post looked at the effects on enhancing the albedo of the earth...however, this is limited to only enhancing the albedo of marine stratiform clouds. This got me thinking about what would be the impact if we increased the albedo of other regions e.g. urban areas and crops

Akbari, et al. (2009) found that by increasing the albedo of urban areas, this could, to some extent, counteract the warming induced by GHG emissions, by increasing the concentration of solar radiation reflected. Through using reflective materials in replace of roofs and pavements (that together make up 60% of urban surfaces) the albedo of urban areas could be increased by 0.1. This would be equivalent to offsetting 44Gt of C02 emissions. At $25 a tonne, this could potentially save $1,100 billion dollars just by changing the albedo of roofs and pavements.

Crops exert an important influence over the climate energy budget because of their difference in albedo compared to soils and natural vegetation. Therefore, one idea proposed is to bio-geoengineer  crops by having specific leaf glossiness to ensure maximum solar reflectance. Ridgwell, et al., (2009) estimates by doing this, temperatures can be reduce by 1°C during summer for much of Central America, if the bio-geoengineered crops are adopted.

Enhancing the albedo of regions will not cause significant changes in temperature, unlike other Geoengineering options, but it will provide society with more time to advance the development and use of low–emission energy and conversion technologies (Hamwey, 2006). Personally, the idea of bio-geoengineering crops sounds a bit scary, as these crops will be then eaten by people, but genetically modifying crops is an idea that has been debated for years, research into whether crops could be modified further could be interesting...However, the idea of increasing the albedo of roofs and pavements does seem more viable...if roofs and pavements were replaced gradually with more reflective material then this could buy us more time, with relatively little inconvenience. Moreover, it would likely cause significant changes to temperatures locally, reducing the urban heat island effect. Overall, it could be a very small step to mitigating global climate change...or would it be an excuse to relax regulations on emissions? To do or not to do...that is the question!

Whitening the atmosphere....

Hey all, so after a week in Greece with leading scientist in the past global and regional climatic change, Mark Maslin, the topic of climate change came up! This coupled with one specific day devoted to understanding micro-climates has inspired the blog post of today!

A couple of years ago, I went to San Francisco. Now seeing how the city is located relatively close to regions such as Los Angeles and Las Vegas, and I was going in summer, I packed very few warm clothes. My family and I realised only after a couple of hours that this was a big mistake. Therefore, we now each have a very warm fleece with a San Francisco label on it that we say we bought as a souvenir on our very first day!. So why am I going down memory lane? And what does this have to do with climate change and micro-climate...well when looking into the concept of micro-climates during the fieldtrip, we learnt the importance of cloud cover and how the concentration of cloud cover influences the amount of solar radiation that reaches the ground. When using this understanding along with typical photos of San Francisco’s Golden Gate Bridge (see Figure 1), the cold temperatures experienced on my summer holiday are now very much understood!

Figure 1:

This brings me on to one geoengineering approach that I have particularly found interesting: the idea of enhancing cloud albedo. The idea that by increasing the white and shiny parts of our earth to increase solar reflectance and reduce temperatures; without severely altering ecosystems or polluting the atmosphere or even crossing the border into space, seems like a wish come true. And people like John Latham put across a very convincing argument!

In the same way that San Francisco has its fog and cloud cover to protect it from the sun, academics such as John Latham and Steven Salter, argue that this idea could be replicated and could influence temperatures on a global scale. Using a fleet of futuristic cloud seeding yachts (see Figure 2) that work by atomising sea water to feed clouds, making them denser and more reflective, the temperature of the earth could be influenced. 

Figure 2:

As the sea water is sprayed into the atmosphere, the freshwater evaporates leaving salt particles which rise into the clouds, attracts water vapour, condenses and increases the density of the clouds. Latham predicts that the warming produced by carbon dioxide emissions could be balanced by 15-20% increases in cloud cover (Latham, 1990). This would roughly equate to 500 litres of water being sprayed into the atmosphere per second, which would require 50 ships to be built per year to keep temperatures stable. This seems doable, especially compared to more radical ideas of solar shades in space.  

So now that we know the science, lets break down this option to see if it is viable solution to climate change?

Advantages: (Latham, 2002)

1. The amount of cooling can be controlled by measuring cloud albedo and using satellites
2. If any unforeseen or adverse impacts occurred, the entire system could be switched off, and cloud properties will return back to normal after a few days
3. This action is benign ecologically and also would not contribute further GHGs

Disadvantages: (Latham, et al.,2008)

1. A lot of further work and understanding is needed
2. Increased water vapour between the oceans and clouds is likely to have a high impact in localized regions
3. If implemented on a global scale, it would result in significant changes to the distribution of temperatures
4. Since the cloud albedo is enhanced only over the oceans, this may result in changes to the land-sea temperature gradient which drives precipitation
5. Unknown climatic impacts e.g on storms

Overall, like with the other Geoengineering options discussed, further work is desperately required (Feingold, et al., 1999). John Latham appears to be spearheading the research in this field, without little opposition or debate regarding the science (He has his name in nearly every paper read on enhancing cloud albedo..the few that exist anyways!). I would feel a lot more comfortable if we threw some more academics into the mix to join in the debate and extend the understanding of what could be a viable option to ameliorate the impacts of climate change!

Ocean fertilisation....a viable approach?

Hey all,

So while we have looked at Geoengineering approaches aimed at reducing the amount of short wave radiation absorbed by the earth, other options include increasing the amount of long wave radiation emitted from the earth, through capturing and storing carbon!

Thanks to Viv’s lecture, the scientific basis for this post, has been provided. However, we will do a quick overview!

The carbon cycle is made up of a series of stocks and fluxes. Currently, the stock of CO₂  in the atmosphere is increasing, this is trapping increasing amounts of longwave radiation and causing temperatures to rise. Therefore, to increase the amount of longwave radiation emitted from the earth rather than trapped, CO₂  needs to be removed/transferred to other stocks.

The ocean is a large carbon sink. The Northern Hemisphere and Southern Hemisphere oceans store on average 2.2GtCyrˉ¹. Through the concept of the biological pump, shown in Figure 1, CO₂  is dissolved in the oceans and taken up by phytoplankton through the process of photosynthesis. When these organisms die, the organic carbon is transported to the sea floor.

Figure1:

Two decades ago, scientists realised that the amount of CO₂  absorbed by phytoplankton , and transported to the deep oceans could be enhanced by adding  iron, which is often a limiting nutrient for growth (Raven and Falkowski, 1999).  Numerous experiments have since been conducted in regions where waters are replete with light and  major plant nutrients, yet phytoplankton stocks are low. Several examples of these regions are shown in Figure 2.

Figure 2:

Although most experiments show noticeable decreases in dissolved inorganic carbon, carbon sequestration, whereby particulate organic carbon sinks to the ocean floor is limited. Once absorbed by the algae, only minimal amounts of carbon are sequestered while the rest is recycled back into the atmosphere. Several studies question whether iron fertilisation would make any significant reductions to the stock of CO₂ in the atmosphere. (Zahriev, et al., 2008; Martin, et al., 1994; Busseler, et al., 2004). Buesseler and Boyd (2003) estimate that the sequestration of the 30% of the carbon produced by human activities would require an area larger than the Southern Ocean. Consequently, more research is needed to determine the perfect conditions that may allow optimal carbon sequestration. However, there is a growing concern over scaling up experiments. Ocean ecosystems are still poorly understood in comparison to terrestrial ecosystems, tampering the food chain could lead to a domino of undesired impacts e.g. De-oxygenated waters, depletion of vital nutrients, all of which would severely affect fish stocks (Davis, 2006).

Geoengineering Projects - are they viable or just plain crazy!

Different groups define the term Geoengineering differently. Some use it to refer to any project that aims to modify the earth’s climate system, while others may only use the term to refer to projects that aim to reduce the amount of short wave radiation absorbed by the earth (Wigley, 2006); (Matthews and Caldeira); (Govindasamy and Caldeira). Either way, a wide variety of projects exist today that can be classified as Geoengineering projects. I have attempted to visually illustrate and group these projects in the image below (Figure 1). The red ring highlights the focus of the post today!

Figure 1

However, it is important to acknowledge that because Geoengineering is a field where ideas are constantly being generated, many proposals are probably not even known about. Moreover, since Geoengineering does have a stigma attached to it, most information on projects are available from sources other than scientific journals (Click here for some random Geoengineering projects found!)

However, when initially researching the field of Geoengineering the majority of the journals found were centered on activities aimed at reducing shortwave radiation; these activities being:

1. Using sunshades to reduce the amount of radiation reaching the top of the atmosphere
2. Using stratospheric aerosols or increased cloud cover to increase the albedo of the atmosphere

Brief explanations of theses activities may be obtained from youtube videos, newspaper articles and journals such as (Trenberth and Dai, 2007);(Wigley, 2006) and (Matthews and Caldeira, 2007). In fact, in numerous panel discussions regarding Geoengineering and even in journals, it is specifically mentioned that the entire stock of research on Geoengineering can be read during the course of one translantic flight, and that all the scientists advocating Geoengineering could fit comfortably in a university seminar room (Victor et al., 2009). This has heavily been reflected in the literature available, because while there are brief explanations of projects from a variety of sources, very few go into any substantial detail. While Geoengineering strategies are touched upon they are still in their early design stage. Several experiments have been conducted on a small scale but fear of academic discredit and due to the blurred boundary between experiments and actual long-term modification of the climate, prevent further full scientific investigations; this is especially true for the schemes aimed to reduce the amount of short wave radiation absorbed the earth.

The first strategy of placing sunshades in space has yet to be tested. It is an idea that has been met with resistance concerning cost, the location of the sun shades and the uncertainty regarding unforeseen impacts on the climate. Although there is consensus regarding the fact that it may cause a decrease in global temperatures, since incoming radiation significantly influences precipitation patterns, wind patterns, pressure systems etc, there is considerable uncertainty regarding the extent to which sunshades may do more harm than good. However, initial calculations have been made:

Lenton and Vaughan (2009) make coarse calculations on the cost and effectiveness of using sunshades in space. They calculate that to offset a doubled pre-industrial atmospheric concentration of CO2, it is assumed that a reduction in incoming solar radiation by 1.8% is required. However, this calculation is based on a static radiative imbalance. In reality, CO2 emissions are increasing by approximately 2ppm/yr, consequently, the radiative imbalance is set to continue increasing. Therefore, to offset the current radiative imbalance and future increases in CO2 then solar shades with a surface area of approximately 35700km2 need to be added every year to space. This equates to approximately 15500 launches per year, carrying 800 000 space flyers of 0.288m2. To me this sounds a little crazy.....but investigations are still being conducted! But at the same time, you can’t help wonder, what are the C02 emissions produced from all those rocket launches?!

In terms of the second project aimed at reducing the amount of incoming radiation absorbed, injecting aerosols into the atmosphere has also been met with considerable resistance. However, the difference with this scheme, is that experiments on both local and global scale have shown its effectiveness at reducing global temperatures (see Figure 2 below!)

Figure 2

The idea of injecting aerosols into the environment originated from past natural experiments. Rapid reductions in temperature have been experienced several times in the past (as shown in Figure 2), and this has been a result of volcanic eruptions injecting several tonnes of particles into the atmosphere. The eruption of Mount Pinatubo in 1991, injected sulphate aerosols into the stratosphere and generated a cooling of a few tenths of degree for several years after the eruption. Therefore, drawing on the climatic effect of large volcanic eruptions, by extension, through purposely injecting sulphate aerosols into the atmosphere then the cooling experienced after 1991 may be replicated. This could consequently compensate for some or even all of the climate warming that has been induced by the emission of GHGs.

Unlike the idea of putting sunshades in space, the concept of injecting particles into the stratosphere in order to increase the albedo of the atmosphere and reduce the amount of short wave radiation absorbed the earth has been naturally tested. This has allowed calculations to be made, the model simulations to be run. Some of the results show the following:

Matthews and Caldeira (2007) simulated the changes in surface air temperature (see Figure 3a and 3c) and precipitation (see Figure 3b and 3d) for the year 2100 relative to 1900. Figure 3a and 3b show the results from model simulations using the IPCCs development scenario A2 while Figure 3c and 3d show model results  when including Geoengineering projects. The results shown in Figure 3c and 3d are a result of a globally uniform factor being applied to incoming solar radiation, as a result of Geoengineering activities. The results show that there is a greater absolute reduction in incoming solar radiation in the Tropics relative to the poles. Consequently, global cooling is not felt uniformly. However, it must be noted that the results shown do not incorporate the technical difficulties and also the scientific uncertainties regarding the deployment and effectiveness of Geoengineering schemes, aimed at reducing incoming solar radiation.

Figure 3

The Figure 3 shows that significant reductions in temperatures may be achieved. However, there are several factors to consider:

1. A rapid decrease in global temperatures due to the injection of aerosols may be met with an even faster rate of increase in temperature if injections are ceased and Geoengineering practices are stopped. This warming rebound may result in several years of very rapid climatic change. This is seen in the diagram shown in Figure 4. The diagram also shows the effect of multiple sequential eruptions of Pinatubo, every year, every two years and every four years. This  highlights how continuous injections of aerosols will be required to meet the required amount of cooling.  
2. The effect on the globe will not be uniform. Depending on where the injections are made, and the trajectory of the particles, this will subsequently affect the extent of cooling experienced in different regions around the globe. This may not suit the interest of all nations.
3.   Even though the injection of aerosols will provide the desired outcome of a reduction in temperature, the impact that it may have on other climate variables in unknown. Moreover, any further health risks are also unknown. Moreover, considering the characteristic of rapid temperature increase if geoengineering practices are stopped, this may lead to significantly damaging impact

Figure 4

Overall, even though the majority of research is centered on these two concepts of reducing the amount of incoming radiation absorbed, the studies highlight how research is still in its infancy. Subsequently, the impact that these Geoengineering projects may have on the planet is still heavily uncertain. Consequently, there is considerable risk. However, natural experiments and results from model simulations has shown that there is potential, that if one day the climate was to experience a tipping point then these schemes may act as an insurance policy, a last resort. But the question is when do we say enough is enough? When do we say that climate change is already having a devastating impact on or lives and it is time to resort to drastic measures? You and I may not feel it is time but what about the people living on the small islands facing rising sea levels? Or the people in Bangladesh even? Or the people living in Africa facing water scarcity? Or what happens when China or India feel they no longer want to curb emissions but the prospect of further increases in global temperature will cripple their ability to provide food for their growing populations? What happens when they get tired of the US and the UK and other developing nations telling them that they have to cut emissions when we won’t even make drastic cuts to our emissions!? (the Australia agreed on reducing emissions by 5%!) Mitigation of global warming is an international effort; however, the use of Geoengineering to curb emissions is not......ergo....the concept of Geoengineering becomes a ticking timebomb! (To be continued.....)

Is mitigation enough?

For years the validity of the idea that global warming is occurring was questioned. Despite a large consensus among the scientific community that climate change was ‘very likely’ due to anthropogenic sources of GHGs, which equates to a >90% certainty, the small percentage of  doubt provided governments with a perfect excuse to delay their action. However, the IPCC’s latest report provides substantial evidence showing how anthropogenic emissions of GHGs are the cause of rising global temperatures. This is evidence that cannot be ignored!

Exhibit A:

Using climate models and data on all the factors (forcings) influencing the climate e.g. sun spot activity, the distance of the earth from the sun, the tilt of the earth etc, along with the rising emissions of CO2 and other GHGs, numerous models and simulations were used to determine how global temperatures would rise over time. Exhibit A shows the results from models using only natural forcings and  also results from models incorporating both natural and anthropogenic forcings. The graphs show that when anthropogenic forcings are included, the increase in temperature experienced is much higher. Therefore, climate change has been established to be partly due to the influence of anthropogenic emissions of GHGs.

Exhibit B shows that the concentrations of these GHGs have risen drastically since the 1750s, and are expected to rise further over the 21^st Century as populations continue to increase, urbanization continues and the demand for energy increases. Although the magnitude of these changes have been experienced before in the earth’s history, never have they been experienced at such speed: CO₂ concentrations are expected to increased to more than double their pre-industrial levels in the next 100 years (Nijssen, 2001).

Exhibit B

Exhibit C

Increases in global temperatures have resulted in a reduction in sea ice extent by 2.7% per decade, as shown in the satellite photos (IPCC, 2007). This decline in sea ice is occurring much faster than predicted by the climate models, as shown in Exhibit D, this has lead to a huge questioning whether the predictions from the climate models can be trusted. Have the predictions been underestimating the impact that rising global temperatures may have?

Exhibit D

So now that there is an overwhelming stock of evidence showing that humans are the cause of global warming, coupled with the fear that climate models are underestimating the impacts of climate change, and along with the enormous reaction in the media with all of the emotive images and movies (see previous blog)....you would think that this would lead to action; that governments would take the necessary steps to reduce emissions in order to curb temperature rises. Did this happen?

Exhibit E

The outcome of UN Climate Summit at Copenhagen - having all the world’s leaders along with all the world’s best scientists all in one city, where substantial evidence is given showing that if global temperatures rise by more than 2 degrees then catastrophic events will occur and yet what was achieved?

Exhibit F

More than a year later: does it look like there is any progress? 

Take a look at today's news!

Geoengineering has been described as a way to solve the symptom but not the cause. It is controversial, highly debated, can seem crazy at times (see the youtube videos in previous blog!), and is generally regarded as a taboo in academic circles. People are even afraid to just mention the idea just in case it will give government leaders another reason not to curb emissions! People have argued that it should only be used as a last resort, but each piece of evidence shown today shows that nothing else is working, so have we reached the last resort yet? (Matthews and Caldeira, 2007). Or maybe we could argue that since it is taking world leaders considerable time to make any steps or come to any conclusions, that maybe all we need is more time....could geoengineering be the solution to this?

I know I have thrown the word out quite a lot....next blog we will walk on the dark side and dare to discuss those highly controversial ideas that may become the saving grace for our planet.

The cause of all the fuss

‘Climate change is one of the most serious environmental challenges facing human and environmental systems’ (Matthews and Caldeira, 2007) – this has been drummed into society in every way possible: from international conferences publicized on the news, to pictures of polar bears on magazine covers and TVs, to commercial movies such as the ‘Inconvenient Truth’ and even ‘The Day After Tomorrow’. All with the purpose to not only make people aware of the issue but also to make people act.  

Scientific and political debate has moved away from questioning whether the world is getting warmer due to the anthropogenic emissions of Greenhouse Gases (GHGs), and has now moved to providing a solution to the problem. Until recently, the only viable solution has been to reduce emission of GHGs such as carbon dioxide, hence all of the emotive images and movies and the international conferences. However, despite international efforts, temperatures are still rising and are continuing to rise. This has led some individuals to explore different ways to stop temperatures from rising. This is how the idea of Geoengineering was born. Or was it?

Some may believe that Geoengineering is just science fiction. Or that it is a product of some crazy scientists. Others view it as a sign that the end is nigh, that we are now moving to radical measures. First of all, let us define was Geoengineering is:

Geoengineering is the ‘intentional modification and/or management of the earth’s climate system’ (Matthews and Caldeira, 2007)

This idea of intentionally modifying the climate is not a new idea. In fact, in 1965, when US President John Lyndon Johnson received the first ever briefing on the consequences of climate change, the only remedy proposed was Geoengineering (Victor et al, 2009). Moreover, even before this, governments and scientists were playing around with climate during the WW2, in the attempt to use the weather as a weapon. The Chinese government relatively recently attempted to modify weather patterns to ensure that it didn’t rain during the Olympic Games. Therefore, Geoengineering is not just science fiction, it doesn’t just originate from crazy/radical scientists and it doesn’t mean the end is nigh? Or does it?

Many argue that the mitigation of climate change through a reduction of emissions is not working. That sooner or later our climate will reach a tipping point, a point of no return, where the climate will rapidly and irreversibly shift (watch The Day After Tomorrow for a full visualisation of this!), so many believe (Crutzen, 2006; Matthews and Caldeira, 2007) that Geoengineering is an option that seriously needs to be considered. Because of this, the purpose of this blog has been devoted to doing exactly that. Geoengineering has been heavily debated in the news, ideas have been brought forward by academics, and already there is a strong discourse on the subject. Just a few of the Geoengineering ideas put forward by academics include: peeing in oceans (see video for a taster..no pun intended!), putting shades in space, spraying particles in the atmosphere, building fake trees etc:

Through considering a range of Geoengineering options, along with the pros and cons of this solution to global warming, and using a variety of sources, we will determine whether or not Geoengineering really is science fiction or a plausible reality. WATCH THIS SPACE!