Geo-Engineering: For or Against?

Having written on the topic of Geo-Engineering for the past few months, I feel that I have developed my understanding of many of the issues surrounding this topic. I started this blog being heavily sceptical of all forms of geo-engineering; since then I have warmed to certain forms.

Personally, I think that solar geo-engineering methods are far too risky; they have many more downsides than upsides. Forms of geo-engineering that involve carbon dioxide removal is where my greatest support lies. These methods aim to reduce the cause of anthropogenic climate change and despite working slowly, have fewer risks and can operate alongside the reduction of greenhouse gas emissions.

Determining whether to use geo-engineering depends on a form of cost-benefit analysis bringing together a variety of factors. Use of geo-engineering involves questions over finances, environmental impacts, political and military motives, feasibility, time scale and unexpected consequences. Only by assessing the multitude of factors can it be possible to determine if any of the geo-engineering techniques are suitable.

I am more positive about geo-engineering than when I started this blog but further research into the impacts of different methods is desperately needed as there is currently insufficient knowledge to make a clear and informed decision.

Why Geo-Engineering may not be the solution

Up until now I have focused on different forms of geo-engineering, discussing both the benefits and drawbacks of these methods. In this post I wish to look into some of the reasons why Geo-Engineering as a whole may not be a feasible solution to anthropogenic climate change. This blog will focus a few key areas, these being: the effect Geo-Engineering can have on regional climate, human error, the neglect of cutting emissions, possible catastrophe,alternative uses of Geo-Engineering (commercial and military) and controlling the temperature.

Effect on regional climate

Geo-Engineering can have a profound effect on regional climate including altering rainfall patterns, surface albedo and local temperatures. A paper from 2016 investigated the effects of solar dimming (reducing the amount of sunlight reaching Earth) through geo-engineering on crop production. Although not fully understood, a number of crop-climate simulations have estimated that crops would be negatively affected by changes in solar radiation and rainfall patterns caused by solar dimming. Importantly, this paper concluded that despite geo-engineering impacting crop yields, when the geo-engineering is turned off, the crops recover to previous levels. The fact that geo-engineering methods do not have lasting effects on crops is beneficial but this does not ignore the fact that crop yields in certain areas may decline under the effect of certain geo-engineering schemes. This must be considered where determining whether to implement certain programmes.

Human error and possible catastrophe

Human miscalculation and societal problems could also bring about major problems for geoengineering. It has been established that, with certain solar geo-engineering techniques, a halting of the process could accelerate warming faster than we are currently seeing. Baum and Maher Jr.(2013) discussed the idea of a double catastrophe linked to stratospheric aerosols. The possibility of political conflict or war leading to the interruption of aerosol injection could destabilise the climate leading to rapid warming. In such instances, the use of geo-engineering could have more negative impacts than business as usual and the reliance on sustaining aerosol injection leaves the planet vulnerable to unintended and unexpected consequences.

Neglect of cutting emissions

Funding and focus on geo-engineering techniques could mean that cutting emissions is neglected. Some have suggested that geo-engineering should be used alongside cutting emissions and that reducing GHG emissions should be the priority. In practice however, this may not be the case as funding would then have to be divided between the two, meaning the technology progresses at a slower rate. Cutting GHG emissions is the most straightforward and lowest risk strategy for reducing the effects of climate change and therefore it may not be necessary to employ a riskier strategy such as geo-engineering. Many forms of geo-engineering are only short term solutions (particularly solar geo-engineering) and they are not understood well enough. Humanity needs to react to climate change now and the most effective and straightforward way to do this is through reducing emissions. Geo-engineering methods would only distract from this objective.

Figure 1: Should we be focusing on cutting greenhouse gas emissions?

Alternative uses of Geo-Engineering

Worryingly, the purpose for carrying out Geo-Engineering methods may not be centred on addressing climate change. Geo-Engineering could also be used for financial gain as well as military use. There is evidence that in the mid-20th century, global superpowers were exploring methods for altering climate to gain an advantage in battlefield warfare. There are existing global agreements such as the ‘Convention on the Prohibition of Military or Any Other Hostile Use of Environmental Modification Techniques’ that was signed in 1976 but it is hard to see no military use of geo-engineering in some form in the future. Many companies supplying geo-engineering may find ways of making their technology more expensive to national governments thus profiting greatly from geo-engineering rather than using it for the greater good. The commercialisation of geo-engineering would set a dangerous precedent that could cause more problems than benefits. I believe that in order to be effective, geo-engineering must be solely used to modify climate as a response to climate change rather than for military or financial gain but realistically it would be very difficult to achieve this.

Controlling the temperature

There are also political issues surrounding the controlling of global temperatures. For example, countries at higher latitudes may want a warmer climate to allow them to grow more crops for export but this may adversely affect countries at lower latitudes. This brings about big debates between nations on what temperature to set climate. Every country would have an agenda and therefore agreeing a ‘temperature setting’ would be difficult and very time consuming. This is time that the planet doesn’t have and therefore geo-engineering may not be the best solution for climate change.

To sum up, it is clear that there are many potential drawbacks to geo-engineering as a whole. Despite this, I still feel that certain methods should not be ignored entirely. If they can be effectively implemented in such a way that they are low risk, work alongside reducing GHG emissions and do not have the potential to be exploited then it is worthwhile considering them as an option. This is a lot to expect but only once these criteria are met do I feel that certain geo-engineering methods should be considered for implementation.

Geo-Engineering: a cost-benefit analysis

Writing frequently around the topic of geo-engineering to modify Earth’s climate either through altering atmospheric carbon or by reducing the solar radiation reaching Earth, it has become clear that the whole issue revolves around a cost-benefit analysis. All geo-engineering techniques bring different costs and benefits and it is up to humans to analyse, assess and come to conclusions on whether any of the methods are suitable or whether business as usual is less risk. Costs can be more than just financial, they can include unintended consequences, time and other environmental impacts. I have advocated the use of carbon dioxide removal techniques because they are low risk but many may support the use of solar geo-engineering because of the greater benefits. This discussion and debate can only be valuable in attempting to determine human response to anthropogenic climate change be it low risk or high reward.

Solar Geo-engineering: research needed

As you may be aware by now, I am fairly sceptical about solar geoengineering techniques on the whole. Having focused heavily on carbon dioxide removal techniques thus far, I felt it would be fair to consider some of the solar geoengineering methods despite my negative opinions towards them. The Youtube video in this post is a Ted Talk on the need for a proper research programme for solar geoengineering techniques. It puts across a lot of the pros and cons of solar geoengineering methods so is well worth a watch if you have 15 minutes spare.

The key message I got from listening to this talk, which was also the objective of the talk, was not that solar geoengineering is necessarily a good (or bad) idea but the fact that there is a desperate need for a serious research programme into the effects of these different schemes. At the moment, there is simply not enough information on the potential benefits and risks. The need for a proper research programme is key to avoiding making ill-informed decisions that could be disastrous.   

Solar geoengineering has been proposed as a way to avoid climate tipping points. This is achieved through reducing the amount of solar radiation reaching Earth, leading to a lowering of global temperatures. There are a number of different methods to achieve this which are described in detail in the Caldeira et al. (2013) paper. The problem with all solar geo-engineering methods is that they do not alter the levels of carbon dioxide in the atmosphere despite decreasing global temperatures. This is potentially risky as if a solar geo-engineering technique were to fail, temperatures would rise at an even faster rate than we see presently.

Another major drawback of solar forms of geo-engineering is the costs of implementation. Injecting sulfate aerosols into the stratosphere is no different to other forms in this regard with high financial costs. In addition to the actual pumping of the sulfur dioxide into the atmosphere, there are high costs associated with the production and transport of this gas. One suggestion is to only use stratospheric aerosols over the Arctic to reduce sea ice melting. This would help to reduce the costs whilst still seeing significant benefits. All forms of geo-engineering are costly, both financially and in terms of climate risk which means humans must be certain of their impacts before attempting to implement them.

The biggest reason to avoid solar geo-engineering is the high risks associated with many of the methods. One method I do see as feasible in the short term is roof whitening. A paper by VanCuren (2012) highlighted the radiative forcing benefits of roof whitening in California, USA. The paper concluded that there could be significant benefits of this form of geo-engineering in California but these benefits are spatially variable depending on climate.

As it is clear to see, I feel that the drawbacks of many solar geo-engineering methods far outweigh the benefits and this is why in this blog I have chosen to focus on the more feasible and cheaper carbon dioxide removal techniques. They may not be as effective at reducing climate change in the short term but at least they are not as risky as many of the solar geo-engineering methods proposed. 

Carbon Dioxide Removal over Solar Geo-Engineering

At this point, I feel it necessary to explain why this blog has heavily focused on the forms of Geo-Engineering that involve Carbon Dioxide Removal (CDR) rather than Solar Geo-Engineering techniques.

The first is that CDR methods address the problem at the root of climate change, the carbon produced through anthropogenic emissions rather than attempting to deal with the issue in a roundabout way by reducing the amount of solar radiation reaching Earth. This ties in neatly with the second reason, there are likely to be fewer unintended consequences associated with CDR techniques. By reducing the atmospheric levels of carbon, CDR methods are attempting to reverse the current trend to prior levels that have already been experienced and studied rather than shifting our climate in an unknown way. Unexpected shifts could lead to further problems that could be worse thanthe current situation.

Another justification for CDR methods is that there are other indirect benefits. Removing carbon dioxide from the atmosphere can help to reverse the current trend of ocean acidification due to the ocean-atmosphere flux, benefiting marine species such as coral which are under the threat of extinction.

Carbon Dioxide Removal approaches are also easier to control than Solar-Engineering methods. It is relatively easy to stop capturing atmospheric CO₂ or stop ocean fertilisation compared to removing large sun reflectors from space or removing chemicals pumped into the upper atmosphere. In addition, pumping aerosols into the upper atmosphere could lead to ozone depletion.

Furthermore, there is likely to be less human error involved in CDR practices in comparison to Solar Geo-Engineering methods because atmospheric carbon dioxide has been widely studied whereas the implications of altering the amount and distribution of solar energy reaching Earth is understood to a lesser degree and because of this makes Solar Geo-Engineering techniques far more risky despite possibly bringing about faster climate responses. Solar Geo-Engineering is seen as having greater issues surround governance, equity and ethics that also create other disincentives for implementing some of these concepts.

Figure 1: Solar Geo-Engineering: (a) reflectors (b) stratospheric aerosols (c) cloud brightening
(d) increasing ocean reflectivity (e) reflective plants (f) roof whitening

Carbon Dioxide Capture: Part II

Carrying on from the last post, Carbon Dioxide Capture is a technique to prevent carbon dioxide from reaching the atmosphere in the first place as well as being a method to remove some of the existing carbon dioxide currently in the atmosphere. The previous post focused on the methods of this form of Geo-Engineering and this post will now look at the benefits, drawbacks and feasibility of this method. Carbon Dioxide Removal techniques are often thought of as longer term schemes compared to some of the solar geo-engineering methods suggested because removal of carbon dioxide is slow and therefore the response of climate is also slow. This needs to be considered when attempting to assess the feasibility of all geo-engineering schemes.

Figure 1: Carbon dioxide capture plant in Malaysia

One key positive of carbon dioxide capture is that the technology to achieve this is already available and in use presently. The processes involved in the capture of carbon dioxide in power plants can be easily applied to atmospheric carbon dioxide by capturing air and processing it. This means that the technology of this form of geo-engineering is far more advanced and more rigorously tested that those of other geo-engineering schemes that are still in the research phase. The option to implement this method is therefore possible in the short term as an attempt to begin to reduce carbon dioxide levels.

Evidence from Iceland has found that underground storage of carbon dioxide is much more promising than first thought. CO₂ pumped underground to volcanic basalt rock converted to a solid far more quickly than previously expected, just two years rather than hundreds to thousands of years. Even more positive is the fact that this rock type is widely distributed worldwide suggesting that this a viable method for storing the carbon dioxide captured from power plants and from the atmosphere. The conversion to solid is more beneficial than storing CO₂ underground as a gas due to the risk of leakages. This further advocates the implementation of carbon dioxide capture and storage as soon as possible.

Despite this, capture of existing atmospheric carbon dioxide would have limited effects on atmospheric CO₂ in the short term because of the ocean-atmosphere flux. This flux is the process by which carbon dioxide is exchanged between the ocean and atmosphere constantly. Around a quarter of carbon dioxide emitted by humans in the last two decades was taken up by the ocean. The oceans are therefore a key carbon ‘sink’ (store). By reducing the amount of carbon dioxide in the atmosphere, the ocean-atmosphere flux would increase the transfer of carbon dioxide from the oceans to the atmosphere – a process known as outgassing. This replacement of the carbon dioxide that had been taken out of the atmosphere therefore would not have significant impacts on climate change for a long period of time. This is not to say that in the short term it is not positive because the removal of carbon dioxide from the oceans would reverse the existing trend of ocean acidification that is threatening corals and other ocean species. Overall, atmospheric carbon dioxide capture would have an influence on climate change in the long term and help reduce ocean acidification in the short term which are both very positive.

Atmospheric carbon dioxide capture is unfortunately far less effective than capture in power plants. Therefore capture of past emissions would have much less impact on climate change. Atmospheric capture is less effective because the concentration of carbon dioxide in the atmosphere is only 0.04% compared to around 10% in power stations. This also makes it far less economically justifiable as CO₂ is costly to capture. There is great variation in the cost of carbon dioxide capture because there are a wide variety of factors at play such as plant size, efficiency, fuel cost, etc.. Despite this, I feel that with the current state of climate change and the expected increases in temperature and other changes associated in the future, the benefits of implementing such schemes both in power plants and for atmospheric capture outweigh the financial costs and the other more minimal environmental costs such as leakages from underground stores.

On the whole it is difficult to estimate the financial costs associated with carbon dioxide capture and storage at power plants and from the atmosphere because of the variety of different factors that play a role, most notably the method of carbon capture. One paper estimated that air capture devices could each capture around 400 tonnes of CO₂ per year. Despite being a relatively small amount, it could still have an impact.

To conclude, I believe there are significant advantages to the use of carbon capture in both power stations and atmospheric capture to reduce the amount of carbon dioxide added to the atmosphere in the future and existing carbon dioxide contributing to climate change. It would also be straightforward to suggest that the benefits of this form of geo-engineering heavily outweigh the negatives. Carbon capture, may be expensive to implement but I challenge anyone to think of a form of geo-engineering that is sufficiently effective that is inexpensive. In order to reverse the impacts of anthropogenic emissions, a large (and expensive) solution is needed. This is simply unavoidable. 

Carbon Dioxide Capture: Part I

I am not ignoring the solar engineering forms of geo-engineering entirely in this blog but at the moment I’m focusing on carbon dioxide removal (CDR) techniques as I feel these will have fewer unknown and unintended consequences because they aim to reverse the fossil fuel trend of adding carbon to the atmosphere and do not try to reduce solar radiation reaching Earth. Atmospheric Carbon Dioxide Capture is a form of CDR geo-engineering that I feel has great potential. This involves taking carbon dioxide out of the atmosphere through chemical reactions and storing it deep underground or using it in industry. Many authors do not consider the capture of carbon dioxide at power plants to be a form of geo-engineering because it is not dealing with carbon dioxide that has already been released to the atmosphere. I personally disagree with this and see the removal of carbon dioxide from power plants as a key way to reduce the effects of climate change into the future on a large scale which is the current objective of all geo-engineering techniques. However, if you hold the view that it is not a form of geo-engineering, the procedures of carbon dioxide removal in power plants mentioned in this article are still applicable to global atmospheric carbon dioxide removal (which is a form of geo-engineering). This is why I feel it is particularly important to write a post on these techniques. This topic will be divided into two posts, the first on the different methods being used and the second on the stores, benefits, drawbacks and feasibility of these techniques.

How does it work?

According to Metz et al. (2005) there are four basic systems for capturing carbon dioxide from fossil fuels and biomass. These are as follows:

1. Capture from industrial process streams
2. Post-combustion capture
3. Oxy-fuel combustion capture
4. Pre-combustion capture

The first of these has been operational for 80 years but the CO₂ captured is still added to the atmosphere as until now there was no reason to store it. This is very unfortunate as, if the incentive to store this carbon had started 80 years earlier, the human race would not be in such a dangerous and unpredictable climate change situation. Implementation of this method therefore seems very straightforward, with few changes needed. Post-combustion capture involves the capture of carbon dioxide from flue gases produced during the burning of fossil fuels and biomass. The CO₂ is then pumped back underground. Ox-fuel combustion capture is very similar to Post-combustion but pure oxygen is used in the combustion and therefore the flue gas is mainly CO₂ and H₂O which are easier to recycle. Finally, pre-combustion capture involves ‘reacting a fuel with oxygen or air and/or steam to give mainly a ‘synthetic gas (syngas)’ or ‘fuel gas’ composed of carbon monoxide and hydrogen.’ A catalytic converter, such as those used on car exhausts, can then be used to produce carbon dioxide and more hydrogen and this can then be separated by physical or chemical absorption leaving hydrogen-rich fuel which can be used in many systems such as boilers and gas turbines. The latter three methods all revolve around the idea of making combustion less polluting to the atmosphere.

The techniques for separating carbon dioxide are varied and each have their merits. The three main processes for separation are shown in Figure 1. The first technology I wish to discuss is called ‘Separation with sorbents/solvents’ (Diagram A in Figure 1). This involves bringing the gas into contact with a liquid absorbent or a solid sorbent that separates the carbon dioxide from the rest of the gas. The sorbent that is loaded with CO₂ is then transported to another vessel where it releases the carbon dioxide following a change in the environment (e.g. heating or increased pressure). This sorbent is then recycled to collect more CO₂ in a cyclical process.

Separation with membranes is a method whereby only certain gases are able to permeate through the membrane. The flow through the membrane is driven by pressure differences. There is currently research and development ongoing to manufacture a membrane suitable for the large scale capture of carbon dioxide. This means this method is less widely used at present.

Cryogenic distillation (Diagram C in Figure 1), describes the process by which gases are converted to liquid through compression, cooling and expansion and then are distilled to capture the CO₂. This form of CDR is currently being carried out at a large scale commercially which suggests that it has great potential.

Figure 1: Main separation process for carbon dioxide capture.

These three capture technologies highlight the different ways carbon dioxide is removed in power plants and during biomass burning. The methods here deal with the carbon dioxide at the source and therefore prevent the carbon from reaching the atmosphere and influencing climate change. Achieving this reduces the need for other extreme methods of geo-engineering that could lead to unintended negative consequences for climate. These systems can also be applied to the removal of carbon dioxide already in the atmosphere. However, due to the lower atmospheric concentrations of carbon dioxide in the atmosphere than in power plants suggests that the efficacy will be less for atmospheric carbon dioxide capture.

This concludes the first part on the topic of how carbon dioxide removal is carried out in power plants and from the atmosphere. The next post will continue on this topic but turn the focus to where the carbon would be stored once it has been captured. In addition to this, the post will look into the benefits and drawbacks to this form of geo-engineering and whether it is feasible as a method to reduce the effects of climate change at a large enough scale to be considered by governments worldwide. 

Geo-Engineering in the news

Geo-Engineering literature is widespread in the academic field with papers exploring a wide variety of different techniques within the two main areas of Solar Geo-Engineering and Carbon Dioxide Removal but is there much of a focus in the newspapers and media? This is as important as the academic research in my opinion as the only way Geo-Engineering methods will be adopted is if there is a global consensus to implement them. The best way of achieving this is making the methods widely known using global news channels. By carrying out a quick look at the term ‘climate engineering’ on Google Trends suggests that, between 2004 and present, there has been an increase in interest in this topic.

An article in the Financial Times titled ‘Scientists grapple with geoengineering plans’ shows that geo-engineering is appearing in well-known newspapers. The article provides a concise overview of geo-engineering in the two main forms. Despite initially being pessimistic about the effectiveness of these methods, the article does highlight some promising news. Experiments in Iceland discovered that, when carbon dioxide was pumped into underground volcanic basalt rock, the conversion to solid carbonate minerals took just two years compared to previous estimates of hundreds to thousands of years.  This is promising for the storage of carbon underground as basalt strata is found all around the world. It is encouraging to see a major newspaper write an extensive article on this topic as it helps motivate people to take geo-engineering seriously.

The New York Times has also discussed the idea of climate by design. This article highlights the issues with human directly managing the climate, stating ‘Who gets to set the global thermostat?' This is particularly important for the politics behind geo-engineering and the coming together of many different countries to instigate it. Some countries at higher latitudes may want the global climate to be warmer to boost food production and access shipping routes in the Arctic whereas others may want climate to be cooler to reduce the chance of droughts. This illustrates why is may be extremely difficult to come to a global agreement.  Another important point raised in this article, quoted from Oliver Morton who is a senior editor at The Economist and has written a book titled ‘The Planet Remade: How Geoengineering Could Change the World’ is that that different academics have different views on the time periods that climate change should be addressed and this means that there are many debates surrounding the validity of geo-engineering.

A final article comes from Bloomberg titled ‘Geoengineering to Alter Climate Moves Closer to Reality.’ The article states, ‘A United Nations body is investigating controversial methods to avert runaway climate change by giving humans the go-ahead to re-engineer the Earth’s oceans and atmosphere’. To achieve the climate change reductions agreed during COP21 last December it seems that geo-engineering is needed. This article points out some strong arguments against geo-engineering including the unpredictable consequences, the fact that it can be hazardous and it is costly to implement. It is interesting that this article puts across the most pessimistic view of geo-engineering for the future of the climate.

It is clear to see that there are mixed opinions on geo-engineering methods in the news but the good thing is that it is being increasingly discussed. Many of the articles provide useful information on the different techniques and the issues surrounding them which is positive as it allows people to judge for themselves. It is vitally important that geo-engineering is discussed further in public circles as it could be very beneficial when attempting to deal with climate change.

The easiest geo-engineering technique?

Geo-Engineering can be divided into to two main categories, solar geo-engineering and carbon dioxide removal (CDR) geo-engineering. The previous post on ocean acidification falls into the latter category. Next I wish to look at another form of CDR geo-engineering, one which I feel can have obvious impacts, is relatively cheap and easy to implement and the barriers to implement this are relatively small. This method is called afforestation/reforestation. Below, I will outline this method and why I feel it is a Carbon Dioxide Removal scheme that we as a planet should be introducing now because it has very few negative repercussions.

Afforestation/reforestation are two distinct terms and it is vital to explain the difference now. Caldeira et al. (2013) explain the differences clearly and concisely:

“Afforestation is the direct human-induced growth of forest on land that has not historically been forested. Reforestation is the direct human-induced conversion of nonforested land to forested land on land that had been previously converted from forest to other uses.”

The planting of new young trees in areas previously covered before human activity is an easy way to increase the storage of atmospheric carbon dioxide because trees take in CO₂ during the process of photosynthesis that takes place during the day. This means that forests are a natural carbon sink (store of carbon). Further to this, trees absorb more carbon dioxide during their early development phase for growth and this means that planting new forests would have a greater impact than existing forests. The planting of new trees is therefore seen to have quick impacts on the atmospheric carbon dioxide levels.

The processes of afforestation and reforestation have clear benefits. In the instance of reforestation, there are relatively few drawbacks as it is just the process of returning land to the habitat that existed there around 300 years ago. Because of this, it is unlikely that reforestation will have any unexpected or dramatic impacts on the planet as a whole which is a particular concern for many of the other geo-engineering schemes proposed. There is also clear understanding of the processes involved and therefore predictions on carbon uptake by trees is more reliably calculated. The ecological benefits for endangered species are noticeable as many of the species now endangered were put in this situation by human clearance of their habitats in the past. Reforestation could help many species recover.

The use of afforestation of new areas would also be beneficial. Research has found that afforestation at low latitudes in tropical climates could produce an added cooling benefit due to increased formation of low clouds that could increase the amount of solar radiation reflected back into space. One ambitious estimate suggested that the use of forest planting could restore all the carbon lost through human deforestation and potentially decrease atmospheric carbon dioxide levels by 40 to 70 ppm by 2100. This is a very optimistic estimate however with other research estimating that if the USA and European countries planted forests over 0.5% of their areas, around 40Mt CO₂ per year could be removed from the atmosphere which is just 0.2% of the annual world anthropogenic CO₂ emissions. Other papers have suggested that a feasible estimate for atmospheric carbon dioxide reductions would be 15-30ppm by the end of the century. Despite this, I still feel that the planting of forests could have other as yet unknown beneficial climate feedbacks that could aid cooling to restore the climate to pre-industrial revolution levels.

There are unfortunately some drawbacks to this method of geo-engineering as there are with all methods. Much of the land that would be used for reforestation was cut down to make way for crops and livestock and this land is still being used for this purpose today. Farmers are unlikely to want to make way and lose their livelihoods to plant some trees and this highlights the main reason why reforestation has not been employed more aggressively in the past. On top of this, the world is under ever growing food insecurity and the demand for food is endlessly increasing. It therefore seems implausible that it will be easy to implement reforestation schemes without harming other sectors.

Afforestation also has some drawbacks with regard to climate. Afforestation in higher latitude areas that are seasonally or permanently covered by snow would lower the albedo (reflectivity) of the area causing more solar radiation to absorbed, actually leading to increases in temperature despite reductions in carbon dioxide. This highlights that the use of afforestation needs to be more carefully studied compared to reforestation as there may be less well understood adverse impacts that alter the climate of a region possibly affecting other systems such as rainfall patterns, monsoons, flooding, etc. These impacts may also occur far away from the afforestation programme meaning larger scale research is necessary.

To end this post, it is useful to consider the extent to which afforestation and reforestation could be implemented. A 2010 paper studied how humans have altered the biomes (different habitat types) between 1700 and 2000. The map below (Figure 1) shows the different anthromes (human biomes) worldwide. The 2000 map shows that a large proportion of the land that used to be forested is now dominated by croplands and rangelands (livestock). This illustrates the potential for reforestation on a large scale. In 1700 over 90% of the world was classed as wild or semi-natural but in 2000, less than 50%of the land was classified in such a way. Personally, I am not advocating a total reforestation of all the land that was previously woodland – that would be completely unachievable in the current global situation with the high demand food but a gradual and progressive reforestation of cropland and rangelands as well as careful afforestation of suitable areas would have an influence on atmospheric CO₂ (albeit small) with relatively few serious drawbacks. What’s not to like?

Figure 1: Anthropogenic biomes (1900 and 2000)

Ocean fertilisation for carbon capture

For this blog post I am going to look at the concept and implementation ocean fertilisation for carbon capture as a form of geo-engineering to reduce carbon levels in the atmosphere – one of the key greenhouse gases that is causing climate change.

So what exactly is ocean fertilisation? Ocean fertilisation refers to the adding of iron or other nutrients to the ocean at a large scale to enhance algal growth in order to increase the uptake of atmospheric CO2. When the algae die, they sink to the sea bed, taking the carbon with them and storing it in the deep ocean. This would benefit the planet as a reduction in atmospheric CO2 would reduce the amount of heat reflected back to Earth thus reducing or reversing the current trend of a warming planet. In order to boost this algal growth, nutrients such as nitrogen (N), phosphorous (P) and iron (Fe) could be added to the ocean waters to stimulate this growth and thus trigger the uptake of more Carbon Dioxide. Figure 1 below shows the biological pump, the process by which carbon dioxide is transferred between the atmosphere and the ocean. Stimulation of this cycle with nutrients is the purpose of ocean fertilisation.

Figure 1: The Biological Pump

One major question with regards to the implementation of ocean fertilisation is the feasibility of it. A study from 2014 looked into the feasibility of ocean iron fertilisation in the Southern Ocean using simulations with a Global Climate Model. This paper concluded that the Southern Ocean would be one of the best areas of ocean iron fertilisation worldwide which could have a noticeable effect on atmospheric carbon dioxide levels. In addition to this, other studies have involved data from a Southern Ocean-Iron Experiment (SOFeX). From this research, ocean fertilisation is a geo-engineering method that is difficult to achieve as the amount of iron required and the frequency to achieve the level of carbon sequestration (uptake of carbon by oceans) that is necessary to influence the climate is difficult to achieve. There are suggestions that commercial ships could deposit iron along the major shipping routes but these ships would be unable to carry the amount of iron needed.

The concept of ocean fertilisation sounds promising but there are a number of other drawbacks that need to be considered. One of the key concerns is ocean acidification. Carbon is a key cause of ocean acidification and by using ocean fertilisation, the oceans would be taking in more carbon, lowering the pH of the water. This can have severe consequences of marine wildlife and coral. In addition, there is a problem known as outgassing which refers to the fact that not all the carbon transferred to the deep ocean will remain there. Carbon is returned to the surface through ocean upwelling and evaporation transfers it into the atmosphere. One piece of research, found that within 100 years, around two-thirds of the carbon transferred to the deep ocean by ocean fertilisation returns into contact with the atmosphere because it is redistributed through the world’s oceans. This emphasises the fact that ocean fertilisation is not a long-term geo-engineering solution unless it is sustained. The process of ocean fertilisation is also slow and therefore it may not be the solution necessary to quickly react to anthropogenic climate change. The use of ocean fertilisation can also reduce oxygen levels in the ocean. This can lead to a loss of marine wildlife and a reduction in biodiversity because they are not well adapted to low oxygen (anoxic) waters. This can kill fish which has a knock on effect for commercial farmers.

So is ocean fertilisation a suitable Geo-Engineering solution? On the surface, ocean fertilisation seems to be a reasonable method of addressing the effects of climate change at a small scale. It is possible to implement quickly and effectively, and at relatively little cost. However, when looking at this method in greater depth, it is clear that there are a great number of problems with it and the suitability of this technique is questionable. In my own personal opinion, I do not feel that ocean fertilisation is the best possible geo-engineering as it is slow, has relatively little effect on global climate and has a number of negative environmental impacts that are difficult to avoid. The focus should be on protecting current ecosystems not destroying one to save the others.

A Better World

Figure 1: Cartoon on climate change

I had intended to add this cartoon the end of my last post but decided against it as I felt it warranted its own post. This cartoon again links in to whether there is a need for Geo-Engineering as well as highlighting the human aspect of resistance to reacting to climate change. At present, action against climate change is happening very slowly – Geo-Engineering is only in the initial research phase – and this got me to question why as a species are we so slow to adopt climate change adaptation or mitigation strategies. Research has found that our brains can’t react to climate change because we are not wired to respond to large, slow moving threats which means that it is particularly difficult to reduce emissions.

This cartoon highlights the confusion surrounding people’s resistance to climate change action as it is clear that the transition to a greener, lower fossil fuel burning economy would actually bring about many personal and health benefits for humans and many other species. Despite this, fracking is on the rise (from 23,000 fracking wells in 2000 to 300,000 in 2015) and fossil fuel consumption is ever increasing. From this, it is clear to see that global energy demand is not decreasing and the end of fossil fuels is not close enough. Because of this, greenhouse gas emissions are unlikely to decrease any time soon and thus carbon levels in the atmosphere are also not going to decline in the near future. In addition, around 30-50% of the Earth’s land has been exploited in some form by human activity and all of this means that human impact on the planet has been so profound that global climate may shift away from natural behaviour for many millennia. It is clear to see from this that the ‘Better World’ pointed out in the cartoon is not going to be achieved through a decrease in fossil fuels in the near future and this emphasises the need for Geo-Engineering to reduce climate change effects until individuals begin to reduce their own consumption and emissions. 

Is there a need for Geo-Engineering?

Have you ever spoken to a friend or colleague who is a sceptic of human induced climate change and been questioned about why you believe climate change exists. You stumble through your arguments with statements like, “the planet is getting warmer” and, “there’s more carbon dioxide in the atmosphere now” and afterwards feeling you’ve failed the human race with your poorly formed case for anthropogenic (human induced) climate change. Proving the validity of climate change is particularly important with reference to Geo-Engineering as, if anthropogenic climate change doesn’t exist, why are we even bothering with Geo-Engineering?

So where to begin? Strangely enough, it’s going to start with the two points mentioned earlier – temperature and carbon dioxide (and other greenhouse gases (GHGs)). I intend to begin with the same graph that I used in my introductory blog post as I feel it so clearly shows evidence for human induced climate change. An article by Crutzen and Stoermer in 2000 placed the start of the Anthropocene at the latter part of the 18^th century which coincides with the introduction of James Watts’ steam engine. This is important because we are now looking to see if there have been dramatic climate shifts since this date. Figure 1 shows carbon dioxide concentrations (top line) and Antarctic temperature (bottom line) for the past 650,000 years using records from Antarctic ice cores. Over the period 650,000 years ago – c.5,000 years ago, carbon dioxide levels never surpassed 300ppm (parts per million) and yet the present day level is 380ppm (technically 400ppm in March of this year). Looking at Greenhouse Gases (GHGs) more carefully in recent history (Figure 2) it is clear to see that there has been a dramatic upward trend in Methane (CH₄) and Carbon Dioxide (CO₂) since around 1800. What a surprise that this coincides with Crutzen and Stoermer’s dating of the start of human impact on climate. In less than 200 years, methane levels have doubled and carbon dioxide levels have increased by a third – this cannot just be natural climatic variation over such a short time scale. A strengthening of the case for temperature variation is also that the ten warmest years since records began have occurred since 2000.

Figure 1: Reconstruction of past atmospheric CO2 concentration (top line) and temperature reconstruction for the Antarctic (bottom line).

Figure 2: Atmospheric carbon dioxide and methane levels between the years 1000 and 2000.

Next, I wish to highlight a key paper by Steffan et al. in 2015 on Earth System Trends. Below are parts of some of the figures in the paper that I thought were particularly useful when looking at human induced climate change. By studying Figure 3, the trend in environmental variables is particularly concerning, especially tropical forest lost and terrestrial biosphere degradation. This used in tandem with Figure 4 that shows economic and societal trends shows the link between the two. The year 1950 is marked on every graph highlighting the sharp (almost exponential in some cases) increase after this date. From this, it is clear to see that human activity as represented by population, Real GDP and Primary Energy use, etc. is having a clear impact on many natural environments including the oceans, tropical rainforests and coastal environments. The similarity in trends post-1950 is too hard to ignore.

Figure 3: Environmental trends (1750 - 2010).

Figure 4: Socio-economic trends (1750 - 2010).

It would be a mistake if I did not directly mention the impact of fossil fuels on anthropogenic climate change in this post. It is already well known that the primary source of carbon dioxide is from fossil fuel burning. The global production of fossil fuel energy has increased rapidly since around 1945 from about 1500 Mtoe of energy to just over 10,000 Mtoe in 2010. In addition to this, presently about 80% of the world’s energy is as a result of fossil fuels usage, suggesting that the adding of carbon dioxide to the atmosphere by humans is unlikely to stop suddenly or any time soon. This points to a likely need for Geo-Engineering alongside a decrease in GHG emissions.

So from this there is a strong case for anthropogenic climate change supported by a number of statistics and these prove a need for Geo-Engineering techniques. This means that if you ever meet any climate change sceptics you’ll know exactly what to say!

Welcome!

Hello and welcome to my blog looking at whether Geo-Engineering is a feasible solution to climate change. I hope this blog will explore some interesting topics within Geo-Engineering to investigate in more depth what methods may be suitable for the human race.

At this stage I have some knowledge on Geo-Engineering (but not extensive) but from what I do know, I am sceptical about it. There always seems to be some downsides to the methods of Geo-Engineering I have heard about already and this is one of the main reasons I have decided to write my blog on this topic. I want to challenge my initial opinions to see if Geo-Engineering is in fact a viable solution (or mitigation) for human induced climate change. Further to this, I chose this topic as I believe something drastic must be done about anthropogenic (human induced) climate change and I want to know whether Geo-Engineering may just be the solution humanity is in need of.

I thought it important in this first blog post to outline why Geo-Engineering may be necessary in the future by looking at climate change and highlighting some of the topics which I wish to cover as this blog goes on. Below in Figure 1 is a graph that shows Carbon Dioxide in parts per million (the top line) and temperature of the Antarctic (°C, the bottom line). As it is possible to observe, CO₂ levels have never been as high as they are now. In fact, they have just recently passed 400ppm in March 2016 which is far greater than any level experienced over the past 650,000 years. It can only be as a result of human activity – mainly the burning of fossil fuels releasing carbon dioxide into the atmosphere. 

Figure 1: Reconstruction of past atmospheric CO2 concentration (top line) and temperature reconstruction for the Antarctic (bottom line).

Geo-Engineering is in its early stages of investigation and I believe it is particularly important to get it right before we as a planet do something we regret. There are a number of different Geo-Engineering techniques that have been mentioned that I will look into in future blog posts. Box 1 below comes from a 2008 paper on potential Geo-Engineering solutions and describes potential methods clearly and succinctly. This goes to show that there are many different possibilities under the concept of Geo-Engineering but may not all be viable or effective. It is clear that all these ideas are only in the research phase – highlighting why I hope this blog will be looking at something relatively new and different.

Box 1: Geo-engineering schemes under discussion.

I hope this blog will be interesting and informative and will attempt to look at a topic that is new and in need of investigation. I plan to look at some of these Geo-Engineering schemes in more detail in future posts as well as some other aspects relating to global environmental change and whether there is a need for Geo-Engineering.