Geoengineering

Geoengineering is one of the most discussed and contentious topics within climate change mitigation. The methods can range from extremely elaborate, like placing large mirrors into orbit, to more feasible techniques, such as whitening buildings.

What is geoengineering?

Geoengineering refers to a “deliberate and large-scale intervention in the Earth’s climatic system with the aim of reducing global warming” (Stilgoe, 2015). The approaches tend to be able to split into one of two broad categories: carbon dioxide removal or solar engineering (Caldeira et al., 2013).

Solar engineering (SE)

In summary, solar engineering is decreasing the amount of solar radiation absorbed by the Earth in order to counter the additional radiative forcing generated by increased GHGs concentrations in the atmosphere – to offset the forcing from a doubling of CO₂, approximately 1.7% of the incoming sunlight (Caldeira et al.,2013). These techniques (Figure 1) tend to be large-scale and would be expensive to implement, and include ideas such as sending mirrors into orbit or injecting aerosols into the stratosphere.

Figure 1. Summary of different SE approaches.
Source: Caldeira et al., 2013

It is generally accepted that such methods could be successful in reflecting sunlight, but the resulting effects are unknown, and in some locations the techniques could worsen the problem of climate change (Caldeira et al., 2013).

Carbon dioxide removal (CDR)

Focussed on alleviating the actual cause of anthropogenic climate change by removing CO₂ from the atmosphere. In comparison to solar engineering, these techniques (Figure 2) are generally of a smaller scale and can be applied more locally. They include approaches such as reforestation, enhancing weathering, or fertilisation of the oceans (Caldeiraet al., 2013).

Figure 2. Summary of CDR approaches
Source: Caldeira et al., 2013

Whilst being typically cheaper and less controversial to implement, CDR methods tend to be slower-acting and so do not present a solution on the short timescales that are necessary to reduce the impacts of climate change.

Comparison of methods

As mentioned above, the offerings from the two streams of approach are largely opposite. SE methods are expensive, controversial, would require international backing to implement, but would be able to reduce warming within years of introduction. CDR would take longer to take effect and so do not offer an immediate solution to global warming, but they are more inconspicuous, usually cheaper (on smaller scales) and are, in most cases, more localised, allowing for independent introduction by individual countries. There are exceptions to this, of course, with ocean fertilisation being a prime example. As seen in Figure 2, this offers significant carbon removal (up to 200 Pg C by 2100), but the most could be almost as controversial as SE techniques; for example, ocean fertilisation could have dramatic effects on coral reefs and would be expensive (Caldeira et al.,2013).

In my opinion, there seems one fundamental difference between SE and CDR approaches, and it’s connected to the issue that is essential to successfully reducing emissions and mitigating climate change. Whilst solar techniques are generally the more novel of the two, they represent the problem that has underlain the failures of action against climate change so far. They are effectively shifting the responsibility of dealing with our emissions to another source: rather than remove the issue that we have caused, they instead focus on altering the Earth system in an even more dramatic way.

I understand, however, that CDR techniques are not obviously not perfect. To implement them on the scale required would financially infeasible, and the response would likely not be rapid enough to solve fast-acting climate change. Limitations of warming to 2^oC by the Paris agreement include geoengineering within them already, and so it must be assumed that they will eventually be introduced in some capacity. To me, the best solution would be a combination of the less controversial techniques from both sets. Biomass energy with CO₂ sequestration involves the capture of CO₂ from power plants running on biomass, allowing of permanent removal of CO₂ from the atmosphere. 3% of the global land area used for this purpose would lead to a reduction of 1 Pg C each year (Caldeira et al., 2013). From the SE approaches, enhancing solar albedo by installing white roofs globally has been modelled to reduce daily high and low temperatures in urban areas by 0.6^oC and 0.3^oC (Caldeira et al.,2013). By introducing a large quantity of smaller initiatives, we may be able to produce some significant temperature and CO₂ reductions. I believe the large-scale SE techniques offer a safety net that should only be used as a last resort, in the failure of other methods.

The carbon tax

In my first post about large and small scale climate change mitigation, I mentioned the carbon tax. The tax is considered to be the main alternative to a cap-and-trade system.

Source

What is it?

Carbon taxing involves adding a financial incentive to cutting emissions: bodies, whether they be firms or households, are taxed for each unit of greenhouse gas emitted, with more carbon-heavy fossil fuel products levied by higher taxes (Lin and Li, 2011).

Does it work?

Lin and Li (2011) review the effect of carbon taxes in reducing CO₂ emissions in five of the countries they have been implemented in (Denmark, Finland, the Netherlands, Norway and Sweden). The authors state that there are two main positive impacts to carbon taxing:

(1)    Promotion of substitutes for fuel products, allowing for development of energy saving and energy efficiency.

(2)    Investment into environmental and clean energy initiatives through the money saved from the carbon tax.

However, there are some clear limitations of the method too. A key one of these is economically-based, in that implementing the tax will lead to increased costs for businesses and lower competitiveness. Another is that the ability of the tax to actually mitigate emissions. Lin and Li (2011) argue that rather than leading to emission reductions, businesses could just raise the prices of the their products or services, leading to customers taking on the cost of tax. Carbon leakage could also increase, as carbon intensive industries migrate from carbon taxing countries to other, more lenient countries (Lin and Li, 2011).

The authors found that the carbon tax had differing effects on mitigation depending on the country studied. In Finland, the tax has reduced the growth of carbon emissions per capita by a statistically significant amount. Denmark, Sweden and the Netherlands also experienced reductions, but not by enough to be of significance statistically. In Norway, an increase in per capita emissions was suggested, but again this was not significant (Lin and Li, 2011). This disparity is likely in some part caused by tax exemptions provided by all countries other than Finland, for example, for the manufacturing industry. It is suggested by the authors that in order to obtain the best results from a carbon tax, a single rate needs to implemented rather than differential rates.

Carbon tax vs cap-and-trade

As stated above, there is a large debate as to whether carbon taxing or cap-and-trade offers the best opportunities for mitigating emissions. Wittneben (2009) argues that the European Union Emission -Trading System (EU ETS), one of the most prominent cap-and-trade schemes (and discussed in this post), has ultimately failed at reducing carbon emissions, despite leading to heavy governmental income. The author states that because carbon taxes are negotiated at a national level, the severity of the tax will factor in the political climate of the nation itself, leading to a theoretically-limitless level of emission reductions. This is opposed to a cap on emissions, which also serves as a cap on reductions. Obviously, this is an argument based more on theory than stone-cold facts, as seen by the effectiveness of the carbon tax in the study by Lin and Li (2011).

Another key argument between the two are background financials, which were studied by Carl and Fedor (2016). Wittneben (2009) suggests that a carbon tax rather than cap-and-trade would lead to more capital being available for green initiatives; however, Carl and Fedor (2016) argue that this might not be the case. Analysing $28.3 billion that is currently generated by 40 countries via “carbon revenues”, they state that $7.8 billion of this goes towards “green” spending. Of the money collected from cap-and-trade, 70% is directed towards “green” spending, compared to carbon taxes, in which 72% of the income goes to government general funds instead. There is more complexity to the argument than this however, as carbon taxes have the ability to generate more capital than cap-and-trade Carl and Fedor (2016).

Cleetus (2011) offers a potential solution encompassing both methods, called the price collar. The hybrid focusses on capping emissions whilst also setting a minimum and maximum price for emission allowances. This method would not set a carbon price or a specific cap on emissions, but would provide bounds in which both of these could occur (Cleetus, 2011). Setting the maximum and minimum prices is a challenge as it must promote the use of low-carbon alternatives but not cause significant economic derailment.

A really good article published on the Guardian from a few years ago covers all three of these methods of mitigation. It is clear that economic methods such as these offer a great opportunity for emission reductions, but they have to be carefully selected for each country.

Finally, for an easy explanation of carbon taxing (using chickens), and a quick comparison of it to cap-and-trade, see the video below:

Top-down vs bottom-up: Part two

In last week’s post, I discussed the effectiveness of top-down mitigation initiatives. For part two of this post, I am moving onto bottom-up strategies.

Bottom-up schemes

Having become increasingly popular as the effects of climate change are understood and felt around the world, bottom-up initiatives are designed so that they can be implemented at the “lowest feasible level of organisation” (Rayner, 2010), whether it be local community, city, regional or national level.

Rayner (2010) states that bottom-up approaches opposes the philosophy of cross-governmental top-down strategies. International top-down strategies requiring universal agreement are forced to appease so many, from a range of backgrounds and with a range of different interests, and this results in a less effective response; in comparison, introducing action at a lower level allows for it to be tailored to the region itself. This means initiatives can be quickly implemented, contrasting top-down and multi-country collaborations that would take considerably longer to take effect.

The author suggests that bottom-up methods need not rely even on the efforts of an entire country, and that cities hold the potential for innovation and collaboration. The C40 Group, that was touched upon in an earlier post is named as a being one of the most successful.

Example: short-lived climate pollutants (SLCPs)

One of the best opportunities for bottom-up mitigation lies with SLCPs, as discussed by Seddon and Ramanathan(2013). Included within this group are emissions of black carbon from soot, tropospheric ozone, methane and HFCs, and reducing SLCPs could lead to a 0.5^oC reduction by 2050, amongst other benefits: for example, a reduction in the 3.5 million deaths from indoor air pollution-sourced black carbon. The authors state that the technology is there for this to be achieved, but presently little is being done. Herein lies one of the potential issues with bottom-up initiatives: their success relies on adoption by the communities they effect. An example of this lies in cutting methane emissions from farms. One way this can be reduced is draining of the fields midseason. From an external viewpoint, this seems simple and straightforward, but in reality, persuading farmers is difficult due to additional risks to crops and complications pertaining to the timing of income (Seddon and Ramathan, 2013).

Is bottom-up the answer?

I think bottom-up has to be play an integral part of climate change mitigation. The top-down approach has not worked anywhere near as well as hoped so far, and in terms of the ability to inspire and outreach to the general public, bottom-up schemes seem more significant.

The ultimate answer, I would imagine, lies in a combination between top-down and bottom-up. Bottom-up has great potential but is not without its issues. For one, most initiatives are more adaptation-based than for mitigation. This is not surprising, given that these are generally smaller projects that are often introduced in direct response to a threat from climate change. Another flaw, highlighted by Rayner (2010), is the fact that bottom-up approaches are exactly what the name suggests – initiatives that occur right at the bottom of public decision making.

The SLCP example above presents the perfect opportunity for action at the top and bottom levels. Cutting down emissions from these particles can be induced at a local level, even if just as simply as decreasing use and demand. For the specific problem of rice fields, working alongside farmers to design a solution that reduces releases of methane whilst not causing significant disruption is important. To go alongside these, multi-national agreements can support and facilitate the same change, as is seen by discussions to ban HFCs (http://www.bbc.co.uk/news/science-environment-37610850). In fact, without the support of top-down schemes, the effectiveness of bottom-up is most likely to be limited. Urwin and Jordan (2008) looked at the interplay between top-down and bottom-up, using the UK as an example. They found that few policies were currently in place to support climate change adaptation and mitigation directly, but found some that currently existed indirectly worked to undermine bottom-up efforts. An example of this was given by the authors in regards to a lake near Cambridge, where plans were in place to recreate a wetland habitat but was made much more complex due to three seemingly-unrelated pieces of legislation.

Top-down vs bottom-up: Part one

A difference in opinion exists as to whether the best strategies for tackling climate change are large-scale, top-down initiatives or smaller, bottom-up schemes.

To most people, the phrase “climate change mitigation” tends to instinctively induce images of grand projects that are usually centred around geoengineering, whether it be by sending giant mirrors into space or injecting aerosols into the stratosphere. The idea of community-led strategies is often overlooked despite being essential to resolving progress. Over the next two posts, I’m going to focus on whether there should be a preference for either top-down or bottom-up mitigation.

Top-down schemes

Top-down initiatives usually spawn out of governmental policy. Following the introduction of the Kyoto Protocol, and the subsequent Copenhagen Accord and Paris Agreement, pressure has mounted on individual states to bring climate mitigation into force. The majority of effort has understandably focussed on emission reduction, with the IPCC estimating that global GHG emissions need to be reduced by 40-70% by 2050 in order to limit warming to 2C.

Cap-and-trade

One of the more revered top-down strategies is that of cap-and-trade programmes (Dirix et al., 2013). These involve placing a maximum level on the emissions of a particular pollutant. Allowances are then calculated based on the cap in the form of a “units” of the emitted pollutant, and these are allocated to each polluting body, for example countries or companies. Units can be traded between bodies, so if an entity is unable to reduce their emissions of a pollutant, they can make up for it with reductions in other areas. An example of a cap-and-trade scheme is the EU ETS, which can be read about here or in Figure 1 below.

Figure 1. How the EU ETS works.
Source

Cap-and-trade leads to emission reductions by gradually lowering the total amount of permitted pollutant. At the beginning of the EU ETS, in 2005, each corporation was given units equal to their current levels of emissions. The scheme has been introduced in three phases over 15 years, with Phase II (2008-2012) reducing emissions by 6.5% compared to the those at the start of Phase I (2005-2008) (Dirix et al., 2013). By the end of Phase III in 2020, emissions will be 21% lower than in 2005.

Dirix et al. state that these schemes are generally seen as successful due to them being able to directly work toward the aim of environmental policy. However, they are not without their critics and are judged by some NGOs to be biased in favour of high-polluting entities.

Carbon tax

Another popular top-down method that seems to be gaining increasing traction is a carbon tax, involving the introduction of a financial cost for carbon released into the atmosphere (Ekins and Baker, 2001). I think this is a really interesting policy idea and so will be focussing on this specifically in a future post rather than in this one.

Geoengineering

Geoengineering is another huge topic that I will focus on in a future blog post. It’s an area that is met with much contention, and is essentially “large-scale efforts to diminish climate change resulting from greenhouse gases that have already been released to the atmosphere” (Caldeira et al., 2013).

Has top-down mitigation worked so far?

As expected, this is not a question with a simple yes/no answer. Dirix et al. argue that climate policy can be judged on two key factors:

1.       Does the policy lower emissions?

2.       Does the policy place the burden equally between parties?

Looking specifically at the EU ETS, the authors consider the policy to fulfil both of the above criteria, due to its ability to not just lower emissions, but also the improvements in market efficiency and price volatility reductions that it offers. The scheme is not perfect, however, and some argue that it favours large corporations, specifically through an over-reliance on offsetting emissions. This is seen by some to be an easy escape route from emission reductions.

Various studies believe that top-down initiatives have not been as successful as hoped. Prins and Raynor (2007) state that though the Kyoto Protocol represented a considerable step by showing a governmental concern for climate change, it ultimately failed in its goals, most notably with no significant emission reductions. The core reason for this is placed with a simple misjudgement of the problem; borrowing a strategy used to tackle issues such as acid rain and ozone depletion, when they are only partly analogous, is considered by some to be an oversight. The complexity of the climate change issue transcends that of the problems for which a global control technique has previously worked.

Prins and Raynor state that the theory that the Kyoto Protocol is based upon, which is effectively cap-and-trade, has failed to take-off. Governmental investment into clean energy is lacking but is nonetheless essential to avoid an energy gap from reductions in fossil fuel usage.

Coal power - is it on the way out?

Last week an article was published on the Guardian which discussed the announcement by Canada that they would phase out coal power by 2030. Coal has been one of the key energy sources since the 19^th century, previously having been heavily relied upon by developed countries but now having shifted to the rapidly developing nations, and in particular China. The dirtiness of coal power means that cutting it out of the global energy budget is essential if we are going to curb emissions.

Figure 1. Global energy consumption since 1820. Coal power has continually increased through this period.
Source

The decision by Canada to cease using coal follows in the footsteps of the UK, France, the Netherlands, Austria, Denmark and Germany, who have all also pledged to move away from it. We are also seeing reductions in the use of coal in China. The country’s coal power tripled between 2000 and 2013, but it has now peaked and has declined by as much as 3% in the last year.

These countries reducing their coal use far from means that coal power is on the way out. China, though decreasing its reliance, is still planning to build new plants, along with both India, Indonesia and other developing nations. Adding Donald Trump into the equation, and the outlook continues to not look so great. Coal power currently makes up 1/3 of the US energy market (USEIA, 2015), and Trump made the promise of increasing “clean” coal production a major focal point of his campaign.

Having previously not had much idea about clean coal I came across the quick video below that explains it, and some of the disadvantages.

It remains to be seen whether coal will again be used more regularly in the US. A number of experts suggest that even if Trump planned on it, the economy could be the major hurdle. As it stands, the price of natural gas is the lower of the two and, with coal-related jobs already lost, further investment would be needed to bring them back.

As detailed in a video from an earlier post, 2030 is considered a key point for when significant emission reductions have to have been started. So much of this is dependent on switching to clean energy, and so the global reliance on coal becomes more imperative, and dangerous, by the day. 

Agricultural mitigation

Following the last post on climate change mitigation within cities, I’m now going to switch to the opposite end of the spectrum and look at rural environments and agriculture.

The industry was responsible for 24% of anthropogenic GHG emissions between 2000 and 2010, placing it second only behind the energy sector. Contributions were largely from livestock, soil and nutrient emissions,and deforestation.

With such a significant proportion of emissions originating from agricultural practices, it is understandable that it has become an epicentre for emission reduction ideas. These range from individual ideas, most notably a simple reduction in the amount of meat consumed  to lower the demand, but research has also been completed into making agricultural practices more environmentally friendly.

Smith et al. (2007) estimated that the potential cut of emissions from agriculture totals as much as 6000 Mt CO₂-equivalent per year. After a bit of quick maths, this equates to the emissions of over 1.2 billion cars (based on the EPA stats for average emissions, and roughly equals the total number of cars on the road globally.

The paper by Smith et al. categorise mitigation strategies into three main principles:

1.       Reducing emissions: the most appropriate methods are location dependent but in a broad sense emissions can be controlled by managing the agricultural ecosystem more efficiently. An example would be using feeds for livestock that help to limit methane emissions.

2.       Enhancing removals: Better management of soils to either increase storage of carbon or slow the rate of release.

3.       Avoiding emissions: Predominantly achieved through the use of crops or residues for energy, helping to lower emissions despite still releasing carbon dioxide.

The study then goes into detail about specific mitigation strategies, broken into the following categories:

- Cropland management

- Grazing land management/pasture improvement

- Management of organic soils

- Restoration of degraded lands

- Livestock management

- Manure/biosolid management

- Bioenergy

Cropland management is probably the most encouraging of these, with none of the strategies shown to produce higher CO₂, CH₄ or N₂O emissions. Specifically, land-use change offers reduced emissions for all three gases with extensive evidence and agreement within the scientific community.

Finally, the paper produces data for the regions that have the highest mitigation potential (Figure 1). Southeast Asia and South America.

Figure 1: Mitigation potential calculated for each country. Southeast Asia and South America hold the most potential for emission reductions.
Source: Smith et al. (2007)

Potential vs reality

Something that is briefly mentioned but generally overlooked by the authors is the disparity between the mitigation potential and the quantity of mitigation that is actually realistic. Smith et al. (2005) studied the level of overestimation of carbon sequestration in European croplands. The paper looked at carbon sequestration data for a number of cropland management methods and the distribution of the different practices through a number of European countries, resulting in an estimate for the total carbon sequestration in each country.

A key finding was that the total cropland area being actively managed decreased in all countries between 1990 and 2000, and was likely to continue to decrease through to 2010. The authors found that carbon sequestration was negligible in most countries, and vastly different to the large estimates for mitigation potential produced by other studies. This gap is put down to economic, social and political barriers, and it is noted that little progress will be made without active backing and encouragement from policymakers.

Despite this, evidence does exist that agricultural emissions are decreasing. The OECD have found that there has been a reduction in emissions within its member countries (listed here) despite an increase production volume of 1.6% per year. It is worth noting, however, that the OECD is formed of developed countries and so is unlikely to be representative of the global picture.

Effect of climate change on agriculture 

There isn’t a one-way relationship between agriculture and climate change. As global temperatures rise and a more variable climate is experienced, the future for one of the most depended-upon sectors becomes increasingly uncertain. The effect on crop yields will be location-dependent, but significant areas are expected to see reductions (Figure 2).

Figure 2: The estimated changes in yield for maize, wheat and rice per country based on projections from the IPSL and Hadley models. Maize appears to be the most negatively impacted crop and is expected to suffer drastic reductions in yield.
Source: OECD

In Kenya, the farming sector is responsible for more than 25% of the GDP and over 75% of the population relies upon agriculture for some part of their earnings. The country’s National Climate Change Action Plan highlighted five key risks that are expected to hinder the sector:

- Less days for crop growth.

- Higher frequency of droughts.

- Reduced planning owing to more unpredictable climate.

- More frequent flooding of agricultural land.

- Increased pests.

These effects are clearly not exclusive to Kenya, and the strain on food production will only worsen as they occur. Climate-smart agriculture (CSA) is an approach championed by the FAO (a short summary video from Youtube is found below) which seeks to achieve locally-driven solutions in response to three key objectives:

- Increases in productivity and income.

- Climate change adaptation.

- GHG emission reductions.

By creating locally-focussed solutions that are aligned with some (or in some cases all) of the above, individual communities are given more help to tackle the detrimental effects climate change could have on their agriculture. The first point relating to increased income is particularly important because, as with the issues relating to carbon sequestration implementation, promotion from governments and authorities is essential.

Case study 2: Eco-cities: The perfect model or just overambitious?

Sino-Singapore Tianjin Eco-city

I’m going to start this post with a couple of videos which present the sustainable efforts of an eco-city in Tianjin, China (and featuring some typical geography video music). Instead of retrofitting sustainable measures to an existing settlement, they are rather building an entirely new city, named Sino-Singapore Tianjin Eco-city, which is located about 40 km from Tianjin city centre.

I find climate change in China particularly interesting. A stigma exists of the country that it is highly polluting, with dirty air and very little care for the environment. Whilst it is true that it is the biggest emitter of carbon dioxide, and air pollutants are a major concern, the steps the Chinese are taking towards climate change leave a lot to be desired of other countries.

But do eco-cities actually work?

The legitimacy of whether eco-cities are working is a topic of much discussion. Flynn et al. (2016) argue that to judge whether their success, we need to critique all areas of the process, including the design and build, and the effect on the behaviour of the new residents.

A key facet of the paper are the findings of a questionnaire of the residents, looking at their attitudes pre- and post-moving into the eco-city. One interesting outcome relates to the mode of the transport used for different activities (Figure 1). In almost all cases, the use of private cars has decreased, although, perhaps ironically as it was one of the major selling points from the videos above, the only case in which it has increased is for travelling to work.

Figure 1. Mode of transports of residents living in Sino-Singapore Tianjin Eco-city compared to previous residence.
Source: Flynn et al. (2016)

The study also presents changes to the amount of walking that residents partake in. 42% of residents said that they walked less regularly than prior to moving, 33% reported it to be similar and just 25% answered that their walking had increased. Again, this shows that the aims of the project are perhaps not as realistic as hoped. Finally, the paper also finds that the whole premise of the eco-city being designed to be more environmentally friendly actually results in residents believing that they can use more energy at their convenience. Rather than the clean energy of the city accompanying a behavioural shift towards more careful use of resources, it appears to possibly be having the opposite effect and leading to a more elaborate lifestyle.

Premalatha et al. (2013) extend this point further, focussing on two zero-carbon eco-cities: Dongtan City in China, and Masdar City close to Abu Dhabi. Dongton was designed as the world’s first-ever zero-carbon city, and was planned to be a model for sustainable city building that could be followed for all future developments. Masdar was even more ambitious by being stated to be the first ever zero-carbon and zero-waste city. 

The authors argue that both cities were over-ambitious in their approaches, and that for a city to sustain life through a truly ‘zero waste’ existence actually contradicts the second law of thermodynamics and that some form of waste must eventually be created. This, along with other shortcomings of both cities, such as an over-reliance on renewable energy, has resulted in both ultimately failing at their aims. Masdar has, for example, had to rely heavily on fossil-fuel-induced energy being imported from Abu Dhabi.

The concluding statements of Permalatha et al. echo those of Flynn et al. For a sustainable city to reach its maximum potential, the character of the residents themselves must adapt too. Installing appliances and creating buildings that are low energy only serve as deflections from the underlying issue – that we rely too much on energy – unless they are accompanied by a change in mindset and lifestyle.

I think the findings of Premalatha do, however, provide a basis of hope for the eco-city in Tianjin. The aim for the city to be more of a stepping stone to sustainable living, with a plan that can be replicated in part because it isn’t gunning for an adoption of 100% renewable energy, means that costs are kept down and the likelihood of other cities and countries following the same formula increases. Whereas a switch to fully renewable could induce a blasé attitude of “It’s clean energy, so I can use as much as I want.”, incremental decline of fossil fuels and ascension of renewables could instead create an opportunity for a reduction in the reliance of energy altogether.