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!