Introduction to Geoengineering - SRM

What is Geoengineering and Solar Radiation Management?

As mentioned in the first post, Geoengineering often refers to 'large-scale efforts to diminish climate change from greenhouse gases that have already been released to the atmosphere' (Caldeira et al., 2013). It can be classified into two major categories, solar radiation management (SRM) and carbon dioxide removal (CDR) - this post will focus on SRM. 

Solar radiation management (SRM) targets to offset the effects of anthropogenic climate change, including high atmospheric CO2 and other greenhouse gases (GHGs) by reducing the amount of solar radiation absorbed by Earth. Since atmospheric CO2 and other GHGs deploy radiative forcing on the Earth's climate system through making harder for the heat coming in to escape from Earth (Caldeira et al., 2013). SRM approaches can be divided into four major kinds: 

     Space-based approaches introduces to reduce the incoming solar radiation reaching Earth, including the installment of mirrors and rings in orbit around the Earth by constellations of spacecraft (Pearson et al., 2006) or placing a thing glass shield using lunar materials near the first Lagrange point (L1) of the Earth-Sun system (Early, 1989). 

     Stratospheric aerosol-based approaches aim to inject sulfate aerosols into the lower stratosphere to cause scattering solar radiation back to space, leading to the cooling of Earth (Caldeira et al., 2013). This idea of injecting aerosols have suggested from looking at the past volcanic eruption such as Mount Pinatubo in 1991, which caused cooling of the earth's surface in following years by almost 0.5 degrees Celsius (Cruten 2006). Even though sulfate aerosol injection could be done in troposphere to cool the earth, it is considered to be more efficient to inject in the stratospheric due to their longer residence time of about 1 - 2 years - while only a week in troposphere - hence the required sulfur for cooling would be much less in the stratosphere injection, compared to the troposphere (Dickinson, 1996). 

     Marine cloud brightening is another way of modifying the reflectivity of the earth, particularly increasing the low-level marine stratocumulus cloud reflectivity (Caldeira et al., 2013). Studies on cloud albedo such as Twomey (1977) suggest that by increasing the number of cloud condensation nuclei (CCN), greater number of cloud droplets would be produced while the droplet size actually drops, then the total cloud droplet surface area will increase and thus the cloud reflectivity. Areas with extensive marine stratocumulus clouds such as the west coast of Africa have been distinguished with potential to adopt such SRM approach (Latham et al., 2008). 

     Surface albedo enhancement will be one of the most well known SRM strategies. It aims to increase the earth's surface albedo through altering the surface reflectivity of the ocean, deserts, urban and rural regions (Caldeira et al., 2013). Methods can range from whitening the roof of the buildings to planting more reflective plants. 

Different SRM strategies: a) using satellites to reflect the incoming radiation back to space, b) injecting sulfate aerosols into the stratosphere, c) marine stratocumulus cloud brightening, d) altering the ocean surface albedo, e) growing plants or crops with high albedo and f) whitening building roofs - adopted from (Caldeira et al., 2013). 

Many scientists advocating the implementation of geoengineering as an effective measure for responding to climate change claims that it can be used with other strategies (to reduce greenhouse gas emissions and increase adaptive resilience to climate change) to accelerate the pace of 'returning' the earth back to pre-industrial level. This may in part because rather 'quick' response of climate system to geoengineering is projected (Matthews & Caldeira, 2007) in computer simulations. Especially, SRM strategies such as whitening the roofs of the building or planting crops with high albedo can be implemented in a fairly easy way, anticipating for a quick response. Hence, some implies that there may be only a little cost in delaying the geoengineering deployment 'in the field' until the earth reaches a very 'dangerous' and imminent situation of climate change (Matthews & Caldeira, 2007).

     However, many oppositions for geoengineering implementation also exist, keeping the debate ongoing. Next post will explore about such debates and the other major geoengineering scheme of CDR.
 

COP22 in Marrakech - happening now!

UN Climate Change Conference 2016 in Marrakech, Morocco

I was going to move onto details about the methods and controversies of geoengineering, but cannot pass without mentioning about the UN climate talks happening now in Marrakech!

"This conference [COP22] comes within a climate of hope and of legitimate aspirations for all of humanity" said COP22 President and Morocco’s Foreign Minister Salaheddine Mezouar (left) at the opening of COP22 in Marrakesh, Morocco - with COP 21 President and France’s environment Minister in charge of climate-related international relations Ségolène Royal.
Source:UNFCCC

Marrakech conference as COP22, CMP12 & CMA1
UN Climate talk happening now in Marrakech serves as 22nd meeting of the Conference of Parties (COP22) to the UN Framework Convention on Climate Change (UNFCCC), 12th session of the COP serving as the Meeting of the Parties to the Kyoto Protocol (CMP12), and lastly the first meeting under the Paris Agreement (CMA1) discussing about the next step of Paris Agreement.

For Paris Agreement 'enter into force', it requires at least 55 'parties' that represents approximately 55% of global greenhouse gas (GHG) emissions and this was met on 5th October already - ready to be discussed during the conference. It has been compared with the Kyoto protocol, which took almost eight years for the 'entry into force', giving expectations for relatively 'smooth' discussions of Paris agreement action plans to be held.


Worthy of attention - fossil fuel companies as 'observer' in the climate conference
During the Marrakech conference, the representatives of global fossil companies including ExxonMobil, Chevron, Peabody energy, BP and Shell have unquestioned access to most of the discussions among delegates of countries and other interest groups. Some countries suggested that with high-GHG emission and fossil fuel companies who argued that they are willing to be as 'inclusive' as possible in the climate talks and also cooperate to minimise the 'conflict of interest'. 

Some questions about their 'real' intentions on this climate conference - are they truly there to encourage more strict regulations for fossil fuel industry that they create profits? 
Also, the contrast between the position of many fossil fuel companies in policy debates before the climate conference and now can be seen as almost 'ironic' - for example, when Peabody Energy went bankrupt, some of the court documents indicated that they were funding more than twenty groups (including trade associations, industry front groups and corporate lobby groups) that cast doubts on human impact on climate change and opposing views on environmental regulations and Peabody will be 'represented at the meeting by six bodies with observer status' (The Guardian, 2016). 

Yet, this view might be biased in some ways - fossil fuel companies might really want to participate in action against the climate change impacts happening..

More to be come from the conference as it is only the beginning!  

Here are the first press briefing with UNFCCC spokesman & COP22 president: 
http://unfccc.cloud.streamworld.de/webcast/unfccc-and-cop-22-president



References
https://www.theguardian.com/environment/planet-oz/2016/nov/05/whats-in-store-at-the-marrakech-climate-talks-and-will-australia-still-back-coal

https://www.theguardian.com/environment/2016/nov/07/marrakech-climate-talks-giving-the-fossil-fuel-lobby-a-seat-at-the-table

http://cop22.ma/en/#whatscop/post/166

Planetary Boundaries

Planetary Boundaries - global climate change management guidance for humans? 

Before moving on to investigating specific management skills for global climate change, I got interested in this idea of 'planetary boundaries' - let's explore this further!


Planetary boundaries
Planetary boundaries defines the "safe operating space for humanity with respect to the Earth system, associated with the planet's biophysical subsystems or processes" (Rockström et al., 2009). It is a recent approach introduced in science, proposing the preconditions for human development when environmental change and Earth's capacity to regulate conditions appropriate for human activities occurred during the Holocene. 
During the Holocene, planet earth had resilience to 'buffer' the disturbances caused by human developments; for example, half of the greenhouse gases emissions were taken up by the nature and much of the heat coming to the Earth were absorbed by the deep ocean. However, as humans have become the major force of change in planetary scale in current Anthropocene, planet earth starts to change and give positive feedbacks in various environments. To tackle this challenge, planetary boundary framework has been suggested. 

There are nine processes of Earth-system associated with major thresholds of the planet, including climate change, rate of biodiversity loss (terrestrial and marine), stratospheric ozone depletion, ocean acidification, global freshwater use, land use change, disturbances in nitrogen and phosphorus cycle, chemical pollution and atmospheric aerosol loading. Three out of nine boundaries are already transgressed currently (see Figure 1). 

Figure 1 - Planetary boundaries criteria - green shades are the proposed safe operating space for each of planetary systems and red wedges are the estimate of current position for each variable. Three systems' boundaries (Biodiversity loss rate, climate change and human interference with Nitrogen cycle) are already been exceeded currently. 
(Source: Rockström et al., 2009).

Studies on planetary boundaries suggest that if the threshold for earth-systems are exceeded, if will result in 'deleterious or potentially even disastrous consequences for humans' (Scheffer et al., 2001). 

Along with readings, I found and watched a TED talk by Johan Rockström, one of the leading scientists researching about the planetary boundaries; 

Are we bankrupting nature?  Johan Rockstrom at TEDxUppsalaUniversity (Source: https://www.youtube.com/watch?v=2Xc8WHtKBio)

During the talk, Johan mentions that us humans need to deeply consider not only about walking such huge 'transformation' that we are going through together, but also recognising that we are in a world where it reached the nature's saturation point and thus share remaining ecological space on Earth. Also, he suggests that it is time for humans to reconnect to the Biosphere, reversing the existing 'order' in human development and earth's environment - where humans are driving economic developments first and then reducing the environmental impacts - and moving onto the new paradigm of 'growth within limits'. 
I agreed to his thoughts and also thought that despite all those efforts to quantitatively and qualitatively define 'safe-operating' spaces of planet earth, if we humans do not start to change views looking at the planet and its values sustaining us, it will have only a little use in managing the degradation that is happening all over the world.  
We are very lucky to live within this diverse and rich biosphere where our society and economy can thrive, so now efforts for appreciating those spaces should be needed in such urgent situation. 




References:

Rockström, J., Steffen, W., Noone, K., Persson, Å., Chapin, F.S., Lambin, E.F., Lenton, T.M., Scheffer, M., Folke, C., Schellenhuber, H.J., Nykvist, B., De Wit, C.A., Hughes, T., Van Der Leeuw, S., Rodhe, H., Sörlin, S., Snyder, P.K., Costanza, R., Svedin, U., Falkenmark, M., Karlberg, L., Corell, R.W., Fabry V.J., Hansen, J., Walker, B., Liverman, D., Richardson, K., Crutzen, P., and Foley, J.A. 2009. A Safe Operating Space For Humanity. Nature. 461.7263: 472-475.

Scheffer, M., Carpenter, S. R., Foley, J. A., Folke C. & Walker, B. H. 2001. Catastrophic shifts in ecosystems. Nature 413: 591–596.