A spoonful of limestone

In the last blog I mentioned the fact that SRM measures won't have the desired effects of reduced the amount of ocean acidification which is currently increasing.

The acidity of the ocean is currently increasing due to the fact that as more CO₂ is taken up by the oceans the buffering capacity of the oceans decreases making the oceans more acidic. 

In 2008, Harvey conducted a study that investigated the feasibility of enhancing the absorption of CO2 from the atmosphere by adding calcium carbonate (CaCO3) powder to the ocean. 

Rau and Caldeira (1999), Caldeira and Rau (2000), and Rau et al. (2007) first suggested this idea. They suggested reacting captured fossil fuel CO2 with limestone in reaction chambers on land before releasing it into the ocean, rather than directly injecting captured CO2 into the deep ocean, as in the conventional ocean carbon sequestration concept (IPCC, 2005). However their scheme avoids the impacts on ocean acidity and the eventual outgassing of about 15% of the injected CO2 that would occur with conventional oceanic carbon sequestration but would require large infrastructure efforts.

However Harvey's method would have the desired outcome of partially reversing the acidification of the ocean and the resultant decrease in calcite supersaturation resulting from the absorption of anthropogenic CO2. 

He states that CaCO3 could be added to the surface layer in regions where the depth of the boundary between supersaturated and unsaturated water is relatively shallow (250–500 m) and where the upwelling velocity is large.

The CaCO3 would dissolve within a few 100 m depth below the saturation horizon, and the dissolution products would enter the mixed layer within a few years to decades, facilitating further absorption of CO2 from the atmosphere based upon a study done by Broecker and Takahashi in 1978. 

This absorption of CO2 would largely offset the increase in mixed layer pH and carbonate supersaturation resulting from the upwelling of dissolved limestone powder (Wunsch and Heimbach, 2000).

Harvey later goes on to conclude that Geographically optimal application of 4 billion t of CaCO3 a-1 (0.48 Gt C a-1) could induce absorption of atmospheric CO2 at a rate of 600 Mt CO2 a-1 after 50 years, 900 Mt CO2 a-1 after 100 years, and 1050 Mt CO2 a-1 after 200 years. 

Those statistics prove promising however there are large caveats which can be placed on a scheme like this which I will discuss later.

Thanks again,

Sam.

Icarus

In my previous post, I mentioned the James Bond Villain-esque 'mirrors in space' idea. Here's a clip from the quite frankly awful James Bond Movie Die Another Day, where the antagonist Gustav Graves uses a mirror (called Icarus..... my cliché alarm just went off) to reflect the Sun's light back to Earth. The geoengineering principal is the same but obviously reflecting the light away from Earth.

Enjoy! (I use that term very very loosely!)

Two-Piece Suites

There are two main suites of geoengineering:

Carbon Dioxide Removal (CDR)

The first group of geoengineering options that I'm going to discuss are based upon the engineered removal of CO₂ from the atmosphere by enhancing land or ocean carbon sink or creating new carbon sinks (Keith, 2000).
However for any CDR option, the effects will decay over time due to natural responses of carbon reservoirs to atmospheric perturbations; it will also decay if carbon storage is not permanent (Lenton and Vaughan, 2009). 
Lenton and Vaughan go on to propose that in the long-term, the only way to return atmospheric CO₂ to pre-industrial levels is to permanently store (in some combination of the crust, sediments, soils, ocean, and terrestrial biosphere) an equivalent amount of CO₂ to the total emitted to the atmosphere. 

Solar Radiation Management (SRM)

The other side of geoengineering ideas seek to rectify the increasing radiative forcing caused by anthropogenic greenhouse gas emissions by reducing the amount of solar radiation absorbed. Some proposals range from the wildly ridiculous and James Bond Villain-esque mirrors in space and other ideas which reduce the amount of solar radiation reaching the top of the atmosphere. The other proposals centre around increasing the reflection of shortwave radiation (albedo) within the atmosphere or at the surface (Keith 2000). 
Generally a doubling of atmospheric CO₂ and the radiative forcing increase which comes with it (3.7 Wm−2) is taken as the target to counteract, although actual anthropogenic radiative forcing will continue to vary over time. Each individual idea has specific merits and drawbacks (NAS 1992; Keith 2000; Schneider 2008; Boyd 2008), which will be outlined in later blog posts. 

However.....

The SRM range of ideas do pose some problems; in particular, reducing incoming solar radiation does not ameliorate ocean acidification caused by rising atmospheric CO₂. Indeed successful planetary cooling would be expected to increase ocean CO₂ uptake, thus amplifying ocean acidification (Matthews and Caldeira 2007). 

That's it for now, take care...

More Design for Change

Just a quick post:
My previous post 'design for change' caused a little bit of a stir and as a result I was handed some documentation by the head of environmental services at Laing O'Rourke detailing their carbon emission efforts.
As a company they've set up the Engineering Excellence Group which is an external and internal consultancy group, with one of their main focusses being on cutting carbon emissions. They again backed up their 50% cut in carbon emissions statement that I mentioned in the Design for Change post.
One interesting part of this literature was the fact that David Cameron recently visited the London Gateway Port, constructed by Laing O'Rourke which used the low carbon DfMA approach. He went as far as to say the project was an "emblem of ambition". If projects like this are gaining the political thumbs up, then perhaps in the near future we will see other companies adopting this approach with full government backing.
Hopefully with this sort of recognition it will start a trigger of ambition in other sectors too and start the ball rolling into a green and sustainable economy.

Geo what?

Geoengineering is perhaps not something that is currently widely known by the public, however it has the potential to be a major player in our future climate.

Broadly defined by the US National Academy of Science (1992) as:

"Large-scale engineering of our environment in order to combat or counteract the effects of changes in atmospheric chemistry"

With Marchetti (1977) first coining the term as a description of CO₂ disposal via injection into sinking thermohaline currents.

So.....?

Put simply, the surface temperature of the Earth results from the net balance of incoming solar (shortwave) radiation and outgoing terrestrial (long wave) radiation (Kiehl and Trenberth, 1997). Geoengineering options attempt to rectify the current and potential future radiative imbalance via either: reducing the amount of solar radiation absorbed by the Earth. This is called Solar Radiation Management (SRM).

The other option is to physically remove CO₂ from the atmosphere and preventing it from returning there. Which can be subdivided into the enhancement or creation of (a) Land and (b) Ocean carbon sinks or (c) creating new sinks. This is known as Carbon Dioxide Removal (CDR).

Why now?

Geoengineering has been proposed in order to moderate anthropogenic climate change and despite some serious social and policy maker opposition, proposals are undergoing serious consideration.
There has been a recent realisation that existing mitigation efforts are proving to be hugely ineffectual on a global scale, shown by post-2000 anthropogenic CO₂ trends as seen in Canadell et al (2007). this has lit a beacon of interest in Geoengineering (Crtuzen, 2006), with a growing number of proposals being brought to light in scientific literature (Boyd, 2008). Both Vaughan and Lenton (2009) and Lenton and Vaughan (2011) have given a broad review of geoengineering proposals. 

I've tried to give a broad overview of Geoengineering here, however there are many major caveats and problems associated with it. I'll go into these in later posts.

Until then...

Design for Change

In my introduction I stressed that much is made of climate change mitigation but I feel that little is understood of the behind the scenes work which is being done in major companies across the world.
There is a huge shift towards innovative design and manufacture to cut carbon by (in the construction industry) up to 50% by 2025 as detailed by the Construction 2025 report (UKGov, 2013).

Taken from the Laing O'Rourke 2013 Annual Review

For example, one of the leaders of this approach is Laing O'Rourke who are championing Zero-Carbon construction, adopting the process of Design for Manufacture and Assembly (DfMA). While I do not fully understand the processes which are involved, it basically involves an early intervention into the design phase and offsite manufacture which reduces energy consumption through advanced thermal efficiency, eliminating waste while cutting the construction process by roughly 30% through concept to completion. 
They state that this has cut carbon emissions by up to 50% although there is little scientific evidence to support this at the moment. 
However if their facts are true and is backed up with scientific evidence, this could be a major step forward to a green future and a better outcome for temperature scenarios. 
Let's hope all construction companies adopt this method soon as it seems promising.
In the interests of UCL the DfMA process is currently being used in the process of building the Francis Crick Institute.

Until next time...  

https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/210099/bis-13-955-construction-2025-industrial-strategy.pdf

http://annualreview2013.laingorourke.com/downloads/pdfs/laing-o-rourke-annual-review-2013.pdf

http://www.laingorourke.com/engineering-the-future/product-and-process-innovation.aspx

Just a few quick definitions of amelioration and mitigation:

I'll start with mitigation as it is probably the term that most people are aware of. Steffan et al (2007) describe mitigation as:
"taking pressure off the Earth system through drastically improved technology and management, wise use of Earth's resources, control of human and domestic animal population, and overall careful use and restoration of the natural environment." This can be done through a wide variety of things such as publicly known renewable energy sources (wind, solar, tidal etc) to wholesale changes in building design and manufacture. 

The amelioration efforts are likened by Vaughan and Lenton (2011) to medicating a sick patient, deliberately treating the climate to decrease levels of atmospheric CO2, this is done through geoengineering techniques which are branched into solar radiation management (SRM) and carbon dioxide removal (CDR).

I'll detail the techniques in later blogs but for now that's it,

Cheers,
Sam.

But Why?

It’s quite an exciting time to blog about this topic, but why you may ask? Many published scientific articles (which there are too many to list here) suggest that the Earth is now leaving (or has already left) the Holocene, which is the name given to the postglacial geological epoch of the past ten to twelve thousand years. During this time, accelerating during the industrial period, humans have become an increasing geophysical force to a point where we are beginning to dominate (Crutzen, 2002). Leading to the suggestion of the ‘Anthropocene’ where humans will be a major force on the Earth System for perhaps many more millions of years. 

Despite the contention surrounding this ‘man-made domination’ human activity is set to leave an undeliable mark on geological history, aside from my own topic; deforestation, mining and road building have released waves of sediment into the oceans and rivers, the increasing acidification of the oceans as they absorb carbon dioxide will dissolve carbonate from deep sediments, and what is likely to be the sixth great mass extinction in Earth’s history will gather speed, adding vivid new markers to the record (Steffan et al, 2007)

But what has this got to do with CO₂?

Fossil-fuel use and land clearance have already emitted perhaps a quarter as much carbon into the atmosphere as was released during one of the greatest planetary crises of the past, the Palaeocene–Eocene Thermal Maximum 55 million years ago (Nature, 2011). Tripati, Roberts and Eagle (2009) stated that the CO₂ levels today have not appeared in the climate record for the past 15 million years.

What have humans got to do with this?

As the most recent IPCC report has stated (AR5) there is >95% confidence that humans have been the dominant driver of warming since the mid-20th century (IPCC, 2013) where atmospheric levels of CO₂ have risen from 310ppm to current levels of just under 400ppm (Steffan et al, 2007) with a drastic increase over the past 100 years (IPCC, 2007) as seen in graph 1. 

Figure 1

Over the next century this trend is very likely to continue as shown in graph 2 as future temperature development in the highest emissions scenario (red) and in a scenario with successful climate mitigation (blue) – the “4-degree world” and the “2-degree world.”

The IPCC is basically stating here that with successful mitigation we can help damper the effects of future warming and this is evidence enough for change in my opinion.

Figure 2

I’ll leave it at that for now, more to come in due course!

Cheers,

Sam. 

Something of an introduction

This is my first foray into the world of blogging, even though blogs are sometimes confined to the world of protohipsters, people who eat way too much food and others who have way too much time on their hands, blogging can have many more useful exertions. There are abounding scientific blogs which aim to sift through all that is written and provide a concise view on a specific issue, this is hopefully what I will be able to do over the coming months.

The topic that I'm going to cover is that of climate change mitigation and the contentious issue of climate amelioration to help reduce the levels of atmospheric CO₂ and therefore help stop radiative forcing and temperature from spiralling out of control. I’m not here to scare monger and provide some sort of climate change hysteria or consternation, I’m just going to provide scientific literature, journalistic articles and some general musings showing the effects that anthropogenic CO₂ has on the climate of our planet and mainly strategies for change. 

The title of the blog I've chosen is to mainly to say that Earth is, obviously, the only planet we have to live on. Therefore a bit of care and attention to where we live is something that should not be shunned.

Over the coming days I’ll provide some background to the topic but for now I’ll leave it at that. I hope you all enjoy reading my blog and I am actually thoroughly looking forward to writing on this topic.

Sam.