Obscured by Clouds

Climate Geoengineering Part 3 of 4
This short series of posts addresses climate geoengineering: "the deliberate large-scale intervention in the Earth’s natural systems to counteract climate change." My aim is to answer the following questions:

1. Prometheus or Icarus? - Why consider climate geoengineering at all?
2. Fire and Ice - A synthetic sulphuric aerosol veil in the stratosphere?
3. Obscured by Clouds - What other geoengineering options are feasible?
4. Kintsugi and the Moral Hazard - What would Jesus do?

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A summary of the first two parts of this series on geoengineering:

• Human-caused climate change is real and building momentum.
• Transitioning from our current fossil fuel economy to a renewable energy economy is a beast to tackle, even if we didn't complicate it with fossil fuel-funded political denial.
• The world's carbon cycle had been balanced for at least 800,000 years.
• Fossil fuels are stored carbon from before the dinosaurs, and industrialized economies since the 1750s have been putting that stored carbon into the atmosphere.
• The excess carbon in the atmosphere (carbon dioxide, CO2) traps the sun's energy, warming the planet. A degree of warming is great, preventing a snowball Earth, but now we're heating the place up with additional trapped warmth. 
• Sulfur dioxide in the high atmosphere (stratosphere) causes a cooling effect on the planet, since it blocks some of the sun's energy from ever making it in to get trapped by CO2.
• One of the main ideas for geoengineering the climate is to intentionally deliver sulfur to the upper atmosphere to block some of the sun's energy.

This post is broken into 4 parts:

1. Carbon Storage - Direct Air and Power Plant Exhaust
2. Carbon Storage - Ocean Fertilization
3. Carbon Storage - Afforestation
4. Cloud Whitening

Carbon Storage - Direct Air Capture and Power Plant Exhaust

"That negative [CO2] emission are likely to be necessary if the chances of two degrees of warming are to be kept low surprises many people. There is a widespread belief that simply stabilizing emissions - emitting the same amount each year - solves the warming problem."

- Oliver Morton, The Planet Remade

The problem is that we've got too much CO2 in the atmosphere due to the burning of fossil fuels. There are other greenhouse gases that we pollute the atmosphere with as well (like methane and nitrous oxide), but CO2 stays up there by far the longest and is much more prevalent. One of the most obvious questions to ask, then, is why don't we just remove the excess CO2 from the atmosphere?

Source.

To get a sense of the challenge, let's consider a quarter teaspoon of salt like in the image above. A quarter teaspoon of salt has about 10,000 grains of salt in it. If we let that spoon represent 10,000 molecules of our atmosphere, just 4 grains of salt in that spoon make up the portion of our atmosphere that's CO2. In other words, the challenge of removing CO2 from the atmosphere is the challenge of finding and filtering out four particular grains of salt from a quarter teaspoon.

The most obvious place to do this filtering is at the source: power plant flues. Approximately 10%-25% of the exhaust from fossil fuel power plants is CO2 (Source). This technology, known as Carbon Capture and Storing increases the cost per watt of electricity generated by at least 20% and as high as 90%. This cost is likely to change, however, given the implementation of carbon taxes and the costs expected due to mitigating the effects of climate change (Source).

"The only way to understand CCS is to actually do it. We cannot do without this, in my view. We're looking for really positive and quick action... Deployment is what we're talking about. Not research." (Source.)

- Nick Otter, CEO of Global Carbon Capture and Storage Institute (GCCSI)

Three problems with carbon capture technology:

1. Once the carbon is captured, where should it be stored? The likely place is injection into geological formations as in the use of advanced oil/natural gas recovery techniques, like fracking. In 1986 a landslide in Cameroon released a cloud of CO2 that suffocated 1,700 people (Source).
2. It costs a lot to implement, especially when retrofitted to existing power plants. Furthermore, power plants that use this technology use about 40% more energy to run (Source).
3. It isn't effective enough. It may remove up to 90% of CO2 in power plant exhaust compared to standard power plants, but we've got to decrease the CO2 in the atmosphere, not just minimize what we're putting up. We don't have the technology for that yet.

This article is an overview of the "world's first power plant with negative emissions", fueled by biomass cut from forests. The diagram below illustrates the process.

Source.

Carbon Storage - Ocean Fertilization

The ocean holds about 50 times the amount of carbon as the atmosphere. Carbon capture and storage in the ocean seeks to increase the amount of carbon the ocean can store, and this would aid in removing more CO2 from the atmosphere.

There are large patches of the ocean rich in the ingredients for life except for a deficiency in iron. By providing those areas with iron we could increase the amount of organisms (phytoplankton) present that could feed themselves on the CO2 in the ocean; the more ocean CO2 they remove, the more CO2 the ocean can absorb from the atmosphere.

Source.

What the diagram above illustrates is that by fertilizing parts of the ocean with iron we'd be promoting the growth of ocean plants that then get eaten by ocean creatures (zooplankton). The carbon in the plants and creatures would eventually fall to the floor of the ocean where it would get stored for a while (estimates of 100 years), though not permanently (Source).

One of the amazing things about this idea is how effective it could be. It's estimated that 10 grams of iron could fix 2,200 pounds (1 tonne) of carbon (a factor of 100,000 to one). In other words, less than .05% of all iron mined might be enough to completely offset human carbon emissions (Source).

Source.

The image above highlights the concerns with ocean fertilization:

1. How much carbon will actually be removed from the atmosphere, and for how long? We know that this isn't a permanent storage of CO2, but just how long isn't clear.
2. How much methane and nitrous oxide will be emitted? Both gases are much stronger greenhouse gases than CO2.
3. What impact on ocean acidification will the added carbon have on the ocean? Remember from part 2 of this series that the oceans will not become acid, but they are already becoming more acidic than much ocean life can handle.

Some experiments were performed in the Southern Ocean and off the west coast of Canada, but the results weren't encouraging: the plankton that benefited most weren't the best suited to getting CO2 into the ocean's depths, and more nitrous oxide was produced than expected (Source). This article is a great overview of the 2012 Canadian experiment, and it also underlines the rogue nature that some groups may in the future adopt as climate change hits the fan.

So as we see again, our mathematical models are good, but Earth's systems are so complex that more experimentation is needed with this idea (and all geoengineering ideas) before we have a complete understanding.

Carbon Storage - Afforestation

"No matter how important forest conservation and reforestation efforts are for many economic, social, and biodiversity reasons, forestry can only be a piece in the large jigsaw puzzle that is (or would be) successful climate change mitigation."

- Climatologist Mark Trexler, Source 

Plants feed on CO2, so planting trees (afforestation - converting land into forests) falls on the list of climate change mitigation strategies.

It has been estimated that in order to remove the amount of industrial CO2 added to the atmosphere at year 2000 levels would take the planting of global forests equivalent to an area twice the size of India. This is an area of land also equivalent to half of the planet's current arable, or farmable, land (Source). China, where just 2% of original forests are intact, currently operates the world's largest afforestation project: 1.5% the area of India each year, with 85% of planted trees not surviving (Source).

Source.

Some challenges with this idea as a major climate change mitigation strategy:

1. Despite progress in fighting deforestation (the global annual rate of deforestation has diminished by 50% since early 1990s), Earth's forests are still shrinking by close to 1 out of every 1000 acres per year (.08%). Forests still shrink due to human population expansion and agricultural uses. (Source.)
2. Planting trees in snowy areas could increase the heat absorption of these areas, canceling the cooling effect of planting them. (And we should still plant them.)
3. The carbon taken out of the atmosphere by new trees doesn't just remove it from the atmosphere; the newly available space left by the removed atmospheric carbon is partly taken up by some CO2 that the ocean will put back up.

Cloud Whitening

"Brightening things to cool them down is something you can do on scales from that of an individual house to a lake to a sea, using everything from micro-sprayed cloud-condensation nuclei to plain old paint."

- Oliver Morton, The Planet Remade 

Source.

After mopping our kitchen floor I like to put a fan to work blowing across the floor surface; this leads to the floor drying much more quickly than without the fan. There's always a layer of water vapor on the surface of water bodies. When I turn the fan on, it blows this water vapor away, and more of the water on the floor is able to evaporate. (Source.)

As water evaporates from large water bodies, it condenses at high elevations due to cooler air. Small particles of dust and pollen in the air make it much easier for the water vapor to condense into water droplets and then clouds. (Source.) Adding new particles into a cloud encourages additional condensation. 

This is the basic principle behind cloud seeding, one method of which was developed by an atmospheric scientist named Bernie Vonnegut (Kurt was given the idea for Ice-nine in Cat's Cradle, one of my favorite books, by H.G. Wells during a visit to his brother's lab).

Cloud seeding sees use around the world, most notably in China. In 2008 China seeded clouds prior to the Olympics to clear the air in Beijing, and they seeded during the Olympics to cause the clouds to rain prior to reaching Beijing and the opening/closing ceremonies. China has also used seeding in response to droughts, intentionally causing rain and snow. However, "there is still no convincing scientific proof of the efficacy of intentional weather modification as it only has 30 percent or less chance of success." (Source.)

While cloud seeding for cloud formation, saturation, and eventual rain or snow uses Vonnegut's silver iodide as particles, cloudships like the ones pictured below would form a fog-like cloud using vapor and salt from the ocean. (Source.)

Source.

It's a fairly straightforward process to increase cloud coverage, and since clouds reflect sunlight before it gets to the lower atmosphere, it's a fairly straightforward approach to keeping global warming at a minimum. In fact, some models suggest that cloud whitening "could produce enough cooling to more or less offset a doubling of carbon dioxide" in the atmosphere. Furthermore, if the process were turned off after having been started, the clouds would return to normal within a couple days at most (Source).

Source.

Issues with cloud whitening:

• Surprise surprise, the biggest issue is a lack of funding for research! More research needs to be done to understand cloud formation and weather and atmospheric processes, but mostly money is needed to fund the prototype project developed by some Silicon Valley engineers. 
• More white will reflect more light (as do 'natural' clouds and snow/ice), but water vapor is a more effective greenhouse gas than CO2. More water vapor in the air, if not reflecting the sun's energy, will trap it.
• We don't know what the weather effects will be. Some models show large impacts on the Indian Monsoon and the Sahel in Africa. 

“Clouds have one of the biggest impacts on global temperature. But they’re one of the most poorly understood parts of the atmospheric system. There’s never been a way to do a controlled study of aerosols and clouds. Their interaction is a big mystery.”

- Kelly Wanser, Silicon Valley entrepreneur, inventor, technologist

The two diagrams below summarize the major geoengineering options:

Source.

Source.

Thank you for reading.

- Check back in a week or so for Part 4 of this series!

"According to two ice-core records from Antarctica, the atmospheric carbon-dioxide level dropped by as much as 8ppm [3.2%] over the second half of the 16th century... When Europeans arrived in the Americas at the end of the 15th century, they brought with them diseases to which Native Americans had no immunity... [that] reduced the population of the Americas over the subsequent decades by 90% - from around 60 million to around 6 million...As a result, some half a million square kilometers which had been under cultivation reverted to scrub and forest, which would have sucked billions of tonnes of carbon out of the atmosphere... [It] is a good bet that at least some of the reduction of the CO2 level seen in the Antarctic ice is a result of all that plant growth."

- Oliver Morton, The Planet Remade

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Please comment if you have a response to this or any of my posts. I'd love to hear from you.