Realism Injection
Let’s talk about Geoengineering
“We are as gods, and might as well get good at it.”
-Stewart Brand, Whole Earth Catalog
Global efforts such as the Paris climate agreement have tried to limit global warming to 2°C above pre-industrial levels.
Despite bold proclamations and enthusiastic rallies, the world is still right on track to hit warmings of 3.2°C. According to a Nature paper from last month, the odds that temperatures will increase by more than 4°C by 2100 is 93% (much higher than the 62% given by the UN Intergovernmental Panel on Climate Change (IPCC) in 2013). In fact, the simulations that most closely match real-world observations of past weather are the ones that now predict 5°C of warming by 2100.
For some clarity, at just 3°C of warming, non-profit organization Climate Central estimates that 275 million people worldwide will be flooded. The worst affected will be cities in Asia, with the largest impact being cities like Shanghai, Hong Kong, and Osaka.
But North America doesn’t get by unscathed either. Miami, for example, would basically cease to exist. In the Miami-Dade county alone, almost $15B of coastal property is at risk of flooding in just the next 15 years. The city has already begun to discuss proposals to elevate roads and even abandon certain neighborhoods in order to protect others.
Total decarbonization is imperative.
I’ve waxed poetics in the past about alternative energy sources, but let’s inject a bit of realism here. While I’m confident that total decarbonization is the overall direction of our civilization, I don’t have much hope of this happening in the timeframe necessary. We’ve tried to achieve global decarbonization in the past, and we’ve repeatedly failed to reach international consensus — twice, thanks to the US pulling out of the agreements made in COP7 (Kyoto) and COP21(Paris).
“[The 1997 Kyoto Protocol] is not acceptable to the administration…Kyoto is dead.” (March 2001)
-Condoleeza Rice, pulling the US out of of the Kyoto Protocol
Even if we were to achieve complete decarbonization in the next few years, we’d still have all of the carbon we’ve already emitted into the atmosphere for decades (carbon remains in the atmosphere for a long time — only 40% of carbon is absorbed by the Earth’s oceans and landmasses within 20 years and 80% in 1,000 years). We need a solution to get rid of the carbon that’s already in the atmosphere.
We need to seriously consider geoengineering.
Geoengineering
Geoengineering is a term that encompasses all technologies that deliberately attempt to affect the Earth’s natural systems.
These technologies have been gaining support for several years, but is still largely frowned upon in the environmental community because we don’t fully understand the complexities of earth systems, and because we’re worried about unforeseen consequences. Some are also worried about the implications on human incentives if we were to provide an alternative to the large behavioral shift that would otherwise be necessary.
The reality, though, is that limiting warming to 1.5°C (the temperature at which irreversible damage can be prevented) almost certainly relies on geoengineering. But the IPCC estimates that stopping at 1.5°C of warming means holding concentrations of atmospheric CO2 at 430ppm, and we already hit 410ppm in April 2017 (we add about 2.5ppm every year, and at an accelerating rate).
It’s a mistake if we don’t start talking about geoengineering solutions. The price of conservation is only going to get more expensive.
Geoengineering falls into two categories: (1) removing carbon dioxide so that our atmosphere traps less heat, or (2) reflecting solar radiation from the earth so there’s less heat to start with.
Carbon Dioxide Removal
In carbon dioxide removal, the classic idea is to just plant a ton of trees. Unfortunately, this won’t be enough. Trees are really just standing stores of metabolized carbon dioxide — they can only pull out as much CO2 from the atmosphere as they need to grow. Even if we were to grow all the trees in the world back to their original size before deforestation, because deforestation only added about 180 billion tons of carbon between 1750 and 2011, this idea would just buy us 4 additional years at our current emissions levels (we currently emit about 40 billion tons of CO2 annually).
One of the solutions to this is BECCS (Biomass Energy, Carbon Capture, and Storage). The idea is similar — we plant trees/crops, but this time, we burn them for energy, capture all of the emissions and bury them deep in the earth, permanently removing CO2 from the atmosphere (it also acts as a fertilizer, further removing CO2). By clearing out space, it makes it possible to continuously extract carbon. The problem is that this would require prohibitive amounts of cropland (1/3 of all arable land on earth).
Rocks are also really good carbon sinks. For example, in a process known as weathering, magnesium rich rocks react with CO2 to form magnesium carbonate on land, and dissolved carbonates form calcium carbonate in water. Weathering is an incredibly slow process, but by grounding up these minerals and sprinkling them over land and sea, these chemical reactions could be sped up. Unfortunately, this would require an enormous amount of silicates — about 15 gigatons to offset yearly global climate emissions, which is a mass equivalent to about 37 million 747 airliners.
An alternative to using land is using the ocean. The ocean is a highly efficient carbon sink — “blue carbon” (ocean and coastal ecosystems like mangroves, salt marshes, seagrasses, and algae) capture about a quarter of CO2 emitted into the atmosphere (though this is slowing down due to warming oceans, saturated waters, etc.). One idea to develop blue carbon ecosystems is to sprinkle the upper layers of the ocean with iron dust, providing phytoplankton algae with nutrients to boost growth. These plants absorb CO2, and when they die, they fall to the ocean floor, taking the captured CO2 with them (or so the theory goes). However, fertilization of oceans was banned by the London Protocol on marine pollution in 2008, due to concerns about the potential damage to marine life.
Some startups are also working on removing carbon dioxide directly from the air. This technology is already proven at scale in coal plants, where amine solutions are used to bind to carbon dioxide molecules. However, this is a completely different challenge if we have to remove carbon from the atmosphere directly, given that the concentration of CO2 in the atmosphere is much lower (about 15% in smokestacks, relative to 0.04% in air). A report in the American Physical society states that it would take nearly 500 kJ to create 1 kg of compressed CO2 with direct air capture — or, to capture our annual emissions, you would need about 400 GW of power, equal to about 120 of the largest nuclear plant in the US. However, this isn’t impossible — if we finally instate a carbon tax of $50 to $100 per ton, it becomes cheaper to capture carbon dioxide emissions than to pollute and pay the tax.
This isn’t a hypothetical anymore, either. 100 countries have indicated that they are interested in an international carbon pricing system, and 40 countries already have a national carbon tax. Additionally, 194 countries still remain committed to the Paris climate agreement, which contains provisions for a carbon cap/tax program.
Solar Radiation Management
Solar radiation management is another geoengineering category that’s more controversial. They would take effect more rapidly and would be cheaper to implement than carbon dioxide removal, but they may also have more unintended consequences, given how early the research is.
In solar radiation management, we control the climate impact of greenhouse gases by reflecting sunlight. One strategy is to inject reflective aerosols, like sulfur dioxide and calcium carbonate dust, into the stratosphere. This builds on observations that large volcanic eruptions in the past have had have a cooling effect on the earth for several years, because volcanic sulfur dioxide gas reflects sunlight. However, the effect is temporary, and these aerosols wash out within a year or so. Additionally, there are unknown consequences. A UK study in Nature revealed that aerosol injection applied in the Northern Hemisphere could result in reduced hurricanes in the Atlantic while initiating a drought in northern Africa, while aerosol injection applied in the Southern Hemisphere could enhance hurricane activity in the Atlantic while increasing rainfall in northern Africa. This kind of procedure with international consequences would necessitate international regulation and approval.
Alternatively, you could alter the troposphere by engineering our clouds. Called marine cloud brightening, we can create low, bright-white clouds by spraying tiny salt particles from sea water, making the clouds more reflective. Adding salt particles acts as a “cloud condensation nuclei,” forming smaller, dispersed, droplets (this is why dark clouds, with large droplets, usually precede rain). With a larger surface area, the bright-white clouds would be able to better reflect sunlight. The problem with this strategy is that by cooling the temperature of the earth, you could also potentially reduce evaporation and, subsequently, rain.
There are also varying levels of crazy depending on how far you want to go — you can even go up to the mesosphere and use asteroid dust to block the sun.
Playing God?
Geoengineering is the culmination of all of our scientific progress. Human civilization is finally advanced enough to purposefully modify the climate (climate change from greenhouse gases doesn’t count — we did that accidentally). But such scientific progress introduces serious questions — what are the conditions under which we can change the climate? Is it just to mitigate the effects of global warming, or can we continue the practice in the future to optimize the climate? What are the international regulations around geoengineering?
We need to answer these questions as a society, but we also need to answer these questions quickly. The human race was hit hard this year by natural disasters exacerbated by climate change. Hurricane Harvey killed 82 people, Hurricane Irma killed 134 people, Hurricane Maria killed 66 people, the California wildfires killed 43 people, the Bangladesh monsoons killed 2,700 people, the Colombian mudslide killed 254 people, and the Sierra Leone flooding killed 312 people. And according to projections, these catastrophic events are about to get much worse.
It’s the Anthropocene era, and humans are as gods. We might as well get good at it.
I’ve written over 35,000 words about 20 topics in energy and environment — check them out if you’re looking to learn about the sector. See my Table of Contents for an index of everything I’ve written about so far.
