Hi everyone,
Winter is coming.
The sea levels are high,
Winter is coming.
The sun is getting hotter,
Winter is coming.

If you are familiar with the television show game of thrones, you will understand what I mean. If you don't watch GoT, let me just put it in a simple way that you will understand “ very soon we are all going to die” and the others in another planet will know that winter came for us.

^{CC0 Creative Commons: Gas emissions}

Global warming is as real as it gets, since the dawn of the earth, the warmest years have been recorded in the past 23 years (11 out the warmest 12 years, according to IIPC Working Group II 2007 climate report ) Sea levels have been following the current trend of Steem price, increasing. Our ecosystem has been disturbed, there is an adage in my native language (yoruba) which when translated loosely goes like this “ Birds are not singing like birds again, rats are not squeaking like rats no more, humans are no longer speaking like humans” simply meaning the world has turned upside down and is in chaos.

I'm sure we both know how we got here, oh! You don't know? Let me remind you, you remember that summer you cut down the trees in the forest near you so you and your friends can have a big campfire? I'm sure you do, remember how when the fire wasn't burning so brightly as you had imagined then you added more fuel and the fire jumped up and started dancing towards the sky.

It's not only you I too have done my part, I have drained the wetlands, I have burnt biomass and fossil fuels. All these that we have done has contributed to the concentration of greenhouse emissions in the atmosphere whose radiative ability (absorbing infrared radiation from the earth surface) has increased geometrically with the ever increasing human population. Although we did different things we achieved the same result, we released our worst enemy to the atmosphere.

As seen in most sci-fi movies where the aliens or zombies come to chase us off our beloved planet, we put aside our differences and fight side by side until our enemies are defeated. Our enemy now is carbon dioxide, the issue of this ever increasing gas can no longer be swept under the rug, but hey! maybe we can bury it underground or deep beneath the ocean.

Why CO₂

We are here already, there is no need for us to continue pointing fingers at each other as to who is making the globe warmer. It's time to look for how to solve our problem, there are certainly various ways to reduce the concentration of CO₂ in the atmosphere.

We breathe in oxygen and exhale CO₂, plants take in CO₂ and give us oxygen back, if we can improve on this cordial relationship between us and these plants by stopping deforestation and encouraging planting of trees, they will help us in reducing the amount of CO₂ in the air. Other methods includes, stopping the draining of wetlands, proper soil cultivation, carbon sequestration, stopping burning of fossil fuels.

Burning of fossil fuels is the chief contributor to the large amount of CO₂ present in the air. Most of these fuels are hydrocarbon and from our basic chemistry we know that when hydrocarbons combust they give off CO₂ and water.

I'm sure we all know why we can't stop using these type of fuels, not only because they are cheap and readily available, they are our greatest source of energy until we can find new and cleaner energy source. Solar enthusiast @Olajidekehinde blogs about solar energy as the future of energy source for us. As we make a green run ☺☺ towards safety we must find an effective way of removing CO₂ from our atmosphere.

Let's back up a bit, I mentioned something earlier carbon sequestration, my teeth are smacking each other trying to pronounce sequestration. Carbon sequestration will once and for all end all of our problems.

What is carbon sequestration

Like the dragons in GoT, when chained and kept in the dungeon they can do no harm, let's call this dragon sequestration. I'm sure you already have the idea of what carbon sequestration will mean. Carbon sequestration is just trapping of the CO₂ produced when we burn those fossil fuels and safely storing it in plants, geological location, and the ocean. The remaining questions are how do we capture CO₂ and effectively store it?

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How do we capture CO₂

In our sinks there is a strainer which helps stop solid wastes from clogging our sink pipelines. When fossil fuels are burnt, their exhaust not only contains CO₂, it contains other gases like Nitrogen, sulphur and the other elements in traces. This other gases are due to the fact that the fossil fuels are burnt in air (air contains, nitrogen, oxygen( which is actually what is required for combustion) , and other gases in traces). All other gases apart from CO₂ are not as harmful as CO₂ is to the atmosphere therefore we must isolate CO₂ from the flue gases.

Although nature (ocean, plants and soil) helps us in removing CO₂ from the atmosphere, the rate at which we produce CO₂ is far greater than the ecosystem’s removal rate. That, is the natural way of removing CO₂, but, advancements in technology have afforded us the opportunity of removing CO₂ artificially.

CDR ( carbon dioxide removal) examples which includes biochar, direct air capture and enhanced weathering are various new technologies whose major functions are to remove CO₂ from the atmosphere.

• Biochar

Although, biochar is not yet fully approved as a carbon dioxide removal method, it's prospect is tantalizing. Produced by burning biomass at high temperature in the presence of little oxygen. It might look like charcoal but it certainly is not charcoal. It aids agricultural process in capturing and storing carbon dioxide. Biochar captures carbon dioxide by adsorption and can store it for over a thousand years.

• DAC

Direct air capture as the name simply means capturing air directly from the atmosphere using different chemical methods and storing it effectively. Most carbon dioxide removal techniques prevents more CO₂ in the atmosphere by not letting it get there. DAC can do this also, but it goes one step further by removing the CO₂ already present in the atmosphere. One( might as well be the best) way to go about this the use of the NaOH in DAC process.

^{Wikipedia Creative Commons: Direct air capture process flow diagram using NaoH}

Lastly, like the strainers in sinks, a filter can be used to separate CO₂ from other flue gases. In chemistry, I was taught that when you pass a bubble of air over calcium hydroxide (lime water), CO₂ is removed from the air and the calcium hydroxide solution turns cloudy. So, probably the filters can be soaked with lime water for improved effectiveness. This method will reduce the amount of CO₂ that goes into the atmosphere but will not remove the amount of CO₂ already present in the atmosphere.

Just like the society uses prison to keep lawbreakers off the streets, we need to find a “prison” for our captured enemy (CO₂).

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Storing captured carbon dioxide

For years now, the major agricultural challenge is on how to preserve and store farm products. @sogless wrote about silos being the lords of storage, If only these lords could store CO₂, the world would celebrate and have a big feast and ritual the Mexicans call Piñata.

Now, let's explore places we can store CO₂, dissect them to the core and analyze their pros and cons.

Ocean stashing

A famous writer once wrote that the ocean has no memory. I find this absolutely true since the ocean might be the safest place to store CO₂, the ocean will simply not remember the CO₂ is even there.

But, how do we even get the CO₂ into the ocean? First of all the CO₂ separated from flue gases must be liquefied. After which it can be pumped into the ocean at various depths ranging from 500m to over 3000m. Although research has shown that the perfect depth to stash liquefied CO₂ is 3000m. This is possible due to the fact that CO₂ is soluble in water and the high pressure at that depth of the ocean keeps the CO₂ at bay. However, injection of CO₂ is believed to disrupt the aqua ecosystem and harm microorganisms near the injection point.

Although the cost of implementation of this method of storage is more expensive than the others, it is the most reliable and offers little chances of leaks which is prominent in the next method I'm about to tell you about.

Rock embedding

Rocks especially sedimentary rocks which have pores containing brine ( salt water solution) are storage media which CO₂ can be kept. Once again, CO₂ is to be liquefied and transferred through pipelines to the base of these rocks depths which are greater than 1 km which is far below drinking water source and where high pressure will keep CO₂ at its state of high pressure.

While it is believed that these rocks have what it takes to store liquefied CO₂ for over a hundred years, heck! Some even believe it has the potential to store for over a thousand years. But, there are growing concerns about leakages of CO₂ due to faults in rocks. The relative abundance of rocks makes them a suitable storing spot.

While it is not all collected CO₂ that is stored, some of it can be put to use. CO₂ are used in oil fields to make exploration easier as it reduces the friction that tries to stop the flow of oil from the rock to the oil well. But, there are not enough oil fields to use up all the excess CO₂ we produce.

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Obstacles facing carbon sequestration

Daniel Schrag, a geologist in Harvard University noted that

although scientific and economic challenges exist, neither is serious enough to point out that carbon sequestration will not work at the scale to help remove trillions of tons of CO₂ emissions over the next century.

As exciting as the prospect of carbon sequestration is looking like, it faces some obstacles which it must clear if it wants to see the light of the day.

First is its energy requirements, it has been noted that carbon capturing systems will use a huge amount of energy. Also, high implementation cost of technologies to be used to capture carbon is also a hurdle that must be jumped. Implementing carbon capturing systems jacks up production costs which most companies find ways to reduce.

This last obstacle has to do with the concerns about leaking of CO₂ from the basement of the rocks. That would defeat the purpose as CO₂ will escape and go back to the atmosphere. I personally worry about what will happen in case of an earthquake or hurricane passing through rocks that have CO₂ stored in it. We might have a carbon dioxide eruption maybe not as dangerous as a volcanic eruption in real time, however the long term effects might take our beloved planet away from us.

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Conclusion

Over the past few weeks I've seen people here on Steemit promoting the green world, @rharphelle wrote about how to create energy without hurting the environment,you can find that here this sort of energy creation should be researched and invested in so as to move away from fossil fuels. @adetola wrote about a green machine that doesn't produce harmful emissions and also doesn't make noise like most diesel or petrol powered machines do. How all manufacturing and power generating equipments can be like the green machine @adetola talked about should be one of our greatest goals. As one might think the cost of going green will be on the high side @greenrun made a brilliant post discussing about the costs of going green and how solar systems can replace the normal government electricity which is produced using machines that uses fossil fuels as source of energy, you can have a look at it and see it doesn't cost as much as you think.

Although I've preached carbon sequestration as our saviour, it does have some negative effects too. Carbon sequestration will delay the laying to rest of fossil fuels as it can be argued that since its emissions can be curbed using carbon sequestration, they can continued to be used thus increasing the amount of CO₂ in the atmosphere, which is ironic.

Carbon sequestration will save us pending the time we can come up with reliable clean energy source. Windmills, solar technology, tidal energy are where we can look into. @ibk-gabriel post on generating electricity from footsteps is an indication of good things to come.

Thank you for taking your time to read my post, do let me know what you think in my comments. Till next time I say bye bye.

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References

Schrag, D.P., et al. 2007. Preparing to Capture Carbon,” Science 315, p. 812. DOI: 10.1126/science.1137632

O'Connor, W. K., Dahlin, D. C., Nilsen, D. N., Rush, G. E., Walters, R. P. & Turner, P. C. 2001 Carbon dioxide sequestration by direct mineral carbonation: Results from recent studies and current status.

IPCC. Working Group II. IPCC; Geneva, Switzerland: 2007. Climate change 2007. Climate change impacts, adaptation and vulnerability.

• Carbon sequestration on NCBI

• Carbon sequestration Britannica

• Carbon sequestration on Wikipedia

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