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a new life skill. We rarely witness evolution on a timeframe
short enough for a single human life to take notice. These changes usually occur over many
lifetimes, the gradual drift of a creatures DNA to best survive their environment. But
in one case in the 1700s humans witnessed evolution with their own eyes, and they caused
it. This metamorphosis coincided with human’s rapid industrialization. We began burning
coal on levels never before seen, and it’s bi-products rapidly changed the landscape
for not just humans, but for the animals that shared the planet with them. The peppered moth was one of those animals,
getting its name from its speckled white and black colouring, designed to camouflage the
moth while it lay on lichen covered tree barks. A black variant was first observed in 1811,
many decades into the industrial revolution. At first the mutation was rare, but human’s
influence on the environment grew, so did their numbers. By 1895, 98% of the peppered
moths in Manchester had this black colouring [1] Surely this black colouring would leave
them exposed, making them easier to spot for hungry birds. In reality, these moths had
adapted to be harder to spot in this newly industrialised world, one stained by soot. And it may be time for humans to follow their
lead. To evolve, or die. The rate we have been spewing these pollutants into our atmosphere
has only risen since this discover. Our carbon dioxide emissions have risen from one thousand
six hundred million metric tonnes to thirty six thousand million metric tonnes since 1865
[2] And despite our best efforts, that number is not declining. Human population and development
are continuing to outpace our efforts to curbed our carbon dioxide emissions. Just as alcohol producing yeast will eventually
create an environment too toxic for itself to survive, humans are pumping the world’s
atmosphere with a gas that will eventually render the world unlivable for many, if something
is not done. So we have to ask ourselves now, are going the way of a mindless single cell
fungi that continue to poison their habitat until they die, or are we going to recognise
that the survival of the next generation is more important? Our previous videos have discussed ways to
mitigate climate change, by planting trees in the Sahara or by using aerosols to block
out the sun. Both are pretty extreme methods, and come with some big risks that could lead
to some unforeseen consequences. Instead of some risky engineering tactic, what if we
could just suck the CO₂ right out of the air, undoing some of the damage that has been
done? Well, in certain circumstances, this is already
happening. Carbon capture and storage (CCS) has been around for years. There are a few
main types of carbon capture, almost all of which happens at power plants, capturing the
carbon that comes directly from the plant. In post-combustion carbon capture, the CO₂
is captured after the fossil fuel is burned. In this method, CO₂ is separated from the
flue gas, which includes CO₂, water vapor, sulfur dioxides and nitrogen oxides, by bubbling
the gas through an absorber column packed with liquid solvents, such as ammonia. In
the most widely used system, once the chemicals in the absorber column become saturated, a
stream of superheated steam at around 120C is passed through it. This releases the trapped
CO₂, which can then be transported for storage elsewhere. [3] In pre-combustion carbon capture, CO₂
is trapped before it's diluted by other flue gases. The fossil fuel is heated in pure oxygen,
resulting in a mix of carbon monoxide and hydrogen. [4]The carbon monoxide is reacted
with water to produce carbon dioxide, which is captured, along with hydrogen. The hydrogen
can be used to produce electricity, and the carbon dioxide is stored. [5] Pre- and post-combustion carbon capture can
prevent 80 to 90 percent of a power plant's carbon emissions from entering the atmosphere.
[6] This is a big deal. The IPCC estimates that carbon capture and storage has the potential
to make up between 10% and 55% of the total carbon mitigation effort until year 2100.
[7] However, this carbon has to be stored somewhere.
It is most often stored underground in a process called geological sequestration, which involves
injecting CO₂ into underground rock formations. It is stored as a supercritical fluid, meaning
it has properties between those of a gas and a liquid. When carbon dioxide is injected
at depth, it will remain in the supercritical condition as long as it stays in excess of
31.1°C and at a pressure in excess of 72.9 atmospheres. Many times, the carbon dioxide
is injected into a reservoir which previously trapped oil and gas, since those areas have
natural rock formations that help to contain the carbon dioxide. While this might be an
okay solution, no one knows for sure what the environmental impact could be if the carbon
dioxide were to leak out into the environment in large quantities. [8] In some instances,
leakage of carbon dioxide underground has been shown to increase plant mortality, reduce
growth and create potentially severe localised damage to ecosystems. For this to be a viable,
safe option, the carbon dioxide would need to remain stored for 100s of years, or even
indefinitely, and the feasibility of this is not certain. [9] Other methods of storing carbon include sinking
it deep below the ocean, at depths under 3500 meters, where it turns into a slushy material
that will sink to the ocean floor under that amount of pressure. [10]But this method is
largely untested, and again, there are concerns about what this could mean for marine life,
and uncertainty on whether or not the CO₂ could eventually make its way back into the
environment. [11] There have been more promising experiments
in carbon storage in Iceland, where researchers have shown that pumping carbon dioxide into
the volcanic rock underground can speed up a natural process where the basalts react
with the gas to form carbonate minerals, which make up limestone. This is an encouraging
development, but has its limitations. It requires large amounts of water: 25 tonnes for each
tonne of carbon dioxide buried, meaning this process would have to be limited to coastal
sites. Another is that subterranean microbes might break down carbonate to methane, another
powerful greenhouse gas. [12] And while 80 to 90 percent of a power plant’s
carbon emissions can, in theory, be captured and stored in one of many ways, what about
all of the other carbon emitting things in our world? Only 25% of global greenhouse gas
emissions come from electricity and heat production at power plants. Transportation, general industry,
and agriculture collectively make up around 60% of greenhouse gas emissions. [13] Is there
a way to capture CO₂ from these sources? Direct air capture has, up to recently, been
a largely theoretical technique in which CO₂ is removed directly from the atmosphere. Theoretical,
because doing this on a scale that would even make a dent has historically been ridiculously
expensive - some experts say as much as $600 per metric ton of carbon dioxide. For reference,
a typical passenger vehicle emits about 4.6 metric tons of carbon dioxide per year. [14]
But recently a team of scientists from Harvard University and the Bill Gates funded company
Carbon Engineering announced that they have found a method to cheaply pull carbon-dioxide
pollution out of the atmosphere - they say for as little as $94, and for no more than
$232 per metric ton of CO₂. This means that it would cost between $1 and $2.50 to remove
the carbon dioxide released by burning a gallon of gasoline in a modern car. And not only
do they suck the CO₂ out of the air with the ability to store it - they will also transform
the carbon back in to gasoline or jet fuel, creating net-neutral carbon based fuels. [15] While this sounds too good to be true, the
methods they use to pull CO₂ out of the air is not too different from what has already
been done for decades. This type of direct air capture starts with
an air contractor, where air is sucked in at high volumes. This structure “wet scrubs”
the air by using a strong hydroxide solution to capture CO₂ and convert it into carbonate.
The hydroxide solution reacts with carbon dioxide to form carbonate ions(CO32−.) This
occurs within a structure which is much the same as an industrial cooling tower. The next step involves a “pellet reactor”
where the carbonate ion reacts with calcium(Ca2+) to form calcium carbonate, in the form of
dried pellets. Then, a circulating fluid heats the calcium
carbonate pellets to decomposition temperature, breaking them apart to release the carbon
dioxide as a gas and leave behind calcium oxide (CaO) [16] Finally, the carbon dioxide is combined with
hydrogen and converted into liquid fuels, including gasoline, diesel, and jet fuel,
using the Fischer-Tropsch process. This is a process where a mixture of carbon monoxide
and hydrogen are converted into liquid hydrocarbons. These reactions occur in the presence of metal
catalysts and typically at temperatures of 150–300 °C. [17] This means the company can produce carbon-neutral
hydrocarbons, meaning if you were to burn this fuel in your car, you would release carbon-dioxide
pollution out of your exhaust and into the atmosphere. But because this carbon dioxide
came from the air in the first place, these emissions would not introduce any new carbon
dioxide to the atmosphere, and no oil would need to be extracted from the earth to power
your car. And perhaps most importantly for the economic viability of this idea, they
can sell the product, which helps to offset costs, allowing them to capture even more
carbon dioxide, to either convert back into hydrocarbons or ultimately store. And backing up their cost estimates of between
$94 and $232 per metric ton of carbon dioxide is the fact that they’ve actually tested
the technology in a prototype plant for a few years in Squamish, British Columbia, which
offers a proof of concept that’s way stronger than simple calculations or computational
models. It currently captures and processes around 1 ton of carbon dioxide per day. [18] However, for this idea to work on a large
scale, the process has to be cost-effective to implement cheaply around the world, without
the massive costs of constructing all-new factory parts. In the pilot plant, they pulled
all this off by designing a factory based entirely on parts that suppliers could already
make cheaply and by keeping careful track of their emissions and costs at each stage
of the design and production process. They are currently seeking funding for an industrial-scale
version of the plant, that will use low-cost renewable energy, that will produce 200 barrels
of synthetic fuel a day, which they hope to complete by 2021. [19] But how much carbon can they realistically
hope to suck out of the air? In 2017, the world emitted about 32.5 gigatons of carbon
dioxide. If this technology were built at a scale to suck all that back out of the atmosphere
at $93 to $232 per ton, simple math shows that the total cost would be between about
$3 trillion and $7.5 trillion. [20] That seems like a lot, but many industries are worth
more than that, including Apple or the airline industry. Definitely a tall order, but not
impossible. For this idea to work globally in pulling
substantial amounts of carbon dioxide from the Earth’s air, there would need to be
hundreds or thousands of scaled-up plants producing hundreds of thousands of barrels
of carbon-neutral fuel to drive down costs further, in the same way that solar and wind
energy costs have plummeted over the past decades with increasing scales However, to keep global warming to less than
2 degrees C, the international target to avoid the most dangerous impacts, we will need negative
emissions, not carbon neutral emissions. We need carbon to be taken out of the atmosphere
and stored permanently, or the problem will only plateau indefinitely. And if Carbon Engineering
is making fuel from their captured carbon, this is only a carbon-neutral plan. But the reality of the situation is that when
you are only capturing and storing carbon, there is no market for that. The only way
to pay for carbon being captured from the air and stored, on a large scale, would be
government subsidies, and to rely on only our governments to solve this problem is certainly
a mistake. And at $100 per ton at the moment, there aren’t enough carbon dioxide buyers
in the market for any other uses to make a dent. Thus, introducing the idea of selling back
the carbon as fuel is a way to fund such an effort. With market demand and money coming
in, companies like Carbon Engineering can improve their technology, expand operations,
store some carbon, and work toward making sure that less oil is extracted from the ground
over time. Critics say that we should simply just not
be taking the carbon out of the ground in the first place, focusing on reducing emissions
rather than capture and storage, or capture and re-use. And some worry that technology
like this will allow us to think that we have no responsibility to reduce emissions. And
it is cheaper to not emit a ton of carbon dioxide in the first place than to capture
it. While these are all definitely valid points, technology like this can and should play a
role in how we tackle climate change. It’s unrealistic to think that every industry,
every consumer, and every government in the world will change their behavior in time to
tackle the rising global temperatures, as much as we wish they would. And technology
like this will go a long way to help mitigate the negative effects of industries where a
carbon zero result is next to impossible, like steel or cement manufacturing, or long-distance
air travel. So this may not be a silver bullet curing
the world of climate change, but it is definitely a technology to be invested in as a tool in
the toolbox to help solve the problem. And with direct air capture able to operate anywhere
where there is air, water, and electricity, every country could in theory, have their
own supply of carbon neutral fuel. In the end, we are not mindless animals who
cannot recognise the effect our behaviour is having on the environment. There are thousands
of people working to solve these problems associated with an ever growing human population,
with hundreds of start-ups using technology for the betterment of humankind. My audience
is full of incredibly intelligent people who are more than capable of contributing to fixing
our problems. So, if you think you have what it takes to improve the world, you have probably
thought about starting a company. You may not know where to start, but this course on
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