Carbon sequestration - artificial vs natural.
Carbon sequestration is a term you will increasingly hear over the
coming years. This article provides a basic explanation of what it is,
some of the suggestions of how humans may go about artificial
sequestration and some of the unknown and dangers involved.
Natural carbon sequestration
Natural carbon sequestration is a cycle that's been happening on this
planet for billions of years. It's simply the process by which nature has
achieved a balance of carbon dioxide in our atmosphere suitable for
sustaining life. Animals expel
carbon dioxide, as do plants during the night; forest fires belch carbon
dioxide into the atmosphere, volcanic eruptions and magma reservoirs deep
beneath the ground also play their part.
With all this carbon dioxide being pumped into the atmosphere, there
needed to be a way of removing it otherwise the surface of the planet
would rapidly overheat.
Nature provided trees, the oceans, earth and
the animals themselves as carbon sinks, or sponges. All organic life on
this planet is carbon based and when plants and animals die, much of the
carbon goes back into the ground where it has little impact on
contributing to global warming.
Nature's fine handling of carbon dioxide in our atmosphere has served
the planet very well... up until man's industrial revolution that has now
thrown the earth's carbon dioxide sinks out of balance. For example, our
oceans have absorbed so much carbon dioxide, they are becoming saturated
Many tree planting programs have been initiated over the years;
originally to assist with preventing erosion, loss of biodiversity and desertification, but
increasingly the benefits of these program are focused around their carbon
dioxide sequestration benefits. The problem is, we've removed so many
trees from this planet over the last couple of hundred years, it's going
to take some time before the millions of trees planted in the last couple
of years mature enough to provide sequestration benefits. Still, it's
great to see the added impetus on tree planting.
Artificial carbon sequestration
Humans are odd creatures - we like to dig stuff up, make it cause havoc
and then try to bury it again - out of sight is out of mind. Coal and oil are great examples. We rip up
the earth to get to these resources and then burn them which causes
massive amounts of carbon dioxide to be released, causing global
Instead of rapidly discontinuing the use of what we know is heating our
planet, researchers are trying to find other ways of defeating Nature to
allow us to continue our lifestyles; or helping it deal with the excess
carbon dioxide we produce - how you view the situation is up to you.
Artificial carbon sequestration refers to a number of processes whereby
carbon emissions are captured at the point of product and then, well,
One proposed method is ocean sequestration whereby carbon dioxide is
injected deep into the ocean, forming lakes of CO2. In theory, the carbon
dioxide will stay down deep due to the pressure and temperature of the
surrounding water; gradually dissolving into that water over time.
Another method is geological sequestration where the carbon dioxide is
pumped into underground chambers such as old oil reservoirs, aquifers and
coal seams that are unable to be mined.
Mineral sequestration is also being considered. In this method, carbon
dioxide is injected into areas rich in Magnesium or Calcium. The carbon
dioxide will react with those elements and combine to form calcium
carbonate (limestone) and magnesium carbonate (magnesite).
Dangers of artificial carbon sequestration
We know that trees remove carbon dioxide from the atmosphere and can do
it very well. They also provide us, animals and insects food and shelter.
It's all the more reason for us to preserve the forests we have left and
to restore ones we've destroyed. We'd be simply replacing what we have
taken in an effort to restore balance. To enhance those efforts, renewable
energy sources such as solar and wind power should be ramped up and
everyone needs to also reduce their consumption. It's pretty simple really
- consume less + more trees + renewable energy sources = less carbon
dioxide = less warming.
Artificial carbon sequestration on the other hand is costly, energy
intensive, relatively untested and has no other side benefits. Not enough
research has been done on the abovementioned artificial processes to
determine any dangers in disposing of carbon dioxide in this way.
But nature has already done some of that research for us - an example
is Lake Nyos, Cameroon, Africa.
The Lake Nyos disaster
Lake Nyos is a lake in a crater of a volcano. A reservoir of magma
which lies beneath the lake bubbles up carbon dioxide into the water in
huge quantities. The depth and temperature of the water keeps much of this carbon
dioxide at the bottom of the lake, allowing it to dissolve naturally or to
bubble to the surface.
On August 21 1986, Lake Nyos belched a massive cloud of carbon dioxide
after an eruption that killed around 1,700 people and 3,500 livestock
nearby and injured thousands more. It's estimated that 1.6 million tonnes of CO2
was released in the event and as CO2 is denser than air, hugged the ground
in a layer thought to be 30 metres deep for quite some time and distance
before it dissipated, suffocating humans and animals in its path. The
outgassing also caused large waves that destroyed trees and other
vegetation close to the lake.
|Lake Nyos, usually with blue waters shown here
shortly after the carbon dioxide outgassing event.
Photo by Jack Lockwood, 1986 (U.S. Geological Survey).
|Many humans and animals were suffocated in the
carbon dioxide cloud that rushed down the flanks of the mountain.
Photo by Jack Lockwood, 1986 (U.S. Geological Survey).
What happened at Lake Nyos could possibly happen again if
we implement artificial deep injection carbon sequestration methods. Our
oceans are already becoming overly acidic and ocean sequestration may
increase this to a stage where marine life struggles to survive. The
bottom line is that scientists just aren't sure of what the long term, let
alone the short term, effects and dangers of geological, ocean and mineral
The earth is not a rubbish tip to be controlled by man;
nature has checks and balances in place for a reason. Playing with those
balances has brought us to the mess we're in today - why test nature
further? The best thing that all of us can do is to:
Reduce our energy and general consumption - this is
the number 1 priority
Look more to renewable sources of energy such as solar
Offset what we can't eliminate by the purchase of
green tags based on renewable energy, plant trees or have them planted
on our behalf.
The amount of research needed to verify various
forms of artificial carbon sequestration as being safe and environmentally
friendly will take many years to complete. We simply don't have that time.
"Global warming - it's our choice"