What is a Carbon Sink

Do you know how issues like deforestation and changing weather affect climate change? Keep reading to learn more about carbon sinks, the biggest threats to natural carbon traps, and how scientists plan to help natural systems by trapping carbon artificially.

Carbon dioxide is a greenhouse gas that eats away at the earth’s atmosphere. Fortunately, we don’t have to regulate it alone. Earth’s forests, oceans, and soil perform a significant amount of regulation on our behalf. These natural features don’t just aid us in keeping the atmosphere hospitable. The land and seas absorb about half of all emissions, which means protecting them is critical.

Scientists also call forests and oceans “sinks” or “carbon sinks” because they absorb a massive amount of carbon monoxide in the atmosphere. The problem we face is that neither the world’s forests nor oceans can keep up with increasing pollution.

Forests as Carbon Sink: How Deforestation Impacts Climate Change

Our planet’s forests are best known for their contribution to essential habitats and ecosystems. Removing those forests, or deforestation, without subsequent replacements does even more damage than just the destruction of ecosystems.

Deforestation often includes a “burning season.” The burning season itself adds a considerable amount of carbon dioxide to the atmosphere, leaving fewer trees behind to handle the output. Fewer forests also contribute to the impact of both human-made and natural forest fires and the pollution that they create.

These roles are essential as climate change contributes to changes in weather patterns that make things like floods and fires more severe. But their role is even more fundamental than many realize or accept. Trees need carbon dioxide to complete photosynthesis, and some of the carbon gets sent on to the soil when those plants die and decompose, remaining trapped in the earth.

Fewer trees result in less need for carbon dioxide for photosynthesis. The trees that remain must then work harder to eat up carbon dioxide, a proposition that’s unsustainable for both remaining trees and the planet. While reforestation and carbons sinks are a good idea for ecosystems, emissions reduction, and flood prevention, it isn’t a solution on its own.

One issue lies in part because logging companies see reforestation as a legitimate reason to continue destroying trees elsewhere. Burning some trees while planting others is a quick fix that doesn’t contribute to the reduction of greenhouse reduction. Additionally, it’s impossible to sacrifice all arable land for tree growth. We also need soil for growing food as the earth’s population grows. The amount of potential for new forests is limited as a result.

Artificial Trees: An Answer to Climate Change?

With logging companies keen to rip out as many trees as they plant, it’s clear that a new solution is needed. The solution needs to be holistic and realistic. For the last decade, climate change scientists placed their attention on what is popularly known as artificial trees.

Klaus Lackner, a scientist, and director of Columbia’s Lenfest Center for Sustainable Energy believes that artificial trees may passively sponge away carbon dioxide. Because artificial trees wouldn’t rely exclusively on the gas needed to complete carbon dioxide, there wouldn’t be a need to limit the gas absorbed.

Instead, scientists could design leaves that work 1,000 more efficiently than natural trees using photosynthesis. Would these trees look like our fake houseplants? Not quite. Because the artificial trees won’t need photosynthesis to survive, they don’t need the natural features required to promote photosynthesis. More importantly, because these trees won’t mimic natural trees, scientists can engineer them differently.

An artificial carbon sink tree might have leaves that overlap each other with little space. Lackner suggests a honeycomb formation to drive efficiency. Additionally, the leaves would more closely resemble a thin plastic. Their coating would feature a sodium carbonate resin that reaches out to grab carbon dioxide from the air.

The gas then goes into storage as baking soda and rests on the leaf. To get rid of the gas, you only need to rinse the leaves and let them dry naturally. With some investment, these trees could remove 10 percent of the annual CO2 emissions. Lackner says that 100 million artificial trees could remove all emissions, and we’d need to plant 1,000 times that figure in forests to do the same.

Oceans and the Carbon Balance

Trees and deforestation get a significant amount of attention in the climate change debate, and the oceans tend to be left by the wayside. The focus on trees began in part because, for a long time, we believed that as we produce more carbon dioxide, the oceans would absorb more. Unfortunately, as the world’s oceans sponge up more CO2, the result is warmer waters.

Warmer ocean waters are best known for their impact on the melting of glaciers and icebergs, destroying habitats and threatening nearby land. However, warmer temperatures also slowed down the circulation of the ocean. Water gets trapped near the ocean surface and can’t find its way out.

As it remains trapped, it gets saturated with carbon. Just as a kitchen sponge can only absorb so much water after saturation, so can the ocean’s carbon sponge. Instead of a steady inhale and exhale, the waters breathe in carbon deeply but struggle to trap and store it and then can’t breathe in more. When oceans fail to trap carbon dioxide, and we continue to produce more of it, more carbon dioxide remains in the atmosphere.

How Does the Ocean Absorb Carbon?

The ocean absorbs carbon through two primary mechanisms. The first, like trees, is photosynthesis. Tiny phytoplankton, plant-like organisms, eat up carbon dioxide as they complete the life-giving process of photosynthesis. Oceans also take on carbon using chemistry. Carbon dioxide naturally dissolves in water. When it reacts with the salinity in seawater, it turns into carbonic acid.

Then, the carbonic acid produces and releases hydrogen ions that work with the carbonate in the seawater to create a molecule called bicarbonate. Unlike other types of carbon, bicarbonate is easier for oceans to retain.

Why Can’t the Ocean Absorb More CO2

So why can’t the ocean absorb more CO2 if it dissolves naturally? Carbon saturation impacts the primary chemical process relied on to dissolve the CO2. Taking on more carbon dioxide than it can handle throws off its pH balance and creates a more acidic ocean. As the chemical composition changes, it struggles to retain water.

The water from the lower layers is cooler and captures more carbon. But as surface temperatures become even warmer, it’s hard for the layers to mix and create a stratified ocean. The surface water then continues to hold more CO2 than it can handle, and the deep ocean remains in place. Also, the stagnant surface water is less hospitable to phytoplankton, the other carbon sucking mechanism.

Can We Help the Oceans?

Scientists continue to come up with ingenious solutions for helping trees and soil, but the ocean’s carbon reaction proves trickier to solve. Recent studies on the movement of the oceans provide a greater understanding of how the oceans moved both in the last thirty years and today. While scientists hail the work as a significant advance in understanding how oceans act as a carbon sink, it doesn’t provide a window into the future.

In theory, the oceans should continue to fluctuate to match the human production of emissions. The argument continues to stand because scientists still believe that the differences they witnessed over the past thirty years may be better in tune with natural variability rather than the shut down of the carbon sink.

The Future of Carbon Sink

As climate change scientists continue to determine natural variations from the impacts of global warming, we will start to see more concrete ideas about how emissions change the earth’s ability to regulate itself.

One thing that remains sure is that the earth has a system for managing carbon emissions, and it is essential for us to protect that system the best way we know how by engaging in sustainable practices, limiting our emissions, and standing up for our forests and oceans.

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