In the first article of this series, we will look at the carbon system as a whole. This system is known as the Carbon Cycle and is part of many cycles that create the habitable planet we live on. This system is complex, and though I will attempt to simplify it, I suggest you use this article as a starting point to research more. Some sources within this article are worth looking at for more in-depth information.
Quintessential to understanding Earth’s cycles is the fact that nothing exists in a vacuum. That is to say that everything affects everything else. It is impossible to alter the amount or composition of one thing without altering something else in some way. It is imperative to understand that humans are a part of the system and subject to nature’s laws. Therefore, human activities affect all life on Earth. When we alter the path of a river, burn fuel, cut down a tree, or build a road, there are consequences.
The key to balance is understanding those consequences, good or bad, in the context of the “Big Picture.” To that end, understanding the “Big Picture” is the first step to making conscious, deliberate choices in our everyday lives to decrease our impact. In the words of Nelson Mandela, “Education is the most powerful weapon we can use to change the world.” Understanding that our choices, from the car we drive to the meat we eat, affect everything else because we are part of this big, beautiful system we call Earth is the first step to creating balance.
Carbon as a Greenhouse Gas
Earth is a closed system, much like a snow globe. Our atmosphere acts like a shield, protecting us from harmful radiation, regulating our temperature, and holding in essential things like oxygen and water. The only thing that can come and go, and must for life to exist, is energy in the form of light and heat (think the sun). However, certain compounds capture heat and hold onto it, keeping it from escaping into space. This heat becomes trapped on Earth (hence the greenhouse analogy). We call these compounds greenhouse gases.
Water vapor (H2O), carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), chlorofluorocarbons (CFCs), and ozone (O3) are greenhouse gases. By burning fossil fuels (oil, natural gas, coal), humans pull carbon out of long-term storage and put it back into circulation. There it can capture heat that would have otherwise escaped. When you start your car or turn on a light, you put carbon into the atmosphere.
Ultimately, this carbon would have been released through natural processes, though slowly, over a long time. The pace at which we release it is shifting the system drastically. In terms of the history of Earth, humans have been pulling massive amounts of carbon out of Earth very fast. In that short time, a lot has changed, causing alarm. The warming trend over the last 50 years (about 0.13° C or 0.23° F per decade) is nearly twice that for the previous 100 years. But even more alarming is that we don’t know the complex consequences of this drastic shift in atmospheric carbon concentration. Science takes time, and quite frankly, all this is happening too fast for us to get a good grip. It would be prudent to slow down our carbon output until we fully understand the consequences of our actions.
The Carbon Cycle in Natural Pathways
The elements on and within Earth exist in finite (limited) quantities. An element is anything listed on the Periodic Table of Elements, such as hydrogen, carbon, helium, etc. While the amount of any given element will remain the same, they can change form. These changes occur due to chemical reactions, temperature, or pressure. Elements combine through chemical reactions to form various compounds, including water and minerals. Regardless of their form, they are trapped on Earth, in the ground, water, atmosphere, or living things. These materials move through the environment, interacting with each other and responding to change in predictable pathways. For example, we understand that if the water is heated, it will evaporate and enter the atmosphere. Once cool, it will fall as rain or snow. We call these pathways biogeochemical cycles. Remember learning about the water cycle in school? That is water’s biogeochemical cycle.
Generically, elements can be stored, or they can be in circulation. In storage, they are removed from the cycle. They are not available to interact with other features in the system. However, they are still subject to temperature and pressure changes. In circulation, elements are actively interacting with the environment and each other. Usually, storage takes place because the material becomes trapped in Earth’s crust. We call these materials minerals and find them valuable for many reasons. An element in the atmosphere, or (generally) water, is considered in circulation and becomes part of Earth’s billions of chemical reactions daily. Life stores elements, but on a shorter time scale than if they were underground. When the living thing dies, the elements it stores are released into the environment and the cycle.
Natural Change, by Natural Forces
Throughout Earth’s history, different elements have been more or less prevalent in circulation versus storage. There was a time when carbon, in the form of carbon dioxide, was more prevalent in the atmosphere than today, and oxygen was scarce. (Curious how scientists find out what atmospheric conditions were like millions of years ago?) Plants evolved in this carbon dioxide-rich environment and began pulling carbon dioxide out of the atmosphere and into their cells. There, carbon converts the sun’s energy into fuel (glucose) the plant can use to power itself. A waste product of this chemical process is oxygen (lucky for us). Photosynthesis forever changed the atmosphere by pulling from the atmosphere and pumping oxygen into the air. Consequently, the chemical makeup of the atmosphere changed. Because everything affects everything else, this chemical change resulted in a difference in the climate.
The chemical composition of our atmosphere is dynamic due to natural processes. These processes include volcanic eruptions, decomposition, changes in Earth’s tilt, and fires caused by lightning. In most cases, these shifts in atmospheric chemical composition are small and therefore have minor effects. But after what we consider a catastrophic event, things change instantly and have significant consequences. When change occurs slowly, life has time to adapt and adjust. When change happens quickly, as it is now, life cannot keep up with the changes, and extinctions occur. The most known example of this is the dinosaurs. After a catastrophic meteor strike and intense volcanic activity, 76% of dinosaur species vanished. However, there have been five major mass extinctions in Earth’s history, all directly resulting from drastic climate changes caused by a catastrophic event.
Long-Term Carbon Storage in Fossils
Analysis of the geochemical record held in Earth’s crust shows us past atmospheric conditions. Studying the past allows us to determine what will happen if a particular chemical is more or less prevalent in circulation. Historically, when carbon dioxide levels in the atmosphere are high, temperatures are high. When the dinosaurs roamed Earth, there was a lot of volcanic activity, releasing massive amounts of carbon dioxide. At that time, there was no ice at the poles as there is now, and average ocean temperatures were 95 degrees. It was a tropical paradise on the coasts, complete with tree-sized ferns, but inland, there were massive barren deserts.
The coal, natural gas, and oil we use today formed during this time. Large plants and tiny photosynthesizing algae pull carbon dioxide from the atmosphere to create their energy. With the carbon locked in their cells, they died and were fossilized. Today we call those dead organisms fossil fuels. We dig them up and burn them to release the energy they hold and generate power. As a result, the carbon they have been storing underground for 65 million years is freed and put back into circulation. This artificial (human-made) carbon release at an unprecedented pace will lead to unique challenges for life on Earth. This event is equivalent to a meteor strike – huge changes in a small amount of time resulting in mass extinction (yes, we are currently in a mass extinction).
The Most Powerful Force
It is a scientific fact that the climate is changing at an unprecedented pace and that it is caused by human activities, in the same way that it is a scientific fact that a pencil will fall to the floor when dropped. The scientific foundation on which climate change sits is the same foundation that medicine is grounded. Science puts what occurs in the natural world into words by gathering evidence and analyzing the data embedded in that evidence.
It is an undeniable truth that humans have always had significant impacts on Earth and, therefore, life on Earth. We have continuously and drastically altered the environment around us. We have done this by damming rivers, building cities in swamps (Washington DC), flattening mountains, and cutting down vegetation. Many of those impacts have positive consequences, but some have adverse effects. Usually, the negative consequences are a direct result of our vast population (7.7 billion humans and counting).
We must band together to innovate and create a solution with far-reaching positive consequences. This common problem-solving is uniquely human and one of the most potent forces on Earth. We have created civilizations from dirt, flying machines from metal forged in fire, and the internet. The key is to create more positive consequences while acknowledging the adverse effects. For any of this to happen, humans must recognize our direct connection to the cycles on Earth. We must first understand that we are a part of these cycles, not the master of them or some force standing on the outside. The key to balance is understanding the “Big Picture,” in which we are a part of the whole. Science helps us place the small things into the context of the big picture by defining our role within the processes on Earth.
NEXT IN THIS SERIES:
Carbon & Us: A look at the current impact of carbon on humans
Your Carbon Footprint: A look at what a carbon footprint is and how to calculate and reduce yours in fun, family-friendly ways.