Introduction to Climate Change and the Global Climate System

Photo by Issy Bailey on Unsplash

With so many climate change issues going on around the world, I wanted to explore more about the environment. As a start to a much longer series, I will be taking you through what’s going on in our world today. We’ll be looking at how we know that climate is changing, how we know that we humans are responsible, and also what the main impacts of this change are.

The first step to looking to solve a problem is understanding that you have a problem. Currently, there are still many people who still believe that climate change is a myth.

There are those in politics who believe that acknowledging climate change means that we have failed or will fail to solve the problem. Before these recent years, climate change policies could be easily put off as there was no immediate short-term reward for politicians to go through with them. Although this view is quickly changing due to the increasing uproar and number of natural disasters around the world, it’s evident that we are already seeing climate change implications.

This series does not seek to do anything other than educate. We are in this process to learn about our environment together. I am new to this as well, and I want to share the knowledge which I have come to find. I am not asking you to donate to a certain charity, I ask that you learn and discuss these climate change issues with me, so we can all be better prepared in future discussions. I thoroughly encourage everyone to research these topics together with me too.

First, explaining the difference between weather and climate. When you step outside, the weather is the state of the atmosphere at that place and time. The climate, on the other hand, is the average weather over a long period (classical period of 30 years), the weather changes frequently day-to-day, but for the first time in Earth’s history, the climate is also changing at an unprecedented pace. This is different from climate variability, which can be a completely natural occurrence.

Climate is what we expect. Weather is what we get. — Mark Twain

Climate System

The climate system is comprised of five major components, the atmosphere, hydrosphere, cryosphere, lithosphere (land surface) and biosphere.

Atmosphere

Earth’s atmosphere is the gas that surrounds our earth today. It’s a bunch of different gases, along with other particles. The largest constituents of the atmosphere are Nitrogen (78% of volume) and Oxygen (21%). There are also variable gases in the atmosphere, which are comprised of multiple gases. Water vapor is the most abundant, and through the hydrologic cycle, it’s added and removed from the atmosphere. Water vapor is the main contributor to Earth’s balance, as well as the natural greenhouse effect. The main difference between water vapor and greenhouse gases is that human activities do not change the concentration of water vapor in the atmosphere.

Ozone is another notable gas to mention here. What most people don’t realize is that there are two types of ozone. The good ozone or ozone in the stratosphere located 10km – 40 km above the Earth’s surface makes up the ozone layer. This protects us from harmful UV-B rays, which is known to cause many skin issues. When greenhouse gases increase, they go into the atmosphere and destroy this good ozone. The bad ozone collects at the ground-level and is harmful to many organisms.

Methane, the last notable gas is released into the atmosphere through fossil fuel operations, livestock and agriculture cultivation. Methane is 28 times more potent compared to the usual suspect carbon dioxide as a greenhouse gas. Luckily for us, although more potent, methane is only trapped in our atmosphere for ~9–12 years, compared to CO2 being trapped for much longer, ranging from 20–200 years.

The impact of greenhouse gases other than CO2 on the environment is measured through a unit called their Global Warming Potential (GWP), which is a measurement of the amount of energy that 1 ton of the atmosphere will absorb over a period of time, relative to CO2. Nitrous Oxide, is 265x more damaging than CO2 over 100 years, and CO2’s GWP is standardized to 1.

The structure of the atmosphere is broken into 5 different layers. Air is most dense at the ground-level and decreases as you move to higher levels of the atmosphere. This is precisely why Mt. Everest climbers experience difficulty breathing near the summit and require adjustment periods.

Climate System

Diving deeper into climate, there are different components as a part of the climate system. Before understanding how climate is changing, we must understand how systems work.

In any system, there are inflows, stocks, and outflows. A stock is an accumulation of something, inflows add to the stock, and outflows subtract from that stock. Here is a wonderful picture from Megan Mcfadden which explains this topic.

In terms of our atmosphere, we will look at the inflow of carbon into the atmosphere, outflow out of the atmosphere and the stock of carbon in the atmosphere.

An additional dynamic to consider in systems is feedbacks. These are situations where flow affects the stock, and the stock affects the flows. Two important feedbacks exist: amplifying feedbacks when the flow affects the stock in a way that makes the effect even stronger and stabilizing feedbacks which are the opposite. Think of amplifying feedbacks as the snowball effect, where a process starts from a small state and slowly builds upon itself to become a much more significant process instead. Stabilizing feedbacks offset certain effects.

Let’s refresh our memory: carbon dioxide comes from various sources in the environment. It comes from natural decomposition of plants, volcanic activity, and combustion of fossil fuels.

One amplifying feedback example is the snow in our North and South poles. As our planet warms, the snow and ice melt, exposing the darker earth, dirt, and vegetation beneath. Lighter objects reflect radiation whereas darker objects absorb it. With darker surfaces now revealed, they heat up even more and cause even more melting of snow and ice, and so on.

A stabilizing feedback example is that when the climate warms, there are more growth periods for crops and vegetation. This vegetation now can absorb more carbon dioxide from the atmosphere, which helps to offset the greenhouse effect.

Human-caused combustion of fossil fuels emits carbon into the atmosphere as an inflow. Trees are crucial in absorbing carbon from the atmosphere as an outflow. Carbon is also dissolved into the oceans and taken up by any marine creatures. If inflows > outflows, the stock of carbon in the atmosphere will increase, which is the main driver of human-caused climate change.

Throughout the next couple of weeks, I will continue to research and learn about the impacts of climate change. We will dive deeper into this topic next time, looking at developing our understanding of Planet Earth. Stay tuned!

Investment banker, global citizen interested in the pursuit and sharing of knowledge. Inquiries to pendorapubs@gmail.com

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