What's So Bad About Carbon Dioxide?
Carbon Emissions! Greenhouse Effect! Booo! Bad!
Is that your general impression of carbon dioxide (CO2)? Most of the time when we hear about carbon dioxide, it’s bad news. The truth is that carbon dioxide is a natural and necessary part of life on our planet! But just like accidentally napping for 4 hours, too much of any good thing can turn bad.
Let’s start with some info you already know. Every time you take a breath, you pull air into your lungs. Our bodies take the oxygen that we need to stay alive and breathe the rest of the air back out. Air is made up of a lot more than oxygen, though, and there are multiple other gases and particles that make up the atmosphere. One of those gases is our arch-frenemy, CO2. In addition to what’s already floating around in the air, our bodies produce CO2 every time we breathe. The cycle of respiration – this process where we breathe in oxygen and out carbon dioxide – is fundamental to the life of humans, animals, and many other organisms. Plants (and square yellow sea sponges) perform photosynthesis, which we can think of as the opposite of respiration. Plants take in CO2 and release oxygen. Without some amount of CO2 plants couldn’t photosynthesize and there’d be little life on earth. I know that you already learned this in high school biology, but I want to remind us of some of the great things carbon dioxide does.
“So if you’re saying we need carbon dioxide in the air in order to live, it can’t be that bad, right?”
Surprise! Life is complicated and it’s not that simple! Even though we need some CO2 to “feed” plants so that humans can live, that same CO2 is one of the biggest problems facing humanity, in my opinion and that of many climatologists. To be fair, I kind of set you up for failure in that last paragraph because I didn’t tell you about the greenhouse effect. Oops.
The earth lives inside a bubble that we call the atmosphere. The atmosphere does a lot of important jobs, like protecting us from the harshest solar rays and asteroids. Another important job is keeping earth at just the right temperature to support life. The earth would be too cold for us to live on if it weren’t for something called the greenhouse effect. Heat energy from the sun passes through the atmosphere and warms the surface of the earth. The earth then radiates that heat energy back toward space, but a layer of “greenhouse gases” in the atmosphere traps a lot of heat energy and sends it back down to the surface again. Take a look at this graphic if that sounds confusing:
This is what we call the greenhouse effect, and it is necessary to keep earth at a livable temperature. Only certain gases create this effect, and carbon dioxide is the most abundant greenhouse gas after water vapor. In general, when there is more greenhouse gas in the atmosphere, the surface temperature of the earth heats up – more heat energy is getting trapped and sent back to the surface. The concentration of CO2 and earth’s surface temperature rise and fall hand in hand, so much so that we can tell what the temperature of earth was in the past just by knowing the atmospheric CO2 levels. We already learned in this article that earth’s temperature has a looooong history of heating and cooling in waves. Can you predict what CO2 levels were doing during those times? Great job! They were also rising and falling at the same times! Take a look at the graph below:
The red line shows temperature going up and down, and the blue line shows CO2 levels going up and down. See how they match? Now take a look at where the blue line goes at the very end of the graph. CO2 is shooting up off the chart today. We both know that also means the temperature is rising. Fast. In earth’s past, carbon dioxide in the atmosphere has come mainly from volcanic activity. At times when there has been more activity than usual in the earth’s crust, CO2 levels and then surface temperatures have shot up. The problem is that today’s carbon dioxide is coming from human activities. Every time we chop down trees and burn fossil fuels, we’re adding CO2 to the atmosphere. The planet has lots of systems that act as checks and balances on each other (including respiration and photosynthesis). These systems make earth resilient, but we as a species are pushing them way past their capabilities.
Your takeaway at this point should be: high CO2 = high temperature. That’s what all the fuss is about. We talked about why rising temperatures are bad in this climate change article, and today we learned about the root cause. Now that we all understand that carbon emissions are a problem, let’s work together to solve it! Let’s shift the debate from whether climate change is real towards how we can slow it down and provide solutions. In order to solve any problem, first you have to understand it. This all brings me to the real reason I’m here on your screen: I believe that when more people are educated about the environment, there are more people trying to help. And there are a lot of ways to help! You can lend a hand by making more environmentally-friendly decisions in your daily life, by respectfully educating your friends and family, and by pressuring big companies to change their practices. I’m not the first person to tell you any of this and I won’t be the last, but I’m making it my mission to be one more voice in the wave of environmentalists. Don’t worry, I burn fossil fuel every day in my car too – but I want to do better. As I research how to incorporate better decisions in my life, I invite you to join in. I’ll do the legwork, all you have to do is read my simple summaries like this one. Stay tuned to learn more about the environment as well as how to help. Let’s leave today better than we found it.
These are the websites I used to check my facts and figures:
https://www.environment.gov.au/climate-change/climate-science-data/climate-science/greenhouse-effect
https://climate.nasa.gov/news/25/tracking-earths-most-abundant-greenhouse-gas/
