Getting to know greenhouse gases
If you've been pulled into conversations about the climate crisis, you may quickly become overwhelmed with the breadth of intermingled topics, most of them negative in tenor and likely foreshadowing our inevitable doom on this planet.
One topic that will most certainly surface in these discussions is greenhouse gases which have been identified as the primary source of our looming climate problems. There is near universal agreement on that, but I have found that while this term conveniently simplifies a range of related problems and provides some much-needed focus for how to address climate change, it is not well-understood by most people.
To help folks who like me, are new to this space, I would like to share some of the notes I've been collecting related specifically to greenhouse gases (GHG) and to the cumulative problems created by the increase in their emissions.
Let's start with the term greenhouse
A greenhouse is an environment where radiation is trapped from escaping and creates more heat than would otherwise be available.
But we like greenhouses, right?
Yes, we regularly build intentional structures to create these artificial environments to foster and support growth, such as indoor gardens. Indeed, we have found positive ways to harness the greenhouse effect in certain circumstances.
A global greenhouse?
To understand why greenhouse gases are getting a bad rap, we can use this simple definition from the folks at NASA:
Greenhouse gases are gases in Earth's atmosphere that trap heat. They let sunlight pass through the atmosphere, but they prevent the heat that the sunlight brings from leaving the atmosphere.
So, the gases that are released into our atmosphere are increasingly absorbing (infrared) radiation, which is increasingly trapping heat, which leads to our entire planet turning into a global greenhouse.
That sounds bad of course, but I found it extremely helpful to learn that greenhouse gases are nothing new or even unique to Earth. In fact, our planet has been handling this "problem" for millions of years!
Water vapor is a greenhouse gas(!)
Many of us learn about the water cycle in grade school where water that comes down as precipitation will eventually warm and evaporate to rise back into the atmosphere.
This is happening all over the world and has been in motion for eons.
An informative article on the NRDC site helps tie evaporating water to the Earth's own greenhouse environment:
"The greenhouse effect is a good thing. It warms the planet to its comfortable average of 59 degrees Fahrenheit (15 degrees Celsius) and keeps life on earth, well, livable. Without it the world would be a frozen, uninhabitable place, more like Mars."
Water vapor is considered the most abundant greenhouse gas on the planet and until recently, was more or less in harmony with the abundant life on Earth. That all changed when humans began to alter the equation. The article goes on to explain:
"Warmer air holds more water. And since water vapor is a greenhouse gas, more water absorbs more heat, inducing even greater warming and perpetuating a positive feedback loop."
So, when we (humans) release additional greenhouse gases into the atmosphere, we are literally changing the climate of the planet by making it warmer.
You can read the full article here.
A metric to remember
When we're talking about climate problems, we are focused on the GHG that we're adding to the mix. It is estimated that we emit 51 billion tons per year. As a species, we have only been doing this a relatively short period of time.
Carbon dioxide is one prevalent greenhouse gas
Carbon dioxide or CO2 is responsible for 37 of the total 51 billion tons or 73% of the total GHG we currently emit. We hear a lot about carbon emissions, perhaps because it is the one that we are more likely to come into contact with on regular basis. For example, burning gasoline in our cars has long been recognized as bad for the environment and has helped accelerate the development and adoption of hybrid and electric alternatives.
It's been easier for most people to think of CO2 as the culprit that needs to be addressed, but carbon dioxide is just a subset of the larger problem - there are other emissions that are as bad or worse.
Beyond CO2, the other prevalent GHGs that you should know about include:
Nitrogen Oxide (NOx)
Sulfur Dioxide (SO2)
Methane (CH4) often associated with flatulent cows but exacerbated by the growth of industrial-scale livestock farms (do a search on CAFOs)
Fluorinated Gases including perfluorocarbons (PFCs) and hydrofluorocarbons (HFCs).
HFCs or hydrofluorocarbons, are super greenhouse gases, manufactured for use in refrigeration, air conditioning, foam blowing, aerosols, fire protection and solvents. HFCs unlike most other greenhouse gases are not waste products but are intentionally produced. HFCs were developed as alternatives to ozone depleting substances that are being phased-out under the Montreal Protocol. Unfortunately, HFCs have a global warming potential 1000 to 3000 times that of CO2, and their use has increased from almost nothing in 1990 to 1,100 million tonnes of CO2e in 2010. (scary source here)
GHGs also originate from burning natural gas, biomass as well as diesel and jet fuel.
Where harmful emissions come from
A simplified analysis that you can easily find online would breakdown the sources of harmful GHG emissions as follows:
25% from Power
24% from Agriculture
16% from Industry
10% from Transportation
If those categories are not immediately familiar or particularly accessible, you might find Bill Gates' layman overview easier to understand:
31% from making things where 16% of CO2 emissions are from steel and cement
27% from plugging in (electricity)
19% from growing things (plants & animals)
16% from getting around (planes, trucks, cargo ships)
7% from keeping warm & cool (heating, cooling, refrigeration)
That pretty much touches everything that we do on a daily basis as individuals but also highlights challenges that come from rapid growth around the globe. As more people continue to populate the planet who want the same modern conveniences and expect to have access to the same goods and services that the rest of the world enjoys, we will only be accelerating our collective need for power, for electricity, for energy - in all its forms.
A final word
This brief overview of the many sources and damaging effects of the multiplying greenhouse gases is only the beginning of the story. From here, we can break down the many parallel efforts that are trying to address each of these. Some are meant to reduce or eliminate emissions, others are offering options for offsetting emissions. Some seem relatively simple and straightforward - almost inevitable, while others are still in very early stages of development.
I will return with more material on this and the related topics. I am certain to weigh in on a sobering realization that the alternatives to halting or reversing the climate crisis are not themselves completely free from hazards. More on that to come!