‘Too Many Blankets’: How Greenhouse Gases Are Overheating Our Planet

Carbon dioxide (CO2) is not the villain some make it out to be. If there was no CO2 in the atmosphere the average temperature of the Earth would be 0 °F, cold enough that the oceans would be frozen over and life probably would not have started on Earth. However, with CO2 at a level of .04% of

the atmosphere, then the average temperature is now at a comfortable level of about 60 °F.

So, what is the problem? The problem is that CO2 levels are now too high and rising. Measured in parts per million (ppm) our level today is way too high. Charles Keeling measured CO2 levels in the 1950s and saw they were increasing. See Figure 1.

The Earth is used to typical cycles of warming and cooling, but the current warming trend we are seeing is proceeding at a rate that experts believe is unprecedented in the past 1,300 years. And almost 97 percent of climate scientists agree that it's our fault (anthropogenic - human caused).

For the last 800,000 years CO2 levels have never been above 300 parts per million (ppm) and when CO2 rose the average temperature of the planet went up. This data is taken from ice cores in Antarctica where s

cientists are able to reconstruct the temperature vs. CO2 level correlation. Low CO2 levels in the atmosphere lead to low temperatures on Earth. Now our level of CO2 is over 400 ppm and rising.

The process of greenhouse gases (most notably carbon dioxide) to regulate the temperature of our planet is a natural process that we call the greenhouse effect. Humans have increased the levels of carbon dioxide, methane, nitrous oxide, and halocarbons in the atmosphere, which has caused the average temperature of the Earth to rise above these normal levels.

Greenhouse gases (GHG) in our planet's atmosphere radiate energy in all directions. Part of this radiation is directed back towards the surface, warming the Earth. The intensity of the downward radiation – that is, the strength of the greenhouse effect – will depend on the atmosphere's temperature and on the amount of greenhouse gases that the atmosphere contains.

Think of this build-up of greenhouse gases like our planet putting on extra blankets: if we sleep without a blanket, heat escapes our body, and we feel cold. But if we have too many blankets, too much heat gets trapped, and we start to sweat. Greenhouse gases have always been critical in keeping our planet toasty enough to support life, however, human activity (mainly burning fossil fuels and deforestation) has pumped way too much into our atmosphere, causing global warming.

Here are some major culprits of this greenhouse effect:

Carbon Dioxide

Carbon dioxide (CO2) does a great job of trapping heat in our atmosphere, preventing Earth from becoming a ball of ice. However, scientists have found that CO2 levels have unnaturally increased by 130 parts per million volume (ppmv) since the beginning of the Industrial Revolution in the mid 19th century. They are also expected to double within the next century.

CO2 contributes to the greenhouse gas effect by being able to resonate with infrared (heat) radiation (while water molecules are able to absorb infrared radiation and hold on to that energy more effectively)

that is trying to escape the Earth’s atmosphere into space. This occurs when a molecule’s resonance frequency is the same as that of the wave, this is true of all greenhouse gases. Once infrared (long wave radiation) is absorbed by the CO2, it can either remain in Earth’s atmosphere, transfer to another greenhouse gas molecule, or continue to escape into space.

Human activity is largely responsible for the recent increase in CO2 emissions as well as the destruction of many significant natural sinks. The majority of CO2 emissions are the result of burning fossil fuels. As of 2017 in our country, 29% of emissions are contributed from transportation and the need for gas and diesel; it is closely followed by electricity, which is responsible for 28% and industry at 22%. Finally, residential and commercial make up 12% with the remaining 9% being from agricultural sources.

In addition to producing excess amounts of CO2 to begin with, humans are rapidly wiping out the forests that would most effectively remove that same excess CO2 from the atmosphere. Motives behind deforestation and logging include using the land for cattle ranching, oil extraction, agriculture, and mining. Furthermore, oil extraction and coal mining only contribute to CO2 emissio

ns as both petroleum and coal emit large quantities of CO2 when burned for fuel. This creates a cycle that accelerates the greenhouse effect at alarming rates.

Methane:

Another potent factor in the phenomenon of global warming is methane (CH₄), a gas that accounted for about 10.2 percent of all greenhouse gas emissions in the United States by human activity in 2017. It is a colorless, odorless, and highly flammable gas found in the troposphere that is used around the world to generate power and heat homes. The sources of methane in the natural world include things like volcanoes, undersea vents, and bacteria in the soil, but more than 70% of the methane we have on the planet today comes from human activity. Currently, natural gas and oil factories, along with power plants, are the most significant sources of methane emissions in the United States.

The main problem that methane causes is that it does the same thing as carbon dioxide, but it’s far more devastating. When it comes to the power to absorb heat from the sun, methane is 84 times more effective at heating up the planet than CO₂.

In the past, this would be balanced by the fact that methane wasn’t being released that often from natural sources (most volcanoes aren’t erupting constantly); Today however, human activity has tipped the scales and made methane a major player in the changing climate of the planet. Methane is put into the air by humans in two major ways: through leaks in natural gas pipes and emissions from livestock, which can be explained by the graphic in Figure 3. The change has been drastic, with methane levels in the atmosphere being more than double what they were in the preindustrial era. With the pace of development in the world today, that level is only going to rise if no action is taken.

Nitrous Oxide:

The Global Warming Potential (GWP) of a greenhouse gas measures how effective that gas is in warming the earth. Since it is being used as a basic point of reference, CO2 has a GWP of 1, meaning a gas with a GWP of n is n times more effective towards warming the atmosphere than CO2.

Nitrous oxide (N2O), a greenhouse gas that is often overlooked, only compensates for approximately 5.6% of greenhouse gas emissions caused by humanity. However, its GWP ranges from anywhere between 265-298, making it the second most destructive of the greenhouse gases, right below the halocarbons.

In addition, N2O molecules remain in the atmosphere for 114 years before dissipating. Only 40% of N2O emissions are a result of human activities, but due to N2O’s extended lifetime, its impact should not be ignored.

Halocarbons

One of the most recognizable pollutants behind carbon dioxide and methane is the infamous killer of atmospheric ozone, chlorofluorocarbons (CFCs). Inventor Thomas Midgley came up with two ideas: putting lead (tetraethyllead) into engines to increase octane and worked on a team to come up with a new refrigerant (Freon) with the chemical name chlorofluorocarbon. Time magazine later called these two inventions on their list of the 50 worst inventions. Midgley contracted lead poisoning and now CFC’s have been largely replaced with other refrigerants, due to the 1987 treaty to limit ozone depleting chemicals (ozone depletion is a separate issue from climate change although the CFC’s are harmful to both issues).

Not only do CFCs and other halocarbons wreak havoc on the atmospheric ozone which shields the Earth from harmful UV (ultraviolet) radiation, but they also are thousands of times more effective than carbon dioxide for trapping heat in the atmosphere. The Intergovernmental Panel on Climate Change (IPCC) rates halocarbons as all being of greater potential to affect the climate, with a majority being a magnitude of 1000 times greater or more, with some reaching as high as 11,000. With their destructive potential for both our climate and our ozone, the family of halocarbons deserves far more attention than they are currently afforded.

Water vapor

Methane and carbon dioxide gets all the attention as being one of the major greenhouse gases. However, water vapor is the most abundant greenhouse gases on the planet, being an extremely good absorber of infrared radiation (heat). As anyone who has heated up a pot of water on the stove knows that it takes a lot of energy to heat the water up.

If you take a walk on the Jersey shore on a hot summer day, the sand, road, and boardwalk will burn your bare feet. But the ocean will feel cool. That is because the water takes a lot of energy to heat up, while the sand and road reflect (give up) that heat to your bare feet. So we are fooled by the water vapor absorbing lots of heat, yet we do not feel it.

Because of this property of water, our oceans are big absorbers of heat. It also is an effective absorber of CO2. That is why we are not really feeling the effects of increasing CO2 and heat: the oceans are diluting the impact by absorbing both. But we cannot keep counting on this; as the ocean are saturated with CO2, the carbon causes it to warm and shake, eventually making it an emitter of CO2. It is just like soda: If you shake the bottle, the dissolved CO2 comes out of the drink. So a positive feedback loop is formed, where the more CO2 the ocean absorbs, the more it warms it up, and the more it warms up, the more CO2 is released to the atmosphere, warming the planet even more.

This is a vicious cycle that can only be stopped by cutting it at its source. If we can reduce the levels of greenhouse gases, we can end global warming and ensure the health of a planet we are entrusted to care for. There is only so much time we have to change course before the irreversible happens.