Apocalypse Now

One of the most prevalent features of modern life are the constant warnings regarding the impact humans have on our environment. Over and over again, we are bombarded by dire predictions of the coming climate apocalypse. We are told that unless we radically reduce our dependence on fossil fuels, the earth’s temperature will skyrocket, resulting in catastrophic storms, heat waves, droughts and floods. Sea levels will relentlessly rise until our coastal cities are devastated. Famine and starvation will beset humanity. The media assures us that virtually all scientists are in lockstep agreement on this issue. Many of our politicians wield the authority of “science” in an attempt to drastically change our energy policy. We’re told that we must very soon markedly reduce or eliminate our utilization of coal, natural gas, and oil. Our energy must instead be derived from “clean” energy sources – primarily windmills and solar panels.

Many people have enthusiastically embraced this climate orthodoxy. They have happily installed solar panels on their rooftops. They turn down their thermostats in the winter time in order to consume less fossil fuels. Perhaps they’ve purchased a hybrid or an electric car. The Toyota Prius is a hybrid vehicle that seems like it’s been around forever. (It was sold in Japan in 1997, and then introduced worldwide in 2000.) Now it seems like all-electric Tesla cars are everywhere! Investors have plowed huge amounts of money into Tesla. The company’s stock sports a stratospheric PE ratio of roughly 1000! Tesla’s total market capitalization value currently sits at an astonishing $750 billion. In fact, Tesla’s cap value is roughly equivalent to the next 9 largest auto makers combined. Yet Tesla expects to sell only around 500,000 vehicles in the coming year. For comparison, other companies like Volkswagon and Toyota each sell more than 10 million cars annually. Obviously, Tesla’s enthusiastic investors believe that electric vehicles will soon dominate the car market and Tesla will lead the way. We shall see.

While predictions of climate catastrophe have spurred some to action, others have been driven to despair. A survey of 30k people worldwide conducted in September of 2019 found that 48% believed global warming would result in human extinction. This is perhaps unsurprising, considering how often we’re told that global warming is an “existential” crisis. Climate activists and some politicians frequently predict that millions or even billions of people will die because of warming temperatures. Recent studies demonstrate climate worries have resulted in sharply increasing levels of anxiety and depression, especially among kids. One survey of British youth in 2020 discovered that 1 in 5 were suffering nightmares related to climate fear. Many kids feel like they have no future because of the impending climate doom.

What is the average person to make of all this? How should Christians respond to the so-called climate crisis? These are the key questions I hope to answer in this blog series. Perhaps the biggest problem in tackling this issue is that most people feel like they just don’t have the expertise to evaluate complicated scientific claims about our climate. They read in the media about all kinds of scary scientific pronouncements and predictions. Some might feel that we just need to trust the “experts.” Many others are reluctant, knowing that experts have a long history of being completely wrong.

The discussion about global warming today is dominated by carbon dioxide and the greenhouse effect. Let’s begin by educating ourselves about these two things. Most people today have very negative connotations when they hear the term greenhouse effect. They might imagine themselves trapped in an actual greenhouse which is stiflingly hot and oppressive. But the reality is that the greenhouse effect is a good thing – a very good thing. Solar radiation travels from the sun to our earth. Roughly 30% of this radiation is reflected by the clouds but most reaches the surface of the earth, warming our planet. Some of the energy reaching the earth’s surface then reflects back out of the atmosphere but part of it is trapped by so-called greenhouse gases. We should be enormously thankful for the greenhouse effect because it keeps the earth’s average temperature at 59 F degrees. Without the greenhouse effect, the earth’s average temperature would plummet to a frigid 0 F. The earth would be completely frozen and human life would not be possible. On the other hand, the greenhouse effect could also drive temperatures far too high. For example, our neighboring planet Venus has a thick atmosphere composed of 96% carbon dioxide (CO2), resulting in a greenhouse effect 100x greater than that on earth. At the result, Venus suffers an unbearable average temperature of 863 F degrees!

So what are these greenhouse gases that help the earth retain the sun’s warmth? Well, unless you’ve been living under a rock, virtually everybody knows that carbon dioxide gets a lot of press as the major cause of the greenhouse effect. Many people also know that there are other significant greenhouse gases such as methane, nitrous oxide (N20), and fluorinated gases. But overall media coverage is dominated by carbon emissions. Most people would be stunned to learn that carbon dioxide is actually not the primary greenhouse gas. That honor goes to good old water vapor. Now the amount of water vapor in the atmosphere varies greatly from time to time. All of us experience changes in humidity. We understand that the amount of water vapor in the air depends in large part upon the temperature. During the winter we encounter blasts of cold, dry air while in the summer it’s often hot and humid. Humidity also varies greatly from place to place. Obviously, deserts have very low humidity which is of course why it cools off so quickly at night. All these factors make it difficult to ascertain exactly how much water vapor contributes to the greenhouse effect. But scientists broadly accept that water vapor accounts for at least 60% of the greenhouse effect and many believe over 90%.

One area of particular concern is the relationship between water vapor and carbon dioxide. There is no question that as CO2 is added to the atmosphere, the temperature will rise to some extent. As the temperature rises, the atmosphere is able to hold more water vapor thereby further increasing the temperature. This is known as a positive feedback loop. Scientists are obviously keen to know how much of a role this positive feedback loop plays. Many climate models often assign a large contribution to the water vapor feedback loop, thereby predicting much higher future temperatures. The story is not so simple though. Warm air containing lots of water vapor will inevitably rise and cool. As the air cools, the water vapor condenses into clouds. As we’ve noted already, clouds reflect sunlight and prevent solar radiation from reaching the earth’s surface. Therefore, we have a potential negative feedback loop. More water vapor forming more cloud cover preventing the sun’s energy from reaching the earth thereby resulting in a cooling effect. So the role of water vapor in the atmosphere is complicated.

There is one fact about the greenhouse effect of carbon dioxide which is rarely (never?) mentioned in the media. As the concentration of CO2 in the atmosphere rises, the warming effect decreases rapidly. This thought is quite foreign to most people, so let’s break it down. Carbon dioxide functions as a greenhouse gas by absorbing heat in the form of infrared radiation coming from the earth’s surface. (Incidentally, CO2 does not absorb all the infrared radiation, only radiation at certain wavelengths.) At low concentrations, adding CO2 increases infrared radiation absorption leading to a relatively large warming effect. However, as CO2 reaches higher concentrations, most of the radiation has already been absorbed. Therefore, adding further carbon dioxide has a diminishing effect. And this effect diminishes rapidly or what mathematicians call logarithmically.

Now the amount of atmospheric carbon dioxide (CO2) is often measured in parts-per-million. The most trusted atmospheric carbon dioxide measurements are made at the Mauna Loa Observatory in Hawaii. As of February 2021, atmospheric CO2 measured 419 parts per million (ppm). In other words, out of every one million molecules in our atmosphere, there are 419 carbon dioxide molecules. Atmospheric CO2 was about 280 ppm in 1750 before the Industrial Revolution. Let’s imagine that atmospheric carbon dioxide increased from 0 ppm to 100 ppm. As you can see from the graph above, this change would cause a large warming effect. But for CO2 to increase from 400 to 500 ppm, the warming effect is only a small fraction of what it had been at the lower concentration. And as CO2 concentrations continue to rise their warming effect will diminish even further.

With all the talk about carbon dioxide, people might be quite surprised to learn that carbon dioxide comprises only a tiny fraction of our atmosphere. The vast majority (99%) of the earth’s atmosphere is composed of nitrogen and oxygen. Nitrogen is by far the most abundant atmospheric gas, accounting for 78% of our atmosphere. The oxygen that keeps us alive accounts for 21%. This leaves only 1% for what scientists call “trace gases.” The most abundant of these trace gases is argon at 0.93%. Carbon dioxide is also one of these trace gases, accounting for only 0.04% of our atmosphere. So, when we talk about atmospheric CO2 rising from about 300 ppm in 1950 to over 400 ppm presently, this change means that CO2 has gone from 0.03% of the atmosphere to 0.04%. In other words, carbon dioxide still accounts for a very tiny overall percentage of the total atmospheric composition.

Even though carbon dioxide only accounts for a tiny percentage of our atmosphere, it’s still vitally important for our planet. Humans and other animals stay alive by breathing oxygen. The cells of our bodies use the oxygen we breathe and the sugar we eat to produce the energy we need to function. This process is called cellular respiration. (And should not be confused with the common use of the word respiration as meaning the use of our lungs to breathe!) The by-products of cellular respiration are CO2 and water. Plants do exactly the opposite: they “breathe” carbon dioxide. In the process of photosynthesis, plants utilize the energy from sunlight to convert water and CO2 into sugar and oxygen. So even though carbon dioxide is only a tiny part of our atmosphere, it’s utterly essential for plant life. In fact, if the level of CO2 were to drop to 150 ppm, most plants could not survive. Since humans and animals depend on plants for food, this would be catastrophic for all life on earth.

Additionally, the relatively low current levels of carbon dioxide already hinder the growth of plants. Scientists have known for over two hundred years that increasing levels of CO2 will greatly benefit plants. Stimulating plant growth by increasing CO2 is known as “CO2 fertilization.” So it’s quite important to recognize that while rising CO2 may have some potentially negative effects, there are clearly positive effects as well. Increasing CO2 will allow plants to grow faster and healthier. This means larger crop yields and more food for people around the world. At higher levels of CO2, plants not only grow faster, but use less water and are more resistant to disease and insects. Trees will grow faster leading to larger forested areas. These effects are not simply theoretical. Satellite studies have already shown that our planet has literally become greener over the last several decades largely due to CO2-driven growth of plants. So, take heart! Carbon dioxide is not a poison or a pollutant. In fact, it could even be said that increasing carbon dioxide levels is the ultimate green policy. When’s the last time you read that in the newpaper?