The Simple Science of Climate Change
There are a couple of pervasive myths about climate change that are frequently exploited by skeptics to deny its existence. The first is that the science underlying climate change is somehow complex or esoteric. Nothing could be further from the truth. The underlying science is very simple. It’s basic high school physics. If you add an impurity to a solution you change its physical properties. The experiment we conducted in high school involved adding salt to water to change its freezing point. Anyone who has ever put salt on an icy sidewalk understands this simple physical phenomenon.
This is the same physical phenomenon behind climate change. An impurity — carbon dioxide — changes the ability of air to retain heat. It’s so simple even a sixteen-year-old can understand it.
The second myth is that this is some kind of new-fangled science, dreamed up by Al Gore in the 1990s. That’s also not true. The phenomenon was discovered in the 1890s by a Swedish scientist named Svante Arrhenius. Arrhenius first showed that water vapor — humidity — changes the ability of air to hold heat. We’re all familiar with this. On a muggy summer day the high temperature might be in the upper 80s while it cools down to the low 70s at night. On a crisp fall “Indian Summer” day it might also reach the upper 80s, but cools into the 50s at night. The reason is that the water vapor in the air holds heat, and the more water vapor — the higher the humidity — the more heat the air holds. It’s the same physical phenomenon as salt changing the melting point of ice.
Arrhenius then discovered that carbon dioxide is far more effective at holding heat in air than water vapor. He published a ground breaking paper on the subject in 1896, and won the Nobel Prize for chemistry in 1904 for this and other discoveries.
A third myth is “global cooling.” Another thing that affects temperature is sunlight. It’s hotter in the sun than the shade, hotter on a sunny day than cloudy a day. In the 1960s scientists wondered if visible pollution — smog — might impact the earth’s temperature, and by the early 1970s they published scholarly articles on the subject. Popular media picked up on the story, with a major article in Newsweek. But as scientists investigated further they determined that the effects of smog were localized — skies in Chicago might be grey but it was clear 20 miles away — so the impact wasn’t significant enough to alter the world’s environment, and therefore didn’t change the consensus that increased CO2 warmed the atmosphere. Unfortunately Newsweek didn’t run a retraction until 2014, so skeptics still reference this debunked story to this day.
Arrhenius’ 1896 paper said that doubling the level of carbon dioxide in the atmosphere would increase global temperature by 5° Celsius. This was based on complex calculations from known data — the size of the planet and its atmosphere, the chemical make-up of the atmosphere, and the impact of CO2 on the ability of air to retain heat. What Arrhenius failed to understand was that the oceans absorb atmospheric CO2, so his calculations were a bit high. But the concept, which is based on simple science, has been proven over the years.
Arrhenius was from Sweden and thought a little warming might be a good thing. On that he was wrong. At the time of his studies there was approximately 250 ppm (parts-per-million) of CO2 in the air. Today it is just over 400 ppm, an increase of over 35%. To date the earth’s overall atmosphere has warmed by approximately 2° Fahrenheit, which has disrupted weather patterns around the world, leading to devastating flooding, monsoons, and hurricanes, as well as the freakishly hot September we just experienced in Lexington.
It’s a phenomenon so obvious, and based on such simple science, that only someone “remarkably ill-informed” could deny it.
