I decided to address the greenhouse effect this week. I didn’t realize that many people do not understand this process until one of my college students turned in an assignment that clearly showed misconceptions. I used to teach this in 8th grade. But I have concerns that because it has become a political issue and therefore controversial, teachers are not teaching this. And it is a fairly simple concept to comprehend.
In a previous blog, I addressed the fact that solar input has not increased over time. The data we collect on the sun is readily available. The argument that global warming and climate change is driven by the sun shows a lack of knowledge about the sun, the atmosphere, the electromagnetic spectrum, the earth’s orbit and what causes seasons (the tilt of the planet). Most people are ignorant of the fact that the earth is closest to the sun in its orbit during January, when the northern hemisphere is having winter. And the reality is, greenhouse effect is more about what is happening here on earth than what is happening on our star.
The greenhouse effect is a process that occurs when gases in Earth's atmosphere trap heat. We’ve known since the late 1800’s that carbon is good at trapping heat energy in the atmosphere from the work of John Tyndall (1820-1893) and Svante Arrhenius (1859-1927). The greenhouse effect is one of the things that makes Earth a comfortable place to live. Without enough carbon dioxide, the earth would be too cold for human life, too much, and it will be too warm for human life.
Carbon dioxide in the atmosphere, along with other greenhouse gases such as water vapor or methane, absorb infrared wavelengths from the sun. When it comes to the problem of climate change, it’s not about what is coming in, it’s about what is not getting out. Greenhouse gases do not let the heat energy (infrared wavelengths) escape back into space. These gases scatter and absorb the infrared frequencies. This increases the kinetic energy of the particles in the atmosphere and now the oceans. This increase in heat energy causes extremes in weather events.
Burning fossil fuels like coal and oil puts more carbon dioxide into our atmosphere. Nature tends toward homeostasis, balance. But the excessive carbon we have put in the atmosphere year after year is beyond the ability of natural systems to absorb or otherwise mitigate. There have been natural events in the deep geologic past that resulted in a similar carbon dioxide imbalance in the atmosphere, but it occurred over hundreds of thousands of years. Last year humans put 34 billion tons of CO2 in the atmosphere. And this has been occurring year after year for decades.
Some say it is unreasonable to claim that mere humans can impact the entire globe in a significant way. I believe it is hubris to think that 7 billion humans would not affect the balance of the ecosystems that sustain our lives. I have also blogged on the concept of carrying capacity, which is defined as the number of people, other living organisms, or crops that a region can support without environmental degradation.
As a species, we have affected the systems that could help mitigate the excess carbon we have put into the atmosphere. Healthy, live soils are actually an effective carbon sink, but we poison our soils with chemicals. Forests can absorb carbon dioxide, but we cut and burn trees constantly. Slowly we degrade life supporting systems, focusing on today’s comfort and convenience in the short-term instead of living sustainably in the long-term.
But the argument that climate change is only about the sun shows a lack of knowledge about this multivariable complex system. Natural events are not causing climate change at this time, human activity which increases greenhouse gases in the atmosphere, is the source of the problem. Natural systems tend toward homeostasis or balance. Short-sighted humans do not.