Carbon dioxide (CO2) is a gas that helps keep solar heat from radiating back into space from Earth’s lower atmosphere (the living zone). CO2 captures heat energy. The more CO2 there is in the atmosphere, the greater its greenhouse gas effect. Proper amounts of CO2 in the atmosphere help keep the living zone on Earth at a habitable temperature.
Since the start of the industrial revolution, energy demand in developing societies has grown immensely. Most energy for development has been supplied by burning coal, oil and natural gas. Burning these fossil fuels combines carbon with oxygen to produce CO2. Pre-industrial levels of CO2 in the living zone hovered near 280 parts per million (ppm). By 2015, atmospheric CO2 concentration had risen to over 400 ppm, and is climbing annually. Hence, fossil fuel burning has been largely blamed for increasing CO2 levels.
How dangerous could this rapid rise of CO2 be? Throughout much of Earth’s geological past, due to the normal slowness of change, atmospheric gases tended to reach a steady state, mostly because of the interplay between plants and processes like mountain building, erosion and normal volcanism.
Occasionally, however, catastrophic events seriously disturbed the steady state. In the deep past, asteroid impacts and nearly continent-sized volcanic eruptions caused climate change and triggered mass extinctions. These events happened so rapidly, geologically speaking, that the ability of plant life to maintain atmospheric steady state was overwhelmed long enough to collapse huge ecosystems, leading to extinctions.
The key is the rapidity of change. It has taken just 200 years for modern Earth to go from 280 ppm CO2 to over 400 ppm. This rise in CO2 is happening so quickly that Earth’s plants may not have enough time to react and re-establish a steady state.
Some would argue this steady rise in CO2, and concomitant atmospheric warming, is a natural phenomenon not caused by burning fossil fuels. Does it really matter what the cause is? As a concerned citizen, I recognize that if there is a reasonable prospect of disaster, one’s best bet is to prepare for the worst, hope for the best, and do what it takes to mitigate the causes. Is it worthwhile taking seriously that Earth’s living zone temperature may rise five degrees Celsius over the next century or so, whatever the cause? On the way to a five degree rise, there will be side effects, including: sea-level will rise significantly as seawater warms and ice caps melt; methane, a greenhouse gas more powerful than CO2, will be released from permafrost; glacier-fed rivers arising in the mountains in western Alberta and elsewhere could become seasonal. Should we wait and see what will happen? Does the greater risk lie in letting things ride or in taking action?
I am firmly on the side of scientists on this issue. I cannot see that huge numbers of international climate researchers are conspiring to do anything except ascertain the potentially deadly effects of rapidly rising CO2 on civilization.
Garth Edwards, St. Albert
