There are two great issues concerning the use of fossil fuels as an energy source. 1. Fossil fuels that power our civilization are in limited supply and if exploited at ever increasing rates, could become scarce in a few generations. 2. The fact that the very use of them is damaging on every scale.
Local pollution from internal combustion engines contributes to the formation of tropospheric ozone which is known to increase premature deaths, especially among those with compromised respiratory capacity. Global scale pollution relates to global warming and ocean acidification. These global scale pollution events have the capacity to radically change the environment in numerous detrimental ways.
Combustion of fossil fuels since the mid 1800s has raised the net carbon dioxide concentration of the atmosphere more than 30 percent — from about 290 to 394 ppm as of this writing. Prior to this the concentration of carbon dioxide was relatively unchanged for more than 400,000 years. Historical concentrations of carbon dioxide can easily be obtained from ice core data. Simply drill down through ice in Greenland or for the longest time, Antarctica. Analysis of tiny gas bubbles in each annual layer of ice reveal the gas composition at the time of the snowfall.
The changing composition of the atmosphere is important because the temperature of the earth is in a delicate balance between the input energy from the sun to the planet and the heat radiated away from the planet. Any change in input or output can impact the balance, and therefore the global temperature. For example, the output of the sun is not absolutely constant, but the measured changes are very small compared to the planetary heat increases being measured.
If the input energy from the sun can’t be blamed on rising temperatures, then the problem must lie with energy output. Carbon dioxide and a couple of other gasses, most notably methane and nitrous oxide, act to prevent heat from radiating away from the planet. The imbalance in the equation is due to the output side, not the input. If the sun shines on a window and you leave your windows closed on a summer day, it will get a lot hotter than if you leave them open, allowing the heat to escape. This is the classic greenhouse effect.
But are temperatures rising, and if so, by how much?
This is a tougher call, for the simple reason that climatic temperatures are a very “noisy” signal. We are looking at a possible elevation of temperature of a degree or two already and several degrees during the next couple of human generations. Those changes are small but significant considering that daily temperatures can vary roughly 40 degrees and three times that annually at some locations.
There are numerous changes to climate and habitat already occurring which are most easily explained due to the burning of fossil fuels. Just a few, but certainly not all, effects are glaciers receding at unprecedented rates, tundra permafrost is thawing, plant and animal ranges are moving both northward and up slope, and the oceans are becoming more acidic.
All these effects destabilize many forms of life on the planet, not the least of which are you and I and generations to come — our future.