What does externality mean? One definition is: “A consequence of an economic activity that is experienced by unrelated third parties.” In the case of coal, many of the externalities are negative. The utility generates electricity, customers consume it, but downwind significant costs are incurred by third parties such as buildings, trees, bodies of water, human health and more.
As a nation, we understood that burning coal produced millions of tons of sulfur dioxide (SO2) which causes acid rain. Several presidents and Congress worked with the EPA successfully to address and mitigate this environmental issue.
We also understand that high mercury (Hg) levels in Adirondack lakes and fish come from the burning of coal west of New York state. Again the Clean Air Act was used to successfully begin to address this issue, and progress is ongoing.
Let’s look back at some recent history.
Dead trees on mountaintops in New England were beginning to be commonplace at higher elevations in the 1970s (see photo). From the Adirondacks to the Green Mountains to the White Mountains, spruce, fir, maple and beech trees began to wither and die. Research by biologists, forest ecologists, chemists and others slowly uncovered what was happening.
They found that the rain, fog and cloud moisture bathing our land and vegetation was acidic, very acidic, and was having profound and far-reaching effects on the environment, human health and elsewhere.
The measured acidity was equivalent to that in vinegar, lemon or tomato juice. It was so strong that essential minerals and nutrients were being leached out of the soil and leaves, which contributed to cellular death. This “acid rain” made hundreds of Adirondack lakes so acidic that most fish died along with other aquatic organisms. Note the map of the Adirondack Park with the most acid lakes in the western portion.