What is a concept that some people don't seem to grasp but is incredibly important?

That there's a huge difference between what looks good and what IS good. Example: this green movement. I'm all about being environmentally conscious, however the way people go about it is often on the looks good side rather than the IS good side. Nuclear power is one of the cleanest and most efficient type of energy we have but most people's ignorance about it and radiation causes a lot of fear. Fukushima was terrible but it was poorly designed. The entire Pacific Ocean isn't contaminated, nuclear power has nearly zero greenhouse emissions and with the technology we're currently developing, we could supply the entire United States with power for 750 years using only the "spent" nuclear fuel that's stored at one waste facility in Tennessee. Wind isn't efficient and is costly. Photovoltaic energy has a huge carbon footprint in manufacturing and very toxic waste. And in order for either of these to be viable option, battery technology needs to be vastly improved and then tied into the grid. Even electric/hybrid cars are pretty bad for the environment. They do use less gas but in order to handle the larger electric deman, they have huge lithium ion batteries. Those batteries are so toxic that they don't have a waste stream. They're being stockpiled in warehouses with no plan on how to safely dispose of them.

/r/AskReddit Thread