Earth Day — celebrated by few, propagandized by many.

The late Senator Gaylord Nelson founded the event in 1970 out of “concern about what was happening to the land, rivers, lakes and air.” Back then, Earth Day was widely observed by participating in environmental clean-up projects — clearing streams of trash and debris, planting trees and so on.

Unfortunately, that sense of personal activism has been largely lost over the last few decades. Instead, we have been told that the best way to address Nelson’s concerns is by using solar panels and wind mills and following government instruction on how much energy to use or what kinds of products to buy.

The problem is that these things do not actually protect the environment. People do. Indeed, our nation’s most precious resource is its people. It is people, after all, who provide the economic wherewithal and discover the technological advances that allow us to pursue environmental improvement.

One such advance — though not widely popular with the Earth Day Industrial Complex — is nuclear power. More so than any other energy source, nuclear technology makes possible the production of massive amounts of clean, reliable and affordable power. In fact, nuclear power — which now provides 20 percent of our nation’s energy — does more to preserve Senator Nelson’s prized environmental resources (land, water and air) than any other energy source, “green” or otherwise.

Conserving land. A traditional nuclear power plant takes up only a few hundred acres. New reactor technologies are even less land-intensive. The power produced by a single nuclear reactor is often enough to keep the lights on for millions of people. Wind and solar, on the other hand, can take thousands or tens of thousands of acres to produce the same amounts of energy. For instance, in order to generate the same amount of power as a single nuclear reactor, wind turbines would have to cover the entire area of the Great Smoky Mountains — that’s over 900 miles.

Of course, land-use considerations extend beyond the size of a plant’s footprint; the amount of land needed to support a plant also matters. Fueling nuclear reactors with uranium is a good choice from a land-use perspective. First, modern mining techniques either leave the earth’s surface mostly undisturbed or restore it once mining operations end. Second, uranium fuel can be recycled and used multiple times. Lastly, uranium mined for other purposes can now be repurposed and used to fuel power reactors. Indeed, half of America’s nuclear energy (or 10 percent of all of our electricity) is produced from uranium that was converted from Russian warheads.

Keeping our waterways clean. Though anti-nuclear activists want you to think otherwise, nuclear power is actually very water friendly. Yes, it uses massive amounts of water to cool plant equipment, but it actually consumes very little of that water. Depending on the cooling system, it either returns the water, untouched by anything radioactive, to its source or releases about half of it through condensation before returning the rest to its source. This approach has virtually no measurable impact on local aquatic life.

Some nuclear power plants, such as the Palo Verde Nuclear Generating Station, do not even use fresh water for cooling. Instead, they use waste water from nearby cities.

Other energy sources have a much greater impact on water resources. Take offshore wind, for example. The proposed Cape Wind project in the Nantucket Sound would consist of 130 wind turbines, spread across 25 square miles. Due to the intermittency of wind, it would take approximately 24 of these projects to produce the same amount of energy as one average-sized new nuclear plant.

Breathable air. Nuclear power emits virtually nothing other than water vapor into the atmosphere. That’s because nuclear fission, which produces the heat used to run the generators, requires no burning. So those most concerned about pollutants such as particulates, sulfur dioxide and nitrogen oxides or emissions like CO2 should be particularly attracted to nuclear energy.

Senator Nelson cited the need to clean our land, water and air as the reason for Earth Day. Nothing has contributed as much to this objective while also meeting America’s energy needs as nuclear power. No wonder the heavily subsidized yet oh-so-trendy alternative energy technologies are considered “green.” It’s the envy, don’t you know?

-Jack Spencer is The Heritage Foundation’s senior research fellow in nuclear energy policy and a technical consultant to the documentary “Powering America.”