All this week around the world, millions of people are holding celebrations related to Wednesday’s Earth Day. Regardless of how (or if) you recognize the day, it’s an example of the dramatic effects collective action can have on our environment. Thirty-nine years ago, when Earth Day was created by Wisconsin Senator Gaylord Nelson, the United States was in dismal environmental shape.

For those alive at the time, who can forget the Cuyahoga River catching fire? It’s a vivid example of the dangers of neglecting our world, and a big reason why polls showed environmental consciousness vaulting from a topic that less than 1% of people considered a serious issue in the mid-1960s to one that has been at or near the top of concerns ever since.

The first Earth Day saw 20 million people gather to call for environmental action. In 2007, the number of people participating in Earth Day globally was reported to top one billion, with more expected this Wednesday.

Cabot Green Investor

The strides in the four decades since are impressive: the creation of the Environmental Protection Agency by President Richard Nixon later in 1970, the restriction of lead paint and DDT a few years later, the development of filtering technology for coal plants in 1979, the creation of the Energy Star program in 1992, the expansion of clean emission requirements on vehicles ranging from cars and trucks to construction and farm equipment in 2004, and much more. Researchers at the start of this year estimated we will all live five months longer than we would have without the air quality strides spawned by the first Earth Day.

As a father, I’m gratified that my baby daughter and her sibling–due late this summer–will grow up breathing cleaner air than I did. As someone with more than a decade’s worth of experience writing about individual investing for Forbes and now for the Cabot Green Investor–and investing for myself for longer–I’m excited by the profit potential not only from the companies capitalizing on the current regulations, but also the ones that stand to benefit from the $115.9 billion of U.S. economic stimulus money I calculate is going toward Green projects, from electric vehicle conversion funding to watershed protection projects to modernizing the electrical grid.

If you think the changes from the efforts of Earth Day are impressive, wait until you see the remarkable changes that will transform our world and our economy in the next few years. Picture next generation highly efficient solar panels that are ideal for diffused light areas that could make solar ubiquitous in the less sunnier northern climes–they are from a company I told my readers about in 2008 and it’s a steal right now.

Envision an American company that is the leading supplier to the Chinese market of both the design and mechanisms of cutting edge wind turbines. My readers made 42% profit on it in just six weeks last summer before we sold ahead of weakness we saw coming in the markets–and no, it’s not GE. I’m watching it to tell subscribers when the time is ripe to jump back in.

Picture companies in industries as diverse as organic coffee, a hot commodity in the trend toward Green lifestyles, to mining lithium, a crucial ingredient in hybrid and electric cars. My readers are sitting on profitable positions in those companies as I write this–although with the market shifting daily, I may have already advised them to sell as you read. Of course, the names of those companies are available only to the readers Cabot Green Investor.