Environmentalism today is generating more interest in the world than at any time since the 1970’s, but environmentalism today is very different from the modern movement that began on Earth Day nearly 36 years ago.

When comparing the environmental movement today to environmentalism back then, two things are evident: First, important goals have been accomplished in the last thirty years. Our air and water are cleaner, wilderness and wildlife have been preserved in great abundance, land development has become a far more thoughtful process, pollution from all sources is drastically reduced, and impressive gains in energy conservation and energy efficiency have occurred.  Overall, environmentalism has been a huge success.

The second thing to recognize about environmentalism now as compared to then is that today environmentalism is an institution. It is taught in our schools, it is a given in political campaigns, it is a value that pervades every public bureaucracy, and the fledgling environmental nonprofit groups of thirty years ago are now powerful organizations. Their budgets, collectively, amount to hundreds of millions per year, and their influence within our public institutions amounts to power over public opinion and policy that is immense and defies valuation.

This is where we find ourselves in 2007 - environmentalism has become a powerful force with a legacy of improvements to our quality of life, our health, our planet. But what direction should environmentalism take today - with energy independence becoming an important priority for all nations, new concerns about global warming, ongoing challenges to preserve wilderness, and unfinished business with respect to air and water pollution?

At a time like this, where the momentum to do anything to achieve energy independence dovetails fitfully with the momentum to do anything to reduce CO2 emissions, policymakers pressured by environmentalists may enact sweeping legislation that could completely change our way of life. But there are two ways environmentalists can go to pursue their core values in the 21st century, and they represent very, very different choices. One of the most fundamental areas where these two choices diverge concerns energy and water policy.

A “supply side” environmentalist - for lack of a better term - would argue that the priority should be to achieve energy and water abundance. To do this, for example, they would advocate construction of nuclear powered desalinization plants, as well as pumping stations and aqueducts. They would advocate increased production of fresh water from seawater, and they would advocate distributing this water to restore every depleted aquifer on earth.

A “demand side” environmentalist, by contrast, would argue that conservation of energy and water is the only approach that could possibly make sense. They would argue that it isn’t possible to produce enough energy for everyone at current levels of consumption. They would fight for energy and water rationing, with punitive fines and even criminal penalties for overuse of these resources.

The supply side environmentalist, in rebuttal, would argue that anyone overusing water and energy could simply pay a small but fair premium for their excess consumption, causing more revenues to accrue to the water and energy companies, who could then use those surpluses to invest in additional energy and water production facilities. A supply side environmentalist would argue there is abundant energy and always will be, because the market sets the price, and as soon as one energy source becomes scarce, the price of all energy rises somewhat, stimulating more investment in these energy alternatives.

Another critical choice for environmentalists is what sort of land use to advocate.  A demand side environmentalist would say we don’t have enough land for new homes, so everyone must live in high-rises, or if they’re lucky, “cluster homes.” A demand side environmentalist would say we don’t have enough land for freeways, or enough energy for personal transportation devices (cars), so road construction must be curtailed in order to force people to choose mass transit.

A supply side environmentalist would say we have plenty of land, and the problem with suburban sprawl is it doesn’t sprawl enough - if homes on the outskirts of cities were “ranchettes” with very large lots, then wildlife could pass through these neighborhoods, and big trees could grow, and the roads would be uncongested, and sprawl would be beautiful instead of ugly. A supply side environmentalist would say there are now cars that emit virtually no pollution and are incredibly energy efficient, and eventually cars will use energy from cheap photovoltaics mounted on everyone’s roof, so build more cars, and double the mileage of roads to encourage car travel.

A demand side environmentalist would say that we need to ration energy and water and land because there are too many people on earth, and that we’ve outgrown our planet’s “carrying capacity.” A supply side environmentalist would say it is rationing that perpetuates poverty, and poverty delays female emancipation, and prosperity accelerates female emancipation, which always results in dramatic lowering of birthrates.

Obviously both approaches - managing demand while also increasing supplies of clean water and energy - is the solution to environmental challenges today.  But it is vital to maintain this balance, and not dismiss the perspective nor the projects coming from the supply side.