Put a price tag on nature? I am not liking this idea.
One anecdote, I heard from a co-worker [0]: There was a elementary school that had some asbestos in its walls. A consultant did some maths and presented his report, starting with "Suppose the live of a child is worth 40,000 Pounds" and went on to conclude that the replacement would probably avoid enough future deaths / illnesses to justify their rather great costs.
The council that received the report rejected it outright, "We can't put a price tag on children." In the end they never replaced the walls.
Moral of the story, the consultant shouldn't have started with the price tag, but just concluded: If you don't do the replacements, you are valuing our children's lives at less than x thousand GBP. And you wouldn't put such a low value on them, would you?
[0] I can ask him for the source, if you are interested.
http://squid314.livejournal.com/260949.html explains the math pretty well:
Contrary to popular belief, you can put a dollar value on human life. That dollar value is $5.8 million. Denying this leads to terrible consequences. Let me explain.
We can do the same sort of thing with the environment. Of course, people get outraged if you frame it the wrong way, since they don't like trading "sacred values" for secular ones. (http://faculty.haas.berkeley.edu/tetlock/Vita/Philip%20Tetlo...)
When the EPA was trying to ban leaded fuel in the 1980s, the debate was largely over the increased costs from the switch (on the order of $1 billion a year) compared to the savings in maintenance from the switch to unleaded fuel. Health effects were factored in, but because of the uncertainty of the resulting benefits most of the cost-benefit analysis focused on measurable factors such as maintenance benefits.
It turned out that when you considered the neurological effect of high blood lead levels in children (decreased IQ) the savings was on the order of billions of dollars per year: http://www.meca.org/galleries/default-file/lead0103_(final).... (12)
Another thing is that most governments and corporations don't necessarily look at the positive benefits so much as the negatives. That's one reason why I like this dollar amount idea. You shouldn't say "each child's life is worth 40,000 pounds," but rather "the potential cost of a lawsuit brought by relatives of a deceased child is in the millions of pounds."
The same method could be applied to valuing nature. You can simply say something like "the value of fisheries from the coast of Japan is $20 billion per year. Any release of radioactivity into the ocean could put TEPCO at risk of this amount in lawsuits."
Corporations and governments don't want to put a price tag on people (even though there are well established pricing models, based on historical disasters). By putting a price tag on the environment they can hopefully do better risk management. Maybe they can make smarter decisions like: "Increasing the size of the Tsunami protection wall will cost an additional $200,000, but will prevent the potential $20 billion in cleanup costs from a radioactivity release incident."
As government property the land is not salable and its true worth is unknown. Currently, businesses approach government and lease access rights for grazing, timber, oil, etc.
This leads to environmentally unsound decisions because most businesses only understand the land as is relevant to their work. And politicians make the deals because it adds jobs, builds the economy, and improves their re-election chances.
If the land was sold, the market would bring a wider range of buyers: developers, businesses, speculators, and environmentalists. Land important to wildlife would be prized by conservationists and their respective charities. They could buy and protect that land, and only permit sustainable development. Farmers could no longer lease cheap graze land from the government, they would have to buy it (and treat it sustainably) or lease it from private owners. Oil producers would have an incentive to work cleanly: if they work clean, the land will resell at a higher price when they finish.
Land is an asset of various values. Setting price tags stops it from being undervalued.
But you have to remember that the market will not factor in the value of externalities. If a wetland is providing $100m in water purification services to a community, the market won't price it at $100m, because the benefit is non-excludable. The price of the wetland ends up being the price of the only protectable property right (the right to exclusive possession) which is a small fraction of the net economic value of the land.
For example, if you fish the wetland, or set up a water front hotel, or drink the water then you have an easement right to clean water. It cuts both ways though; if a polluter moves to unoccupied land and pollutes 10 barrels a day, then he has an easement right to continue polluting at this rate.
A $100m mining project versus the beauty of a forested mountain.
People go "protect people, not plants!" and build the mine.
If it becomes a debate about:
A $100m mining project versus a mountain ecology that provides $120m in ecological services to the surrounding community, then the public reaction is different.
People have to understand that environmental protection isn't just about protecting aesthetic value. It's about the very real fact that when a land developer fills in a wetland to make a condo complex, everyone in the surrounding community has to spend $$$ to replace the water purification, flood control, etc, services the wetland was providing. It's literally about private parties being able to make a profit at the cost of the public.