At What Point...

Been lurking and reading many posts by advocates and skeptics regarding human effect on global warming.

A recent flight across country really startled me. I had a window seat and was amazed at how much the surface of the US has been altered by human endeavors (farming, housing, roads, industrial, comercial, retail etc.). Long periods of the flight were over areas where there was less than 10% natural vegetation left. Nowhere during the flight did I see more than 50%. It absolutely proved to me that humans have the capacity to change the entire surface of the planet. Always living in fishing towns in Maine and Gloucester, MA it's also apparent that the same can be said for the oceans. I've also driven through coal mining country and you can see how mountain ranges can easily be leveled into rubble.

Of course there are two extremes 1) "no humans ever walked the planet" 2) "only humans and pavement cover the surface". They are both silly, but it's hard to argue that we don't have to capacity to make the planet uninhabitable or at least very unpleasant if we took that course. Unchecked population growth alone would do that no matter what kind of car we drove.

The flight also left me with the thought that if the earth were a tomato in my fridge, it would be rotten enough to throw out.

Anyhow, After that long into, I'd like to ask both sides of the argument:

Advocates: At what point would humans NOT have a detrimental effect?
Skeptics: At what point DO humans have a detrimental effect?

Politically, how would you get us to or keep us from that point?

p.s. if you haven't taken a flight lately, it's the best way to get a first hand look at what is changing. It allows you to see the "lack of forrest through the trees" in a way that you can't from an SUV or Prius.

--Joe

 

The US is more heavily forested than in 1900.

Is human modification of the surface detrimental?

 

The U.S. once had about one billion acres of forests.

About 300 million acres has been cleared.

 

There's slighly more forest now than in 1900, but vastly less than there was in 1800.

In 1900, the appalachian hillsides had all been clearcut to be used as farmland. It was poor farmland, those farms went bankrupt, the forest returned there. That's where most of the gains come from. The Pacific Coast, Rockies and South all have less forest than they had in 1900.

 

Is forest intrinsically more valuable than farmland?

 

At the edge of deserts forest are much more valuable.

In the corn belt...farmland is more valuable.

Unless you grow black walnut trees. Black walnut is very valuable.

In 20 years you could make a ton of money in walnut forest.

 

I'm not sure that comparing current levels to those of the 1900's is a very strong argument. All kinds of regulations were created at that time as a response to what was observed from the deforestation and forestry practices of the industrial revolution. That was long before environmental issues were such a heated topic. Things were much more practical then.

As to surface modification being detrimental or not - you offered me a question to answer my question, so I'll return the favor with two more. How well would NYC (~500 sq mi) fair if it was isolated with a large glass bubble that didn't allow air, water, food or exhaust in or out? How much of the planet can we convert in the same manner before it's a problem?

--Joe