may be more important than even the ghgs from automobiles, in other words, the ghgs released from destroying forests and grasslands and agriculture may be much worse than from the cars that are needed in sprawl-land.  Globally, about 30% of greenhouse gases come from deforestation and issues related to agriculture, so paving over ecosystems is bound to release massive amounts into the atmosphere.  However, to my knowledge noone has quantified that.

I would also note that it would be nice if someone was as passionate about the ecosystem loss resulting from sprawl as commenter stopgreenpath is about ecosystems lost from building transmission lines and wind and solar farms.

It's also important to note the social justice issues involved, that owning and operating an automobile can be a large drain on personal finances.

"Globally, about 30% of greenhouse gases come from deforestation and issues related to agriculture, so paving over ecosystems is bound to release massive amounts into the atmosphere.  However, to my knowledge noone has quantified that."

Just the release of nitrous oxide (296x the GHG effect of CO2) from chemical fertilizer is equal to 2/3 the CO2 uptake of the crop being fertilized.

On the other hand, with organically fertilized ag, carbon sequestration of cropland could even exceed the level of natural carbon sinks like conservation land.

Adding soil ammendment/fertilizer derived from biodigestor recycling of waste stream components added with dead wood and extra cellulose like weed and algae overgrowth removed from polluted lakes and rivers, could build soil carbon sinks right onto cropland.

Cropland that has been stripped of carbon during the industrial chemical ag revolution.  I still think Branson owes me 25 million for this concept, hehey.

http://amazngdrx.blogharbor.com/blog John Schneider, Northern Wisconsin

how much soil-based carbon sequestration has been elminated by building suburbs?  When something gets paved over does that lead to more greenhouse gases?  Do lawns help?  

I was just thinking about those Jon.  Chem lawns don't sequester much carbon, but underneath the sod, organically fertilized lawns could accept tons of carbon.

Concrete and buildings definitely stop sequestration, but could they make up for that as solar collector space, in the case of concrete over parking lots?  I think so.

For extra fuel production from algae for Branson's jets and a nice carbon offset to make air travel green, huge algae farms could be built on the ocean.  Extract the oil from the filtered algae with pyrolisis in a solar comcentrating furnace, then the remaing cellulose can be recycled as soil ammendment.  

Building soil around the world back up to the 20 to 30 foot level of american prairies before the advent of chemical ag, that burned all that soil up, releasing the CO2 into the atmosphere over the last century or so.  The added GHG benefit is the increased growth rate of plants feeding on this healthy soil, that means more CO2 removed and stored in the soil by crops, lawmns, and restored conservation land.

Not to mention the biogas produced could backup wind, wave, and solar powered grids.

Sprawl could be greened with the appropriate energy/ag GHG fixes.  Mass electric transit and plugin hybrids would have to be part of it too.

But imagine mega-cities in the US, Europe, India and China, for instance, sprawling out without green energy/ag re-evolution?

http://amazngdrx.blogharbor.com/blog John Schneider, Northern Wisconsin