The recent launch of Tata’s “Nano,” along with the high interest in the Smart “Fortwo” micro-hybrid car, indicate rapid steps towards a scenario where hundreds of millions of affordable, gas-sipping vehicles are sold over the next 10-20 years - a most welcome development. After all, the independently owned automobile is probably one of the most liberating innovations in the history of the world. So how will the world adapt to 1.0 billion more automobiles on the roads?

Per acre, almighty Redwoods are among the greatest carbon sinks.

In our latest interactive online spreadsheet, “Can Forests Offset Automotive CO2” we evaluate the impact of 1.0 billion new cars on the road in terms of the ability of reforestation to absorb their CO2 emissions. In our metric-friendly spreadsheet (you can view all variables in both imperial and metric units) we assume 1.0 billion cars, averaging 10,000 miles per year each, averaging 50 miles to the gallon. We further assume, based on excellent data from the U.S. Government’s Carbon Dioxide Information Analysis Center (CDIAC), that 50 tons of carbon can be sequestered per acre of forest in a 75 year cycle. Input your own assumptions!

The table “Major Ecosystem Complexes Ranked by Carbon in Live Vegetation” from CDIAC is interesting in that it shows the most productive forests for sequestering carbon are the temperate coniferous rainforests of North America, at around 15 kilograms of carbon per square meter, with tropical equatorial rainforests coming in second at around 10 kg per square meter.

Overall, our spreadsheet indicates that under these assumptions, it would take about 1.1 million square miles of new forest to sequester the CO2 emissions from 1.0 billion new cars - and these new forests would retain the capacity to absorb CO2 at this rate throughout their growth cycle of 75 years.

There are a lot of conclusions to draw from this. Reforestation is clearly not going to offset all automobile emissions - everyone knows that - but during the transition from cars powered by fossil fuel to zero-emission cars, forests hold surprising potential. If we are going to start treating carbon as currency, it appears that the emissions from the 1.0 billion additional cars destined to be on our roads, at the least, could be offset by planting slightly more than 1.0 million square miles of new forests - a desirable amount of worldwide reforestation.

Even if one is skeptical regarding CO2’s role in climate change, there are many benefits to treating carbon as currency. Exposing the chicanery of the CO2 opportunists - and the attendant dangers improper implementation poses both to the environment and to individual freedoms - should not blind anyone to the utility of the concept.