Carbon offset fees charged by some airlines are like pardons sold by the church during Middle Ages, activists say angrily.
At best it could help assuage some enviroguilt conscience, but that is not sufficient to fight global warming caused by the relentless emission of greenhouse gases.
British Airways and Scandinavian Airlines System had launched such programmes early this year and the Australian airlines Qantas followed suit in September.
Basically they all enable travelers to calculate the amount of carbon dioxide generated per person by their trip, assign a monetary value to it and make a voluntary payment through the airline's Web site to a third-party company that funnels the money to green projects - government-approved carbon dioxide abatement schemes, including grants for renewable energy sources, tree-planting projects and improvements to energy efficiency.
A flight from Australia to Los Angeles, for instance, has been calculated to generate around 1.4 tons of greenhouse gases per passenger, which the airline says can be offset by paying just 17 Australian dollars (US$14.50; euro10.46) per flight.
The aviation industry accounts for about 2 percent of the world's carbon dioxide emissions and has come under increasing pressure from environmental campaigners.
This offset fees programme resembles Kyoto Protocol's clean development mechanism which allows industrialised countries committed to reducing emissions of greenhouse gases to count reductions achieved through investments in green projects in developing countries.
Annalee Newitz, writing in Alternet, a noted website, recalls that Catholic Church sold wealthy people indulgences to offset the spiritual cost of their sins and assure a place for them in heaven.
Geoffrey Chaucer's classic work The Canterbury Tales, written in the late 1300s, makes fun of the thoroughly corrupt pardoner character, a bombastic weirdo who constantly tries to sell everybody official-looking papers that would pardon them for their sins. Chaucer was just one of many thinkers at the time who criticized the idea that any sin can be forgiven with a little gold.
Polluting the environment isn't a sin in the Christian sense, and yet carbon offset fees are clearly indulgences for a modern, scientific age.
China is industrializing in order to make its citizens richer, but last week the Chinese National Population and Family Planning Commission published a report showing that environmental pollution from coal mining has caused the incidence of birth defects to jump 40 percent in the past six years.
There's no carbon offset price you could pay to fix that. Nor is there an easy way to prevent such disasters from happening in the future if most of the world agrees that industrialization is the road to wealth.
"Do we use our carbon indulgence money to fund Chinese populations' return to preindustrial life, thus dooming that nation to a second-class economic status?" Annalee Newitz wants to know.
Preservationist Marc Ancrenaz and his colleagues get it right in a recent article for PloS Biology in which they argue that preserving biodiversity must go hand in hand with eradicating poverty.
"Most traditional conservation efforts were typically designed to exclude human residents," Ancrenaz's group writes. "This failure to consider the interests of local communities has resulted in a general lack of support for conservation and subsequent degradation of protected areas." In other words, if you don't help the people in a region, it doesn't matter how many carbon offsets you buy -- the area will still suffer.
Ancrenaz discusses two novel preservation programs that incorporate community development in their biodiversity agendas: the Kinabatangan Orangutan Conservation Project in Borneo and the Tree Kangaroo Preservation Program in Papua New Guinea.
Both programs train and hire locals as researchers who can help preserve the habitats of orangutans and tree kangaroos, respectively.
Most urgently needed are programs that help locals develop new sources of wealth without requiring them to engage in logging or factory farming to earn money.