IN 2008 an article in New Scientist suggested that the biggest problem arising from the epidemic of obesity is the additional carbon burden that fat people who tend to eat lots of meat and travel mostly in cars place on the environment.
Airlines began to sell offsets which offered passengers a way to invest in projects that reduced carbon emissions. In theory, that would compensate for the greenhouse gas caused by their flights. It seems like neither the goals nor acceptable emissions are clear and morality is often mistaken for science.
Greenhouse-gas emissions have risen rapidly in the past two centuries and levels today are higher than at any time in at least the past 650 000 years. In 1995, each of the six billion people on earth was responsible, on average, of one tonne of carbon emissions.
Oceans and forests can absorb half that amount. Although specific estimates vary, scientists and policy officials increasingly agree that allowing emissions to continue at the current rate would induce dramatic changes in the global climate system.
To avoid the most catastrophic effects of those changes, we will have to contain emissions at a steady level for a decade and then reduce them by at least 60 to 80% by the middle of the century.
Yet even if all carbon emissions stopped today, the earth would continue to warm for at least another century.
Facts like these have transformed carbon dioxide into a strange, but powerful new currency difficult to evaluate yet impossible to ignore.
Scientists say each person makes a contribution to global warming. Carbon dioxide is the best known of gases that trap heat in the atmosphere. Other elements such as water, vapour, methane and nitrous oxide also play a role.
Virtually every human activity, from watching television to buying a pint of milk, has some carbon costs associated with it. We all consume electricity generated by burning fossil fuels; most people rely on petroleum for transportation and heat.
Emissions from those activities are not hard to quantify. Watching a plasma television for three hours every day contributes to 250kg of carbon to the atmosphere each year, an LCD is responsible for less than half that number.
Yet the calculations required to assess the full environmental impact of how we live can be dazzlingly complex. To sum them up on a label will not be easy.
Should the carbon label on a bottle of peanut butter include the emissions caused by the fertilizer, calcium and potassium applied to the original crop of peanuts?
What about the energy used to roast peanuts once they have been harvested or to mould the bottle and print the labels? Seen this way, carbon cost multiply rapidly. According to the Stockholm Environment Institute, during the festive season, each person emits 650kg of carbon.
As a source of global warming, the food we eat and how we eat is no more significant than the way we make clothes or travel or heat our homes and offices. It certainly does not compare to the impact made by thousands of factories scattered throughout the world.
Yet food carries enormous symbolic power so the concept of “food miles” (which is the distance a product travels from the farm to your home) is often used as a kind of shorthand to talk about climate change in general. The world’s biggest priority is to reduce emissions of greenhouse gases.
However, in our collective rush to make choices that display personal virtue, it seems we may be losing sight of a large problem.
For example, as we feel good about the organic potatoes we buy, environmental scientists argue that half these emissions from these potatoes could come from the energy we use to cook them.
If we leave the lid off and boil them at a high heat and then mash the potatoes, from a carbon standpoint we might as well rush to a fastfood joint and spend our money buying hot chips.
Researchers had to calculate the amount of energy required to plant seeds for the ingredients (potatoes) as well as to make the fertilizers and pesticides used on those potatoes.
Next, they factored in the energy required for diesel tractors to collect the potatoes then the effects of picking, cleaning, storing and bagging them.
The packaging and printing processes also emit carbon dioxide and other greenhouse gases as does the petroleum used to deliver those crisps to stores.
Finally, the research team assessed the impact of throwing the empty packets in the bins, collecting the garbage in a truck, driving to a landfill and burying them.
In the end, the researchers from the Carbon Trust found that 75g of greenhouse gases are expended in the production of every small packet of potato chips.
It is a logical and widely held assumption that the ecological impacts of transporting food, particularly on airplanes over great distances are far more significant than if that food was grown locally.
There are countless books, articles, websites and organisations that promote the idea. There is even “100 mile-diet” which encourages participants to think about “local eating for global change ” Eating locally produced food has become such a phenomenon, in fact, that word locavcore was named 2007 word of the year by the New Oxford American Dictionary.
Each company can make voluntary (but legally binding) commitment to reduce emissions of greenhouse gases, including carbon dioxide ,methane, nitrous oxide and hydroflourocarbons.
In return, they receive allowances as long as they meet their targets from both a political and economical perspective, it would be easier and cheaper to reduce the rate of deforestation than to cut back significantly on air travel.