Advances in the Science of Climate Change

weekend I joined six academics on a panel at the annual meeting of the American
Association for the Advancement of Science. The focus of our talks was on
emerging science of the food system’s contribution to climate change – and my
role was to talk about how Bon Appétit Management Company has been implementing science in every
day practice through our Low Carbon Diet program. I give a lot of talks on this subject, but don’t write
that much. A recent exception is the piece I wrote for Sustainable Industries

In November 2005, when I persuaded Bon Appétit Management Company
Foundation’s forward-thinking board to let me develop a program that
would shed light on the food system’s connection to climate change, An
Inconvenient Truth hadn’t been released, a majority of Americans
thought climate change was hocus pocus, and the distance food traveled
was assumed to be the food system’s most serious contributor to global
warming. We’ve come a long way in three years toward understanding that
climate change is occurring and acknowledging its true causes.

Curiously, though, we still refuse to recognize that food is an
enormous contributor to climate change. It’s as if we don’t want it to

Distributed among all its component parts, the food system represents
one-third of worldwide greenhouse gas emissions but most analysts have
yet to take it seriously. They should. Although individuals may forego
buying extra “stuff” during the economic downturn, we’re not eating
appreciably less. If anything, the food system’s percentage as a
contributing factor will likely rise.

Analysts might be forgiven for miscalculating the food system’s
contribution because it is extremely hard to measure. Government
statistics don’t help much. Data from the U.S. Environmental Protection
Agency, for example, divide sectors somewhat arbitrarily –
transportation, manufacturing, and agriculture, for example – while the
food system spans all three, and more. When the U.S. pulled out of the
Kyoto Protocol, our obligation to measure emissions was dismissed,
making a harder task even more difficult. 

But even a dedicated effort to measure emissions would need a
particularly robust accounting method to characterize the food system’s
contribution to climate change. We’d have to move beyond simply
counting carbon dioxide and factor in much more potent greenhouse gases
that the food system produces in abundance, including methane and
nitrous oxide. We’d also have to assign responsibility for domestic
demand of foods produced abroad and delivered by various speedy (read:
highly emitting) modes of transportation. If we weren’t buying
hothouse-grown tomatoes and air-freighted asparagus in winter, would
producers in other countries make them?

To paraphrase common wisdom, the devil is in the methodology details.

Nowhere is methodology more debated than when it comes to consumption
of meat, and beef in particular. A 2006 study released by the United
Nations (UN) Food and Agriculture Organization reported in detail how
the livestock sector is responsible for nearly one-fifth of global
greenhouse gases. The report used an expansive methodology, measuring,
for example, forest land turned over to grazing that previously
absorbed atmospheric carbon.

As with anything published by the UN, the study has become a catalyst
for conservative critics who see it as fodder for groups intent upon
limiting personal food choices. One such commentator wrote: “If
livestock production disappeared tomorrow, wouldn’t we just be
transporting more tofu around?” The writer obviously failed to note
that methane emissions from ruminant animals’ digestive systems and the
deforested land needed to raise the animals are by far the most
significant source of emissions from the meat industry, not
transportation or promotion of a specific diet.

Commentators on the left often miss the point as well. When PepsiCo
(NYSE:PEP) announced last month that it  used Carbon Trust methodology
to measure the emissions associated with Tropicana orange juice, the
first comment in a popular environmental blog was not praise for the
company’s proactive use of rigorous transparent tools, but a question
about how Tropicana compared with organic orange juice. Different juice
options just aren’t the issue. Nuances won’t address food's significant
climate change impacts.

Ninety-eight percent of Americans eat meat, and very few meat eaters
don’t eat beef. A similarly high percentage eats cheese and other dairy
items, all products of ruminant cows, goats and sheep that naturally
belch methane (and release some methane through their waste). While
some activists offer veganism as the answer, I’m persuaded that this
plea will only change the habits of few and turn off the many who need
to embrace the idea of eating less livestock products.
Consider this fact: If all the meat eaters in North America eliminated
meat one day each week, it would do more than tripling the number of
vegetarians. The same effect would occur if meat eaters simply reduced
their portion sizes by 15 percent. But is 15 percent enough?

If our goal is to reduce greenhouse gas emissions 80 percent by 2050,
then clearly the answer is no. But consumers’ willingness to change
their personal food choices is only one necessary step.

The food system is not environmentally benign. It’s time to stop
subsidizing cheap feed and water and regarding animal waste as an
uncontrollable byproduct. Today, food seems off limits in the climate
debate, not because of methodology concerns but because food is
emotional stuff and we’re uncomfortable with having our personal
choices questioned. But this isn’t really about personal choices; it’s
about public responsibility.

It’s also time to become accustomed to thinking of meat and cheese as
“special food” rather than simply as lunch and dinner. While that
represents a special challenge for food producers, for the rest of us,
there’s no better place to start than with catered corporate meetings,
or what we choose for dinner tonight.   

– Helene York, Director of the Bon Appétit Management Company Foundation