It may seem a bit quixotic to address a problem no one can see, but that's what organizations do when they make plans to mitigate greenhouse gas emissions. Emissions arise invisibly from almost every aspect of our daily lives -- from the fuel in our cars to the food on our plates. Locally, the topic has been discussed in relation to UNC's plans to build Carolina North. It seems almost impossible to keep track of the greenhouse gas problem, let alone any progress toward our goals.

But keeping track has become a necessity in the age of "An Inconvenient Truth." Accounting protocols sprang up in the 1990s with the Kyoto Protocol, an international agreement to stem the flood of greenhouse gases (GHGs) into our atmosphere. Carbon dioxide is the most abundant of the Kyoto-regulated gases, but methane and nitrous oxide are even more potent. To simplify the balance sheet, scientists and regulators began to express the warming potential of each gas in relation to carbon dioxide, calling them "carbon dioxide equivalents."

With a common measurement system, governments, companies and non-government organizations began to tally their yearly emissions expressed in carbon dioxide equivalents. This yearly snapshot became known as a "carbon footprint." By updating it on a regular basis, a company could more easily set goals and mark progress.

Goal setting has become a matter of debate. Though some scientists predict that we will need to drastically cut emissions in the next decade to avoid catastrophic climate changes, the actual GHG reduction targets and time to implementation vary widely across organizations. Some opt for reductions to a base-year level, like returning to 1990 emission levels. Others opt for a normalized approach -- reaching per capita or per dollar of revenue targets. Still others, like UNC and more than 600 other signatories of the American College and University Presidents Climate Commitment (ACUPCC), have chosen to be carbon neutral as soon as possible.

Carbon accounting is like fiscal accounting, with a balance sheet of assets and liabilities. In this case, carbon emissions stand in as liabilities. The goal of organizational carbon management is to reduce these liabilities through energy conservation, renewable power and alternative transportation. In some cases, it's technologically impossible or financially prohibitive to completely eliminate an emission source such as air travel. To achieve carbon neutrality, the organization must put assets onto its balance sheet -- carbon reduction efforts that occur elsewhere. We call these carbon offsets, and they represent another controversy. Some argue that because the atmosphere is global, it doesn't matter how or where the emission reduction occurs. Others believe offsets represent an environmental buy-off that prolongs the problem rather than solving it. Our philosophy at UNC is that we don't want to use carbon offsets except as a last resort.

As an early signatory of the ACUPCC, UNC pledged to achieve carbon neutrality and has completed and published a comprehensive inventory of its 2007 greenhouse gas emissions. We are focused on developing a Climate Action Plan, a document outlining how the campus expects to achieve its goal. The action plan will include interim milestones and describe the policies and technologies required to mitigate the greenhouse gas emissions from transportation, building energy, new development and other sources. It will also identify funding mechanisms and investment strategies that will support these initiatives.

The Climate Action Plan is a necessary tool for any group that wishes to control its greenhouse gas emissions as it represents a set of tangible actions that help manage the invisible contributors to global climate change. Carolina North is a part of the carbon reduction planning we are doing now.

Daniel Arneman, Ph.D., is UNC's greenhouse gas emissions specialist. To see UNC's 2007 Greenhouse Gas Inventory and Retrospective, go to http://sustainability.unc.edu/Portals/0/Documents/UNC_Chapel_Hill_GHG_Inventory.pdf