Climate Change Background
The Intergovernmental Panel on Climate Change, the premier international scientific group reporting on the science of global warming, confirmed last month (2/07) that humans are very likely to have caused the warming observed over the past hundred years, and that continued emissions of greenhouse gases by humans will warm the planet further. Human societies emit greenhouse gases by driving cars, heating buildings, growing food, harvesting forests, and raising livestock: all these activities produce carbon dioxide, methane, and nitrous oxide, the three major greenhouse gases warming the Earth. Reflecting the global trend, annual temperatures in Flagstaff have risen over the past 50 years, increasing by more than 0.3 ºF per decade (see the chart), a rate slightly higher than the global mean.

Greenhouse gases are a critical and natural part of Earth’s atmosphere, creating the mild climate that makes the planet favorable to life. These gases insulate the earth, trapping heat and warming the surface, just like a light blanket keeps the chill off during a Flagstaff summer night. Humans are thickening this natural atmospheric blanket by producing more greenhouse gases. Like throwing on an extra down comforter in the summer, the blanket may be getting too thick.

Climate models implicate global warming in extreme weather events – heat waves, droughts, even hurricanes. Global warming will affect food production, increase the ranges of diseases borne by heat-tolerant insects like ticks and mosquitoes, and threaten human settlements near the coasts as sea levels rise. Natural ecosystems respond too. The ranges of many plant and animal species have shifted poleward in the past 100 years. Plants bloom earlier, and leaves fall later, compared to earlier periods when Earth’s climate was cooler. Continued warming will amplify these changes.

Climate Change and Northern ArizonaUniversity

How does NAU contribute to global warming? Like almost all human organizations – whether nations, cities, businesses, universities, or other entities – NAU emits greenhouse gases that warm the planet. These gases are carbon dioxide, methane, nitrous oxide, and a few others like sulfur hexafluoride. In terms of NAU’s greenhouse gas footprint, electricity goes from the heel to about the middle of the foot (50%). The ball of the foot (40%) is natural gas. Transportation contributes three toes worth (8%), solid waste is the fourth toe (1%), and other miscellaneous sources add up to the pinky toe (<1%). We are still in the process of quantifying contributions from land use. This could be like waiting for the other shoe to drop, as land use can emit large amounts of greenhouse gases, but in our case it may be finding we’re a size 7 instead of a size 9: careful land management could actually take up greenhouse gases from the atmosphere. We’ll have more on this soon as the data become available.