Pre-Industrial Revolution, the concentration of CO2 remained around 280 parts per million by volume (ppm). In 2009, the concentration increased to about 386 pmm. Including other greenhouse gases, the total effect was 464 ppm CO2 equivalents.
Since 2001 the University of Michigan’s Center for Sustainable Systems has developed a growing set of factsheets that cover topics including energy, water, food, waste, buildings, materials, and transportation systems. Each factsheet presents important patterns of use, life cycle impacts and sustainable solutions. They are designed to inform policymakers, business professionals, students and teachers. The factsheets are peer-reviewed and updated annually.