Reducing Carbon Emissions as Consumers

In this episode of Michigan Minds, Gregory Keoleian, PhD, talks about ways consumers can reduce their carbon footprint in three areas of their daily lives: home, mobility and diet. Keoleian co-founded and serves as director of the U-M Center for Sustainable Systems. He is also a Peter M. Wege Endowed Professor of Sustainable Systems at the U-M School for the Environment and Sustainability, and a professor in the Civil and Environmental Engineering department at the U-M College of Engineering. His research focuses on the development and application of life cycle models and metrics to enhance the sustainability of products and technology. 

“Our mission [at the Center for Sustainable Systems] is to develop and apply systems-based models and metrics to enhance sustainability of systems. And our vision is focusing on accelerating the sustainability transformation of these systems. And that includes mobility systems, shelter, water, food systems and energy systems.”

“The Intergovernmental Panel on Climate Change (IPCC) has determined that we need to reduce our carbon emissions in half by 2030 and we need to hit carbon neutrality by 2050. And their latest report has indicated that we’re really falling short in terms of the trajectory to get to those targets,” Keoleian says.

Consumers can play an important role in the efforts to reduce carbon emissions, simply by making small changes in their daily lives. Keoleian breaks down the areas in which most greenhouse gasses are emitted in the U.S., noting that transportation and construction account for the largest amount of emissions, with food production responsible for about one-fifth. Automobiles account for two-thirds of the overall emissions in the transportation sector, and residential homes create half of the emissions in the building sector. 

In reference to the three areas that emit the most greenhouse gases, Keoleian discusses ways consumers can reduce energy consumption and carbon-related emissions at home. Since heating and cooling accounts for over 40% of energy use in the U.S., Keoleian says that consumers should focus on insulating the exterior of their houses, including the walls and roof. He says that the  EPA estimates homeowners can save an average of 15% on heating and cooling costs by air-sealing their homes and adding insulation in attics, floors over crawl spaces and basements.

2021 U.S. Residential Energy Consumption by End Use

Keoleian also discusses the importance of transitioning heating equipment from natural gas to clean electricity.

“And then I would turn to heating equipment. The most efficient is a geothermal heat pump that moves heat from the ground into your home very efficiently. A less expensive option is an air source heat pump. In Michigan, I would recommend you install a cold climate certified air source heat pump.”

Upgrading appliances can also help consumers save on both energy costs and emissions, Keoleian says. CSS research conducted over the last 20 years on optimal replacement timing for appliances found that refrigerators older than 15 years should be replaced, based on energy use, greenhouse gas emissions and operating costs. 

Other recommendations include washing clothes with cold water, using electric stoves and dryers instead of gas, and switching to LED lightbulbs, which can save 90% in terms of operating energy. 

Keoleian says that scraping off food rather than rinsing dishes before loading the dishwasher is the most efficient way to wash dishes. He also recommends turning off  the dishwasher’s heated-dry function.

Transitioning to electric vehicles, “right-sizing” and “trip-chaining” are three things  consumers can do to reduce carbon emissions.

“Right-sizing is where you schedule and match the most efficient vehicle in your household with a specific trip purpose.”  says Keoleian, noting that, for example, a household might choose to use a sedan for dropping children off at school rather than a larger vehicle like an SUV. Research from CSS has shown that households can save 20% on energy and fuel costs just by better allocating vehicles. He also notes that trip-chaining or bundling is an effective way to reduce emissions. Picking up groceries on the way home from work instead of making a separate trip is an example of trip chaining, Keoleian says. 

“In addition…to reduce your mobility footprint, you should consider taking advantage of public transportation, which in many cases is underutilized, but can be much more efficient.” 

The third sector is food waste. An estimated 30 to 40 per cent of the food available for human consumption in the U.S. is either lost or wasted, he says. 

“We really need to consider better shopping practices, and better management of food at home to avoid spoilage. Each pound of food waste that we could avoid will have direct benefits in reducing carbon emissions across the food supply chain, from production to processing to retail. All those could be reduced just by doing a better job of managing our diets, or what we’re going to cook and when we shop.”

Keoleian says diet shifts from animal to plant-based can also help reduce carbon emissions. Plant-based proteins such as legumes (dried peas, lentils, beans, etc.), soy products (e.g., tofu) and nuts and seeds will dramatically reduce emissions. These shifts can also have added benefits such as reduced grocery bills and lower risk for diet-related chronic conditions such as cardiovascular disease, type 2 diabetes and obesity. 

“What’s important here is that each of us can play a role and make a difference. Whether it’s simple actions like turning off lights or replacing incandescent bulbs with LEDs, or reducing your food waste, line drying your clothes or bundling trips or making bigger investments, significant investments, like insulating your attic or installing heat pumps or buying an electric car. All of these actions are beneficial.”

This series is ongoing throughout April 2023. Subscribe to Michigan Minds for more episodes.