Household Consumption Significant Driver of Climate, Other Environmental Impacts

Environmental Footprint: The world’s workshop  - China - surpassed the United States as the largest emitter of greenhouse gases on Earth in 2007. But if you consider that nearly all of the products that China produces, from iPhones to tee-shirts, are exported to the rest of the world, the picture looks very different.

“If you look at China’s per capita consumption-based (environmental) footprint, it is small,” says Diana Ivanova, a PhD candidate at Norwegian University of Science and Technology’s Industrial Ecology Programme. “They produce a lot of products but they export them. It’s different if you put the responsibility for those impacts on the consumer, as opposed to the producer.”

Household consumption biggest threat to planet.

That’s exactly what Ivanova and her colleagues did when they looked at the environmental impact from a consumer perspective in 43 different countries and 5 rest-of-the-world regions. Their analysis, recently published in the Journal of Industrial Ecology, showed that consumers are responsible for more than 60 per cent of the globe’s greenhouse gas emissions, and up to 80 per cent of the world’s water use.

“We all like to put the blame on someone else, the government, or businesses,” Ivanova says. “But between 60-80 per cent of the impacts on the planet come from household consumption. If we change our consumption habits, this would have a drastic effect on our environmental footprint as well.”

The analysis allowed Ivanova and her colleagues to see that consumers are directly responsible for 20 per cent of all carbon impacts, which result from when people drive their cars and heat their homes.
But even more surprising is that four-fifths of the impacts that can be attributed to consumers are not direct impacts, like the fuel we burn when we drive our cars, but are what are called secondary impacts, or the environmental effects from actually producing the goods and products that we buy.

A good example of this, Ivanova says, is water use.

Cows, not showers.

When you think about cutting your individual water use, you might think about using your dishwasher very efficiently, or taking shorter showers.

Those aren’t bad ideas on their own, but if you look deeper, like the NTNU researchers did, you’ll find that much of the water use on the planet is gulped up by producing the things that you buy.

 Consider beef. Producing beef requires lots of water because cows eat grains that need water to grow. But because cows are relatively inefficient in converting grains into the meat that we eat, it takes on average about 15,415 litres of water to produce one kilo of beef.

Dairy products require similarly large amounts of water to produce.

When a group of Dutch researchers looked at the difference in producing a litre of soy milk with soybeans grown in Belgium compared to producing a litre of cow’s milk, they found it took 297 liters of water to make the soy milk (with 62 per cent of that from actually growing the soybeans) versus a global average of 1050 liters of water to produce a liter of cow’s milk.

Processed foods, like that frozen pizza you bought for dinner last night, are also disproportionately high in water consumption, Ivanova said. Making processed foods requires energy, materials and water to grow the raw materials, ship them to the processor, produce the processed food items and then package the final product.

This is particularly bad news when it comes to chocolate, which is one of the most water-intensive products we can buy. It takes a shocking 17,000 liters to produce a kilo of chocolate.

Richer countries, larger impacts

The researchers also looked at environmental impacts on a per-capita, country-by-country basis.

Renewable energy for home use key factor.

While the information is sometimes surprising—Luxembourg has a per capita carbon footprint that is nearly the same as the United States—it mostly follows a predictable pattern. The richer a country is, the more its inhabitants consume. The more an individual consumes, the bigger that person’s impact on the planet.

But the differences between individual countries are extremely high, Ivanova said.

“The countries with the highest consumption have about a 5.5 times higher environmental impact as the world average,” she said.

The United States is the overall worst performer when it comes to per capita greenhouse gas emissions, with a per capita carbon footprint of 18.6 tonnes CO₂ equivalent, the unit used by researchers to express the sum of the impacts of different greenhouse gases, such as carbon dioxide, methane, nitrous oxide and sulphur hexafluoride.

The US was followed closely by Luxembourg, with 18.5 tons CO₂ equivalent, and Australia, with 17.7 tons CO₂ equivalent. For comparison, China’s per capita carbon footprint was just 1.8 tons CO₂ equivalent. Norway, at 10.3 tons CO₂ equivalent per capita, was three times the global average of 3.4 tons CO₂ equivalent per capita.

The results for individual countries also reflect the effects of the electricity mix, or the fuel source that countries rely on for electric power. The prevalence of nuclear or hydroelectric power in countries such as Sweden, France, Japan and Norway means that these countries have lower carbon footprints than countries with similar incomes but with more fossil fuels in their energy mix.

 For this reason, Ivanova says, a significant portion of household impacts from Sweden and France come from imports (65 and 51 per cent respectively), because the products that are imported are mostly produced with fossil fuels.

An enormous database allows comparisons.

The researchers relied on an extremely large and detailed database that NTNU developed in partnership with colleagues from the Netherlands, Austria, Germany, the Czech Republic and Denmark called EXIOBASE.

The database describes the world economy for 43 countries, five rest-of-the-world regions and 200 product sectors, which allows researchers to ask questions about how different products or countries affect the environment.

Environmental impact for countries based on household consumption.

They were also able to ask how an average consumer in each of the countries or regions affects the environment as measured by greenhouse gas emissions (tons CO₂ equivalent), water use (in cubic meters), land use (in 1000 square meters) and material use (in tons).

The 43 countries represent 89 per cent of the global gross domestic product and between 80-90 per cent of the trade flow in Europe, as measured by value.

No surprises: take the bus, eat vegetarian or vegan

The advantage of identifying the effects of individual consumer choices on the different environmental measures is that it pinpoints where consumers in different countries can cut back on their impacts.

“Households have a relatively large degree of control over their consumption, but they often lack accurate and actionable information on how to improve their own environmental performance,” the researchers wrote in the journal article reporting their results.

Eventually, the goal is to be able to use this information to guide policy, Ivanova said. The effort is a part of the GLAMURS project, an EU-funded effort designed to promote greener lifestyles and environmentally responsible consumption in Europe.

In the meantime, two easy ways to cut your environmental impact are to stop eating meat, and cut back on your purchases, she said.

Currently, EU consumers spend 13% of their total household budget on manufactured products. If the average EU consumer switches away from spending money on these manufactured products to paying for services instead, this would cut close to 12 per cent of the EU’s current household carbon footprint, Ivanova said.

 “Any activity where we have a choice of buying a product or using a service, the service will have much less impact,” she said.

Source: Gemini

 

Big Environmental Footprints

21 percent of households account for almost 50 percent of greenhouse gas emissions. 

Energy conservation in a small number of households could go a long way to reducing greenhouse gas emissions, scientists are reporting. Their study, which measured differences in energy demands at the household level, appears in the ACS journal Environmental Science & Technology. 

McMansion (Photo credit: opacity)

Dominik Saner and colleagues point out that the energy people use to power their homes and to satisfy their mobility needs accounts for more than 70 percent of emissions of carbon dioxide, the main greenhouse gas involved in global climate change. To cope with that problem, policymakers and environmentalists have focused largely on the supply side, for instance, electric power plants, heating systems and cars that release carbon dioxide into the atmosphere. Saner and his team decided to take a close look at the other end of the equation - how energy consumption for housing and land-based mobility at the household level impacts greenhouse gas emissions. 

Their study of more than 3,000 households in a Swiss town found that only 21 percent of the households accounted for almost 50 percent of greenhouse gas emissions. The biggest factors contributing to a few families having a disproportionately large environmental footprint were large living spaces (which use energy for heating, lighting and cooling) and long commutes in private vehicles. "If their emissions could be halved, the total emissions of the community would be reduced by 25 percent," the scientists concluded.

The authors acknowledge funding from the Competence Center for Energy & Mobility and Swisselectric Research. Original article: ACS Publications.

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Energy-Efficient Manufactured Homes 

Like site-built homes, new manufactured homes (formerly known as mobile homes) can be designed for energy efficiency and renewable energy. You can also remodel or retrofit older manufactured homes to improve energy efficiency and/or add renewable energy equipment. Manufactured homes are built in a factory on a permanent chassis, then transported to a building site and installed.

Manufactured Home Energy-Efficient Retrofit Measures

There are many differences between manufactured (mobile) homes built before the U.S. Department of Housing and Urban Development (HUD) Code took effect in 1976 and those built afterward. If you have a pre-1976 manufactured (mobile) home, you can make the following energy efficiency improvements to reduce heat loss:

• Install energy-efficient windows and doors
• Add insulation to the belly
• Make general repairs (caulking, ducts, etc.)
• Add insulation to your walls
• Install insulated skirting
• Install a belly wrap
• Add insulation to your roof or install a roof cap.

Experiments conducted on pre-1976 manufactured homes by the National Renewable Energy Laboratory (NREL) from 1988 to 1991 found that these retrofit measures resulted in a 31% reduction in heating fuel usage.

Exterior of a manufactured home (Image: Wikipedia)

There are three common methods used to add roof insulation to the existing cavity: drilling and tube blowing from the inside, drilling and tube blowing from the top, and rolling back the roof and blowing into the now open cavity. Instead of filling the existing cavity, some installers prefer to use roof caps for insulating.

Although the insulating performance of roof caps is inferior to blown-in insulation, they come in kits that include insulation boards (usually of dense fiberglass) with a synthetic rubber or metal covering. Roof caps can insulate the roof to R-19 without disturbing the existing roof, and if all leaks in the old roof covering are sealed, the old roof acts as a vapor retarder, eliminating moisture problems and the need for ventilation. Be aware that rolling back the roof to add insulation can lead to realignment problems and leaks, necessitating mechanical ventilation to alleviate moisture condensation problems in the roof cavity.

Blowing loose-fill insulation into an existing manufactured home is difficult because of the narrowness of the wall and roof cavities. Pre-1976 home walls often have only 2-inch by 2-inch studs (5.08 cm × 5.08 cm) (new manufactured houses are required to have at least 2-inch by 4-inch [5.08 cm × 10.16 cm] studs), and roof trusses complicate the process of adding more roof insulation.

Blowing insulation into wall or ceiling cavities and/or installing roof caps is a job for a trained professional with proper equipment. Neither activity should be attempted by even the most capable do-it-yourselfer, as permanent structural damage and/or personal injury could easily result. A good source for a recommendation of a capable contractor-installer would probably be the Weatherization Department of your local Community Action Agency.

To further improve your manufactured home's energy efficiency, consider:

• Caulking and weatherstripping windows and doors, especially if you can't replace them with more energy-efficient ones
• Air sealing any openings around plumbing fixtures and ducts
• Using energy-efficient lighting and appliances. 

You can use renewable energy to provide electricity, heating, and cooling for your manufactured home. Renewable energy systems not only lower energy costs, but also reduce pollution from fossil fuels.

You might consider:

• Installing a geothermal heat pump (GHP), which can provide space heating and cooling. GHPs are most cost-effective to install at the same time as the manufactured home. The systems can’t be moved, so GHPs only work for permanently sited manufactured homes.
• Using passive solar design by adding a sunspace, orienting the home to maximize solar exposure, landscaping for energy efficiency, and using shading devices.
• Investigating solar water heating. Although the lightweight construction of some manufactured homes limits roof support for heavy solar collectors, you can use lightweight roof-mounted air collectors for water heating or install the heavier liquid-type solar collectors on the ground. These systems are best suited for manufactured homes that are seldom moved.
• Installing solar electric or photovoltaic (PV) systems, which are light enough to install on the roof of a manufactured home.
• Installing a small wind electric system to generate electricity if your manufactured home is or will be located in a rural area on at least one acre of land.
• Installing a microhydropower system to generate electricity if your manufactured home is or will be located where you have access to flowing water. Although you can move a microhydropower system, you can't take the hydropower resource with you, which makes these systems best suited for permanently sited manufactured homes.

Manufactured Home HUD Code Requirements

Manufactured homes are subject to the Manufactured Home Construction and Safety Standards or “HUD Code” rather then local building codes, and display a red certification label on the exterior of each transportable section. The HUD code is a set of manufactured home industry standards published and maintained by HUD that establishes standards for design and construction, strength and durability, fire resistance, energy efficiency, transportability, and quality control. It also sets performance standards for the heating and air conditioning, plumbing, thermal, and electrical systems.

For more information, visit the Manufactured Housing Institute and the HUD Homes and Communities FAQ section. Original article via the Department of Energy.

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