Tag Archives: slow variables

Cities, Reorganization

Building Transformation: CO2 emissions and change

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According to the US government’s new report North American Carbon Budget and Implications for the Global Carbon Cycle buildings in North America contribute 37% of total CO2 emissions, while US buildings correspond to 10% of all global emissions (for more see Andrew Revkin’s weblog). This fact means that improving the environmental efficiency (in terms of carbon intensity) in the US has a big potential to reduce global emissions. The summary of Chapter 9 of the report writes:

The buildings sector of North America was responsible for annual carbon dioxide emissions of 671 million tons of carbon in 2003, which is 37% of total North American carbon dioxide emissions and 10% of global emissions. United States buildings alone are responsible for more carbon dioxide emissions than total carbon dioxide emissions of any other country in the world, except China.

USA CO2 emission sources

Carbon dioxide emissions from energy use in buildings in the United States and Canada increased by 30% from 1990 to 2003, an annual growth rate of 2.1% per year. Carbon dioxide emissions from buildings have grown with energy consumption, which in turn is increasing with population and income. Rising incomes have led to larger residential buildings and increased household appliance ownership.

These trends are likely to continue in the future, with increased energy efficiency of building materials and equipment and slowing population growth, especially in Mexico, only partially offsetting the general growth in population and income.

Options for reducing the carbon dioxide emissions of new and existing buildings include increasing the efficiency of equipment and implementing insulation and passive design measures to provide thermal comfort and lighting with reduced energy. Current best practices can reduce emissions from buildings by at least 60% for offices and 70% for homes. Technology options could be supported by a portfolio of policy options that take advantage of cooperative activities, avoid unduly burdening certain sectors, and are cost effective.

On WorldChanging Patrick Rollens writes the scale of expected construction in the USA. While construction contributes to CO2 emmissions, new infrastructure that is CO2 neutral or negative can substantially reduce emissions. Rollens reports on estmates that suggest that in about half of all buildings existing in 25 yearswill be new. This offers a great opportunity for both green building, but also building more green urban areas. In Remaking the Built Environment by 2030 he writes:

By 2030, about half of the buildings in America will have been built after 2000. This statistic, courtesy of Professor Arthur C. Nelson’s report for the Brookings Institution, means that over the next 25 years, we will be responsible for re-creating half the volume of our built environment.

The report has been around since 2004, but Nelson re-examined his own findings last year to see if the housing market’s downturn impacted the forecast. The sheer volume was essentially unchanged, and the mainstreaming of the green movement that’s occurred in the last two years presents a colossal challenge–and a magnificent opportunity–for the burgeoning sustainable building industry.

Nelson’s report states that the country will need about 427 billion square feet of space (up from 2000’s total volume of just 300 billion). Moreover, only a small portion of this space can be acquired by renovating existing real estate. We’re already well on our way; the U.S. Green Building Council estimates that we’re developing about twice times as fast as the associated population growth. Every new building built between now and 2030 should be seen as an opportunity to push the envelope and transform our structured world.

Cities, Greenlash, Vulnerability

How slow change increased California’s fire risk

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California firesThe Christian Science Monitor article California’s age of megafires describes how California’s fire risk has been increased by slow changes in fire suppression (but probably not in California), climate change, longer fire season, and house construction in the wildland-urban interface:

Megafires, also called “siege fires,” are the increasingly frequent blazes that burn 500,000 acres or more – 10 times the size of the average forest fire of 20 years ago. One of the current wildfires is the sixth biggest in California ever, in terms of acreage burned, according to state figures and news reports.The trend to more superhot fires, experts say, has been driven by a century-long policy of the US Forest Service to stop wildfires as quickly as possible. The unintentional consequence was to halt the natural eradication of underbrush, now the primary fuel for megafires.

Three other factors contribute to the trend, they add. First is climate change marked by a 1-degree F. rise in average yearly temperature across the West. Second is a fire season that on average is 78 days longer than in the late 1980s. Third is increased building of homes and other structures in wooded areas.

“We are increasingly building our homes … in fire-prone ecosystems,” says Dominik Kulakowski, adjunct professor of biology at Clark University Graduate School of Geography in Worcester, Mass. Doing that “in many of the forests of the Western US … is like building homes on the side of an active volcano.”

In California, where population growth has averaged more than 600,000 a year for at least a decade, housing has pushed into such areas.

“What once was open space is now residential homes providing fuel to make fires burn with greater intensity,” says Terry McHale of the California Department of Forestry firefighters union. “With so much dryness, so many communities to catch fire, so many fronts to fight, it becomes an almost incredible job.”