Tag Archives: CO2 emissions

Peak Travel?

A new paper in Transport Reviews by Adam Millard-Ball and Lee Schipper asks Are We Reaching Peak Travel? Trends in Passenger Transport in Eight Industrialized Countries.

Ball and Schipper looked at data from 1970-2008 in the United States, Canada, Sweden, France, Germany, the United Kingdom, Japan and Australia.  They show that increases in passenger activity have driven energy use in transport, because growths in activity have swamped increases in efficiency.  But the relationship between travel and GDP changed during the last decade.  Previously increases in GDP lead to increases in travel, but in the last decade travel seems to have plateaued, and this halting of growth does not appear to be due to increases in gas prices.  This is shown in Figure 2 in their paper.

One of the challenges in planning for the future is anticipating inflection points in ongoing trends.  This paper could have made this point stronger if they compared predicted vehicle use against actual vehicle use, but that was not their main point.

They write:

As with total travel activity, the recent decline in car and light truck use is difficult to attribute solely to higher fuel prices, as it is far in excess of what recent estimates of fuel price elasticities would suggest. For example, Hughes et al. (2006) estimate the short-run fuel price elasticity in the U.S. to range from -0.034 to -0.077, which corresponds to a reduction in fuel consumption by just over 1% in response to the 15% increase in gasoline prices between 2007 and 2008. In reality, per capita energy use for light-duty vehicles fell by 4.3% over this period.

…[in these countries transportation sector] the major factor behind increasing energy use and CO2 emissions since the 1970s – activity – has ceased its rise, at least for the time being. Should this plateau continue, it is possible that accelerated decline in the energy intensity of car travel, some shifts back to rail and bus modes, and at least somewhat less carbon per unit of energy might leave absolute levels of emissions in 2020 or 2030 lower than today.

via Miller-Mcune

Building Transformation: CO2 emissions and change

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.