comment: This is an IPAT-S script. IPAT-S is an open-source scripting language for developing sustainability scenarios. It can be run using the free IPAT-S software, available from: http://ipat-s.kb-creative.net/ For more information, please contact the author of IPAT-S, Eric Kemp-Benedict (eric@kb-creative.net) :comment base year 2002 scenario year 2012 # US Census Bureau pop projection categories dimension Population 'Low', 'Medium', 'High' summvar Emissions{Population}, Pop{Population} ratio EmissionIntensity, GDPperCap # Emissions given by an index relative to the base year Emissions.by = 100 # US Census Bureau population projections # http://www.census.gov (Accessed 7 Dec 2002) Pop{Population = 'Low'} = 278.8, 294.1 Pop{Population = 'Medium'} = 280.3, 304.8 Pop{Population = 'High'} = 282.1, 318.9 # Bush Administration emission reduction target is # 18% decrease in intensity over next 10 years # (from Feb 2002) EmissionIntensity = incr[-18%] # This is key input: GDP per cap growth rate number IncomeGR = <2.0%> GDPperCap = growth(IncomeGR) chain Pop >> GDPperCap * EmissionIntensity -> Emissions report Emissions as "Emissions (2002 = 100)" # HTML Output print: Emissions Scenarios for the U.S.

CO2 Emissions for the U.S.: An Outlook to 2012

Introduction

In early 2002, President Bush of the United States put forward a plan for mitigating the country’s greenhouse gas emissions. The goal of the plan is to decrease the emission intensity (emissions per dollar GDP) by 18 percent over the following 10 years. Whether this will also lead to a decrease in total emissions depends on how rapidly GDP increases. Increases in GDP, in turn, depend on how fast incomes (GDP/capita) grow, and how fast the population itself grows.

Scenario Assumptions

Emission intensity is assumed to drop by 18% over the next 10 years, following the Bush Administration plan. Income per capita is assumed to grow in the scenario at ["%.1f", 100 * IncomeGR]% per year between [y.first] and [y.last], leading to an overall increase of ["%.0f", 100 * ((1 + IncomeGR)^(y.last - y.first) - 1)]% over the scenario period. For population, three scenarios are presented, corresponding to the middle, low and high population projections of the U.S. Census Bureau. In the middle projection, population increases by ["%.1f", 100 * ((Pop.last{Population = 'Medium'}/ \ Pop.first{Population = 'Medium'})^(1/(year.last - year.first)) - 1)]% per year on average, compared to a rate of ["%.1f", 100 * ((Pop.last{Population = 'Low'}/ \ Pop.first{Population = 'Low'})^(1/(year.last - year.first)) - 1)]% per year for the low projection, and ["%.1f", 100 * ((Pop.last{Population = 'High'}/ \ Pop.first{Population = 'High'})^(1/(year.last - year.first)) - 1)]% per year for the high projection.

Scenario Results

Population and income growth lead to rising GDP, offsetting the 18% decline in emission intensity over the decade. The net effect is an increase in emissions in all scenarios, with an annual rate of ["%.1f", 100 * ((Emissions.last{Population = 'Medium'}/ \ Emissions.first{Population = 'Medium'})^(1/(year.last - year.first)) - 1)]% in the medium scenario, and with rates ranging from ["%.1f", 100 * ((Emissions.last{Population = 'Low'}/ \ Emissions.first{Population = 'Low'})^(1/(year.last - year.first)) - 1)]% per year for the low projection to ["%.1f", 100 * ((Emissions.last{Population = 'High'}/ \ Emissions.first{Population = 'High'})^(1/(year.last - year.first)) - 1)]% for the high projection.

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