Green Wombat

With little fanfare, the U.S. Environmental Protection Agency this week released its inventory of greenhouse gas emissions in the United States between 1990 and 2005. As Congress considers legislation to cap green gas emissions, the inventory is an important snapshot of which industries will face the biggest challenges in reducing their contribution to global warming. The report also contains some disturbing stats on the jump in extremely potent greenhouse gas emissions from synthetic chemicals used to make computer chips and other products (more on that below.) Total greenhouse gas emissions in the U.S. rose 16.3 percent between 1990 and 2005 while the economy grew 55 percent. Carbon dioxide accounted for 84 percent of the U.S.’s greenhouse gas emissions, with 94 percent of the CO2 produced by fossil fuels. With 5 percent of the planet’s population, the U.S. in 2005 was responsible for 22 percent of carbon dioxide emitted worldwide from burning fossil fuels. Power plants contribute the most spew, responsible for 41 percent of the nation’s C02 emissions in 2005. Cars, trucks and other transportation were the second-biggest emitters, accounting for 33 percent of CO2 that year. Emissions from cement production have grown 38 percent since 1990 – an indication that there will be plenty of opportunity to develop green building technologies in a carbon constrained world. And all that stuff we buy to fill our McMansions? Much of it ends up being burned in municipal waste plants. Rampant consumerism helped fuel a 91 percent increase in carbon emissions from waste combustion between 1990 and 2005.

Off most people’s radar screens are greenhouse gas emissions from of a group of synthetic chemicals used in industrial manufacturing – hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6). Although they account for only 2.2 percent of the U.S.’s greenhouse gas emissions, the chemicals are extremely potent. SF6, for instance, has a global warming potential 23,900 times that of carbon dioxide. Since 1990, emissions from these chemicals has spiked 83 percent. "SF6 and PFCs have extremely long
atmospheric lifetimes, resulting in their essentially irreversible accumulation in the
atmosphere once emitted," the EPA report states. "Sulfur hexafluoride is the most
potent greenhouse gas the [Intergovernmental Panel on Climate Change] has
evaluated."  Ironically, the chemicals were approved as substitutes for ozone-depleting chlorofluorocarbons used in air conditioners and refrigerants and the big jump in emissions comes from those uses. The chemicals are also used by companies like Intel (INTC) and Advanced Micro Devices (AMD) to make semiconductors, and in industrial manufacturing to produce aluminum. In addition, they play a role in the transmission and distribution of electricity. The good news is that aluminum makers like Alcoa (AA) have decreased emissions from HFCs, PFCs and SF6s by 84 percent, and other industrial uses of the chemicals have declined dramatically as well. Emissions from chip making, however, rose nearly 50 percent between 1990 and 2005, though they have remained fairly flat in recent years.   

Cow power – and pig power – entrepreneurs could play a key role in reducing methane emissions from manure by capturing the gas and using it to produce electricity.

The move to industrial-scale dairies and pig farms in the U.S. over the past decade helped drive methane emissions from manure up by 34 percent between 1990 and 2005, according to the EPA. Methane’s global warming potential is 21 times that of carbon dioxide. One bright spot: More trees – in forests and urban areas – helped result in a 15 pecent increase in carbon absorption between 1990 and 2005.