Thursday, June 5, 2014

GHG reductions - some info



Big news recently on the environmental front, the President announced that the EPA will be promulgating rules to limit the allowable amounts of greenhouse gasses that can be emitted by power plants: So, per USA Today:

"... Taking a historic step to fight climate change, the Obama administration proposed a plan Monday that aims to slash carbon dioxide emissions from existing power plants 30% by 2030 and could accelerate the nation's shift away from coal.  

The Environmental Protection Agency plan, which is President Obama's largest climate effort so far, could help the United States prod other countries like China to pledge similar emissions cuts as part of a new international treaty that's slated for negotiation next year in Paris. The controversial 645-page plan, expected to trigger legal challenges, sets different reduction targets for each state and gives them flexibility in how to achieve them. Yet it aims for a 30% national reduction of heat-trapping CO² emissions, from 2005 levels, by 2030 -- an amount that the EPA says is equal to annual emissions from powering more than half of U.S. homes....  

Thwarted by Congress' inability to pass a bill to lower carbon emissions, Obama is pushing his own approach. Last June, he asked the EPA to use its authority under the Clean Air Act to limit power plant emissions, which account for the largest share — nearly 40% — of total U.S. emissions. Coal-fired facilities could be hardest hit, because they emit more carbon than other power plants. 

The rule will not take effect for at least two more years. Obama has asked the EPA to finalize it in June 2015 and initially wanted each state to submit its plan by June 2016. The EPA proposal gives states until 2017 or, if they make joint efforts with other states, 2018..."

Predictably this has set off a major squabble in Washington and across the country... This blogger has been reading the news and trying to figure out exactly how much of a cut is being mooted. Per the news snippet above it is "a 30% reduction of emissions from existing power plants by 2030." Or is it really "a 30% national reduction by 2030"? It can hardly be both if emissions from existing power plants only account for "nearly 40%" of the national total!

Another article says: "... Obama also said the proposal will help the U.S. get closer to his goal of cutting greenhouse gas emissions 17 percent below 2005 levels by 2020, a commitment he made in 2009 at a climate change conference in Copenhagen..."


This set this blogger to wondering... a) How do they calculate the amount of "greenhouse gasses"?  b) Why is it that 2005 is chosen as the base year? And other things...

Well, according to the EPA: "...An emissions inventory that identifies and quantifies a country's primary anthropogenic sources and sinks of greenhouse gases is essential for addressing climate change. This inventory adheres to both (1) a comprehensive and detailed set of methodologies for estimating sources and sinks of anthropogenic greenhouse gases, and (2) a common and consistent mechanism that enables Parties to the United Nations Framework Convention on Climate Change (UNFCCC) to compare the relative contribution of different emission sources and greenhouse gases to climate change..." The following graph shows the various factors used to convert multiple greenhouse gasses into CO2 equivalents. In other words HFC-23 or trifluoromethane is over eleven thousand times as potent as carbon dioxide!


As to the choice of 2005 as the base year, this blogger is still in the dark. Perhaps it is because 2005 was (almost) the historical high point of U.S. GHG emissions. It certainly wouldn't be the first time that a President set an "ambitious" goal while making sure that 'progress' would be seen to be made during his terms in office, but while leaving the bulk of the effort to a successor!





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