Methane, the primary component of natural gas and among the more potent greenhouse gases, has far more of an effect on climate change than carbon dioxide. But determining the factor that should be applied to measure its relative warming affect is still being debated.
To crunch its numbers, the EPA calculated the average concentration of methane in the atmosphere over a 100-year period and determined that over that period methane is 21 times more potent than carbon dioxide. Using that equation, a ton of methane emissions is the equivalent of 21 tons of carbon dioxide.
But some scientists argue that the impact of methane gas should be calculated over a shorter time period, because methane degrades quickly, and because gas drilling releases large quantities of methane into the atmosphere all at once, likely concentrating and amplifying the effect.
Robert Howarth, an environmental biology professor at Cornell University, used research from the United Nations to calculate that if methane's potency were considered over 20 years rather than 100 years, it would be 72 times as powerful as carbon dioxide in terms of its warming potential.
Figured that way, the climate effect of methane from natural gas would quickly outpace the climate effect of carbon dioxide from burning coal. Howarth's research is incomplete and has been criticized because at first he failed to figure in methane emissions from coal mining. But he said that after correcting his error, the emissions from coal barely changed, and the data still showed that the intensity of methane could erase the advantages of using natural gas.
"Even small leakages of natural gas to the atmosphere have very large consequences," Howarth wrote in a March memorandum [2], which he says is a precursor to a more thorough study that could begin to scientifically answer these questions. "When the total emissions of greenhouse gases are considered … natural gas and coal from mountaintop removal probably have similar releases, and in fact natural gas may be worse in terms of consequences on global warming."
Howarth says his latest calculations show that the type of shale gas drilling taking place in parts of Texas, New York and Pennsylvania leads to particularly high emissions and would likely be just as dirty as coal.
Environmental groups say factual data on how much methane is emitted from gas fields—and what the warming affect of that methane is—should be locked down before major policy decisions are made to shift the nation toward more reliance on gas.
"You can't just assume away some of these sources as de minimus," said Tom Singer, a senior policy analyst for the Natural Resources Defense Council who focuses on emissions reporting in New Mexico. "You need to get a handle on them before you can make a determination."
Less Pollution Means More Profit
The EPA tracks fugitive and vented methane emissions through a program called Natural Gas STAR and then works to get drilling companies to save money by stanching their leaks and selling the gas they capture for profit. It was a discrepancy in the Gas STAR data that prompted the EPA to sharply revise the government's greenhouse gas statistics late last year.
According to Gas STAR's most recent figures, at least 1.6 percent of all the natural gas produced in the United States each year, about 475 billion cubic feet, is assumed to be leaked or vented during production. But those numbers were reported before the EPA adjusted its greenhouse gas estimates, and they are expected to rise when the new estimates are plugged into the calculation. If companies could capture even the gas leaked in Gas STAR's current estimates, it would be worth $2.1 billion a year at today's prices and would cut the nation's emissions by more than 2 percent right off the bat. Several studies show that maintaining and installing equipment to capture the emissions pays for itself within 24 months.
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12 Comments
Add CommentThe article states:
Reply | Report Abuse | Link to this"The administration and Congress are seeking not just a steady, independent supply of energy, but a fast and drastic reduction in the greenhouse gases associated with climate change."
A lofty goal, but as I understand, after 200 years of accumulation, the current atmospheric co2 levels will not dissipate any time soon, even if humanity eliminated all of its GHG emissions.
The article continues:
"To crunch its numbers, the EPA calculated the average concentration of methane in the atmosphere over a 100-year period and determined that over that period methane is 21 times more potent than carbon dioxide. Using that equation, a ton of methane emissions is the equivalent of 21 tons of carbon dioxide."
That's a nice trick. For example, no matter how much methane was released into the atmosphere during the next ten years, the current 100 year rolling average would be primarily determined by the average during the years of 1920-2010. That works for them!
Finally:
"The EPA now reports that emissions from conventional hydraulic fracturing are 35 times higher than the agency had previously estimated. It also reports that emissions from the type of hydraulic fracturing being used in the nation's bountiful new shale gas reserves, like the Marcellus, are almost 9,000 times higher than it had previously calculated, a figure that begins to correspond with Robert Howarth's research at Cornell."
And that's the good news. The bad news is that it's called 'hydraulic fracturing' because it involves pumping enormous amounts of water and minerals (to protect drill bits, etc.) into a huge area, as I understand often contaminating ground water and potentially even critical fossil aquifers used by many millions for drinking water and agricultural irrigation.
If we run out of potable water we may have to use all of our energy desalinating seawater! Potable water is also an extremely critical resource for this, the largest human population that's ever existed, even considering only the U.S.
No matter how much lipstick you put on them, coal, oil, and natural gas still remains very dirty pigs. I know we are concerned about nuclear plants' storage system becoming dirty bombs, leaks at the plant radiating whole communities, and the cost is just mind boggling, but if you do not want to consider Geothermal, which has a 1.5% foot print compared to natural gas at 80%, coal at 90%, and nuclear at an undetermined amount, then nuclear is our only choice. Even though a solar array in Arizona is producing more power than a normal nuclear plant and one river hydro plant in New York is producing enough energy for the whole community of 70,000 and it has even been make friendly to fish...and you don't want to consider electric cars being charged from geothermal, hydro, solar, or wave, then lets go with nuclear and keep our fingers crossed that we don't start glowing green and plunging America into another economic crises from the expense of building nuclear plants.
Reply | Report Abuse | Link to thisEither way, we should/must eliminate all fossil fuel burning plants and transportation.
Since natural gas is now understood to be more equivalent to coal in its "greenhouse effect", we should decide to just burn more coal for power production. It's cheaper and more plentiful. Besides, gas is more suitable for heating homes and businesses and should be reserved for this use.
Reply | Report Abuse | Link to thisThis magazine has long touted the Green point of view rather than a Scientific stance.
Reply | Report Abuse | Link to thisNow in quick succession we have the article on the detrimental effects on forests caused by growing crops for bio fuel followed by a contra report on gas. Wind & solar surely must follow. Eventually we will get to the only Scientific solution. Nuclear.
The old ingrained bias is going to die hard however otherwise why regurgitate the old discredited article from the November 2009 issue A Plan to Power 100 Percent of the Planet with Renewables.
Pathetic.
Methane has no effect on climate. Methane absorbs the same photons that are already totally absorbed by water vapor. Therefore, we cannot blame natural gas for any climate effects.
Reply | Report Abuse | Link to thisNatural gas escapes naturally everywhere. If we do not use the gas it will escape anyway.
We should monitor oxygen instead of CO2 since oxygen also absorbs infrared photons.
In my last comment, I did not supply a reference. Graphs are available at Wikipedia in the article Greenhouse Gas. The graphs show that methane absorbs photons that water vapor totally absorbs already. The graphs also show that oxygen absorbs photons, and so we should measure it. CO2 absorbs all 15-micron photons and so it cannot cause an increased greenhouse effect. This means that burning natural gas or oil or coal will not alter climate. Reduction in oxygen caused by burning fossil fuels will reduce oxygen-caused greenhouse effects and thus cause cooling to counter warming.
Reply | Report Abuse | Link to thisMethane and CO2 will still absorb infrared photons bec. there is almost unlimited supply from the sun. White light when absorbed by earth's surface infrared is radiated. Water vapor is the most abundant greenhouse gas but we don't worry about it bec. it's natural and not man-made. Maybe we should worry. 2% increase in humidity has same radiative forcing as all CO2 emitted since 1750.
Reply | Report Abuse | Link to thisEventually the structure of modern society is going to have to change. Public utilities are going to have to focus on energy storage just as much as energy generation. Fossil fuels are going to slide into decreased production, even with improved extraction methods.
Reply | Report Abuse | Link to thisI almost never agree with JamesDavis or Soccerdad but on this topic I'm in total accord with them. It is long past time to stop messing around and start a real, meaningful effort to eliminate fossil fuels entirely.
The solution to the problem is often said to be CCS. But as CCS will not be applied generally for at least 50 years, we should decarbonise natural gas now using hydrocarbon pyrolysis. This process removes the carbon from methane as coke, leaving clean hydrogen as an energy source. The inert coke can safely go into landfill. The Technology needs to be developped at an industrial scale, but it is cheap and non-polluting.
Reply | Report Abuse | Link to thisThe accident at three mile island although causing damage only to the power station cost far more lives than the Chernobyl incident.
Reply | Report Abuse | Link to thisThe Hysterical over reaction delayed the introduction of clean nuclear power in the USA for at least fourty years leading to the loss of inumerable lives due to polution from coal fired power stations and global warming.
It needs to be remembered that the biomass(corn, fodder beets, etc used to make ethanol, is perfect starch-free feed for cattle, stopping the livestock's methane production, and using the same resources twice! A fact not talked about much by the opponents of ethanol!
Reply | Report Abuse | Link to thisHow long doe it take to screen Comments? I made one regarding ethanol and it seems to have disappeared.
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