Most of the methane that is released is expected to be broken down by
bacteria as it rises up through the ocean sediments and through the water column before it
reaches the surface of the ocean. The decomposition of methane occurs at the result of
two biological processes:
• anaerobic oxidation of methane by bacteria in the sediments of the ocean floor
• aerobic oxidation of methane by bacteria in the water column. "
In particular aerobic decomposition involves the same chemical reaction as burning methane, i.e.
CH4 + 2 O2 → CO2 + 2 H2O
The result is not good ;-
"Aerobic Oxidation: When methane is broken down aerobically by bacteria in the water
column they use oxygen to facilitate the process, producing carbon dioxide which
dissolves in the seawater. This process negatively impacts marine environment in two
ways:
1. Carbon dioxide promotes ocean acidification.
2. Aerobic oxidation of methane utilizes oxygen within the water column which could
result in the expansion of oxygen depleted zones across the ocean. Oxygen
depletion can result in mass mortalities of marine organisms – oxygen poor zones
are unable to support animals that need oxygen for survival and are thus typically
devoid of marine life.
Even more alarming is that if ocean acidification is left unchecked it could potentially
initiate a Great Mass Extinction Event, as there is increasing evidence pointing to high
atmospheric carbon dioxide concentrations and rapidly acidifying oceans having triggered
four of the previous five Great Mass Extinctions.
Based on geological records it can be assumed that hydrates have broken down on a
large scale numerous times in the Earth’s history, leading to extreme global warming and
massive extinctions of organisms on the sea floor and beyond.
The evidence is overwhelming that natural gas has no net climate benefit in any timescale that matters to humanity.
In fact, a shocking new study concludes that just the methane emissions escaping from New Mexico’s gas and oil industry are “equivalent to the climate impact of approximately 12 coal-fired power plants.” If the goal is to avoid catastrophic levels of warming, a recent report by U.K. climate researchers finds “categorically no role” to play for new natural gas production.
Sadly, the International Energy Agency (IEA) has just published a “Commentary” on “the environmental case for natural gas,” that ignores or downplays key reasons that greater use of natural gas is bad for the climate.
In the real world, natural gas is not a “bridge” fuel to a carbon-free economy for two key reasons. First, natural gas is mostly methane (CH4), a super-potent greenhouse gas, which traps 86 times as much heat as CO2 over a 20-year period.
That’s why many, many studies find that even a very small leakage rate of methane from the natural gas supply chain (production to delivery to combustion) can have a large climate impact — enough to gut the entire benefit of switching from coal-fired power to gas for a long, long time.
Second, other studies find — surprise, surprise — natural gas plants don’t replace only high-carbon coal plants. They commonly replace very low carbon power sources like solar, wind, nuclear, and even energy efficiency, which is often overlooked as a major alternative to fossil fuels. That means even a very low leakage rate wipes out the climate benefit of fracking.
Indeed, researchers confirmed in 2014 that — even if methane leakage were zero percent — “increased natural gas use for electricity will not substantially reduce US GHG [greenhouse gas] emissions, and by delaying deployment of renewable energy technologies, may actually exacerbate the climate change problem in the long term.” Exactly. In fact, a 2016 study found that natural gas and renewables are competing directly with each other to replace coal plants in this country.
So it’s no surprise that the new analysis by researchers at the Tyndall Centre for Climate Change Research finds that “there is categorically no role for bringing additional fossil fuel reserves, including gas, into production.” The scientists explain that we have simply dawdled too long, and if we are to have any plausible chance of staying below 2°C, carbon dioxide emissions need to be driven to near zero levels by mid-century, particularly for the industrialized countries who have historically generated the most cumulative carbon pollution.
The IEA analysis, however, essentially ignores the possibility that any significant amount of new natural production will go toward replacing carbon-free sources, even though it’s already clear in this country that natural gas competes most directly with renewables. It’s also clear that some of the power from the money-losing nuclear power plants that have been shut down recently was replaced by natural gas.
Equally surprising, the IEA analysis uses an untenable leakage rate for methane of 1.7 percent. In a webinar detailing its findings, the IEA explains that it used the official EPA estimates of methane leakage as a starting point — supposedly because the U.S. has the best data — and then factored in industry estimates. But the EPA estimate (which was 1.2 percent and is now 1.5 percent) has been widely criticized.
Back in 2014, a comprehensive Stanford study published in Science concluded “A review of more than 200 earlier studies confirms that U.S. emissions of methane are considerably higher than official estimates. Leaks from the nation’s natural gas system are an important part of the problem.”
The Stanford analysis found a leakage rate of 5.4 percent (plus or minus 1.8 percent) — enough to give natural gas no net climate benefit for decades, even if it only replaced coal (which it doesn’t).
These conclusions have been confirmed by data and observations from a later 2014 study as well as 2016 satellite data and surface observations analyzed by Harvard researchers. Certainly there is not complete agreement between every study, but there is little doubt that U.S. methane leakage rates are considerably higher than the official numbers from the EPA, which themselves are mostly based on industry-provided estimates, not actual measurements.
So it’s indefensible to use EPA numbers and industrial estimates to estimate methane leakage, as the IEA does.
Alfred Tennyson wrote:We are not now that strength which in old days
Moved earth and heaven, that which we are, we are;
One equal temper of heroic hearts,
Made weak by time and fate, but strong in will
To strive, to seek, to find, and not to yield.
ROCKMAN wrote:Ghung - I don't see where "learning" has anything to do with the problem. Consumers are not "forced" to burn fossil fuels. They not only chose to burn fossil fuels but demand the right to do so. And they'll remove anyone from the conversation that tries to take that "right" away without replacing it with an ACCEPTABLE alternative.
dohboi wrote:Yes, at very great expense we are starting to reinstall a tiny fraction of what once was a vast and sprawling network of urban and interurban trams and passenger trains. Would have been much much cheaper not to rip them up in the first place. IIRC, some countries in Latin America are still making good use of some of those trolley cars.
Alfred Tennyson wrote:We are not now that strength which in old days
Moved earth and heaven, that which we are, we are;
One equal temper of heroic hearts,
Made weak by time and fate, but strong in will
To strive, to seek, to find, and not to yield.
Alfred Tennyson wrote:We are not now that strength which in old days
Moved earth and heaven, that which we are, we are;
One equal temper of heroic hearts,
Made weak by time and fate, but strong in will
To strive, to seek, to find, and not to yield.
The ocean anoxia CH4 cannon is going to go off this century. Due to the area coverage of the anoxic zones and the volume of biogenic carbon cycling through them, we are looking at massive amounts of CH4 pumped from the oceans. All the attention is on the crysophere CH4. The non-cryosphere CH4 will make sure that most of the cryosphere CH4 is released.
People have no instincts about ocean biochemistry. It is a very sensitive system and the assumption that the current chemical regime will stay intact until 2100 or later is simply wrong. Now that we have direct evidence of a major error in the estimate of past ocean temperatures (on the high side), the ocean anoxia regime is guaranteed and the trends seen in observations are not to be dismissed.
The trend that will lead to a tipping point by around 2035
Methane-producing microbes may be responsible for the largest mass extinction in Earth's history. Fossil remains show that sometime around 252 million years ago, about 90 percent of all species on Earth were suddenly wiped out -- by far the largest of this planet's five known mass extinctions. It turns out that Methanosarcina had acquired a particularly fast means of making methane, and the team's detailed mapping of the organism's history now shows that this transfer happened at about the time of the end-Permian extinction.
The perpetrators, this new work suggests, were not asteroids, volcanoes, or raging coal fires, all of which have been implicated previously. Rather, they were a form of microbes -- specifically, methane-producing archaea called Methanosarcina -- that suddenly bloomed explosively in the oceans, spewing prodigious amounts of methane into the atmosphere and dramatically changing the climate and the chemistry of the oceans
Return to Environment, Weather & Climate
Users browsing this forum: No registered users and 19 guests