 |
|
| Science Forum Index » Environment Forum » Greenhoax Bait And Switch... |
|
Page 1 of 1 |
|
| Author |
Message |
| bo n o... |
 Posted: Fri Nov 06, 2009 10:29 pm |
|
|
|
Guest
|
30 Oct 2009
In the face of ever mounting evidence that CO2 is incapable of causing the
level of global devastation prophesied by climate change catastrophists a
new villain is being sought.
The leading candidate is nitrous oxide (N2O), better known as laughing gas.
A report in Science claims that N2O emissions are currently the single most
important cause of ozone depletion and are expected to remain so throughout
the 21st century.
The IPCC rates N2O as 310 times as potent a greenhouse gas as CO2 on a 100
year time scale.
Is this a greenhouse gas bait and switch, or are the global warming
alarmists trying to up the ante?
Nitrous oxide is a colorless non-flammable gas with diverse uses. It is used
as an oxidizing agent to boost power output from internal combustion engines
and as a propellant for canned whipped cream.
Historically, it was used as an anesthetic in surgery and dentistry.
Inhaling the gas can cause euphoric effects, which led to it being named
"laughing gas." Public exhibitions and private "happy gas" parties were all
the rage during the mid-19th century. Recreational use continues to this
day, but for the environment N2O may be no laughing matter.
A. R. Ravishankara, John S. Daniel, Robert W. Portmann, all scientists at
the US National Oceanic and Atmospheric Administration Earth System Research
Laboratory, claim that limiting future N2O emissions would enhance the
recovery of the ozone layer from its depleted state and would also reduce
the anthropogenic global warming.
They call reigning in the currently unregulated gas a "win-win for both
ozone and climate." This is because, while N2O on its own is a potent GHG,
it also damages the ozone layer which protects Earth's surface from UV
radiation and provides a cooling effect for the atmosphere.
I have previously commented on the Global Warming Potential of various
greenhouse gases but not addressed nitrous oxide specifically. N2O was one
of the GHGs that the IPCC claimed to understand in their last full report
(AR4).
Also included in the general category of greenhouse gases was ozone (O3),
though the confidence level was only rated as "medium" for its contribution.
As can be seen from the chart below, ozone behaves differently in the lower
atmosphere (troposphere) and upper atmosphere (stratosphere). It is the
stratospheric ozone layer that N2O damages, reducing the cooling effect of
that layer.
As you may recall, depletion of the stratospheric ozone layer by human-made
chemicals, referred to as ozone-depleting substances (ODSs), was one of the
major environmental issues of the 20th century.
As a result of the Vienna Convention for the Protection of the Ozone Layer
most of the world's nations signed the Montreal Protocol on Substances That
Deplete the Ozone Layer (MP). The MP has been highly successful in reducing
the emissions and concentrations of chlorine- and bromine-containing
halocarbons limiting ozone depletion and helping recovery of the ozone
layer. These substances can be tens of thousands of times more potent GHGs
as CO2 and were the historically dominant ODSs. Since these man-made
substances have been successfully regulated scientists have turned their
attention to N2O as the next most potent threat to Earth's ozone layer.
Nitric oxide and nitrogen dioxide (NO and NO2), generically referred to as
nitrogen oxides (NOx), are known to catalytically destroy stratospheric
ozone. The primary source of stratospheric NOx are surface N2O emissions,
hence the new interest in nitrous oxide emissions.
Nitrous oxide shares many similarities with the now banned
chlorofluorocarbons (CFCs). N2O, like CFCs, is stable when emitted at ground
level, but breaks down when it reaches the stratosphere to form nitrogen
oxides, which in turn trigger ozone-destroying reactions. Both substances
have human emissions sources but, unlike CFCs, N2O also has natural sources.
Nitrous oxide is emitted from soil fertilization, livestock manure, sewage
treatment, combustion and certain other industrial processes. In nature,
bacteria in soil and the oceans break down nitrogen-containing compounds,
releasing N2O. About one-third of global nitrous oxide emissions are
attributed to human activities. Ravishankara et al. report that N2O is now
ozone enemy number 1:
Even though N2O's ODP is only 0.017, roughly one-sixtieth of CFC-11s, the
large anthropogenic emissions of N2O more than make up for its small ODP,
making anthropogenic N2O emissions the single most important of the
anthropogenic ODS emissions today. For example, the global anthropogenic
emission of N2O now (produced mainly as a byproduct of fertilization, fossil
fuel combustion and industrial processes, biomass and biofuel burning, and a
few other processes) is roughly 10 million metric tons per year compared
with slightly more than a million metric tons from all CFCs at the peak of
their emissions.
Here ODP stands for ozone depletion potential, which compares the amount of
stratospheric ozone destroyed by the release of a unit mass of a chemical at
Earth's surface to the amount destroyed by the release of a unit mass of
chlorofluorocarbon 11, CFC-11 (CFCl3). The researchers conclude that, if N2O
emissions continue unabated, their impact could be 30% higher than the CFC
peak in 1987. Ecologists and environmental activists count the rescue of the
ozone layer as a major triumph, does this mean that the celebration was
premature? Are we certain that the ozone layer is once again threatened by
human emissions? Here is what the study says:
It should be noted that the largest uncertainty in ODP-weighted emission
comparisons comes from the uncertainties in the emission estimates of N2O,
rather than in the calculated ODP. The magnitudes of the sectoral emissions
of N2O, mostly from agricultural practices and industrial sources, are
highly uncertain, but the total human-caused emissions are constrained by
observed increases in N2O concentrations and N2O's lifetime.
As with carbon, all the intricacies of the nitrogen cycle are not understood
by modern science. In particular the mechanisms that convert free nitrogen
gas, N2, into biologically useful compounds. "Current global ocean nitrogen
budgets do not balance, which suggests that existing models miss or
underestimate some contributions to oceanic nitrogen fixation," reports
Robinson W. Fulweiler in a perspecive article (see "Fantastic Fixers ") from
the October 16, 2009, issue of Science. Moreover, recent studies have found
higher rates of nitrogen fixation in coastal sediments and more abundant
nitrogen-fixing organisms in the open ocean than previously suspected.
In that same issue of Science Anne E. Dekas et al. describe a community of
archaea and bacteria in deep-sea sediments that can fix nitrogen. Their
report, entitled "Deep-Sea Archaea Fix and Share Nitrogen in
Methane-Consuming Microbial Consortia," reveals direct evidence of a
previously unknown environment for nitrogen fixation that can deliver
biologically usable nitrogen to deep-sea sediments. This exciting study
provides a link between the carbon, nitrogen, and sulfur cycles.
Dekas et al. used the Alvin submarine to sample sediments from a seep off
the coast of California. Credit : Victoria Orphan, California Institute of
Technology
According to the study: "Using single-cell-resolution nanometer secondary
ion mass spectrometry images of 15N incorporation, we showed that deep-sea
anaerobic methane-oxidizing archaea fix N2, as well as structurally similar
CN-, and share the products with sulfate-reducing bacterial symbionts. These
archaeal/bacterial consortia are already recognized as the major sink of
methane in benthic ecosystems, and we now identify them as a source of
bioavailable nitrogen as well."
Many mysteries still remain, such as why N2 fixation in anoxic marine
sediments, which often contain ammonia compounds, should occur at all. These
findings have important implications for Earth's environment and once again
highlight how much mankind doesn't understand about nature. "The current
discrepancy in the oceanic fixed N budget underscores the possibility of new
sources of fixed N in nontraditional and potentially unexpected habitats,"
the study concludes. "N2 fixation in ANME-2, combined with the diversity of
nifH genes recovered from marine sediments here and previously, suggests
that our inventory of marine diazotrophs is incomplete and that we are only
beginning to understand the extent and importance of benthic marine N2
fixation."
If there is an effort afoot, to shift the focus of climate change study from
CO2 to nitrogen compounds, it may be ill advised-it appears that the
nitrogen cycle is as poorly understood as the carbon cycle.
One final warning comes from Ravishankara et al.: "N2O could be an
unintended byproduct of enhanced crop growth for biofuel production or iron
fertilization to mitigate CO2 emissions. Such an enhancement would lead to
the unintended "indirect" consequence of ozone layer depletion and increased
climate forcing by an alternative fuel used to curb global warming." In
other words, we had best be damned careful in our efforts to "cure" global
warming.
Indeed, according to P. J. Crutzen et al., writing in Atmospheric Chemistry
and Physics (see "N2O release from agro-biofuel production negates global
warming reduction by replacing fossil fuels"), much of the rush to biofuels
could actually be worse for the environment than current fuels. Their 2007
study reported: "When the extra N2O emission from biofuel production is
calculated in "CO2" global warming terms, and compared with the
quasi-cooling effect of "saving" emissions of fossil fuel derived CO2, the
outcome is that the production of commonly used biofuels, such as biodiesel
from rapeseed and bioethanol from corn (maize), can contribute as much or
more to global warming by N2O emissions than cooling by fossil fuel
savings."
This knowledge has not dampened the enthusiasm for ethanol and biodiesil in
some quarters. Ignoring repeated reports that biofuels are bad for the
environment, governments around the world press ahead with expensive
subsidies for their production.
Biofuels, clean coal and cottage industry solar power are just a few of the
scams that have popped up to take advantage of global warming hysteria.
Climate scientists are reassessing the accuracy of climate change claims but
the true believers continue to preach imminent disaster.
Global warming is the scam of the century and it won't be going away anytime
soon-there's too much money to be made and political influence to peddle.
And the biggest climate change scam of all is about to resurface in America,
it's called Cap and Trade.
Be safe, enjoy the interglacial and stay skeptical.
COMMENT
Hmmmm.......
Submitted by rkeyo on Sun, 11/01/2009 - 18:31.
Interesting how EVERYTHING "harmful" to the environment is integral to the
well-being of mankind. Coincidence? Only if one still believes in the Tooth
Fairy...
http://www.theresilientearth.com/?q=content/laughing-gas-knocks-out-co2
Warmest Regards
Bon z0
"It is a remarkable fact that despite the worldwide expenditure of perhaps
US$50 billion since 1990, and the efforts of tens of thousands of scientists
worldwide, no human climate signal has yet been detected that is distinct
from natural variation."
Bob Carter, Research Professor of Geology, James Cook University, Townsville |
|
|
| Back to top |
|
|
|
|
|
All times are GMT - 5 Hours
The time now is Tue Nov 24, 2009 4:42 pm
|
|