Bob MacGregor wrote:
Subj: Browning of Planet Earth -Reply
Date: 98-07-17 09:04:29 EDT
From: RDMACGREGOR@gov.pe.ca (Bob MacGregor)
To: LionKuntz@aol.com, sanet-mg@shasta.ces.ncsu.edu, phrc031@unlvm.unl.edu
Yes, more CO2 does enhance plant growth, assuming all other factors
remain adequate. However, Lion is partly right about browning.
Actually, a hotter earth means more circulation of water. The downside
is that it also means a higher evaporation rate and, worse, a
rearrangement of climate zones. This may work out as an improvement
for some folks in Russia, China, and Canada, but middle-lattitude people
might well be in the situation Lion describes.
A couple of final notes about this: although prediction of the impacts of
global warming is extremely imprecise, given its long-term nature, the
general consensus is that weather "events" will become more frequent
and severe (ie, more heat energy in the atmosphere equals more severe
storms). Also, the areas close to the equator are not expected to
experience the same amount of change that would occur in the
temperate or near-artic (and antarctic) zones.
=========================================
Lion writes: In a northern state of Mexico it recently didn't rain for four
years, but it would take decades to replace living mature trees which died
during that four years. The "moving spotlights" are roving the planet,
causing local apocalypse. These brown spots will persist even if there is a
yearly average of more rain per decade, even when accounting for the lull
period in that average. Kudzu, or English Ivy might green the area as seen
from a weathersat, but it will be different on the ground than it ever was
before. We are coming to the end of the fourth interglacial which
complexifies all predictions by another magnitude.
=========================================
Bob wrote:
A prospective corn farmer in Northern Manitoba might think this global
warming stuff is great, but even wilder fluctuations in annual weather
patterns cannot be good news for prairie farmers, nor would I expect a
water-deficit cotton farmer in Texas to look forward to even hotter, drier
summers.
Unfortunately, I still don't see any reasonable prospect for the world NOT
to consume all the fossil fuels that are economically recoverable (even if
we cut 'way back on our profligate consumption of fossil fuels, someone
else in the world will likely pick up the slack, so we'll still be stuck with
the greenhouse problem). That being the case, what can we do about
the concommitant rise in atmospheric CO2? There is a good overview
of this issue and the various, proposed solutions in the June 1998 issue
of Discover Magazine ("Carbon Cuts and Techno-Fixes").
=========================================
Lion writes: Consumption of carbon is not the same as burning it into CO,
CO2 and other complex carbon aerosols. Carbon cycles constantly, but a
massive extinction event stored nearly the entire global biomass into fossil
carbon of the so-called "carbonaceous period" from which we mine our
petroleum, coal and asphalt. In humus only 40% is fixed in living bodies, the
remaining 60% exhaled by microbes into the atmosphere. The plant carbon
respiring, fixing, decay and release is basically an annual cycle with 100%
recycling and no long-term fixation. Trees are the only long-term
(relatively) fixing, or sequestration, of carbon, and forests are being
consumed faster than the global rate of consumption of fossil carbon. The
only safe storage place is trees, as the most efficient impounders of carbon,
operating multistoried vertical efficiency, and holding the carbon for a
century or more. Prior to the first ice age there were vast global forests of
sequoia sempervirums who could store carbon for a thousand years per tree, and
store it in containers hundreds of feet tall.
=========================================
Bob wrote:
In Canada, it is estimated that agriculture directly contributes about 10%
of greenhouse gas emissions (CO2, CH4, N20). If you take into account
all the industrial emissions upstream (ie, input industries) and
downstream (eg, food transportation, processing and distribution), I'd
guess that current agri-food _system_ contributes in the 1/4 to 1/3 range
of total greenhouse gas emissions.
Carbon storage (sequestration) in soils has been discussed on this list
before; generally, the low- or no-chem folks are 'way ahead of the pack
=========================================
Lion writes: I don't have any basis for making a percentage estimate on
carbon aerosol inputs from agriculture, other than measure the percentage of
fossil carbon consumed in all stages of agriculture. The annual cycle of
plants is 100% as I said above, so inputs from outside provide the ag
contribution to surplus emissions. Numbers from 10% up to 50% might be
appropriate, depending on counting toilet-paper tree farms, and lumber from
the Department of AGRICULTURE'S National Forest timber programs removing
mature high-efficient carbon-fixers and replacing with immature low-efficiency
seedlings. All harvested wood returns to aerosol carbon eventually.
Deforestation for agriculture or low-density housing replaces high-density
carbon storage forests with net carbon aerosols.
=========================================
Bob wrote:
here. Similarly, the lower-input ag and local marketing people likely
consume fewer fossil fuel calories -- and therefore have fewer
emissions -- than the conventional/chemical ag folks. Still, before the
sustainable ag folks get too puffed up with pride, consider that very few
farmers do not use internal combustion engines for production and/or
distribution of their produce. Also, as was discussed before on this list,
per food calorie moved, a small truck going to a local farmer's market
might contribute a lot more emissions than a trainload -- or semi-trailer --
of veggies going halfway across the country. Finally, a lot of the
contribution of agriculture to greenhouse gases is CH4 from livestock
(especially cattle burps and farts); I haven't yet heard that organic
cattle produce less methane than typical feedlot cattle.
Its a very complex topic and there aren't any simple solutions. It is
certainly worthwhile to take the time to poke holes in the one-sided,
misguided, misleading, and short-sighted propaganda of the
power/mining industries about the wonderful benefits of more CO2.
Keep up the good work.
BOB
rdmacgregor@gov.pe.ca
=========================================
Lion writes: I propound local inputs, local markets, ecological synergy of
high intensity productivity, near zero mechanizated no-till farming, with a
portion of the land set aside of nature, including mature trees.
Organic farming cycles as much carbon as any other type of farming: the
cellulose and lignin are made from aerosol carbon and are released one way or
another. Plants simply cycle every year the same basic amount. Animals do
also, organic or otherwise. It is the release into the atmosphere of fossil
carbon which adds to the "normal" annual amount being cycled endlessly. There
is an entire biosphere buried in the earth which is being added to the carbon
usually cycled by this living biota. At the same time, long-term carbon
storage (forests) are being reduced to aerosolization exactly when they are
required to be increased.
Whether or not there are "simple" solutions, or "complex" solutions, they
will have certain features in common: ways must be found to value trees more,
to destroy them for trivial reasons must not be accepted, higher density
agriculture which uses less land to produce more can take off the burden to
remove forests for low-yield low-intensity agriculture, and aerosolization of
carbon ought to have a socially valuable necessity.
People must be held responsible for their environmental impacts. This
means each and every one. The day of mandatory "Lifetime Personal
Environmental Impact Statement" will come in your lifetime -- you will have to
prove that you take responsibility to see that you provide ALL the resources
you need to provide before you bring more population into the world.
Because humans are NOT an endangered species, checks and balances
(including human laws) must restrain any species from getting so out of
balance that the global ecology is threatened. This might mean that some
investors will not get rich doing nothing, and that some pollution laws will
hold the caps on utilities effluents. It might mean limits on agricultural
practices. It might mean every American teenager shouldn't own their own car.
=========================================
To Unsubscribe: Email majordomo@ces.ncsu.edu with "unsubscribe sanet-mg".
To Subscribe to Digest: Email majordomo@ces.ncsu.edu with the command
"subscribe sanet-mg-digest".