THE BROTHERS FOLEY DEVELOP A SENSE OF HUMUS

Awhile ago I wrote about Dr. Jonathan Foley, an environmental scientist
at the
University of Wisconsin, who is so appalled at the lack of government
action on
global warming that he has taken matters into his own hands.  Through energy
efficiency and solar energy he and his family have greatly reduced their
use of
gas, oil, or coal (whose burning produces the greenhouse gas carbon
dioxide). 
When they do burn fossil fuel, they see that a tree is planted or a
patch of
prairie restored to take the carbon dioxide they've generated back out
of the
atmosphere.

Jon Foley has been corresponding with his brother David, who designs "green"
buildings in Maine, about whether David can rack up carbon-absorbing
credit for
his organic garden.  When David and his wife Judy started gardening
about 10
years ago, their soil tested just one percent organic matter.  Now it
tests 7.7
percent (an astonishingly high number, about twice as high as most farm
soils). 
That difference is made up of carbon taken by plants out of the
atmosphere -- a
reverse-greenhouse effect.

Jon, the numbers guy, has gone to work estimating David and Judy's carbon
credits.  Here, for you gardeners who want to quantify your own
contribution to
the climate -- and for policymakers who'd like to reward farmers for
climate-stabilizing behavior -- is how he went about it.  The quotes are from
Jon's emails to David.  I've translated units from his proper scientific metric
s
back to the crazy American system we all understand.

"The biggest uncertainty relates to how deep the organic matter is going into
the soil.  I assume that the change in soil organic matter is confined
to the
top 8 inches.  I suspect that you're actually leaching humus into deeper soil,
which would affect the result a lot.  So this is a conservative estimate."

A silt-loam soil, Jonathan says, weighs roughly 85 pounds per cubic
foot.  Eight
inches of it weighs 56 pounds per square foot.

Organic matter is about 58 percent carbon.  So soil with one percent organic
matter contains (hmmm, one percent of 58 percent of 56 pounds) 0.3
pounds of
carbon per square foot.  Soil with 7.7 percent organic matter contains 2.5
pounds of carbon per square foot.  David and Judy have increased the
amount of
carbon in every square foot of their garden by 2.2 pounds.

It's a big garden, 0.4 acres.  (Actually it's a communal garden, which
David and
Judy share with their neighbors.)  That's 17,424 square feet.  Multiply
by 2.2
pounds of carbon per square foot -- let's see here -- that makes over 38,000
pounds of carbon removed from the atmosphere -- 19 tons!

Jon writes to David: "You have sequestered 19 tons of carbon into your garden
over the last 10 years.  If you think that the soil test is
representative of a
deeper soil profile (let's say 16 inches instead of 8), then scale that number
up.  This is impressive!  The average American releases 6 to 6.5 tons of carbon
into the atmosphere each year.  So you have offset about three years of an
average American's emissions."

David Foley is no average American, given his energy-efficient house and frugal
consumption habits.  He and Judy have also planted over a thousand trees and
shrubs.  I'm willing to give them credit for offsetting their last ten
years of
carbon emissions.  But, I pointed out to David, he's not likely to get
that soil
any richer in humus.  What's he going to do to offset the next ten years?

He replied, "It's true that we've 'shot our wad.'  You can never earn
more than
a one-time credit for tree-planting or building soil organic matter. 
But if
everyone would do that, it would give us a great breathing space to make the
transition to sustainable energy sources.  And, of course, the organic matter
we've built up helps the garden grow wonderfully and holds onto water to
help us
get through droughts."

This little calculation could go beyond gardening.  This month the world's
nations reconvene in a climate bargaining session, where a central issue
will be
how to account for carbon sequestration.  If, say, Costa Rica will be charged
for the gasoline burned by its growing car fleet, shouldn't it get
credit for
the fact that it is restoring its forests?  If the U.S. helps Guatemala plant
trees, couldn't we count that against our own rising carbon emissions?

 U.S. negotiators will be pushing hard for the idea of paying cash for carbon
sequestration.  (The Clinton administration would rather pay someone
else to
plant forests than question our gas-guzzling SUV habit.)  If "carbon trading"
flies, it seems fair to reward every kind of carbon-fixing, including building
soil humus.  Farmers who increase the humus content of their soil should
be able
to charge us all for slowing the crazing of the climate.

By the same token, anyone who levels a forest or runs down soil carbon should
have to pay.  That's fair.  Climate change puts real and huge costs onto
everyone.
Carbon sequestration can only be a temporary strategy toward stabilizing the
climate.  Jon Foley estimates that if we grew back every forest and
restored the
humus in all the agricultural land in the world, we would only offset 25-30
years of our economy's present carbon emissions.  Still, a turn in that
direction could help the climate a bit and farmers a lot.

Says David, "Imagine farmers being able to supplement their incomes by farming
the way they should.  Imagine a transfer of income from CO2-emitting
corporations back to farmers.  Wow!"
 
(David and Jon Foley's email addresses are, respectively,
 and .)

(Donella H. Meadows is an adjunct professor of environmental studies at
Dartmouth College and director of the Sustainability Institute, a
think/do tank that promotes sustainable systems.  See www.sustainer.org)
Copyright 2000 Sustainability Institute

Ez a level arrol szolna, hogy hogyan lehetne javitani a jovore
vonatkozo kilatasainkat. Ennek legjobb megoldasat az oktatasban latom.
Nem kell valami hatalmasra gondolni, ha a "tarsadalom" eroteljesebben
kepviselne az un. alapveto erkolcsi ertekeket (ne lopj, ne haracsolj stb)
mar jobban mennenek a dolgok, es vannak egyertelmu dolgok, amik a 
kornyezetvedelemmel kapcsolatosak es a "legkevesbe ertelmes" embernek is
folfoghatok, mar csak sajat erdekebol is (ne szemetelj, mert akkor
szemetdombon fogsz lakni, ne bantsd az erdot, mert akkor rossz lesz a
levego, ne egyel meg mindent gyorsan, mert akkor 10 ev mulva semmid sem
lesz, hasonlo egyszeru jelszavak). Erdemes lenne elgondolkodni arrol is,
hogy 
a mindenhol letezo kulonfele vallasokat esetleg ujra nagyobb szerephez
juttatni, ugyanis a hit nagyon eros kontroll es altalaban pozitiv ertekeket
kepvisel. Persze vannak ellenpeldak (pl. eroszakos fanatizmus, de 
ez nem egy elkepzelt vilag, ahol a szabalyok alol nincsenek kivetelek)
Megsem konnyu ez, hiszen nagyon sok logikusnak latszo dolog
letezik, ami megis szinte athatolhatatlan falakba utkozik a vegrehajtaskor.
Pl. valoszinuleg egyszerubb lenne ingyen osztogatni az ovszereket es az
antibebi-tablettakat a fejlodo orszagokban (persze ahol vallasi es egyeb
okok nem tiltjak) mint aztan ehezok tizmillioit segelyezni, a haborukrol,
torzsi es egyeb villongasokrol, nemibetegsegekrol nem is beszelve - ezek
nagy reszenek okat en a tul nagy nepesseg miatti oriasi szukossegben latom.
Megsem ez tortenik. 
Hogy ugymondjam, rosszul mukodik a "konyveles", azaz a dolgok nem
a megfelelo helyen szerepelnek a szep nagy globalis "merlegben", es
valoszinuleg legtobben mashogy cselekszenek, mint ahogy azt elveikben
valljak.

Na mindegy, ezeket mindenki tudja szerintem

Udv 
Kun Laszlo

Kedves Ivan!

> Felreertes van. A szam napkollektorra vonatkozik
> nem napelemre.
> A kollektor melegvizet ad nem aramot. Napelemnel
> a szam joval
> kisebb lenne (mondjuk 1/3-a, 1/5-e).

A félreértés nem olyan nagy mint gondolod.

Kaproz Zoltán írta :

> Pl. Budapesten 1 m2 jó minőségű napkollektorral évente kb.
250 - 400 kWh
> energia nyerhető.
> (a jelenlegi 30-50%-os hatásfokok mellett).

A jó minoségü napelem táblák már megközelítik ezt a %-os
értéket. Az áráról most ne beszéljünk.
Egyébként sem ez a lényeg. A földön rendelkezésre álló
energiaforrások szinte mindegyikét a nap bocsátja
rendelkezésünkre. Nyilván, ha a környezetet óvni akarjuk a
minél közvetlenebb felhasználás a cél. Annak senki nem
számol utána, hogy a napból érkezo energia átalakítása szél,
vagy víz energiává milyen hatásfokkal sikerül a
természetnek. Csak azt tudjuk, hogy mi ezt a "süritett
energiát" egyszerübben tudjuk felhasználni, mint a
közvetlenül a napból érkezöt.

> Es a 100m2  hazbol 20-at
> elfoglalnak az akkumulatorok (a nap nem akkor sut, amikor
> vilagitani akarsz)

Ez igaz. Itt az alapvetö probléma, az összegyüjtött energia
tárolása. Ezt  _kell_ a müszakiaknak megoldani!

> es az aramatalakitok
> (egyenfeszultsegu Tv-t,
> szamitogepet stb. meg nem talaltak ki, villanysutohoz,
> vizmelegiteshez, porszivohoz megfelel). Maradjunk inkabb a
> melegviz termelesnel. Persze tarolora akkor is
> szukseg van.

A TV, a rádió, a számítógép, szinte kivétel nélkül mind
egyenárammal müködik!
Egyik nélkülözhetetlen alkatrészük a hálózati tápegység,
amely a hálózati áramból a készülék üzemeltetéséhez
szükséges nagyságú egyenáramot állítja elö.

Üdvozlettel : Szu

Kedves Kornyeszesek!

Az energia vitahoz csak annyit szeretnek hozzaszolni, hogy a fotovoltatikus
napelemekkel termelt energia nem csak akkumulatorokban tarolható el, hanem -
mivel egyenaram keletkezik - vizet bontva hidrogent lehet eloallitani. Az
autogyarak szinte mindegyike kiserletezik a hidrogen-tuzeloanyag cellas hajtass
al

(pl. Frankfurtban, ill. Kanadaban orszaguti forgalomban is vannak ilyen
jarganyok), de sok mukodo hidrogen robbanomotor is pofog - vizparat. A hidrogen
tarolasa meg nem legtokeletesebb, de itt is biztatoak a kiserletek (pl. BME
Kozlekedesmernoki kar). A napelemek hatasfokanak javulasara is jok az eselyek,
kiserletben mar 30% folotti eredmenyeket ertek el (nem szilicium alapu elemmel)