Objavljeno : 12.12.2016.
Borba protiv zagrevanja planete može biti ugrožena
oslobađanjem metana, gasa koji ima mnogo jači uticaj na klimu nego
ugljen-dioksid, i čije ispuštanje se za poslednjih 10 godina drastično povećalo,
upozorili su istraživači 12. decembra. Istraživači koji su koordinirali svetsku
procenu emisija, u kojoj je učestvovalo 80 naučnika iz 15 zemalja, upozorili su
da je neophodno hitno se posvetiti proceni količine emisije metana i njihovom
smanjenju.
Nakon blagog usporavanja između 2000. i 2006. godine,
koncentracija metana u atmosferi je u deceniji koja je usledila porasla za 10
puta, pokazalo je istraživanje objavljeno u žurnalu Ert sistem sajens data
(Earth System Science Data).
"Zadržavanje zagrevanja klime na manje od dva
stepena Celzijusa već predstavlja osetan izazov", istakli su istraživači u
biltenu "Environmental riserč leters" (Environmental Research
Letters) povodom ciljeva koje je međunarodna zajednica postavila Pariskim sporazumom
2015. godine.
Upozorili su da će taj cilj postati još teže ostvariv
ukoliko se osetno i brzo ne smanji emisija metana. Problem je što istraživači
imaju više pretpstavki o razlozima dramatičnog rasta količine tog gasa u
atmosferi - od korišćenja fosilnog goriva, preko topljenja zamrznutog tla
subpolarnog permafrosta, do poljoprivrede što je najverovatnija opcija.
Koncentracija metana u atmosferi u sve bržem je porastu
od 2007. godine, uz posebno osetan rast 2014. i 2015. godine, a takav trend
rasta nije predviđen nijednim srednjim scenariom svetskog referentnog izveštaja
o klimi Međuvladinog panela o klimatskim promenama (IPCC).
"Zabrinjavajuće je što se tempo povećanja približava
najpesimističnijem sčenariju", ukazala je Marijela Sonoa (Marielle
Saunois) sa Univerziteta Versaj Sen Kenten (UVSQ).
Zagonetka zvana metan
Metan je drugi po značaju gas sa efektom staklene bašte
koji je proizvod ljudske delatnosti, doprinosi zagrevanju sa 20%, ima 28 puta
jači efekat na globalno zagrevanje nego ugljen-dioksid, iako se manje zadržava
u vazduhu, oko 10 godina.
Mere protiv zagrevanja do sada su uglavnom bile usmerene
na ugljen-dioksid koji je posledica sagorevanja fosilnog goriva - uglja, nafte
i gasa, i čini 70% gasova sa efektom staklene bašte.
Izvore metana je i teže utvrditi, jer ih je više, i
dobrim delom dolazi iz takozvanih prirodnih izvora, vlažnih zona i geoloških
formacija. Istraživanje pokazuje da je 60% emsija vezano za ljudsku delatnost,
pri čemu 36% dolazi od poljoprivrede, pre svega od gasova koje tokom varenja
ispuštaju goveda i drugi preživari, kao i od gajenja riže, i prerade otpada.
Istraživači smatraju da ne treba zanemariti ni ulogu
fosilnih goriva u tom porastu, budući da je 21% emisija metana posledica
korišćenja ugla, nafte i gasa jer je curenje metana veoma često u raznim
fazama, od vađenja do distribucije ovih goriva.
"Od 2000-ih godina ugalj je u Kini veoma mnogo
korišćen, a i korišćenje gasa u SAD je povećano", navode naučnici.
Metan se može oslobađati i topljenjem permafrosta -
zamrznutog sloja tla blizu polova, i to je jedan od velikih strahova
klimatologa, mada po rečima jednog od autora istraživanja, istraživača Filipa
Buskea (Philippe Bousquet), za sada nema neuobičajenog povećanja koncentracija.
Buske upozorava da postoji opasnost da se emisije
povećaju vremenom, ali smatra da se tu govori o decenijama.
Dobra vest - lakše smanjiti emisije metana nego CO2
Naučnici još ne mogu da objasne razloge drastičnog
povećanja zabeleženog u dve prethodne godine.
"Može biti da je reč o prirodnim izvorima. Ali,
ukoliko se to produži na preko tri ili četiri godine, to će biti znak sigurne
veze sa ljudskom delatnošću", naveo je Buske.
Konkretne mere za smanjenje emisija metana već sada su
moguće, ukazuju naučnici, i kao rešenja navode "metanizere" -
postrojenja za proizvodnju energije od organskih izvora na imanjima, traže i
izmenu protokola o navodnjavanju polja pirinča, i lov na nekontrolisanu emisiju
metana.
"Emisije metana je moguće smanjiti lakše i uz manje
prinude, nego u slučaju ugljen-dioksida, i to uz podsticaje inovacijama i
razvoju. Ne treba da se toga lišimo", insistira Filip Buske.
Izvor: AFP
Foto: Wikimedia
logo Association
Posted: 12.12.2016
The fight against the warming of the planet can be
compromised release of methane gas, which has a much stronger impact on the
climate than carbon dioxide, and whose discharge for the past 10 years has
increased dramatically, the researchers warned on 12 December. Researchers
who coordinated global assessment of emissions, which was attended by 80
scientists from 15 countries, have warned that it is necessary to urgently
devote estimate the quantity of methane emissions and their reduction.
After a slight slowdown between 2000 and 2006, the
concentration of methane in the atmosphere is in the decade that followed
increased by 10 times, according to a study published in the journal Ert Sajens
data system (Earth System Science Data). "Retention of climate warming to
less than two degrees Celsius but it represents tangible challenge," the
researchers noted in the bulletin "Environmental riserč leters"
(Environmental Research Letters) regarding the goals that the international
community has asked the Paris Agreement in 2015.
They warned that if the goal is to become even more
difficult attainable if not significantly and quickly reduce emissions of
methane. The problem is that researchers have more problematisations of the
reasons for the dramatic growth in the quantity of this gas in the atmosphere -
from the use of fossil fuels through the melting of permafrost frozen soil
subpolarnog to agriculture as the most likely option.
The concentration of methane in the atmosphere in an
accelerating been increasing since 2007, with particularly noticeable growth in
2014 and 2015, and this upward trend is not anticipated by any medium reference
scenario global climate report by the Intergovernmental Panel on Climate Change
(IPCC). "It is disturbing that the rate of increase approaching the most
pessimistic scenario," pointed Marijela Sono (Marielle Saunois) at the
University of Versailles Saint-Quentin (UVSQ).
Conundrum Called
methane
Methane is the second most significant greenhouse gas
emissions, which is the product of human activity contributes to warming with
20%, has 28 times more impact on global warming than carbon dioxide, although
less reserves in the air for about 10 years. Measures against warming have so
far mainly focused on carbon dioxide, which is the result of burning fossil
fuels - coal, oil and gas, and accounts for 70% of greenhouse gases.
Sources of methane is more difficult to determine because
there are several, and largely comes from so-called natural sources, humid
zones and geological formations. Research shows that 60% emsija related to
human activity, while 36% comes from agriculture, especially from the gases
that are released during digestion of cattle and other ruminants, as well as
the cultivation of rice, and processing of waste.
Researchers believe that one should not neglect the role
of fossil fuels in this rise, since 21% of methane emissions due to the use
point of view, oil and gas because of the leakage of methane often in various
stages, from extraction to distribution of the fuel.
"Since the 2000s coal in China is very much used,
and the use of gas in the US has increased," the researchers said.
Methane can be released and melting permafrost - frozen
soil near the poles, and this is one of the great fears of climate scientists,
although according to one of the authors of the study, researchers Philip
Buskea (Philippe Bousquet), for now there is no unusual increase in
concentration.
Buske warns that there is a risk that emissions increase
with age, but believes that this is about for decades.
The good news -
easier to reduce emissions of methane than CO2
Scientists still can not explain the reasons for the
drastic increase recorded in the previous two years. "It may be that it is
a natural resource.
But if it is to extend over three or four years, it will
be a sign of a secure connection with human activity," said Buske.
Concrete measures to reduce methane emissions now are
possible, the researchers suggest, as solutions allegations
"metanizere" - plants producing energy from organic sources on farms,
and seek amendment of the protocol on irrigated rice fields, and the pursuit of
uncontrolled emission of methane.
'Methane emissions can be cut more easily and with less
restraint, than in the case of carbon dioxide, and with incentives for
innovation and development. I do not need to divest ourselves of that,
"insists Filip Buske.
Source: AFP
Photo: Wikimedia
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