Scientists Just Discovered Their Past Carbon Budget Guesses Have All Along Been Twice As Wrong As They Thought
A new assumption about carbon budgets reveals climate scientists have been vastly underestimating (by a factor of 2) the amount of carbon absorbed by the ocean for decades. Every past carbon budget estimate has been twice as wrong as the current estimate.
When it comes to the ocean heat fluxes and source vs. sink carbon budget estimates, climate scientists have been providing little more than educated guesses for decades.
For example, climate models have long suggested the ocean heat fluxes may only vary around 1 W/m². But “objective” analyses of oceanic latent heat flux (LHF) using different assumptions (equations) reveals fluxes were likely closer to 10 W/m² during 1981-2005 (Yu and Weller, 2007). So our modeled guesses were off by a factor of 10 compared to newer analyses.
Image Source: Yu and Weller, 2007
Ocean carbon sink processes not understood and driven by natural variability
McKinley et al. (2017) analyzed ocean carbon sink estimates and was willing to admit that due to a lack of observation, we lack a “detailed, quantitative, and mechanistic understanding of how the ocean carbon sink works…”
In addition, because internal variability in oceanic carbon uptake is so massive and largely unobserved, we cannot yet detect an anthropogenic influence.
McKinley and co-authors go so far as to acknowledge the “change in CO2 flux over 10 years (1995-2005)…is due almost entirely to the internal variability” because in most ocean regions “the forced [human-induced] trends in CO2 flux are too small to be statistically significant” and the “variability in CO2 flux is large and sufficient to prevent detection of anthropogenic trends in ocean carbon uptake on decadal timescales.”
Image Source: McKinley et al. (2017)
The Southern Ocean absorbs more than 10 times less carbon than previously thought
The Southern Ocean is where the largest portion of anthropogenic carbon (from our emissions) is said to be absorbed, or Earth’s largest oceanic CO2 sink.
Just 2 years ago, a carbon uptake analysis (Gray et al, 2018 with a Physics Today press release) that utilized estimates from biochemical floats instead of estimates from ships suggested the exact opposite of what had been previously thought. Instead of absorbing close to 1 petagram of carbon (PgC) per year, the Southern Ocean is barely even a carbon sink at all – just 0.08 PgC of yearly absorption. In fact, large regions of the Southern Ocean near Antarctica are a net source of CO2 to the atmosphere.
In other words, when estimates are float-based rather than ship-based, one estimate is more than 10 times different than the other.
Image Source: Physics Today
The global ocean absorbs 2 times more CO2 than previously thought
And now a new study (Buesseler et al., 2020) has scientists insisting that all of our previous estimates of global ocean carbon uptake are substantially wrong because we’ve been measuring from a fixed depth rather than varying depths.
Previously scientists had been using flux estimates from the “canonical fixed 150-m depth.” The new-and-improved way to assess carbon uptake is from varying but often much shallower depths: the euphotic zone (Ez). This is the section of the upper ocean layer that sunlight is able to penetrate, and it can “vary from less than 20 m to almost 200 m” in depth.
When we use the Ez to estimate carbon absorption versus export, the absorption changes from 2.8 petagrams of carbon (PgC) per year to 5.7. So the global ocean sink can be more than doubled just by varying the depth of measurement rather than using a fixed depth.
So, up to this point, scientists’ past guesses about ocean carbon uptake have been emphatically wrong. We can be assured, though, that our current guesses are anywhere from 2 to 10 times less wrong than the last ones.
Image Source: Buesseler et al., 2020 and press release
This article appeared on the NoTricksZone website at https://notrickszone.com/2020/09/07/scientists-just-discovered-our-past-carbon-budget-guesses-have-all-along-been-twice-as-wrong-as-we-thought/]]>
Wanasayansi wamegundua kuwa makadirio yao ya bajeti ya kaboni ya zamani yamekuwa na makosa mara mbili kuliko walivyofikiria - Dhana mpya kuhusu bajeti ya kaboni inaonyesha wanasayansi wa hali ya hewa wamekuwa wakipunguza sana (kwa sababu ya 2) kiasi cha kaboni inayomenywa na bahari kwa miongo kadhaa. Makadirio yote ya bajeti ya kaboni ya zamani yamekuwa na makosa mara mbili kuliko makadirio ya sasa. Kwa mujibu wa utafiti wa utafiti wa joto la bahari na takwimu za bajeti ya kaboni ya chanzo dhidi ya sink, wanasayansi wa hali ya hewa wamekuwa wakitoa kidogo zaidi ya dhana za elimu kwa miongo kadhaa. Kwa mfano, mifano ya hali ya hewa kwa muda mrefu imedokeza mtiririko wa joto la bahari inaweza tu kutofautiana karibu 1 Wm2. Lakini uchambuzi wa objective wa mtiririko wa joto la bahari (LHF) kwa kutumia dhana tofauti (mlinganisho) unaonyesha mtiririko ulikuwa karibu na 10 Wm2 wakati wa 1981-2005. Kwa hivyo, makadirio yetu ya mfano yalikuwa mbali na sababu ya 10 ikilinganishwa na uchambuzi mpya. "Mfano: Yu na Weller, 2007: ""Mambo ya bahari ya carbon sink hayaeleweki na kuendeshwa na mabadiliko ya asili"" McKinley et al." "Mchunguzi wa utafiti wa utafiti wa CO2 ya bahari, D. H. H. Smith, alisema: ""Kwa sababu ya ukosefu wa uchunguzi, hatuna uelewa wa kina, wa kiasi, na wa utaratibu wa jinsi sinki ya kaboni ya bahari inafanya kazi.""" "Makampuni ya kimataifa ya CO2 na makampuni ya kimataifa ya CO2 na makampuni ya CO2 na makampuni ya CO2 na makampuni ya CO2 na makampuni ya CO2 na makampuni ya CO2 na makampuni ya CO2 na makampuni ya CO2 na makampuni ya CO2 na makampuni ya CO2 na makampuni ya CO2 na makampuni ya CO2 na makampuni ya CO2 na makampuni ya CO2 na makampuni ya CO2 na makampuni ya CO2 na makampuni ya CO2 na makampuni ya CO2 na makampuni ya CO2. """ Bahari ya Kusini inachukua zaidi ya mara 10 chini ya kaboni kuliko ilivyodhaniwa hapo awali Bahari ya Kusini ni mahali ambapo sehemu kubwa ya kaboni ya binadamu (kutoka kwa uzalishaji wetu) inasemekana kunyonya, au sinki kubwa zaidi ya bahari ya CO2 ya Dunia. "Mwaka mmoja uliopita, utafiti wa ""carbon uptake analysis"" (Gray et al, 2018 na Physics Today press release) ambao ulitumia takwimu kutoka kwa floats za biochemical badala ya takwimu kutoka kwa meli, ulionyesha kinyume kabisa cha kile kilichokuwa kimefikiriwa hapo awali." Badala ya kunyonya karibu petagram moja ya kaboni kwa mwaka, Bahari ya Kusini ni karibu hata sink ya kaboni kabisa - 0.08 PgC ya kunyonya kwa kila mwaka. Kwa kweli, maeneo makubwa ya Bahari ya Kusini karibu na Antaktika ni chanzo cha CO2 ya hewa. Kwa maneno mengine, wakati makadirio ni float-msingi badala ya meli-msingi, makadirio moja ni zaidi ya mara 10 tofauti na nyingine. "Kama ilivyoelezwa hapo juu, ""bahari ya dunia inachukua CO2 mara mbili zaidi ya ilivyodhaniwa hapo awali, na sasa utafiti mpya (Buesseler et al., 2020) una wanasayansi wakisisitiza kwamba makadirio yetu yote ya awali ya uchukuaji wa kaboni ya bahari ya kimataifa ni sahihi kwa sababu tumekuwa tukipima kutoka kina cha kudumu badala ya kina tofauti.""" Kwa mfano, katika eneo la euphotic (Euphotic Zone) kuna njia mpya ya kupima mwanga wa kaboni kutoka kwa kina cha chini. Hii ni sehemu ya safu ya juu ya bahari ambayo mwanga wa jua unaweza kupenya, na inaweza <unk> kutofautiana kutoka chini ya m 20 hadi karibu m 200 <unk> kwa kina. Kwa mfano, kwa mfano, kwa mfano, kwa mfano, kwa mfano, kwa mfano, kwa mfano, kwa mfano, kwa mfano, kwa mfano, kwa mfano, kwa mfano, kwa mfano, kwa mfano, kwa mfano, kwa mfano, kwa mfano, kwa mfano, kwa mfano, kwa mfano, kwa mfano, kwa mfano. Kwa hiyo, kina cha bahari chaweza kuzidi maradufu kwa kubadilisha kina cha kipimo badala ya kutumia kina cha kawaida. Kwa hiyo, hadi wakati huu, nadharia za zamani za wanasayansi kuhusu kunyonya kaboni baharini zimekuwa zisizo sahihi kabisa. Hata hivyo, tunaweza kuwa na uhakika kwamba makadirio yetu ya sasa ni ya kati ya mara mbili hadi kumi ya makosa ya mwisho. "Kama ilivyoelezwa katika taarifa ya gazeti la The Guardian, ""Mwanzoni mwa mwaka huu, utafiti wa NoTricksZone ulionyesha kuwa idadi ya watu wanaotumia nishati ya kaboni katika mazingira ya hewa ni ya juu zaidi kuliko ilivyodhaniwa."""