[HN Gopher] Extreme El Nino weather switched off South American'...
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Extreme El Nino weather switched off South American's carbon sink
Author : geox
Score : 93 points
Date : 2023-09-04 17:48 UTC (5 hours ago)
(HTM) web link (www.leeds.ac.uk)
(TXT) w3m dump (www.leeds.ac.uk)
| photochemsyn wrote:
| Full article, open access, is at Nature Climate Change:
|
| Sensitivity of South American tropical forests to an extreme
| climate anomaly (04 Sep 2023)
|
| https://www.nature.com/articles/s41558-023-01776-4
|
| First time I've seen the word, "necromass" though:
|
| > "Among the key processes governing the carbon balance of
| tropical ecosystems are the rates of tree growth, which takes
| carbon into the biomass pool, and tree mortality, which transfers
| it to necromass. In turn, both growth and mortality are likely to
| depend closely on plant available water, temperature and their
| fluctuations."
|
| Curiously old-growth forests seem to slowly draw down CO2 even at
| mature stage[1], it may end up sequestered in soil (see also peat
| bogs, permafrost carbon, etc.). This leads some credence to the
| notion that recent human activity has 'refertilized' the
| environment with CO2 - although since we're apparently back to
| CO2 levels last seen in the Pliocene, 3-5 mya, now would probably
| be a good time to stop. Re-creating widespread ocean anoxia is
| not a good idea, even if that's what allowed most oil & gas
| deposits to form some hundred million years ago.
|
| [1] Old-growth forests as carbon sinks (2008).
| https://www.nature.com/articles/nature07276
| akira2501 wrote:
| The actual paper, which is a PHd thesis, is titled "Impact of the
| 2015-2015 El nino on Tropical Forests." It suggests that it is
| possible under _sustained_ hot and dry conditions, not single
| year weather events, for the carbon sink of _some_ forests to
| become reversed. This hyperbolic article even has to end with the
| same conclusion, that if we manage to keep the forests standing,
| the carbon sink will NOT become "switched off."
|
| It's odd to see an institution engage in such absurd
| sensationalism on one of it's own researchers thesis. The carbon
| sink doesn't have a "switch" that "El nino" somehow magically
| presses.
| [deleted]
| [deleted]
| [deleted]
| Loquebantur wrote:
| You are misrepresenting the science here. This wasn't "just a
| PhD thesis" in particular.
|
| Also, your take of this to be "sensationalism" is very odd. The
| danger of imminent tipping points turning "climate change" into
| "climate catastrophe" is absolutely real.
|
| > _The researchers today report their findings in the journal
| Nature Climate Change. The study united the RAINFOR and PPBio
| research networks, with dozens of short-term grants enabling
| more than 100 scientists to measure forests for decades across
| 123 experimental plots._ _The plots span Amazon and Atlantic
| forests as well as drier forests in tropical South America._
|
| > _These direct, tree-by-tree records showed that most forests
| had acted as a carbon sink for most of the last 30 years, with
| tree growth exceeding mortality. When the 2015-2016 El Nino
| hit, the sink shut down. This was because tree death increased
| with the heat and drought._
| jiofj wrote:
| [flagged]
| wredue wrote:
| Now wait till the forests burn and instead of being a carbon
| sink, they become a carbon contributor.
|
| Hi Canada!
| Waterluvian wrote:
| I think our peatlands are of considerably greater concern.
| raffraffraff wrote:
| In Ireland we're burning ours, like a bunch of idiots.
| fluoridation wrote:
| Those trees are made of carbon that was already in the
| atmosphere, and they will release it back into it whenever
| they die in the next couple centuries anyway. Trees are
| basically irrelevant as carbon capture, unless they're
| cultivated to maturity and then buried underground.
| dools wrote:
| If you're in a sinking boat it is the amount of water
| inside the boat that you worry about, rather than the
| amount of water in which the boat is floating.
| fluoridation wrote:
| If you're in a sinking boat you should worry about how
| fast water is coming in, not about how much water is
| inside. Would you rather be carrying 10 tons of water
| without leaking, or 1 ton of water and taking in half a
| ton per minute?
| realusername wrote:
| That's not how it works, the time the carbon got stored
| has an effet on the climate, the same way that 1 euro
| tomorrow isn't the same as one euro today.
| seizethecheese wrote:
| > trees are basically irrelevant as a carbon sink.
|
| Some quick googling shows me that all flora on earth hold
| about 1000 gigatons of carbon, whereas we are releasing
| about 40 gigatons per year. Doesn't seem irrelevant.
| fluoridation wrote:
| Meaning we would need to plant the entire current flora
| every 25 years just to break even. Sounds pretty close to
| irrelevant.
| developer93 wrote:
| They tie up carbon for 100+ years, they're hardly
| irrelevant
| mnky9800n wrote:
| Depends on if you are a climatologist or a geologist.
| fluoridation wrote:
| They buy a little bit of time. That's it.
| hgomersall wrote:
| Nonsense, a region that is forested has a proportion of
| carbon locked up in biomass indefinitely. If that region
| is deforested and no longer has any carbon locked up in
| biomass that is unambiguously a net source of carbon.
| fluoridation wrote:
| It's not locked up, it's continuously flowing in and out
| of that ecosystem. It's only locked up when it gets
| buried and can't return back to the atmosphere (except
| through technology). There's any number of reasons why a
| forest could get disrupted and die out besides
| intentional deforestation.
| civilitty wrote:
| The situation with Canadian forests is much worse. The
| Amazon accounts for 20% of the global carbon sink but the
| meters-thick layer of peat below Canadian forests is a
| third of all carbon _stored_ (along with the peatland in
| Russia, which is also burning).
|
| There's enough carbon stored in that peat to double or
| triple the CO2 ppm which would be absolutely catastrophic
| to the planet.
| IG_Semmelweiss wrote:
| >>>You are misrepresenting the science here.
|
| Please don't equate weather simulations, and excel
| statistical models, and estimates, to actual science.
| olddustytrail wrote:
| These are not statistical models, they're physical models.
|
| Please don't equate your ignorance of a field with
| knowledge.
| IG_Semmelweiss wrote:
| model = not science.
|
| Model is probabilistic by nature. Science is
| deterministic by necessity.
|
| Both can create knowledge for sure.
|
| My only point is this is not science. The article even
| calls it research, not science. The article doesn't
| mention the word science, even once.
| hgomersall wrote:
| No, science is probabilistic by nature. Science seeks to
| generate models to explain reality. The process is to
| test said models against reality (probabilistically).
| Daishiman wrote:
| [flagged]
| PheonixPharts wrote:
| I think it's far more far to say the opposite: science is
| an ever evolving model of the world, but science is
| always just a _model_.
|
| F = ma is a model.
|
| And you may try to limit your argument to only
| "statistical models = not science" but then you would be
| dismissing essentially all social sciences but also
| ecology, geology, climate science, not to mention every
| single aspect of statistical mechanics.
|
| Science is essentially hypothesis testing where
| hypothesis represent models of how the world works.
| Didn't you even take high school physics where you spend
| considerable time running experiments and writing up why
| they _don 't_ exactly match the formula's prediction in
| the book?
|
| Would you mind explaining what model-free science looks
| like? Is it just cataloging observations?
| IG_Semmelweiss wrote:
| >>> Would you mind explaining what model-free science
| looks like? Is it just cataloging observations?
|
| Anything that can be tested and replicated with all
| things exactly equal, except that which is the hypothesis
| being tested.
|
| Most if not all of social science, ecology, geology,
| climate science may not be possible to do this way, since
| it often involves humans and/or earth, and its physically
| impossible to duplicate earth, or a human (with identical
| thoughts,feelings, or experience)
| mnky9800n wrote:
| Dude the ideal gas law is all that matters. After that
| it's all just malarkey.
| mnky9800n wrote:
| [flagged]
| amaranth wrote:
| I take it you disregard pretty much all of quantum
| physics then?
| _Algernon_ wrote:
| Literally everything in science is some form of model.
| From the simplest linear regression to the most
| sophisticated climate models.
| SamoyedFurFluff wrote:
| Did you read the post you're replying to, which quotes the
| article being that it is measuring specific plots of land
| on specific trees? There's no estimates or simulations
| here. The only excel models I bet are just formulae
| executions.
|
| By that logic if I measure the weather outside every day,
| and say the average weather for the past month outside my
| house is x, I've created a model and therefore not real,
| lol
| WillPostForFood wrote:
| _However, intact tropical South American forests overall were
| no more sensitive to the extreme 2015-2016 El Nino than to
| previous less intense events, remaining a key defence against
| climate change as long as they are protected._
|
| https://www.nature.com/articles/s41558-023-01776-4
| photochemsyn wrote:
| They're simply reporting that conditions of high temperature
| and drought reduce photosynthetic fixation rates more than they
| do total respiration rates (and fire losses). What's
| significant about the research is that they actually quantify
| these rates using a network of hundreds of carefully monitored
| forest plots across the region, it's not based on a computer
| model.
|
| Overall they report that the tropical forest across this region
| became carbon-neutral, i.e. no more carbon was taken up than
| was released. Looks like careful rigorous science to me.
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(page generated 2023-09-04 23:01 UTC)