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wili

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Re: Carbon Cycle
« Reply #400 on: September 29, 2017, 08:27:19 AM »
More failures of major carbon sinks, which are now turning into sources, this time tropical forests:

 Alarm as study reveals world’s tropical forests are huge carbon emission source

Forests globally are so degraded that instead of absorbing emissions they now release more carbon annually than all the traffic in the US


https://www.theguardian.com/environment/2017/sep/28/alarm-as-study-reveals-worlds-tropical-forests-are-huge-carbon-emission-source

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gerontocrat

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Re: Carbon Cycle
« Reply #401 on: September 29, 2017, 11:20:33 AM »
More failures of major carbon sinks, which are now turning into sources, this time tropical forests:

 Alarm as study reveals world’s tropical forests are huge carbon emission source

Forests globally are so degraded that instead of absorbing emissions they now release more carbon annually than all the traffic in the US


https://www.theguardian.com/environment/2017/sep/28/alarm-as-study-reveals-worlds-tropical-forests-are-huge-carbon-emission-source
Also a major contribution to the 6th Mass Extinction currently underway and which at the current rate of progress will wipe out virtually all vertebrate life on earth by mid-century.

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Pmt111500

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Re: Carbon Cycle
« Reply #402 on: September 29, 2017, 02:04:58 PM »
Just had to log on to check if the rainforest-study had been mentioned here. This looks like the endgame to 4-6---12 °C above 1950s, is about to begin. It feels quite ok to be rather aged and childless.
Cooling the outside by heat pump.

Pmt111500

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Re: Carbon Cycle
« Reply #403 on: October 02, 2017, 03:30:19 PM »
It could be time for a wide survey of natural carbon sinks still working.
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sidd

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Re: Carbon Cycle
« Reply #404 on: October 02, 2017, 09:04:06 PM »
" ...  wipe out virtually all vertebrate life on earth by mid-century. "

 Any references ?

sidd

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Re: Carbon Cycle
« Reply #405 on: October 02, 2017, 09:46:47 PM »
" ...  wipe out virtually all vertebrate life on earth by mid-century. "

 Any references ?

sidd


I don't know if this is what gerontocrat was referring to or not:

Gerardo Ceballos, Paul R. Ehrlich, and Rodolfo Dirzo (2017), "Biological annihilation via the ongoing sixth mass extinction signaled by vertebrate population losses and declines", PNAS, vol. 114 no. 30,   E6089–E6096, doi: 10.1073/pnas.1704949114

http://www.pnas.org/content/114/30/E6089.abstract

Abstract: "The population extinction pulse we describe here shows, from a quantitative viewpoint, that Earth’s sixth mass extinction is more severe than perceived when looking exclusively at species extinctions. Therefore, humanity needs to address anthropogenic population extirpation and decimation immediately. That conclusion is based on analyses of the numbers and degrees of range contraction (indicative of population shrinkage and/or population extinctions according to the International Union for Conservation of Nature) using a sample of 27,600 vertebrate species, and on a more detailed analysis documenting the population extinctions between 1900 and 2015 in 177 mammal species. We find that the rate of population loss in terrestrial vertebrates is extremely high—even in “species of low concern.” In our sample, comprising nearly half of known vertebrate species, 32% (8,851/27,600) are decreasing; that is, they have decreased in population size and range. In the 177 mammals for which we have detailed data, all have lost 30% or more of their geographic ranges and more than 40% of the species have experienced severe population declines (>80% range shrinkage). Our data indicate that beyond global species extinctions Earth is experiencing a huge episode of population declines and extirpations, which will have negative cascading consequences on ecosystem functioning and services vital to sustaining civilization. We describe this as a “biological annihilation” to highlight the current magnitude of Earth’s ongoing sixth major extinction event."
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sidd

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Re: Carbon Cycle
« Reply #406 on: October 02, 2017, 10:20:50 PM »
Thanx for bringing up the Ceballos paper, it had slipped my mind. But it does not support the claim that virtually all vertebrates will be gone by midcentury. Barring meteor impact or Siberian/Deccan Traps scale event I find the claim difficult.

sidd

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Re: Carbon Cycle
« Reply #407 on: October 02, 2017, 11:21:05 PM »
Thanx for bringing up the Ceballos paper, it had slipped my mind. But it does not support the claim that virtually all vertebrates will be gone by midcentury. Barring meteor impact or Siberian/Deccan Traps scale event I find the claim difficult.

sidd

Well, if human population growth combined with climate change were to trigger World War III by midcentury, then the claim become imaginable; however, I do not know that that is what gerontocrat was implying or not.
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Daniel B.

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Re: Carbon Cycle
« Reply #408 on: October 03, 2017, 01:56:31 PM »
Thanx for bringing up the Ceballos paper, it had slipped my mind. But it does not support the claim that virtually all vertebrates will be gone by midcentury. Barring meteor impact or Siberian/Deccan Traps scale event I find the claim difficult.

sidd

The Ceballos paper, along with many others, extrapolate the decline of other animal species due to human over-hunting and habitat destruction.  Most of the talk about the sixth mass extinction refer to these causes.  While we have taken many steps to stem overhunting and have worked to conserve several species, the destruction of many natural habitats is still progressing.  These have much greater consequences for life than the actual carbon uptake of the forests.

AbruptSLR

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Re: Carbon Cycle
« Reply #409 on: October 03, 2017, 08:09:10 PM »
The Ceballos paper, along with many others, extrapolate the decline of other animal species due to human over-hunting and habitat destruction.  Most of the talk about the sixth mass extinction refer to these causes.  While we have taken many steps to stem overhunting and have worked to conserve several species, the destruction of many natural habitats is still progressing.  These have much greater consequences for life than the actual carbon uptake of the forests.

It is certainly a mistake to look at climate change in a vacuum, but just because there are many problems/stresses (e.g. over-population, resource depletion, pollution, warfare, systemic fragilities etc.) in the world today, doesn't that climate change won't be the 'straw that broke the camel's back'. 
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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Re: Carbon Cycle
« Reply #410 on: October 04, 2017, 02:35:50 AM »
A major stressor/extinctor is the rapid shift of climate zones. It is no longer about some megafauna like wooly elephants or about some local ecosystems or civilizations committing agricultural suigenocide or postcolumbian perverts burning down American forests to make soap... The background extinction rate is already that of a major catastrophe.

gerontocrat

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Re: Carbon Cycle
« Reply #411 on: October 04, 2017, 12:03:39 PM »
" ...  wipe out virtually all vertebrate life on earth by mid-century. "

 Any references ?

sidd
I repeat a post I put up some time ago and remembered to save.

Who needs Climate Change to implement the 6th Mass Extinction ?

Robertscribbler.com has just put this up:-
Half-way to Catastrophe — Global Hothouse Extinction to be Triggered by or Before 2100 Without Rapid Emissions Cuts
Fossil Fuel Burning = Race Toward a 6th Mass Extinction

Trouble is, the 6th Mass Extinction is well underway without much help from climate change. The following links give a clue:-

http://www.pnas.org/content/114/30/E6089.full  -
"Biological annihilation via the ongoing sixth mass extinction signaled by vertebrate population losses and declines"

https://www.scientificamerican.com/article/vertebrate-populations-plummet-in-4-decades/
Vertebrate Populations Plummet in 4 Decades

"Deforestation and other human actions have cut the populations of mammals, birds, amphibians and fish by 58 percent since 1970"

https://www.theguardian.com/environment/2016/oct/27/world-on-track-to-lose-two-thirds-of-wild-animals-by-2020-major-report-warns
"World on track to lose two-thirds of wild animals by 2020, major report warns
Living Planet Index shows vertebrate populations are set to decline by 67% on 1970 levels unless urgent action is taken to reduce humanity’s impact"

http://www.pnas.org/content/113/49/14079.full
Large numbers of vertebrates began rapid population decline in the late 19th century

"Significance
The current rate of species extinction is ∼1,000 times the background rate of extinction and is attributable to human impact, ecological and demographic fluctuations, and inbreeding due to small population sizes. The rate and the initiation date of rapid population decline (RPD) can provide important clues about the driving forces of population decline in threatened species, but they are generally unknown. We analyzed the genetic diversity data in 2,764 vertebrate species. Our population genetics modeling suggests that in many threatened vertebrate species the RPD on average began in the late 19th century, and the mean current size of threatened vertebrates is only 5% of their ancestral size. We estimated a ∼25% population decline every 10 y in threatened vertebrate species."

Yes, climate change is now an increasingly major contribution to this process but mankind was doing a pretty good job anyway. 

PS: I did a quick and dirty projection, based on the assumption that population depreciation tends to be on a reducing balance basis, i.e. x percent loss each year of the remaining population. The studies quoted above suggest x is about 2.5%.

That suggests a remaining vertebrate total population of between 10 and 20 % by 2050 compared with 1970.

Real mathematicians are needed to estimate how many individual species extinctions that implies, and also assumes pressures on vertebrate populations remain the same in the future.

So maybe total extermination of vertebrates by 2050 is an exaggeration. Or maybe not.
« Last Edit: October 04, 2017, 12:27:10 PM by gerontocrat »
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Daniel B.

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Re: Carbon Cycle
« Reply #412 on: October 04, 2017, 05:30:21 PM »
The Ceballos paper, along with many others, extrapolate the decline of other animal species due to human over-hunting and habitat destruction.  Most of the talk about the sixth mass extinction refer to these causes.  While we have taken many steps to stem overhunting and have worked to conserve several species, the destruction of many natural habitats is still progressing.  These have much greater consequences for life than the actual carbon uptake of the forests.

It is certainly a mistake to look at climate change in a vacuum, but just because there are many problems/stresses (e.g. over-population, resource depletion, pollution, warfare, systemic fragilities etc.) in the world today, doesn't that climate change won't be the 'straw that broke the camel's back'.

Possibly.  However, I think that any of those other causes could accomplish the decline (and eventually extinction) all by themselves.

jai mitchell

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Re: Carbon Cycle
« Reply #413 on: October 06, 2017, 05:46:52 AM »
https://scienmag.com/carbon-feedback-from-forest-soils-will-accelerate-global-warming-26-year-study-projects/

Quote
WOODS HOLE, Mass. — After 26 years, the world's longest-running experiment to discover how warming temperatures affect forest soils has revealed a surprising, cyclical response: Soil warming stimulates periods of abundant carbon release from the soil to the atmosphere alternating with periods of no detectable loss in soil carbon stores. Overall, the results indicate that in a warming world, a self-reinforcing and perhaps uncontrollable carbon feedback will occur between forest soils and the climate system, adding to the build-up of atmospheric carbon dioxide caused by burning fossil fuels and accelerating global warming. The study, led by Jerry Melillo, Distinguished Scientist at the Marine Biological Laboratory (MBL), appears in the October 6 issue of Science.

Melillo, J.M. et al (2017) Long-Term Pattern and Magnitude of Soil Carbon Feedback to the Climate System in a Warming World. Science
http://science.sciencemag.org/content/358/6359/101
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AbruptSLR

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Re: Carbon Cycle
« Reply #414 on: October 14, 2017, 04:20:45 PM »
The linked article uses the Amazon as a canary in the coal mine for all tropical rainforest deterioration & it errs on the side of least drama by ignoring anthropogenic deforestation and possible synergies with other positive feedback mechanisms (like the ENSO as a climate attractor).  Nevertheless, this article finds that following a short period of biomass grow, most rainforest die-back will occur rapidly as GMSTA increases from 1 to 3C.  The attached image forces a climate model with SRES A1 and finds major die-back of the Amazon before 2100; however, I note that this die-back may occur faster (if the effective ECS this century is higher than the model assumed):

Title: "Climate Change & Anthropocene Extinction 23: Amazon ‘tipping point’ is a sliding process, from +1C"

http://www.bitsofscience.org/climate-change-amazon-tipping-point-7540/

Extract: "In this article we try to quantify the Amazon rainforest climate tipping point, based on available scientific literature. We conclude there’s no real basin-wide threshold temperature to activate the forest-killing biome switch. Rather it seems to be a sliding process, that we are already largely committed to under current CO2 concentrations.

The most rapid warming-induced die-back of the Amazon rainforest probably occurs at a global average temperature rise from 1 to 3 degrees Celsius above the pre-industrial climate. The vegetation effect is delayed, initially masking part of the damage. Yes, that’s sadly yet more climate inertia…"
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AbruptSLR

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Re: Carbon Cycle
« Reply #415 on: October 16, 2017, 05:48:29 PM »
RealClimate has an interesting post focused on the use of OCO-2 to monitor the influence of El Ninos on the Carbon Cycle:

Title: "O Say Can You CO2…"

http://www.realclimate.org/index.php/archives/2017/10/o-say-can-you-co2/

Extract: "As part of a series of OCO-2 papers being published this week, a new Science paper by Junjie Liu and colleagues used NASA’s comprehensive Carbon Monitoring System to analyze millions of measurements from OCO-2 and other satellites to map the impact of the 2015-16 El Niño on sources and sinks of CO2, providing insight into the mechanisms controlling carbon-climate feedback.

Uncertainty in Carbon-Climate Feedbacks is important

We’ve known for decades (Rayner et al, 1999) that El Niño influences the productivity of tropical forests and therefore CO2, but we had very few direct observations of the effects because they are so remote. Field experiments on the ground and aircraft profiling of CO2 over tropical forests have documented the impact of heat and drought on forest productivity, but they are few and far between. Vigorous convective mixing in the deep tropics also dilutes changes in near-surface CO2 much more than at higher latitudes, so low-altitude sampling contains relatively less information about carbon sources and sinks."
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GeoffBeacon

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Re: Carbon Cycle
« Reply #416 on: October 17, 2017, 05:53:39 PM »
HELP!

I've been looking at a PDF of the Carbon Project's Carbon Budget 2016. It has a graphic, Carbon quota for a 66% chance to keep below 2°C, with a sub-heading
Quote
The total remaining emissions from 2017 to keep global average temperature below 2°C (800GtCO2) will be used in around 20 years at current emission rates

This is the image:



(How do I do inline images?) <use the img tags, or highlight the image link address and then press the img button in the editor above the comment (next to the f sign, middle row, under the italics button). If you click the 'modify comment' button for this comment, you can see what I did; N. Thanks; Geoff>

I have also downloaded some of the numbers for CO2 emissions from RCP 2.6. Have I got the following right?

Quote
Net emissions for RCP2.6 are 824 Gt CO2 - for fossil fuel and cement. Adding in 180 Gt of CO2 from changes in land use for the period 2017 to 2100 give total CO2 emissions of 1004 Gt of CO2 – much larger than the 816 remaining CO2 quota. (Note: Wildfire emissions count as land use change emissions.)

The worse news is that World CO2 emissions are exceeding the emissions in the hypothetical numbers that are in the RCP2.6 CO2 scenario. CO2 emissions, including land use change, were 49.1 Gt CO2 in 2016, 11% more than in the RCP 2.6 scenario for that year.

These are only for CO2. Other climate pollutants are treated separately.

I got the 824 Gt CO2 emissions (2017 to 2100) from 889 Gt CO2 positive emissions (2017 to 2072) less 65 Gt CO2 negative emissions (20673 to 2100).

I'm not necessarily asking for a reworking of this (though that would be welcome) but is this result so unexpected that I must have misunderstood.

I thought RCP2.6 was our savior. Am I wrong?
« Last Edit: October 18, 2017, 12:31:21 PM by GeoffBeacon »
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Daniel B.

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Re: Carbon Cycle
« Reply #417 on: October 18, 2017, 03:17:55 PM »
HELP!

I've been looking at a PDF of the Carbon Project's Carbon Budget 2016. It has a graphic, Carbon quota for a 66% chance to keep below 2°C, with a sub-heading
Quote
The total remaining emissions from 2017 to keep global average temperature below 2°C (800GtCO2) will be used in around 20 years at current emission rates

This is the image:



(How do I do inline images?) <use the img tags, or highlight the image link address and then press the img button in the editor above the comment (next to the f sign, middle row, under the italics button). If you click the 'modify comment' button for this comment, you can see what I did; N. Thanks; Geoff>

I have also downloaded some of the numbers for CO2 emissions from RCP 2.6. Have I got the following right?

Quote
Net emissions for RCP2.6 are 824 Gt CO2 - for fossil fuel and cement. Adding in 180 Gt of CO2 from changes in land use for the period 2017 to 2100 give total CO2 emissions of 1004 Gt of CO2 – much larger than the 816 remaining CO2 quota. (Note: Wildfire emissions count as land use change emissions.)

The worse news is that World CO2 emissions are exceeding the emissions in the hypothetical numbers that are in the RCP2.6 CO2 scenario. CO2 emissions, including land use change, were 49.1 Gt CO2 in 2016, 11% more than in the RCP 2.6 scenario for that year.

These are only for CO2. Other climate pollutants are treated separately.

I got the 824 Gt CO2 emissions (2017 to 2100) from 889 Gt CO2 positive emissions (2017 to 2072) less 65 Gt CO2 negative emissions (20673 to 2100).

I'm not necessarily asking for a reworking of this (though that would be welcome) but is this result so unexpected that I must have misunderstood.

I thought RCP2.6 was our savior. Am I wrong?

No, not necessarily.  Those calculations for cumulative emissions from the Carbon Project are based on an equilibrium climate sensitivity (ECS) of 3.0, and their 3670 Gt comes from the 67% probability.  The calculations for a 50% probability is 4440, corresponding to an ECS of 2.5 (33% is 5760, ECS of 2.0).  The RCP2.6 scenario falls in between these two values.  Based on your value of 1004 Gt by 2100 and the Carbon Project analysis, temperatures under the RCP2.6 scenario would remain below 2C as long as the ECS is below 2.86, a probability of 62%.  Clear as mud?

GeoffBeacon

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Re: Carbon Cycle
« Reply #418 on: October 18, 2017, 04:58:49 PM »
Thanks Daniel

I have just spent ages (and ages) redoing this. I'm going to post what I've done before looking at your kind response.
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GeoffBeacon

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Re: Carbon Cycle
« Reply #419 on: October 18, 2017, 05:21:23 PM »
CARBON BUDGETS AND RCP2.6

I've been looking at this further and been comparing the Global Carbon Project's Carbon Budgets for 2016 and 2015 and found another useful diagram.  I had some confusion due to the fact that the diagram in the “2015 budget document” showed data to the end of 2014 but the similar diagram in the 2016 budget document  showed data to the end of 2016 - moving on a year. Here are the diagrams, with a little bit of extra annotation.

A: From Carbon Budget 2015: Heading “The total remaining emissions from 2014 to keep global average temperature below 2°C (900 GtCO2 ) will be used in around 20 years at current emission rates”.



From Carbon Budget 2016:  Heading  “The total remaining emissions from 2017 to keep global average temperature below 2°C (800 GtCO2 ) will be used in around 20 years at current emission rates”.



I interpret the diagrams like this

1) “Total quota 3670”: 3670 Gt CO2 is 1000  GtC as per Allen et. al Warming caused by cumulative carbon emissions towards the trillionth tonne.

2) “Non-CO2 770”: It is assumed that the effect of non-CO2 pollutants will have a similar climate effect on the carbon buget to emissions of 770 Gt of CO2.

3) Emissions of CO2 from fossil fuels between the ends of 2014 and 2016 have reduced the remaining carbon budget by the difference between 1542 Gt CO2 (A) and 1465 Gt CO2 (B) ie. 77 Gt CO2. This is two years worth of fossil fuel and cement emissions (38.5 Gt CO2/year?).

4) Emissions of CO2 from land use change have reduced the remaining carbon budget by the difference between 542 Gt CO2 (A) and 533 Gt CO2 (B) ie. 9 Gt CO2. This is two years worth of fossil fuel and cement emissions (4.5 Gt CO2/year?).

5) The “total remaining CO2 quota” has reduced from 903 Gt CO2 to 816 GtCO2 i.e. by 87 GtCO2. That averages at 43.5 Gt CO2/year.

In (A) the remaining budget is split between future land use change and future fossil fuel and cement emissions. I'm not sure where the “Future  LUC 138” comes from but I note that the numbers given in the RCP2.6 tables give “Other CO2 emissions”. These total 122 Gt CO2 between the end of  2016 and 2072. Year 2072 is the date that RCP2.6 goes into negative emissions fossil fuel and cement.

Taking 122 Gt CO2 off the “total remaining CO2 quota” at the end of 2016 gives 694 Gt CO2.

That's just over 91 tonnes CO2 each when it's spread over the world's population.  Using this methodology, I think we may have about 25% extra budget to emit non-CO2 emissions. That would take us to 120 tonnes CO2e each.

The average UK citizen gets through that in about eight years – if we do the decent thing and  measure emissions on a consumption basis rather than cheating and measuring on a production basis like our government does.

However,  there's lots of reasons for thinking the climate situation is worse. 

Anyway, according to my spreadsheet, RCP 2.6 runs out of the 816 Gt CO2 remaining budget in 2047 and that budget is for a 2°C rise in global temperature and we seem to be soaring way above RCP 2.6.
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Re: Carbon Cycle
« Reply #420 on: October 18, 2017, 05:23:52 PM »
Daniel

Quote
Clear as mud?

No very helpful.

Thanks.

Geoff
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Re: Carbon Cycle
« Reply #421 on: October 18, 2017, 06:05:35 PM »
CARBON BUDGETS AND RCP2.6

I've been looking at this further and been comparing the Global Carbon Project's Carbon Budgets for 2016 and 2015 and found another useful diagram.  I had some confusion due to the fact that the diagram in the “2015 budget document” showed data to the end of 2014 but the similar diagram in the 2016 budget document  showed data to the end of 2016 - moving on a year. Here are the diagrams, with a little bit of extra annotation.

A: From Carbon Budget 2015: Heading “The total remaining emissions from 2014 to keep global average temperature below 2°C (900 GtCO2 ) will be used in around 20 years at current emission rates”.



From Carbon Budget 2016:  Heading  “The total remaining emissions from 2017 to keep global average temperature below 2°C (800 GtCO2 ) will be used in around 20 years at current emission rates”.



I interpret the diagrams like this

1) “Total quota 3670”: 3670 Gt CO2 is 1000  GtC as per Allen et. al Warming caused by cumulative carbon emissions towards the trillionth tonne.

2) “Non-CO2 770”: It is assumed that the effect of non-CO2 pollutants will have a similar climate effect on the carbon buget to emissions of 770 Gt of CO2.

3) Emissions of CO2 from fossil fuels between the ends of 2014 and 2016 have reduced the remaining carbon budget by the difference between 1542 Gt CO2 (A) and 1465 Gt CO2 (B) ie. 77 Gt CO2. This is two years worth of fossil fuel and cement emissions (38.5 Gt CO2/year?).

4) Emissions of CO2 from land use change have reduced the remaining carbon budget by the difference between 542 Gt CO2 (A) and 533 Gt CO2 (B) ie. 9 Gt CO2. This is two years worth of fossil fuel and cement emissions (4.5 Gt CO2/year?).

5) The “total remaining CO2 quota” has reduced from 903 Gt CO2 to 816 GtCO2 i.e. by 87 GtCO2. That averages at 43.5 Gt CO2/year.

In (A) the remaining budget is split between future land use change and future fossil fuel and cement emissions. I'm not sure where the “Future  LUC 138” comes from but I note that the numbers given in the RCP2.6 tables give “Other CO2 emissions”. These total 122 Gt CO2 between the end of  2016 and 2072. Year 2072 is the date that RCP2.6 goes into negative emissions fossil fuel and cement.

Taking 122 Gt CO2 off the “total remaining CO2 quota” at the end of 2016 gives 694 Gt CO2.

That's just over 91 tonnes CO2 each when it's spread over the world's population.  Using this methodology, I think we may have about 25% extra budget to emit non-CO2 emissions. That would take us to 120 tonnes CO2e each.

The average UK citizen gets through that in about eight years – if we do the decent thing and  measure emissions on a consumption basis rather than cheating and measuring on a production basis like our government does.

However,  there's lots of reasons for thinking the climate situation is worse. 

Anyway, according to my spreadsheet, RCP 2.6 runs out of the 816 Gt CO2 remaining budget in 2047 and that budget is for a 2°C rise in global temperature and we seem to be soaring way above RCP 2.6.

I am not sure what the future land use changes were either, but they disappeared from the most recent graph.  Possibly, they were lumped in with the total CO2 quota.  Curious how in 2014, 900 Gt would be used in around 20 years, and now, 816 Gt will be used in around 20 years.

rboyd

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Re: Carbon Cycle
« Reply #422 on: October 19, 2017, 01:27:08 AM »
The research is tending to an ECS at the higher end of the range than assumed in these carbon budgets, plus they do not take into account feedbacks (soil carbon, clouds, albedo etc.), plus they underestimate the effect of methane, plus the land use numbers are highly suspect. Apart from that, these carbon budgets are really useful /sarc.

There is no carbon budget if we take any realistic view of things and/or use a better (i.e. much higher than 2 out of 3, even in Russian Roulette its 1 out of 6) probability of success.

It will be interesting to watch the UN IPCC attempt to keep the carbon budget story going when confronted with updated scientific findings.

Daniel B.

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Re: Carbon Cycle
« Reply #423 on: October 20, 2017, 01:32:45 PM »
The research is tending to an ECS at the higher end of the range than assumed in these carbon budgets, plus they do not take into account feedbacks (soil carbon, clouds, albedo etc.), plus they underestimate the effect of methane, plus the land use numbers are highly suspect. Apart from that, these carbon budgets are really useful /sarc.

There is no carbon budget if we take any realistic view of things and/or use a better (i.e. much higher than 2 out of 3, even in Russian Roulette its 1 out of 6) probability of success.

It will be interesting to watch the UN IPCC attempt to keep the carbon budget story going when confronted with updated scientific findings.



Have you seen these?  http://www.nature.com/nclimate/journal/v7/n9/fig_tab/nclimate3357_F1.html
https://www.hindawi.com/archive/2017/9251034/
https://principia-scientific.org/recent-co2-climate-sensitivity-estimates-headed-towards-zero/



GeoffBeacon

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Re: Carbon Cycle
« Reply #424 on: October 20, 2017, 03:21:03 PM »
I've put my postings above on my BrusselBlog website with some extra bits.  It seems clear that the effects of increased wildfires are not in models or the emissions trajectories specified in RCP2.6.

In RCP2.6: exploring the possibility to keep global mean temperature increase below 2°C by van Vuuren et. al, the developers of RCP 2.6 make no mention of wildfire activity. Also an increase in wildfire activity was not included in the computer models for the IPCC’s AR5.

Policy makers point to RCP 2.6 with the message “if we can keep emissions close to RCP2.6 levels, dangerous climate change can be avoided”. (See the end of Lord Stern’s lecture, The Stern Review +10: new opportunities for growth and development.)

If we can't trust RCP 2.6 as a safe target to aim for, what can we trust?

Obvious questions for me are

Quote
1. Have wildfires been included in any scenarios for the future of our climate?

2. Why can’t representative carbon pathways be fed into climate models to tell us about the effects burning down forests, flying and eating beef?

3. How hard is (2)?


Il faut cultiver notre cité-jardin
The Sustainable Plotlands Association

Shared Humanity

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Re: Carbon Cycle
« Reply #425 on: October 23, 2017, 06:25:27 PM »
More failures of major carbon sinks, which are now turning into sources, this time tropical forests:

 Alarm as study reveals world’s tropical forests are huge carbon emission source

Forests globally are so degraded that instead of absorbing emissions they now release more carbon annually than all the traffic in the US


https://www.theguardian.com/environment/2017/sep/28/alarm-as-study-reveals-worlds-tropical-forests-are-huge-carbon-emission-source
Also a major contribution to the 6th Mass Extinction currently underway and which at the current rate of progress will wipe out virtually all vertebrate life on earth by mid-century.

And most of us shortly thereafter.

Shared Humanity

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Re: Carbon Cycle
« Reply #426 on: October 23, 2017, 06:26:59 PM »
Just had to log on to check if the rainforest-study had been mentioned here. This looks like the endgame to 4-6---12 °C above 1950s, is about to begin. It feels quite ok to be rather aged and childless.

4 children (1 adopted) and 1st grandchild on the way. It is sad and depressing.

Shared Humanity

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Re: Carbon Cycle
« Reply #427 on: October 23, 2017, 06:31:56 PM »

It is certainly a mistake to look at climate change in a vacuum, but just because there are many problems/stresses (e.g. over-population, resource depletion, pollution, warfare, systemic fragilities etc.) in the world today, doesn't that climate change won't be the 'straw that broke the camel's back'.

Possibly.  However, I think that any of those other causes could accomplish the decline (and eventually extinction) all by themselves.

Your point being?

Daniel B.

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Re: Carbon Cycle
« Reply #428 on: October 23, 2017, 07:13:53 PM »

It is certainly a mistake to look at climate change in a vacuum, but just because there are many problems/stresses (e.g. over-population, resource depletion, pollution, warfare, systemic fragilities etc.) in the world today, doesn't that climate change won't be the 'straw that broke the camel's back'.

Possibly.  However, I think that any of those other causes could accomplish the decline (and eventually extinction) all by themselves.

Your point being?

That climate change will be a minor contributor to extinctions.  Most plants and animals would be able to adapt to climate perturbations much easier that overhunting, pollution, or total habitat destruction. 

AbruptSLR

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Re: Carbon Cycle
« Reply #429 on: October 23, 2017, 08:34:10 PM »
That climate change will be a minor contributor to extinctions.  Most plants and animals would be able to adapt to climate perturbations much easier that overhunting, pollution, or total habitat destruction.

Climate change doubters and skeptics like denigrate, and then ignore, one positive feedback mechanism at a time.  Unfortunately, there many serious positive feedback mechanisms (such as that discussed in the linked article about carbon emissions from the planet's soils) that have been omitted from AR5 and CMIP5 projections.  Thus we may not know whether we have crossed a tipping point until it is too late.

Title: "One of the oldest climate change experiments has led to a troubling conclusion"

https://www.washingtonpost.com/news/energy-environment/wp/2017/10/05/one-of-the-oldest-climate-change-experiments-has-led-to-a-troubling-conclusion/?utm_term=.59cc09198793

Extract: One of the regular complaints of climate change doubters and skeptics is that scientific projections of a dire future are too heavily based on computer simulations, or models, which — they say — rest on a variety of questionable assumptions.

But a major climate change study published Thursday relied not on models but experimental data — a 26-year record of observations, no less — to reach a conclusion perhaps just as worrying. The research, tracking the emissions of carbon from artificially heated plots of a forest in Massachusetts, reinforces fears about the possibility of a climate change “feedback” involving the planet’s soils, one that could pile on top of and substantially worsen the ongoing warming trend triggered by the burning of fossil fuels."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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wili

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Re: Carbon Cycle
« Reply #430 on: October 23, 2017, 10:31:55 PM »
Daniel seems to be ignoring the mass of evidence that most and probably all of the previous mass extinction events were driven primarily by global warming.
"A force de chercher de bonnes raisons, on en trouve; on les dit; et après on y tient, non pas tant parce qu'elles sont bonnes que pour ne pas se démentir." Choderlos de Laclos "You struggle to come up with some valid reasons, then cling to them, not because they're good, but just to not back down."

TerryM

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Re: Carbon Cycle
« Reply #431 on: October 23, 2017, 11:13:13 PM »
Just had to log on to check if the rainforest-study had been mentioned here. This looks like the endgame to 4-6---12 °C above 1950s, is about to begin. It feels quite ok to be rather aged and childless.

4 children (1 adopted) and 1st grandchild on the way. It is sad and depressing.


My condolences.


Any concerns about whether they stay until the last ship has sailed, or bail out while still flying high? To mix a few metaphors before serving on the aft deck of the Titanic.


Terry

sidd

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Re: Carbon Cycle
« Reply #432 on: October 24, 2017, 06:09:47 AM »
Re: " ...  most and probably all of the previous mass extinction events were driven primarily by global warming. "

I am not sure this is true. Cites ?

sidd

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Re: Carbon Cycle
« Reply #433 on: October 24, 2017, 08:13:23 AM »

It is certainly a mistake to look at climate change in a vacuum, but just because there are many problems/stresses (e.g. over-population, resource depletion, pollution, warfare, systemic fragilities etc.) in the world today, doesn't that climate change won't be the 'straw that broke the camel's back'.

Possibly.  However, I think that any of those other causes could accomplish the decline (and eventually extinction) all by themselves.

Your point being?

That climate change will be a minor contributor to extinctions.  Most plants and animals would be able to adapt to climate perturbations much easier that overhunting, pollution, or total habitat destruction.

That's what I think too. No matter where I go, habitats are degraded not because of climate change but because of mechanical and chemical destruction through agriculture. Then add expanding cities and hunting/ fishing and you have the perfect storm for extinctions. 

Without all the human impact, most species would just migrate in the light of a warming climate.

Bernard

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Re: Carbon Cycle
« Reply #434 on: October 24, 2017, 01:58:00 PM »

No matter where I go, habitats are degraded not because of climate change but because of mechanical and chemical destruction through agriculture. Then add expanding cities and hunting/ fishing and you have the perfect storm for extinctions. 

Without all the human impact, most species would just migrate in the light of a warming climate.

There is a caveat to those points. Destruction by direct impact (agriculture, expanding cities, overfishing/hunting) can be stopped rather "rapidly", in a generation, say, if there is a real political will and action (which is, I agree, wishful thinking in the current state of affairs). Degraded soils can be restored in a matter of years, fishing and hunting policies can be enforced, urbanism controlled, etc. Even overpopulation, public enemy #1, can be curbed. All those are doable to some extent, and efforts are made here, there and everywhere in this direction. Far from enough, but not completely hopeless.
BUT the time scale of ongoing climate change will span for centuries whatever action we take now, because of all the feedback loops already at work and the huge inertia already built. Look at the Keeling curve and how it steadily grows despite whatever we do or don't about carbon. Even if we change something about the other causes, climate change is here to stay. And migration to better places is not an option for most species, far from it. If you are a fish or frog in a mountain lake or stream and the drought is drying up your home, you don't migrate. You dry on spot.
Maybe other direct causes are more obvious right now, but secondary impacts of climate change will be more and more prevalent I'm afraid. Of course, if we do nothing about the former, the latter will just be the last hit of the hammer on the nails of our coffins.

AbruptSLR

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Re: Carbon Cycle
« Reply #435 on: October 24, 2017, 03:40:59 PM »
I note that climate change does not only mean emissions of GHGs from anthropogenic fossil fuels.  It also includes all other anthropogenic radiative forcings such as changes in surface albedo, deforestation, acidification of the oceans, and all associated feedback mechanisms.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

Daniel B.

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Re: Carbon Cycle
« Reply #436 on: October 24, 2017, 04:30:27 PM »
Re: " ...  most and probably all of the previous mass extinction events were driven primarily by global warming. "

I am not sure this is true. Cites ?

sidd

It appears to not be so.  This link lists what many think are the primary causes of the "Big 5" mass extinctions:

1.  The Ordovician event (443 Myr) is thought to be due to periods of intense glaciation
2.

https://www.nature.com/nature/journal/v471/n7336/fig_tab/nature09678_T1.html

Daniel B.

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Re: Carbon Cycle
« Reply #437 on: October 24, 2017, 04:45:15 PM »
Sorry, got cut off.

1.  Ordovician event (440 Myr ago) is thought to have been cause by periods of intense glaciation and recession.
2.  Devonian event (360 Myr ago) by global cooling, likely caused by an asteroid impact or volcanism.
3.  Permian event (250 Myr ago)  by the eruption of a Siberian volcano (although this may have been ultimately caused by an asteroid impact leading to the eruption.
4.  Triassic event (200 Myr ago)  Atlantic volcanic lava flow, although an asteroid impact has not been ruled out.
5.  Cretaceous event (65 Myr ago)  suspected cause is an asteroid impact in the Yucatan, although volcanic activity in India has been cited frequently also.

In none of these was the primary cause listed as "global warming."

wili

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Re: Carbon Cycle
« Reply #438 on: October 25, 2017, 03:37:45 AM »
And what does 'volcanic activity' produce?
"A force de chercher de bonnes raisons, on en trouve; on les dit; et après on y tient, non pas tant parce qu'elles sont bonnes que pour ne pas se démentir." Choderlos de Laclos "You struggle to come up with some valid reasons, then cling to them, not because they're good, but just to not back down."

TerryM

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Re: Carbon Cycle
« Reply #439 on: October 25, 2017, 03:39:09 AM »
Sorry, got cut off.

1.  Ordovician event (440 Myr ago) is thought to have been cause by periods of intense glaciation and recession.
2.  Devonian event (360 Myr ago) by global cooling, likely caused by an asteroid impact or volcanism.
3.  Permian event (250 Myr ago)  by the eruption of a Siberian volcano (although this may have been ultimately caused by an asteroid impact leading to the eruption.
4.  Triassic event (200 Myr ago)  Atlantic volcanic lava flow, although an asteroid impact has not been ruled out.
5.  Cretaceous event (65 Myr ago)  suspected cause is an asteroid impact in the Yucatan, although volcanic activity in India has been cited frequently also.

In none of these was the primary cause listed as "global warming."


How fortunate for us!
Our Anthropomorphic Suicide will be the first in the world's long history.


Perhaps only god can make a tree, but certainly only civilized man can pull the whole thing down on his own head.


With Trump out of the Paris Accord, perhaps we can now put some real teeth in the agreement. Say by putting CO2 based tariffs on every internationally traded item. If Mr. Keeting's curve continues upwards, so will our tariffs.
If we break a few countries, these will be among the worst offenders, and begging for food is preferable to dying of heat stroke.
Terry

wili

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Re: Carbon Cycle
« Reply #440 on: October 25, 2017, 03:45:20 AM »
Hints:

"Viluy magmatism may inject enough CO2 and SO2 into the atmosphere to generate a destabilised greenhouse and ecosystem..."

https://en.wikipedia.org/wiki/Late_Devonian_extinction#Magmatism

"A recent hypothesis put forward is that the volcanism [from Siberian Traps] was a trigger that led to an explosion of the growth of Methanosarcina, a microbe that then spewed enormous amounts of methane into Earth's atmosphere...

at the peak of the extinction, the Earth underwent lethally hot global warming, in which equatorial ocean temperatures exceeded 40 °C (104 °F)"

https://en.wikipedia.org/wiki/Siberian_Traps

... I could go on, but anyone who wants to can look this sh!t up and see the truth, unless they are hell-bent on ignoring it or trying to distract others from it.

"A force de chercher de bonnes raisons, on en trouve; on les dit; et après on y tient, non pas tant parce qu'elles sont bonnes que pour ne pas se démentir." Choderlos de Laclos "You struggle to come up with some valid reasons, then cling to them, not because they're good, but just to not back down."

sidd

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Re: Carbon Cycle
« Reply #441 on: October 25, 2017, 05:07:59 AM »
I entirely accept that there is evidence for some of the Great Extinctions being due to greenhouse or hothouse state, and there is good discussion in the series by Kidder and Worsely, as I have posted before. But I am not convinced as to the Devonian and Ordovican extinctons.  As to the postulated magmatic driven CO2 impact for the Devonian, I am not sure that outweighs the evidence for extensive glaciation, probably driven by evolution of the first forests in the Devonian pulling CO2 down.  But that last is a conjecture, as is the hypothesis relating magmatic eruption to the Devonian extinction.

sidd

wili

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Re: Carbon Cycle
« Reply #442 on: October 25, 2017, 05:38:06 AM »
"...there is evidence for some of the Great Extinctions being due to greenhouse or hothouse state..."

Thanks, sidd. That's the main point. And I'm sure you have a far better grasp of the relevant science than most others here, including myself.

As you recall, the whole thing came up because some have been downplaying the potential role of ghgs/gw in extinctions. There is, indeed, good evidence that some were indeed due primarily to ghg's build up leading to gw.

So there is very good reason to expect that our current breakneck rate of gw will bring about many extinctions and likely at least greatly exacerbate the current mass extinction event now well underway. Would you agree?
"A force de chercher de bonnes raisons, on en trouve; on les dit; et après on y tient, non pas tant parce qu'elles sont bonnes que pour ne pas se démentir." Choderlos de Laclos "You struggle to come up with some valid reasons, then cling to them, not because they're good, but just to not back down."

sidd

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Re: Carbon Cycle
« Reply #443 on: October 25, 2017, 09:16:50 AM »
Agreed that current extinction event is partly driven by human fossil carbon exhaust leading to CO2 forcing. But I think human killing of mega/micro fauna and flora and human driven habitat destruction is at least as much to blame.

sidd

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Re: Carbon Cycle
« Reply #444 on: October 25, 2017, 02:14:49 PM »
Agreed that current extinction event is partly driven by human fossil carbon exhaust leading to CO2 forcing. But I think human killing of mega/micro fauna and flora and human driven habitat destruction is at least as much to blame.

sidd

Compared to past episodes, the recent temperature change pales in comparison to large warming and/or cooling estimated to have occurred during past mass extinctions (the estimated temperature drop of the seas during the Devonian event was 15F!).  Check out the animals on the endangered species list.  Habitat loss is estimated to be the main threat to 85% of those species listed.  Overhunting/fishing is the main threat to most of the others. 

https://www.worldwildlife.org/species/directory
http://wwf.panda.org/about_our_earth/species/problems/habitat_loss_degradation/

Shared Humanity

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Re: Carbon Cycle
« Reply #445 on: October 25, 2017, 02:42:49 PM »
Agreed that current extinction event is partly driven by human fossil carbon exhaust leading to CO2 forcing. But I think human killing of mega/micro fauna and flora and human driven habitat destruction is at least as much to blame.

sidd

Compared to past episodes, the recent temperature change pales in comparison to large warming and/or cooling estimated to have occurred during past mass extinctions (the estimated temperature drop of the seas during the Devonian event was 15F!).  Check out the animals on the endangered species list.  Habitat loss is estimated to be the main threat to 85% of those species listed.  Overhunting/fishing is the main threat to most of the others. 

https://www.worldwildlife.org/species/directory
http://wwf.panda.org/about_our_earth/species/problems/habitat_loss_degradation/

So human driven habitat destruction is the main threat to 85% of the species listed and likely then for the actual extinction of a similar percentage. Meanwhile we are determined to engage in planet wide habitat destruction as a result of human driven climate change. The difference being that previous habitat destruction required an aggressive migration of humans with the resultant hunting and agriculture temporarily altering a landscape that could rebound in several generations. This time we are destroying habitats across the planet without ever having to set foot in them using a method that will outlast human civilization.

I feel much better now.

Shared Humanity

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Re: Carbon Cycle
« Reply #446 on: October 25, 2017, 02:50:08 PM »
Trust me, cutting down trees and turning vast areas of the planet into agricultural land while stripping every form of stored carbon, from trees to fossil fuels to support industry with its resultant pollution pales in comparison to altering the most basic processes of the planet like the carbon cycle or acidifying the oceans. We (humans) are now engaging in a living organism driven, planet wide habitat destruction (modification) not seen since the reign of bacteria and other small life forms.

And yes, I believe BAU extinction will rival the Permian extinction.

Shared Humanity

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Re: Carbon Cycle
« Reply #447 on: October 25, 2017, 02:53:59 PM »
So now, can we get back on topic on this science thread that is intended to present for discussion the carbon cycle and the changes occurring as a result of climate change? The kinds of contributions that Bruce Steele intended for and provided when this thread was created.

Shared Humanity

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Re: Carbon Cycle
« Reply #448 on: October 25, 2017, 03:07:54 PM »
For example, I am very concerned about ocean acidification impacting phytoplankton in the oceans and the long term impact on organic carbon deposition and the resultant levels of atmospheric CO2 and oxygen.

https://pubs.geoscienceworld.org/geology/article-abstract/24/10/867/206380/carbon-isotopes-and-the-rise-of-atmospheric-oxygen?redirectedFrom=fulltext

We know, for example, that seasonal variations in northern hemisphere terrestrial plant activity and the resultant carbon uptake causes the seasonal variation in atmospheric CO2.

http://onlinelibrary.wiley.com/doi/10.1029/JD090iD06p10529/full

Doesn't this suggest that any negative impacts on plant activity caused by increasing CO2 levels (ocean acidification) can impact O2 levels as well? More simply, reduced carbon uptake necessarily means reduced oxygen production and atmospheric oxygen levels, doesn't it?

Since I am not a scientist, I do not know if my fear is warranted.

(Would love to have my concerns set aside by contributions here from people better informed than me.)
« Last Edit: October 25, 2017, 03:28:01 PM by Shared Humanity »

Shared Humanity

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Re: Carbon Cycle
« Reply #449 on: October 25, 2017, 04:21:38 PM »
If I interpret this correctly, reduced atmospheric oxygen due to less robust carbon uptake presents no risk to humans or any other life form.

https://www.wildsafe.org/resources/outdoor-safety-101/altitude-safety-101/high-altitude-oxygen-levels/

It would appear that ocean acidification and oxygen deprivation and its effects on the food chain are what to worry about.
« Last Edit: October 25, 2017, 04:28:16 PM by Shared Humanity »