Trajectories of the Earth System in the Anthropocene

[Unitedwestand13]

A new study from the proceedings of the national Academy of Sciences.

From the abstract.

We explore the risk that self-reinforcing feedbacks could push the Earth System toward a planetary threshold that, if crossed, could prevent stabilization of the climate at intermediate temperature rises and cause continued warming on a “Hothouse Earth” pathway even as human emissions are reduced. Crossing the threshold would lead to a much higher global average temperature than any interglacial in the past 1.2 million years and to sea levels significantly higher than at any time in the Holocene. We examine the evidence that such a threshold might exist and where it might be. If the threshold is crossed, the resulting trajectory would likely cause serious disruptions to ecosystems, society, and economies. Collective human action is required to steer the Earth System away from a potential threshold and stabilize it in a habitable interglacial-like state. Such action entails stewardship of the entire Earth System—biosphere, climate, and societies—and could include decarbonization of the global economy, enhancement of biosphere carbon sinks, behavioral changes, technological innovations, new governance arrangements, and transformed social values.

http://www.pnas.org/content/early/2018/07/31/1810141115

 

[Hawkeye10]

A new study from the proceedings of the national Academy of Sciences.

From the abstract.


Trajectories of the Earth System in the Anthropocene | PNAS

The ability to adapt is THE key to survival.

How many of these Modern Morons never got educated enough to know even the fundamentals?

 

[longview]

A new study from the proceedings of the national Academy of Sciences.

From the abstract.


Trajectories of the Earth System in the Anthropocene | PNAS

The problem with the idea of amplified feedbacks, it that if they existed at a very high level we would have already
seen the effects. Keep in mind that the feedbacks cannot discriminate between the causes of input.
If the feebacks exists, then they have always existed.
The .2 C of warming that occurred before 1940, would have been through almost two amplification cycles,
if Hansen's 37.5 year ECS time is correct.

 

[Surface Detail]

A new study from the proceedings of the national Academy of Sciences.

From the abstract.


Trajectories of the Earth System in the Anthropocene | PNAS

Yes, it is well known that the Earth's climate is an unstable system, prone to shift dramatically in response to relatively small input changes. The series of interglacial periods within the current ice age are a good illustration of this. This means that a linear response to the large stimulus of AGW is by no means assured, and this stimulus could very well result in an irreversible step change in the Earth's climate. It is reckless to the point of insanity for humanity to continue emitting GHGs at its current rate.

 

[Empirica]

A new study from the proceedings of the national Academy of Sciences.

From the abstract.

Trajectories of the Earth System in the Anthropocene | PNAS

Dadgummit! Just when I thought it was safe ta go back in the water!

And here I got this seriously hot new billabong bikini and matching beach bag!

What's next?! Global road work with orange barrels and lane closures everyday at lunch hour?!

Fercrisake people; I do my best shopping at lunch hour...I feel some serious road rage coming on here! :crazy3:

 

[Jack Hays]

A new study from the proceedings of the national Academy of Sciences.

From the abstract.


Trajectories of the Earth System in the Anthropocene | PNAS

[h=1]Wacky claim: Planet now at risk of heading toward ‘hothouse Earth’ state[/h]From the Stockholm Resilience Center and the mind of Hans Joachim Schellnhuber comes this nutball press release. Keeping global warming to within 1.5-2 degrees C may be more difficult than previously assessed, according to researchers. An international team of scientists has published a study in the Proceedings of the National Academy of Sciences (PNAS) showing…

1 day ago August 6, 2018 in Alarmism.

 

[Jack Hays]

Climate News
Hothouse Earth – an extremely dodgy proposition

No new science, no new data, no new scenario and consequently no new cause for panic. Dr David Whitehouse, GWPF Science Editor It’s been a long heatwave in much of Europe which has prompted questions like ‘what is the influence of climate change on this year’s heatwave?’ Some claim that it’s twice as likely to…

. . . Whatever way the evidence points, wherever the argument goes or the temperature changes in the future, the media have loved the “Earth’s on Fire,” headlines. But if you thought that was bad wait for the apocalypse. A new paper claims were are heading to a “Hothouse Earth,” and perhaps soon. Cue the heatwave fever on steroids.
The first thing to bear with the paper that suggest this is that it is a “Perspective” paper in the Proceedings of the National Academy of Science of the USA. . . .

Yet, it is not a research paper and contains nothing new in the way of climate science. It is a future scenario pieced together by quoting selected (cherry-picked) references with a lot of hand-waving in-between. The author’s say it’s not conclusive, and they hope it’s not going to be true. They have a responsibility to ask the question, they claim, admitting it’s extreme.
The report starts as it continues. It says the formalisation of the Anthropocene – the controversial ‘geological’ epoch in which mankind allegedly dominates natural processes – is being considered by the stratigraphic community. Just a few days after this paper was accepted for publication, the International Commission on Stratigraphy decided against endorsing the Anthropocene, saying that we live in the Meghalayan Epoch instead. However the authors then go on to say that it is actually irrelevant what the geological community decides, they are going to claim the Anthropocene exists anyway. Human activity, they conclude, now rivals geological forces. . . .

 

[Surface Detail]

Climate News
Hothouse Earth – an extremely dodgy proposition

No new science, no new data, no new scenario and consequently no new cause for panic. Dr David Whitehouse, GWPF Science Editor It’s been a long heatwave in much of Europe which has prompted questions like ‘what is the influence of climate change on this year’s heatwave?’ Some claim that it’s twice as likely to…

. . . Whatever way the evidence points, wherever the argument goes or the temperature changes in the future, the media have loved the “Earth’s on Fire,” headlines. But if you thought that was bad wait for the apocalypse. A new paper claims were are heading to a “Hothouse Earth,” and perhaps soon. Cue the heatwave fever on steroids.
The first thing to bear with the paper that suggest this is that it is a “Perspective” paper in the Proceedings of the National Academy of Science of the USA. . . .

Yet, it is not a research paper and contains nothing new in the way of climate science. It is a future scenario pieced together by quoting selected (cherry-picked) references with a lot of hand-waving in-between. The author’s say it’s not conclusive, and they hope it’s not going to be true. They have a responsibility to ask the question, they claim, admitting it’s extreme.
The report starts as it continues. It says the formalisation of the Anthropocene – the controversial ‘geological’ epoch in which mankind allegedly dominates natural processes – is being considered by the stratigraphic community. Just a few days after this paper was accepted for publication, the International Commission on Stratigraphy decided against endorsing the Anthropocene, saying that we live in the Meghalayan Epoch instead. However the authors then go on to say that it is actually irrelevant what the geological community decides, they are going to claim the Anthropocene exists anyway. Human activity, they conclude, now rivals geological forces. . . .

Yawn. Professional AGW denier denies AGW on spoof science website.

 

[Jack Hays]

Yawn. Professional AGW denier denies AGW on spoof science website.

The ad hominem is the refuge of those without an argument.

 

[Jack Hays]

Who Pushed the Alarmist Domino – Scientists or the Media?

Posted on 08 Aug 18 by BENPILE • Leave a comment
Few have missed the fact that Trajectories of the Earth System in the Anthropocene, published two days ago is a reworking of 1990s ‘runaway global warming’ hypothesis, now dubbed ‘Hothouse Earth’. The abstract: We explore the risk that self-reinforcing feedbacks could push the Earth System toward a planetary threshold that, if crossed, could prevent stabilization … Continue

Richard Tol
✔@RichardTol





This.

Note also that the paper was "reviewed" and "revised" in 18 days.

With 16 authors, many senior, you would typically need 18 days to get an initial reaction.

 

[longview]

Perhaps it is worth quantifying these self-reinforcing feedbacks.
We can start with the IPCC's forcing chart.
http://www.realclimate.org/images/ipcc_rad_forc_ar5.jpg
Total forcing since 1750 2.29 wm-2 (1.13 to 3.33 error bar)
The most often used conversion says that each Wm-2 causes .3 C of warming,
So the warming would look like .687 C with a (.339 to .999 error bar)
Since 1750, the total observed warming is roughly .9 C, (HadCrut4, first and last decade average)
so the observed warming minus the forcing warming would tell us how much of the observed warming could
possibly be from self-reinforcing feedbacks.
.9 - .687 = .213 C (.561 to -.1 error bar),but the climate is very complicated, and there is latency between the input and the output
of these self-reinforcing feedbacks. The period of this latency is between 10.1 years and 40 years.
Maximum warming occurs about one decade after a carbon dioxide emission - IOPscience
We also know that before 1940, there was .2 C of warming.
If 100% of the unknown warming is from these self-reinforcing feedbacks,
then it would be a result of less than 2 cycles of those feerbacks acting on that .2 C of input.
To get to an output of .213 C from an input of .2 C in 2 cycles, would require a feedback factor of ~1.44.
.2 X 1.44=.288 (cycle1) and .288 X 1.44= .414 ( .2+.213).
This is not what the actual feedback factor is, but establishing the upper limit,
other factors like warming from other causes, would only reduce that number.
The bottom line is that the self-reinforcing feedbacks cannot be high enough to cause the catastrophic warming predicted.

 

[Jack Hays]

My favorite article is from the Onion: Climate Researchers Warn Only Hope For Humanity Now Lies In Possibility They Are Making All Of This Up

 

[Visbek]

The problem with the idea of amplified feedbacks, it that if they existed at a very high level we would have already seen the effects.

Not if it takes time, or higher temperatures, for feedbacks to kick in.

For example, permafrost doesn't melt at the drop of a hat; temperatures have to be high enough first. Guess what? We haven't quite hit that point yet. Permafrost is just starting to melt, and change from a carbon sink to a carbon source.

If the feebacks exists, then they have always existed.

Or, not. Permafrost hasn't always existed, in the exact same amounts, at all times. Same for rain forests, deserts, water vapor levels and so forth.

The .2 C of warming that occurred before 1940, would have been through almost two amplification cycles,
if Hansen's 37.5 year ECS time is correct.

Or, not. It wasn't enough to melt permafrost; it wasn't enough to dry out forests; it wasn't enough to melt ice sheets and change albedos; it didn't alter ocean salinity as much as the current and future amount of warming. The list goes on.

 

[longview]

Not if it takes time, or higher temperatures, for feedbacks to kick in.

For example, permafrost doesn't melt at the drop of a hat; temperatures have to be high enough first. Guess what? We haven't quite hit that point yet. Permafrost is just starting to melt, and change from a carbon sink to a carbon source.



Or, not. Permafrost hasn't always existed, in the exact same amounts, at all times. Same for rain forests, deserts, water vapor levels and so forth.



Or, not. It wasn't enough to melt permafrost; it wasn't enough to dry out forests; it wasn't enough to melt ice sheets and change albedos; it didn't alter ocean salinity as much as the current and future amount of warming. The list goes on.

How much time? How high a temperature? Why would earlier warming not be amplified also?
How long has the permafrost edge been melting?
Off hand, I would say the edge of the permafrost has been just a short distance behind the retreating glaciers
for about the last 12,000 years. We likely lost a lot more permafrost in those early years, since it covered a much larger area.
The permafrost is not "just starting to melt", it has been melting for all of Human civilization.

 

[Visbek]

How much time? How high a temperature?

That depends on the specific feedback. There are also uncertainties. E.g. there is a lot of debate over when permafrost will start to melt, how fast it can melt, how that will impact the carbon cycle, and so on.

How long has the permafrost edge been melting?

Permafrost has been stable for thousands of years; in some areas, permafrost is hundreds of thousands of years old. It may have been stabilized by layers of peat, which are more likely to be destroyed by forest fires in a warming world.

Wide-spread melting of permafrost is very recent, possibly the past 5-10 years. We are right at the start of seeing the effects.

Off hand, I would say the edge of the permafrost has been just a short distance behind the retreating glaciers
for about the last 12,000 years. We likely lost a lot more permafrost in those early years, since it covered a much larger area.

Offhand, permafrost is a very complicated topic, and we are barely scratching the surface of it. So guesses like that are useless.

While we did likely lose lots of permafrost at the end of previous ice ages (a runaway process that took thousands of years, btw), there is still a large amount of permafrost in the world. Continuous permafrost covers maybe 1/3 of Russia, and 1/4 of Canada.

Thus, expected melting of permafrost could add anywhere from 0.13 to 1.69 °C of warming by 2300 (https://www.nature.com/articles/ngeo1573).

And yes, this could turn into a runaway process. As the Arctic warms, more permafrost melts, thus GHGs are likely to be released, which warms the Arctic more, which increases permafrost melt, and so on.

 

[longview]

That depends on the specific feedback. There are also uncertainties. E.g. there is a lot of debate over when permafrost will start to melt, how fast it can melt, how that will impact the carbon cycle, and so on.



Permafrost has been stable for thousands of years; in some areas, permafrost is hundreds of thousands of years old. It may have been stabilized by layers of peat, which are more likely to be destroyed by forest fires in a warming world.

Wide-spread melting of permafrost is very recent, possibly the past 5-10 years. We are right at the start of seeing the effects.



Offhand, permafrost is a very complicated topic, and we are barely scratching the surface of it. So guesses like that are useless.

While we did likely lose lots of permafrost at the end of previous ice ages (a runaway process that took thousands of years, btw), there is still a large amount of permafrost in the world. Continuous permafrost covers maybe 1/3 of Russia, and 1/4 of Canada.

Thus, expected melting of permafrost could add anywhere from 0.13 to 1.69 °C of warming by 2300 (https://www.nature.com/articles/ngeo1573).

And yes, this could turn into a runaway process. As the Arctic warms, more permafrost melts, thus GHGs are likely to be released, which warms the Arctic more, which increases permafrost melt, and so on.

Actually we only know how old the existing permafrost is, we do not know what used to be permafrost, and now is not
and when and how long it took to not be permafrost.
Also the observed warming, with the majority being in winters and evenings, is less likely to effect rapid melting of permafrost.
Part of the fear factor is permafrost, is methane, but the climate sensitivity of methane is vastly overblown.
The American Chemical society has methane's doubling climate sensitivity as much lower than CO2's
https://www.acs.org/content/acs/en/climatescience/atmosphericwarming/climatsensitivity.html

For the increase of CH4 from about 375 to about 675 ppb, ΔFCH4 ≈ 0.3 W·m–2.

If CO2 increased from 375 ppb to 675 ppb, the imbalance would be 3.1 Wm-2, or about 10 times as great.

 

[Visbek]

Actually we only know how old the existing permafrost is, we do not know what used to be permafrost, and now is not
and when and how long it took to not be permafrost.

That doesn't change anything about estimates of warming resulting from the melting of existing permafrost.

Also the observed warming, with the majority being in winters and evenings, is less likely to effect rapid melting of permafrost.

Or, scientists who are actually in the field, making observations, have noticed that permafrost is starting to melt.

Part of the fear factor is permafrost, is methane, but the climate sensitivity of methane is vastly overblown.

Or, not. Your link indicates that the ACS accepts the IPCC figures. Methane warms the environment more than CO2, but it has a much shorter lifespan in the atmosphere. It's less of a concern than CO2 overall, but still a major GHG.

And it's not exclusively CH4 held in permafrost, there's massive amounts of CO2 locked into the permafrost.

Nothing you're writing changes anything about the estimates of the impact of melting permafrost.

 

[late]

nutball...

When a nutball says someone else is a nutball...

This is how science often works. You throw out an idea, and then there's a fight. I am seeing what looks like an increase in support (among scientists, not kooks) for the idea of a synergetic response (called dominoes in the article).

Science takes time, but things don't look good. Here's an example, there's a massive fire in Siberia. Scientists have worried for decades about the permafrost burning, and all that carbon getting released into the atmosphere. This could be that...

Now, back to our regularly scheduled propaganda, brought to you by the Koch brothers.

 

[longview]

That doesn't change anything about estimates of warming resulting from the melting of existing permafrost.



Or, scientists who are actually in the field, making observations, have noticed that permafrost is starting to melt.



Or, not. Your link indicates that the ACS accepts the IPCC figures. Methane warms the environment more than CO2, but it has a much shorter lifespan in the atmosphere. It's less of a concern than CO2 overall, but still a major GHG.

And it's not exclusively CH4 held in permafrost, there's massive amounts of CO2 locked into the permafrost.

Nothing you're writing changes anything about the estimates of the impact of melting permafrost.

Actually the ACS figure shows the methane warms the environment about 10 times less than CO2.
Also, the speed of the melting of the permafrost may be nothing unusual, but part of an ongoing process.
Like I said we really do not know the "normal" rate of permafrost loss.

 

[Visbek]

Actually the ACS figure shows the methane warms the environment about 10 times less than CO2.

And again, the ACS agrees with the IPCC estimates of actual impact.

Also, the speed of the melting of the permafrost may be nothing unusual, but part of an ongoing process.

Says the individual who basically knows nothing whatsoever about permafrost

Like I said we really do not know the "normal" rate of permafrost loss.

Actually, we do have a decent idea. We didn't discover permafrost yesterday. If there had been significant melting or retreat of permafrost, we'd have some hints from historical and instrumental records.

 

[longview]

And again, the ACS agrees with the IPCC estimates of actual impact.



Says the individual who basically knows nothing whatsoever about permafrost



Actually, we do have a decent idea. We didn't discover permafrost yesterday. If there had been significant melting or retreat of permafrost, we'd have some hints from historical and instrumental records.

You may say the words, but that dose not change the numbers from the ACS page.
https://www.acs.org/content/acs/en/climatescience/atmosphericwarming/climatsensitivity.html

The increase in CO2 from about 185 to about 265 ppm gives a radiative forcing of

ΔFCO2 = (5.35 W·m–2) ln(265/185) = 1.9 W·m–2

The radiative forcing for CH4 is determined in a way analogous to that for CO2.
For the increase of CH4 from about 375 to about 675 ppb, ΔFCH4 ≈ 0.3 W·m–2.

But let's play with the math a bit to validate their numbers.
They say that the increase in CO2 from 185 ppm to 265 ppm resulted in 1.9 Wm-2 of imbalance,
So 1.9/ln(265/185)=5.28 (they rounded the 1.9), as the multiplier.
2XCO2, 5.35 X ln(2)=3.71 Wm-2
The same rule should apply to CH4, which they said increased from 375 ppb to 675 ppb, and produced .3 Wm-2 of imbalance.
.3/ln(675/375)= .510,

2XCH4, .510 X ln(2)=.354 Wm-2

Yep according to the numbers published by the American chemical society,
Doubling the CH4 level would produce less then 1/10th of the energy imbalance as doubling the CO2 level.
So much for your statement "Methane warms the environment more than CO2"
what else are you wrong about?

 

[Lord of Planar]

Yep according to the numbers published by the American chemical society,
Doubling the CH4 level would produce less then 1/10th of the energy imbalance as doubling the CO2 level.
So much for your statement "Methane warms the environment more than CO2"
what else are you wrong about?

They all fail to consider the reality of where the slope is at on a log curve. They are too ignorant to understand that RE and GWP are made up variables for their horror story.

 

[Visbek]

But let's play with the math a bit to validate their numbers.

Here we go

Yep according to the numbers published by the American chemical society,
Doubling the CH4 level would produce less then 1/10th of the energy imbalance as doubling the CO2 level.

CO2 is measured in parts per million.
CH4 is measured in parts per billion.

We use a measure called Global Warming Potential (GWP) to compare the effects of different greenhouse gases. It measures how much energy 1 metric ton of a specific gas retains in the atmosphere. CO2 is the baseline, so the GWP of CO2 is always 1.

If you're looking at a 20 year period (GWP20), methane is 70-80 times higher than CO2. For the more standard 100 year period (GWP100), methane is around 30 times higher than CO2.
https://en.wikipedia.org/wiki/Global_warming_potential
https://www.epa.gov/ghgemissions/understanding-global-warming-potentials

And again, the concern about permafrost isn't primarily methane. It's CO2. It's right there in the title of the article I linked:
Significant Contribution to Climate Warming From the Permafrost Carbon Feedback (emphasis added)

Permafrost soils contain an estimated 1,700 Pg of carbon, almost twice the present atmospheric carbon pool. As permafrost soils thaw owing to climate warming, respiration of organic matter within these soils will transfer carbon to the atmosphere, potentially leading to a positive feedback. Models in which the carbon cycle is uncoupled from the atmosphere, together with one-dimensional models, suggest that permafrost soils could release 7–138 Pg carbon by 2100.... We estimate that this feedback could result in an additional warming of 0.13–1.69 °C by 2300.


Last but not least, the ACS accepts the consensus on climate change. Oddly enough, there is no mention of any Mystery Natural Cycles causing interference patterns.
https://www.acs.org/content/acs/en/policy/publicpolicies/sustainability/globalclimatechange.html

These are the kinds of things you miss, when:
a) You don't bother to learn the basics
b) You start with a conclusion ("melting permafrost can't be a real feedback")
c) You cherry-pick statements that you assume fit your conclusion

 

[longview]

Here we go



CO2 is measured in parts per million.
CH4 is measured in parts per billion.

We use a measure called Global Warming Potential (GWP) to compare the effects of different greenhouse gases. It measures how much energy 1 metric ton of a specific gas retains in the atmosphere. CO2 is the baseline, so the GWP of CO2 is always 1.

If you're looking at a 20 year period (GWP20), methane is 70-80 times higher than CO2. For the more standard 100 year period (GWP100), methane is around 30 times higher than CO2.
https://en.wikipedia.org/wiki/Global_warming_potential
https://www.epa.gov/ghgemissions/understanding-global-warming-potentials

And again, the concern about permafrost isn't primarily methane. It's CO2. It's right there in the title of the article I linked:
Significant Contribution to Climate Warming From the Permafrost Carbon Feedback (emphasis added)

Permafrost soils contain an estimated 1,700 Pg of carbon, almost twice the present atmospheric carbon pool. As permafrost soils thaw owing to climate warming, respiration of organic matter within these soils will transfer carbon to the atmosphere, potentially leading to a positive feedback. Models in which the carbon cycle is uncoupled from the atmosphere, together with one-dimensional models, suggest that permafrost soils could release 7–138 Pg carbon by 2100.... We estimate that this feedback could result in an additional warming of 0.13–1.69 °C by 2300.


Last but not least, the ACS accepts the consensus on climate change. Oddly enough, there is no mention of any Mystery Natural Cycles causing interference patterns.
https://www.acs.org/content/acs/en/policy/publicpolicies/sustainability/globalclimatechange.html

These are the kinds of things you miss, when:
a) You don't bother to learn the basics
b) You start with a conclusion ("melting permafrost can't be a real feedback")
c) You cherry-pick statements that you assume fit your conclusion

Do you know how a log curve works?
Equations like 5.35 X ln(data_point_high/data_Point_low) describe the amount of change along the curve between the two
data points, in this case as part of a doubling curve, the ratio is important, not the actual level.
AGW is solely based on energy imbalances, Global Warming Potential, is a made up number that does not change the amount of energy imbalance
for a doubling the level of the greenhouse gas.
So if the multiplier for CO2 in 5.35, and the multiplier for CH4 is .510, then those numbers work anywhere on the curve.

As to your points,
a) What basics do you think I am missing, CO2 has a lower climate sensitivity than what is used in the models.
b) I never said melting permafrost cannot be a real feedback, I said we have no way of known if the rate of melting permafrost
is any different than what has been ongoing for centuries.
c)I try and look at the supported data, CO2's greenhouse effect is minimally supported, and what is there is low,
the amplified feedbacks have almost zero support, and without amplified feedbacks AGW is of no concern.

 

[Visbek]

Do you know how a log curve works?

Sigh

Did you bother to notice that "parts per billion" is a little bit smaller than "parts per million?" The increase of CH4 discussed in that article was 0.3ppm. Meaning that compared to CO2, it requires far, far less CH4 to double the amount of CH4 in the atmosphere.

In other words: You're using an absurd, and deeply wrong, standard to compare the impact of these two gases.

This is why we use GWP. It compares the results of increasing 1 ton of CO2, to that of increasing 1 ton of CH4, or N2O, and so on.

a) What basics do you think I am missing

Pretty much everything.

b) I never said melting permafrost cannot be a real feedback, I said we have no way of known if the rate of melting permafrost
is any different than what has been ongoing for centuries.

Yes, that's pretty much the same as denying that current permafrost melting is a feedback. It's a weak ad hoc argument which doesn't even try to learn why we believe permafrost has been stable since the end of the last ice age.

c)I try and look at the supported data, CO2's greenhouse effect is minimally supported

Then your research skills suck, because it is very thoroughly tested and documented. Again, it is obvious that you haven't even bothered to try and learn the basics.

the amplified feedbacks have almost zero support

So much for "I don't deny the feedbacks!"

without amplified feedbacks AGW is of no concern.

Fun fact! Feedbacks exist, and are probably responsible for about half the warming we've seen so far. And again, we have not hit any sort of ceiling, it is just going to keep getting warmer. So yes, AGW is a major concern.