Australian Politics Forum - Evidence for global warming.

Ajax

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Re: Evidence for global warming.
Reply #240 - Jun 16^th, 2019 at 10:16am

Robot wrote on Jun 15^th, 2019 at 10:35pm:

Ajax wrote on Jun 15^th, 2019 at 1:12pm:

https://i.ibb.co/mc5qJqb/AGW.jpg

The first one:

http://www.longrangeweather.com/images/gtemps.jpg

http://www.longrangeweather.com/global_temperatures.htm

Quote:

By Climatologist Cliff Harris and Meteorologist Randy Mann

Quote:

Global temperature chart was complied by Climatologist Cliff Harris that combined the following resources:
"Climate and the Affairs of Men" by Dr. Iben Browing.
"Climate...The Key to Understanding Business Cycles...The Raymond H. Wheeler Papers. By Michael Zahorchak
Weather Science Foundation Papers in Crystal Lake, Illinois.

Robot wrote on Jun 16^th, 2019 at 12:11am:

Ajax wrote on Jun 15^th, 2019 at 1:12pm:

https://i.ibb.co/mc5qJqb/AGW.jpg

Graph number three:

https://www.iceagenow.com/Medieval%20Warm%20Period1.jpg

According to this site, the graph was drawn by "analytical chemist Hans Schreuder", although the original is no longer available.
https://www.iceagenow.com/The_IPCC_is_lying.htm

Here's the original from the IPCC's First Assessment Report.

https://i.postimg.cc/RZgHCWyN/AR1-pg202.png

https://www.ipcc.ch/site/assets/uploads/2018/03/ipcc_far_wg_I_full_report.pdf

Looks like Hans Schreuder misrepresented the IPCC, by increasing the scale of the vertical axis by almost 4 times.

(Nice of him to provide some Vikings context, though.)

Still, the IPCC figure is a bit...low quality. The caption says:

Quote:

Figure 7.1: Schematic diagrams of global temperature variations since...the last thousand years The dotted line nominally represents conditions near the beginning of the twentieth century

What the hell is a "schematic diagram" and why is it even in there? There's a story about it in the Appendix of this paper by Jones et al, if you care to read it, but the bottom line is this

Quote:

the curve used by IPCC (1990) was locally representative (nominally of Central England) and not global, and was referred to at the time with the word ‘schematic’.

http://shadow.eas.gatech.edu/%7Ekcobb/jones09.pdf

What are you trying to say here my friend that we DONT have cool and warm cycles.............???

Kind of missed the point, laughs on you.......... Wink

As for CO2 and temperature correlating show me where this occurs and I will believe.

The facts are

CO2 does play a part in keeping the Earth warm to a certain point.

BUT

The effects of CO2 are logarithmic....fact........!.... Wink

BTW when we had thousands of parts per million of CO2 in the atmosphere there was no runaway greenhouse effect, why should there be one now.

Today we have some of the lowest amounts of atmospheric CO2 in our history.

Do you know what the CO2 levels are in a submarine.....???

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« Last Edit: Jun 16^th, 2019 at 10:26am by Ajax »

1. There has never been a more serious assault on our standard of living than Anthropogenic Global Warming..Ajax
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Ajax

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Re: Evidence for global warming.
Reply #241 - Jun 16^th, 2019 at 10:18am

Medieval warm period warmer than today.

Dahl_Jensen et al 1998
Wagner & Melles 2001
Kaplan et al 2002
Jiang et al 2002
Moore et al 2001
Grudd et al 2002
Seppa & Birks 2002
Dansgaard et al 1975
Korhola et al 2000
Naurzbaev et al 2002
Vaganov et el 1996
Briffa et al 1998
Scweingruber & Briffa 1996
Knudsen et al 2004
Grinsted et al 2006
Besonen et al 2008
Wagner et al 2008
Vare et al 2009
Norgaard-Pedersen & Mikkelsen 2009
Andresen et al 2004
Vinther et al 2010
Kobashi et al 2010
Kobashi et al 2008
Stuiver et al 1995
Dansgaard et al 1975
Jenings & Weiner 1996
Johnsen et al 2001
Vinther et al 2010
Larsen et al 2011
Hill et al 2001
Joynt & Wolfe 2001
Hantemirov & Shiyatov 2002
Andersson et al 2003
Helama et al 2005
Mazepa 2005
Weckstrom et al 2006
Jiang et al 2007
Zabenski & Gajewski 2007
Grudd 2008
Justwan et al 2008
Scire et al 2008
Axford et al 2009
Bjune et al 2009
Cook et al 2009
Fortin & Gajewski 2010
Buntgen et al 2011
Divine et al 2011
Ran et al 2011
Velle et al 2011
D’Andrea et al 2012
Esper et al 2012

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1. There has never been a more serious assault on our standard of living than Anthropogenic Global Warming..Ajax
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Ajax

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Re: Evidence for global warming.
Reply #242 - Jun 16^th, 2019 at 10:24am

Robot wrote on Jun 15^th, 2019 at 11:45pm:

Ajax wrote on Jun 15^th, 2019 at 1:12pm:

https://i.ibb.co/mc5qJqb/AGW.jpg

The second one:

https://i.postimg.cc/MHDmG2sb/Hieb.png

The original can be found here:
Climate and the Carboniferous Period by Monte Hieb
https://www.geocraft.com/WVFossils/Carboniferous_climate.html

Looking at this graph, you'd think that there isn't any correlation between CO₂ and temperature. But for some reason, the source for the CO₂ figures, Berner & Kothavala, states that temperature is dependent on CO₂.

Quote:

Revision of the GEOCARB model (Berner, 1991, 1994) for paleolevels of atmospheric CO2, has been made with emphasis on factors affecting CO2 uptake by continental weathering. This includes: (1) new GCM (general circulation model) results for the dependence of global mean surface temperature and runoff on CO2,for both glaciated and non-glaciated periods, coupled with new results for the temperature response to changes in solar radiation;

https://www.geocraft.com/WVFossils/Reference_Docs/Geocarb_III-Berner.pdf

Berner & Kothavala also mentions another factor driving global temperatures: solar forcing. I have no idea why Monte Hieb left it out of his graph, but it's ironic since climate "skeptics" often insist that climate change is mostly driven by the sun.

https://i.postimg.cc/Kjz5pcrk/Ribas.png

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/293C0314...

Scotese has updated his temperature sketch since Hieb last updated his graph:

https://i.postimg.cc/2S4pdmkF/Scotese-Poster01-Center-Top-small.jpg

https://www.researchgate.net/publication/309324713_A_NEW_GLOBAL_TEMPERATURE_CURV...

Scotese has removed the sudden jumps between "ice house" and "hot house".

Like Berner & Kothavala, Scotese also mentions that greenhouse gases are a factor in global temperature:

Quote:

Most of the time, the global temperature gently rises and falls in response to gradual changes in orbital and solar parameters, ocean currents, sea level, atmospheric chemistry (greenhouse gases), and other factors. These changes occur over millions of years.

If you were to impose solar irradiance on Monte Hieb's graph, it would also appear to imply that there is no correlation between solar irradiance and global temperature. So if you're dense enough to think this graph refutes the theory that CO₂ causes changes in climate, then you could at least be consistently thick and conclude that it also refutes the theory that solar irradiance causes changes in climate.

The chemical analysis is still valid......... Kiss

Show me a proxy without an element of uncertainty.

https://www.geocraft.com/WVFossils/Reference_Docs/Geocarb_III-Berner.pdf

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1. There has never been a more serious assault on our standard of living than Anthropogenic Global Warming..Ajax
2. "One hour of freedom is worth more than 40 years of slavery & prison" Regas Feraeos

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Ajax Gold Member Offline CO2 has never controlled temperature on Earth Posts: 11070 Australia Gender:	Re: Evidence for global warming. Reply #243 - Jun 16^th, 2019 at 10:28am What is false about this graph..............???
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lee

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Re: Evidence for global warming.
Reply #244 - Jun 16^th, 2019 at 11:49am

According to Knudsen et al there is a multi decadal oscillation of between 55 and 75 years over the last 8000 years. And that a linear trend of at least 70 years should be used to remove the contribution by the Multi Decadal Oscillation.

https://www.nature.com/articles/ncomms1186

It is interesting that there was the recent report of the slowing Greenland Jakobshavn Glacier talks of slowing and thickening because of cooler oceanic waters.

"The researchers conclude that the slowdown of this glacier, known in the Greenlandic language as Sermeq Kujalleq, occurred because an ocean current that brings water to the glacier's ocean face grew much cooler in 2016. Water temperatures in the vicinity of the glacier are now colder than they have been since the mid-1980s."

https://www.jpl.nasa.gov/news/news.php?feature=7356

The scientists think it has something to do with the North Atlantic Oscillation overturning.

Which could in turn be Knudsen et al's Multi Decadal Oscillation of 50 to 75 years.

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Re: Evidence for global warming.
Reply #245 - Jun 16^th, 2019 at 12:10pm

Robot wrote on Jun 15^th, 2019 at 8:18pm:

I've highlighted Evans' claim that the Business as Usual scenario has occurred. In order for Evans to arrive at this conclusion, he has to ignore the abatement achieved as the result of the Kyoto Protocol, which is not factored into the Business as Usual scenario in the 1990 report:

"Was the 1997 Kyoto protocol a success? That depends on how you interpret the numbers."

"Although overall global emissions rose, the 38 countries collectively reduced their output by 2 GtCO2 per year from 2008 to 2012 compared with 1990 levels. That makes the treaty sound like a success.

But the emissions of former Soviet states had plummeted before the deal was even signed, meaning a reduction of 2.2 GtCO2 per year cannot be attributed to the protocol. Discount that, and the 38 failed to meet their target.

The US and Canada, however, signed the deal but did not stick with it. If they are excluded, the remaining 36 apparently met their target of a reduction of 0.5 GtCO2 per year, even if the 2.2 Gt cited above are excluded.

Mixed picture
However, 10 countries achieved their targets only by buying carbon credits. This means that 0.3 GtCO2 per year of the claimed reductions were not true cuts.

What’s more, emissions in developed countries fell by 1 to 2 GtCO2 per year because of the financial crisis – so without it, the 36 countries might not even have come close to meeting their collective target.

That is not all. Some of the reductions may be due to “carbon leakage”: emissions shifting to developing countries such as China rather than ceasing altogether. Nor does the protocol include the fast-rising emissions from aviation or shipping. And many would argue that the targets were far too modest in the first place."

https://www.newscientist.com/article/2093579-was-kyoto-climate-deal-a-success-fi...

But perhaps you can point to where Kyoto was a major success.

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Re: Evidence for global warming.
Reply #246 - Jun 16^th, 2019 at 3:47pm

Ajax wrote on Jun 16^th, 2019 at 10:09am:

I gave you the source IPCC FAR 1990 which is still valid today.

Yes, I checked your source and there is no mention of 2.78°C. That number comes from Hansen et al, 1981. You clearly didn't get it from IPCC AR1.

Ajax wrote on Jun 16^th, 2019 at 10:16am:

What are you trying to say here my friend that we DONT have cool and warm cycles.............???

Not at all. My point was simple: the graphs you posted are garbage.

If you want to show the occurrence of warm and cool cycles, it shouldn't be hard to find one made by real climate scientists that reconstructs temperatures from temperature data.

You shouldn't have any need to rely on a silly "chart" by "climatologist" Cliff Harris, or an exaggerated squiggle that incorrectly reproduces a crappy schematic.

Ajax wrote on Jun 16^th, 2019 at 10:16am:

The effects of CO2 are logarithmic....fact........!.... Wink

Just like lee, you seem to think this means something that it doesn't.

http://www.ozpolitic.com/forum/YaBB.pl?num=1464603949/6012#6012

Ajax wrote on Jun 16^th, 2019 at 10:16am:

BTW when we had thousands of parts per million of CO2 in the atmosphere there was no runaway greenhouse effect, why should there be one now.

Even with thousands of parts per million of CO₂ in the atmosphere, there isn't going to be a runaway greenhouse effect (that turns us into a Venusian hothouse) because the Earth reaches a thermal equilibrium where the amount of heat captured from the sun is balanced out by the amount of heat radiated into space.

So we have no reason to expect a runaway greenhouse effect. You probably meant something else.

Ajax wrote on Jun 16^th, 2019 at 10:16am:

Today we have some of the lowest amounts of atmospheric CO2 in our history.

Which is lucky for us, because the sun is much hotter than it used to be.

Ajax wrote on Jun 16^th, 2019 at 10:24am:

The chemical analysis is still valid......... Kiss

Show me a proxy without an element of uncertainty.

https://i.ibb.co/hC15SVY/GEOCARBII.jpg

https://www.geocraft.com/WVFossils/Reference_Docs/Geocarb_III-Berner.pdf

I can only assume from this response that, despite posting the graph, you don't even know what point the author was trying to convey.

Ajax wrote on Jun 16^th, 2019 at 10:28am:

What is false about this graph..............???

https://i.ibb.co/5kCc7Fq/ipcctempco2.jpg

See my previous reply:

Robot wrote on Jun 15^th, 2019 at 8:18pm:

Ajax wrote on Jun 15^th, 2019 at 1:12pm:

How those computer models got it oh so wrong.

https://i.ibb.co/5kCc7Fq/ipcctempco2.jpg

Google image search suggests this graph originated with this self-published PDF:
The Skeptic’s Case: Who Are You Going To Believe—The Government Climate Scientists or The Data? by David M.W. Evans
jonova.s3.amazonaws.com/guest/evans-david/skeptics-case.pdf

Evans' source for the IPCC predictions? The policymakers' summary of the IPCC First Assessment Report. Evans' footnote:

Quote:

IPCC First Assessment Report, 1990, page xxii (www.ipcc.ch/ipccreports/far/wg_I/ipcc_far_wg_I_full_report.pdf) in the Policymakers Summary, Figure 8 and surrounding text, for the business-as-usual scenario (which is what in fact occurred, there being no significant controls or decrease in the rate of increase of emissions to date). “Under the IPCC Business-as-Usual (Scenario A) emissions of greenhouse gases, the average rate of increase of global mean temperature during the next century is estimated to be about 0.3°C per decade (with an uncertainty range of 0.2°C to 0.5°C).

I've highlighted Evans' claim that the Business as Usual scenario has occurred. In order for Evans to arrive at this conclusion, he has to ignore the abatement achieved as the result of the Kyoto Protocol, which is not factored into the Business as Usual scenario in the 1990 report:

Quote:

In the Business-as-Usual scenario (Scenario A) the energv supply is coal intensive and on the demand side only modest efficiency increases are achieved Carbon monoxide controls are modest, deforestation continues until the tropical forests are depleted and agricultural emissions of methane and nitrous oxide are uncontrolled For CFCs the Montreal Protocol is implemented albeit with only partial participation Note that the aggregation of national projections by IPCC Working Group III gives higher emissions (10 20%) of carbon dioxide and methane by 2025.

AR1: Scientific Assessment of Climate Change
https://www.ipcc.ch/site/assets/uploads/2018/03/ipcc_far_wg_I_full_report.pdf

Basically, Evans is evaluating a prediction for a scenario (Business-as-Usual) that didn't come to pass.

As lee helpfully point outs, BaU doesn't just leave out the Kyoto Protocol, it also leaves out the collapse of the Communist bloc and the Global Financial Crisis.

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Re: Evidence for global warming.
Reply #247 - Jun 16^th, 2019 at 4:04pm

Robot wrote on Jun 16^th, 2019 at 3:47pm:

Even with thousands of parts per million of CO2 in the atmosphere, there isn't going to be a runaway greenhouse effect (that turns us into a Venusian hothouse) because the Earth reaches a thermal equilibrium where the amount of heat captured from the sun is balanced out by the amount of heat radiated into space.

So we have no reason to expect a runaway greenhouse effect.

perhaps you need to read wider.

BTW - at what temperature is this thermal equilibrium? Wink

"Runaway global warming on our planet remains a distinct possibility in the decades and centuries ahead, scientists reported Monday in a new study, warning that a "hothouse Earth" threatens the very “habitability of the planet for human beings.”

https://www.usatoday.com/story/tech/science/2018/08/06/hothouse-earth-runaway-gl...

The paper underlying it -

https://www.pnas.org/content/115/33/8252

With Australia's very own Will Steffan as lead author.

Robot wrote on Jun 16^th, 2019 at 3:47pm:

As lee helpfully point outs, BaU doesn't just leave out the Kyoto Protocol, it also leaves out the collapse of the Communist bloc and the Global Financial Crisis.

Yep which show the input of Kyoto is minuscule, if any. That was't what you were trying to portray ; was it. Grin

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Re: Evidence for global warming.
Reply #248 - Jun 16^th, 2019 at 4:37pm

lee wrote on Jun 16^th, 2019 at 4:04pm:

"Runaway global warming on our planet remains a distinct possibility in the decades and centuries ahead, scientists reported Monday in a new study, warning that a "hothouse Earth" threatens the very “habitability of the planet for human beings.”

https://www.usatoday.com/story/tech/science/2018/08/06/hothouse-earth-runaway-gl...

The paper underlying it -

https://www.pnas.org/content/115/33/8252

With Australia's very own Will Steffan as lead author.

As usual, the media exaggerates the science.

Steffen et al doesn't predict a runaway greenhouse effect; they predict that we could end up with a "hothouse Earth". The Earth has had "hothouse" periods in the past but has avoided becoming a boiling hellscape (like Venus) because the system reaches an equilibrium point.

You can see these hothouse periods in Scotese's chart, and you can see the warming isn't a "runaway" trend.

https://www.researchgate.net/publication/309324713_A_NEW_GLOBAL_TEMPERATURE_CURV...

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Re: Evidence for global warming.
Reply #249 - Jun 16^th, 2019 at 4:49pm

Robot wrote on Jun 16^th, 2019 at 4:37pm:

As usual, the media exaggerates the science.

Actually the science tends to exaggerate the science. Wink

Robot wrote on Jun 16^th, 2019 at 4:37pm:

The Earth has had "hothouse" periods in the past but has avoided becoming a boiling hellscape (like Venus) because the system reaches an equilibrium point.

"This so-called "hothouse Earth," where global temperatures will be 7 to 9 degrees Fahrenheit (4 to 5 degrees Celsius) higher than preindustrial temperatures and sea levels will be 33 to 200 feet (10 to 60 meters) higher than today, is hard to imagine — but easy to fall into, said a new perspective article published today (Aug. 6) in the journal Proceedings of the National Academy of Sciences. [Top 9 Ways the World Could End]

In the article, a group of scientists argued that there is a threshold temperature above which natural feedback systems that currently keep the Earth cool will unravel. At that point, a cascade of climate events will thrust the planet into a "hothouse" state. Though the scientists don't know exactly what this threshold is, they said it could be as slight as 2 degrees C (around 4 degrees F) of warming above preindustrial levels.

Sound familiar? The 2 degrees C mark plays a big role in the Paris Agreement, the landmark 2016 agreement signed by 179 countries to combat climate change by reducing carbon emissions (the same one that the U.S. announced it would withdraw from last year). In that accord, countries agreed to work to keep global temperature rise well below 2 degrees C, and ideally below 1.5 degrees C, above preindustrial levels this century."

https://www.livescience.com/63267-hothouse-earth-dangerously-close.html

" natural feedback systems that currently keep the Earth cool will unravel"

That is precisely the meaning of runaway global warming, the natural feedback systems not being able to cope.

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Re: Evidence for global warming.
Reply #250 - Jun 16^th, 2019 at 4:57pm

lee wrote on Jun 16^th, 2019 at 4:49pm:

That is precisely the meaning of runaway global warming, the natural feedback systems not being able to cope.

You and Ajax need to come to an agreement on what meaning of "runaway" you want to use, instead of engaging in false equivocation.

Ajax wrote on Jun 16^th, 2019 at 10:16am:

BTW when we had thousands of parts per million of CO2 in the atmosphere there was no runaway greenhouse effect, why should there be one now.

lee wrote on Jun 16^th, 2019 at 4:49pm:

Robot wrote on Jun 16^th, 2019 at 4:37pm:

As usual, the media exaggerates the science.

Actually the science tends to exaggerate the science. Wink

Robot wrote on Jun 16^th, 2019 at 4:37pm:

The Earth has had "hothouse" periods in the past but has avoided becoming a boiling hellscape (like Venus) because the system reaches an equilibrium point.

"This so-called "hothouse Earth," where global temperatures will be 7 to 9 degrees Fahrenheit (4 to 5 degrees Celsius) higher than preindustrial temperatures and sea levels will be 33 to 200 feet (10 to 60 meters) higher than today, is hard to imagine — but easy to fall into, said a new perspective article published today (Aug. 6) in the journal Proceedings of the National Academy of Sciences. [Top 9 Ways the World Could End]

In the article, a group of scientists argued that there is a threshold temperature above which natural feedback systems that currently keep the Earth cool will unravel. At that point, a cascade of climate events will thrust the planet into a "hothouse" state. Though the scientists don't know exactly what this threshold is, they said it could be as slight as 2 degrees C (around 4 degrees F) of warming above preindustrial levels.

Sound familiar? The 2 degrees C mark plays a big role in the Paris Agreement, the landmark 2016 agreement signed by 179 countries to combat climate change by reducing carbon emissions (the same one that the U.S. announced it would withdraw from last year). In that accord, countries agreed to work to keep global temperature rise well below 2 degrees C, and ideally below 1.5 degrees C, above preindustrial levels this century."

https://www.livescience.com/63267-hothouse-earth-dangerously-close.html

" natural feedback systems that currently keep the Earth cool will unravel"

Another media article exaggerating the science. You should quote the paper directly or not bother at al.

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Re: Evidence for global warming.
Reply #251 - Jun 16^th, 2019 at 5:43pm

Robot wrote on Jun 16^th, 2019 at 4:57pm:

You and Ajax need to come to an agreement on what meaning of "runaway" you want to use, instead of engaging in false equivocation.

Ajax wrote Today at 8:16am:
BTW when we had thousands of parts per million of CO2 in the atmosphere there was no runaway greenhouse effect, why should there be one now.

You need to learn to read. Neither of us believe in runaway global warming, you don't believe in runaway global warming, but the scientists do because the natural feedbacks won't be able to cope apparently. Wink

Robot wrote on Jun 16^th, 2019 at 4:57pm:

Another media article exaggerating the science.

Perhaps you should look at the link in the livescience paper. Wink

The link is to Will Stefans paper.

"This analysis implies that, even if the Paris Accord target of a 1.5 °C to 2.0 °C rise in temperature is met, we cannot exclude the risk that a cascade of feedbacks could push the Earth System irreversibly onto a “Hothouse Earth” pathway. "

If it is irreversible it means natural feedbacks won't work. It will be runaway global warming.

"The human-created Stabilized Earth pathway leads to a basin of attraction that is not likely to exist in the Earth System’s stability landscape without human stewardship to create and maintain it. Creating such a pathway and basin of attraction requires a fundamental change in the role of humans on the planet. This stewardship role requires deliberate and sustained action to become an integral, adaptive part of Earth System dynamics, creating feedbacks that keep the system on a Stabilized Earth pathway."

Yep. natural feedbacks won't cope.

"Our analysis suggests that the Earth System may be approaching a planetary threshold that could lock in a continuing rapid pathway toward much hotter conditions—Hothouse Earth. This pathway would be propelled by strong, intrinsic, biogeophysical feedbacks difficult to influence by human actions, a pathway that could not be reversed, steered, or substantially slowed."

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Re: Evidence for global warming.
Reply #252 - Jun 16^th, 2019 at 5:55pm

lee wrote on Jun 16^th, 2019 at 5:43pm:

Robot wrote on Jun 16^th, 2019 at 4:57pm:

You and Ajax need to come to an agreement on what meaning of "runaway" you want to use, instead of engaging in false equivocation.

Ajax wrote Today at 8:16am:
BTW when we had thousands of parts per million of CO2 in the atmosphere there was no runaway greenhouse effect, why should there be one now.

You need to learn to read. Neither of us believe in runaway global warming, you don't believe in runaway global warming, but the scientists do because the natural feedbacks won't be able to cope apparently. Wink

I don't care what either of you believe.

You and Ajax are clearly referring to different things when each of you refers to "runaway" effects.

lee wrote on Jun 16^th, 2019 at 5:43pm:

"This analysis implies that, even if the Paris Accord target of a 1.5 °C to 2.0 °C rise in temperature is met, we cannot exclude the risk that a cascade of feedbacks could push the Earth System irreversibly onto a “Hothouse Earth” pathway. "

If it is irreversible it means natural feedbacks won't work. It will be runaway global warming.

"The human-created Stabilized Earth pathway leads to a basin of attraction that is not likely to exist in the Earth System’s stability landscape without human stewardship to create and maintain it. Creating such a pathway and basin of attraction requires a fundamental change in the role of humans on the planet. This stewardship role requires deliberate and sustained action to become an integral, adaptive part of Earth System dynamics, creating feedbacks that keep the system on a Stabilized Earth pathway."

Yep. natural feedbacks won't cope.

"Our analysis suggests that the Earth System may be approaching a planetary threshold that could lock in a continuing rapid pathway toward much hotter conditions—Hothouse Earth. This pathway would be propelled by strong, intrinsic, biogeophysical feedbacks difficult to influence by human actions, a pathway that could not be reversed, steered, or substantially slowed."

This is what I mean: you're referring to something entirely different than Ajax. If we use your meaning of "runaway" then the Earth has been through many cycles of "runaway" warming, leading to "hothouse" conditions.

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Re: Evidence for global warming.
Reply #253 - Jun 16^th, 2019 at 6:04pm

Robot wrote on Jun 16^th, 2019 at 5:55pm:

If we use your meaning of "runaway" then the Earth has been through many cycles of "runaway" warming, leading to "hothouse" conditions.

That is rather silly isn't it? What happened to those natural feedbacks that couldn't be reversed? They somehow reversed themselves? Grin

You do understand "irreversible" don't you?

Maybe ancient man geoengineered a feedback that has since been deemed to be natural?

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« Last Edit: Jun 16^th, 2019 at 6:09pm by lee »

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Re: Evidence for global warming.
Reply #254 - Jun 16^th, 2019 at 6:23pm

lee wrote on Jun 16^th, 2019 at 6:04pm:

Robot wrote on Jun 16^th, 2019 at 5:55pm:

If we use your meaning of "runaway" then the Earth has been through many cycles of "runaway" warming, leading to "hothouse" conditions.

That is rather silly isn't it? What happened to those natural feedbacks that couldn't be reversed? They somehow reversed themselves? Grin

You do understand "irreversible" don't you?

It's "irreversible" in that there's nothing that humans could do to stop the Earth from becoming a hothouse. It doesn't mean that the Earth will be a permanent hothouse, although it may last for millennia, nor does it mean that the warming will continue to go on forever until the oceans boil and we end up like Venus.

lee wrote on Jun 16^th, 2019 at 6:04pm:

Maybe ancient man geoengineered a feedback that has since been deemed to be natural?

If you think humans were around during the Triassic or Cretaceous, you should stop getting your science from Saturday morning cartoons. Wink

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