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Author Topic: Where are we now in CO2e , which pathway are we on?  (Read 17280 times)

Stephan

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #200 on: October 10, 2020, 10:00:51 PM »
Is there a way to change the final value to CO2e, in ppm?
And a way to compare the sum of them with what we have, by example, versus 1980?

Here you go, Juan:

I converted the radiative forcing back into CO2 equivalents. Please find the values for each January of the following years. Please also keep in mind that these numbers only represent the four "NOAA gases" CO2, CH4, N2O and SF6. Therefore the "true" value is higher than that.

Jan 1980 372.2 ppm
Jan 1990 394.8 ppm (+22.6 ppm or +6.1%)
Jan 2000 415.7 ppm (+20.9 ppm or +5.3%)
Jan 2010 440.4 ppm (+24.7 ppm or +5.9%)
Jan 2020 473.4 ppm (+33.0 ppm or +7.5%)

The latest value (June 2020) represents a CO2 equivalent of 477.1 ppm (annual increase of 3.6 ppm). I will report this equivalent in future, once a month, when NOAA adds the latest monthly averages to its website.

It is obvious that we are on an exponential track. The smaller increase during the 1990s is a consequence of the breakdown of the Soviet Union's and its allies' economy after the revolutions of 1989/90. 
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kassy

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #201 on: October 11, 2020, 01:34:03 AM »
That is quite the progression.

Now there were always two ways of looking at it. OK so 1 you have got a number for  the CO2eq but what does it actually mean.

What does it mean for the actual world?

For this you can look to graphs and theories or alternatively you look out of the window and see what is already happening.

We will lose the arctic ice some time the next decade , we have already comittted to a whole lot of sea level rise. Somewhere out there we are comitting to a protocol to stop some dangerous undefined future climate change while ignoring where we already are.

And we are on the edge of going from ice house to hot house earth. So much things will change so drastically before we do anything meaningful.

Þetta minnismerki er til vitnis um að við vitum hvað er að gerast og hvað þarf að gera. Aðeins þú veist hvort við gerðum eitthvað.

nanning

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #202 on: October 11, 2020, 09:48:10 AM »
Thanks for that, Stephan.
What CO₂e factor do you use for methane?
I would expect the total to be more than a bit above 500ppm, using a short-term factor of 80.

--

I agree with kassy and oren.
But 'we' do meaningful stuff, we aren't doing nothing. But it is not mitigation but the opposite; worsening the problem even more. Year in year out. We can't even stop deforestation. Governments have no power over large international companies and these companies WILL NOT STOP WITH DESTRUCTION because their investors want more profit of them. Nice system eh? Out of control, just like the climate and biosphere destruction.
"It is preoccupation with possessions, more than anything else, that prevents us from living freely and nobly" - Bertrand Russell
"It is preoccupation with what other people from your groups think of you, that prevents you from living freely and nobly" - Nanning
Why do you keep accumulating stuff?

Stephan

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #203 on: October 11, 2020, 06:59:19 PM »
I do not use a factor for methane, but I convert the actual concentration into radiative forcing (values listed in my posting). I sum up all the radiative forcings of the four "NOAA gases" and re-convert them into CO2 equivalents using the same formula I use to convert CO2 concentrations into radiative forcing.

There has been a lengthy discussion how to do it some months ago in this thread, because before that I had used the factors 28 and 80. But this is scientifically not correct as I was told.
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Stephan

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #204 on: November 06, 2020, 07:42:33 PM »
To finalize my update on greenhouse gases here is the summary of the four postings in the individual gas concentration threads.

More radiative forcing of the "NOAA gases" (CO2, CH4, N2O, SF6) in July 2020 than in July 2019, but less than in June 2020, because CO2 and CH4 reach their seasonal maximum in May.

The values [W/m²], change to June 2020 and change to July 2019:
CO2 2.136    (- 0.025)    (+ 0.034)   
CH4 0.519    (- 0.000)    (+ 0.005)
N2O 0.206   (+ 0.001)    (+ 0.004)
SF6  0.0054 (+ 0.0001)  (+ 0.0002)
sum  2.865  (- 0.026)    (+ 0.043) (rounding differences)

The relative annual increase is 1.49 %, a little bit higher than June 2020.

This recalculates to a CO2eq of 474.8 ppm (annual increase of 3.7 ppm).
« Last Edit: November 06, 2020, 07:51:59 PM by Stephan »
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Tom_Mazanec

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #205 on: November 06, 2020, 10:45:00 PM »
But aren't there other GHGs, Stephan, like CFCs and HFCs?
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Stephan

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #206 on: November 06, 2020, 10:50:22 PM »
Yes, of course. See my posting Oct 10, where I state that the true value is higher than that I had just posted. I only take care of these four "NOAA gases" because their concentration is followed on a daily (CO2) or monthly basis (CH4, N2O, SF6) by NOAA.
In the end I think that the absolute value itself is not too interesting. So I focus on the increase which I think is concerning, and please do not forget the slightly exponential development of all of these four gases, where we all should have taken a U-turn decades ago...
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Ken Feldman

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #207 on: November 09, 2020, 06:46:12 PM »
But aren't there other GHGs, Stephan, like CFCs and HFCs?

SF6 represents the "15-Minor" greenhouse gases that NOAA tracks.  As you can see by the image below,  CO2 represent the bulk of the warming and CH4 most of the rest.  The 15 minor, with the CFCs that have been reduced due to the Montreal Protocol to protect the ozone layer, combined with N2O roughly equal the forcing from CH4.

« Last Edit: November 09, 2020, 06:55:44 PM by Ken Feldman »

kassy

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #208 on: November 13, 2020, 05:37:56 PM »
So i ran into this article:

Quote
Science journal U-turns on claim that global warming cannot be stopped after British experts cry foul

Richard Betts, a professor of climate impacts at the University of Exeter:
 'While the press release suggests that global warming may now be unstoppable for centuries, the model result in this paper is not convincing as support for that message.

Andrew Watson, a Royal Society research professor at the University of Exeter, said that he did not agree with the press release describing global warming as potentially catastrophic, 'given that it occurs over 500 years'.

Some scientists hailed Scientific Reports' findings as significant. 'This study provides evidence for what we don't want to hear: that global heating may have already become self-reinforcing, and that we have therefore passed the point of no return for halting long-term climate change,' Phillip Williamson of the University of East Anglia said.

https://www.dailymail.co.uk/sciencetech/article-8942619/Ending-greenhouse-gas-emissions-not-stop-global-warming.html

The actual article:
An earth system model shows self-sustained melting of permafrost even if all man-made GHG emissions stop in 2020

https://www.nature.com/articles/s41598-020-75481-z

The model they use is fairly simple to put it mildly:
Abstract. We have made a simple system dynamics model, ESCIMO (Earth System Climate Interpretable Model), which runs on a desktop computer in seconds and is able to reproduce the main output from more complex climate models. ESCIMO represents the main causal mechanisms at work in the Earth system and is able to reproduce the broad outline of climate history from 1850 to 2015.

https://esd.copernicus.org/articles/7/831/2016/


What did they find? Some background:

Quote
Method
We used ESCIMO to simulate the development of the global climate system from 1850 to 2500 under different assumptions concerning the emission of man-made GHGes. ESCIMO is a system dynamics model that includes representations of the world’s atmosphere, oceans, forests (and other land types), biomass—and their interactions. It is described here5. The source code with documentation is available online6.

In the first simulation reported here, “Scenario 1”, we assume that humanity reduces man-made GHG emissions to zero by 2100. In the second simulation, “Scenario 2”, we assume that emissions are cut much faster—to zero in 2020. In both cases man-made emissions remain zero thereafter.

Results
The result is shown in Fig. 1. In both scenarios the global temperature keeps rising for hundreds of years—to around + 3 °C in 2500—after a temporary decline in this century in conjunction with the decline in man-made emissions (Fig. 1c).

So where does effect come from:


Scenario 1
Scenario 1 describes the result when we assume that man-made emissions peak in the 2030s and decline to zero in 2100 (see Fig. 1, solid lines). This is the “most likely” scenario as described here7.

Quote
The historical part of the simulation (1850–2015) and the ensuing 60 years (2015–2075) are intuitive and understandable. Rising emissions of man-made GHGes lead to an increase in the concentration of GHGes in the atmosphere (Fig. 1b,d). This, in turn, leads to a rise in the global average surface temperature because GHG molecules block outgoing long-wave (heat) radiation from the surface. The warming is enhanced by the increased amount of water vapour which accumulates in a warmer atmosphere because H2O is a strong greenhouse gas which blocks other frequencies (Fig. 1f). The warming leads to rising sea levels because of thermal expansion and glacier run-off. Difficult to detect, but of great significance for the years beyond 2150, surface albedo starts a slow and smooth decline as the ice and snow cover melts, making the planet darker and leading to more absorption of short-wave (SW) radiation in the surface (Fig. 1h).

So what happens in the realistic scenario:

Quote
In Scenario 1 the temperature passes a temporary peak around 2075 at + 2.3 °C above pre-industrial times. The temperature then falls for 75 years (2075–2150) to + 2 °C. There are two reasons: (a) the concentration of GHGs in the atmosphere declines, and (b) heat is used to melt on-land glaciers and Arctic ice.

Furthermore, the concentration of CO2 declines (from its all-time peak of 450 ppm in 2050) through two processes: (a) CO2 is gradually absorbed in the ocean surface (and later transported into the deep ocean), and (b) CO2 is gradually absorbed in the biosphere. CO2 in the atmosphere is converted through photosynthesis into biomass in living matter and soils at a rate that is determined by the temperature and the amount of CO2 in the atmosphere. By 2150 all on-land snow and ice are gone in ESCIMO Scenario 1 (except in Greenland and Antarctica, which require thousands of years to melt).

While the developments to 2150 are understandable, developments in ESCIMO beyond 2150 are more surprising (counter-intuitive). As shown in Fig. 1 the temperature once more starts rising. The surprising fact is that this rise takes place 50 years after man-made emissions have ceased, and after the concentration of CO2 in the atmosphere has been significantly reduced through absorption in oceans and biomass.

The explanation (in ESCIMO) is as follows. While GHG concentrations—and thus their forcings—fall from 2070 to 2150, the effect of surface albedo continues on its smooth upward path throughout this period. Its time development is much slower than that of GHGes. It is the result of mainly Arctic ice melting—but it has enough ‘momentum’ to push the climate system back onto a path of rising temperatures, with its secondary effects of raising humidity and permafrost melting, which then in turn help the system become warmer and warmer, even if man-made GHG emissions are zero. A cycle of self-reinforcing processes is established. See Fig. 2a.

So the model is really simple but is there anything in the IPCC models to counter these effects? Or to put it more simply what do they show for the same trajectories?

Essentially this a very simple general model that shows us we are already in dangerous territory because we overshot whatever the goal was to keep the permafrost stabile.

Þetta minnismerki er til vitnis um að við vitum hvað er að gerast og hvað þarf að gera. Aðeins þú veist hvort við gerðum eitthvað.

wehappyfew

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #209 on: November 13, 2020, 05:51:14 PM »
Assuming we retain any kind of technology, we're going to end up doing some kind of solar radiation blocking, either stratospheric aerosols, or space based shades.

What will be the consequences? Who knows.

The chief source of problems is solutions to previous problems.