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Author Topic: Where are we now in CO2e , which pathway are we on?  (Read 10810 times)

Tom_Mazanec

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #50 on: January 31, 2020, 11:21:25 PM »
Quote
Be that as it may, average of 2010 to average of 2019 sounds like 9 years to me, rather than 10. What am I missing?

First 2010
Second 2011
Third 2012
Fourth 2013
Fifth 2014
Sixth 2015
Seventh 2016
Eighth 2017
Ninth 2018
Tenth 2019
 
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Ken Feldman

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #51 on: January 31, 2020, 11:57:41 PM »
I did click on the link, but these numbers were not immediately apparent while browsing it. I did not download any data files though.
Be that as it may, average of 2010 to average of 2019 sounds like 9 years to me, rather than 10. What am I missing?
Why not take the last actual available annual global average (2019? 2018?), compare it to the annual global average of 2010, and compare these numbers and their diffs to what the RCPs had to say about the same timespan (2018-2010 or 2019-2010)? Sounds liks a more proper comparison to me.

The RCP tables in the IPCC report go by the decade, so 2010, 2020, 2030, 2040, …

We can wait a year and go with your approach, I was offering up something we can do now.

wdmn

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #52 on: February 01, 2020, 02:33:45 AM »
Sorry Ken, I misunderstood, and it's because I am a bit mixed up as to the point of this thread.

The title asks, which pathway are we on? I believe that means, which CO2eq pathway are we on, rather than CO2, and the reason that we originally wanted to calculate CO2eq is because there are a bunch of us on this board who think that the RF from CO2eq using GWP10 is an important figure to have, and we can't find it anywhere.

But I shouldn't speak for others, I've just heard that expressed by a few people.

Personally, the reason I'm interested in CO2eq is that a recent study suggested RF from anthro aerosols in 2008 was ~ -2W/m^2. If we looked at RF from CO2eq using GWP10 instead of GWP100 could it be that we're actually masking ~1.5C of warming? That we've actually passed CO2 doubling and TCR is ~2.7C and ECS>5C? I know some of the CMIP6 models had values of ECS and TCR that are similar.

I realize this is unlikely, but I'd like to know how long ago CO2eq passed (assuming it has) a doubling of pre-industrial.

We can't use any of the IPCC models for this assuming that none of them use the GWP10 numbers when thinking about CH4 or NO2.


kassy

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #53 on: February 01, 2020, 04:08:20 PM »
I am a bit mixed up as to the point of this thread.


1) Looking at the numbers to see which RCP we were closest too.

There was a recent discussion in the ASLR thread about which RCP scenario we were on and that interested me. So one goal was moving that discussion out of that thread because it has a steady stream of updates so the discussion would be buried soon and it is too interesting.

2) Possibly using the Co2e for that

(and moving related discusssion out of ML CO2 thread)

3) At some point see how the Carbon Clock data on the budget matches up to the numbers.

4) RCPs change to SCP or whatever so we could track that change if needed.

Basically lets play with numbers and see if we can learn from that.

I realize this is unlikely, but I'd like to know how long ago CO2eq passed (assuming it has) a doubling of pre-industrial.


And to check things like that.

I would like to see the comparison using "instantaneous value of the radiative forcing of the stock (concentration) of greenhouse gases in the atmosphere" see #25 for details.



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wdmn

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #54 on: February 03, 2020, 08:27:31 AM »
I don't believe the below graph has been posted yet and seems essential to the topic of this thread.

Assuming I'm reading this graph right we are well above RCP 8.5 at this point for CO2eq, as we are already above 450ppm CO2eq according to all of the numbers presented in this thread...

Also, I still haven't figured out how you get from ppb in CH4 to ppm in CO2eq if it's not using the GWP multiplier (some posters in this thread have claimed that GWP is not for atmospheric CO2 concentrations).
« Last Edit: February 03, 2020, 08:37:43 AM by wdmn »

wolfpack513

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #55 on: February 03, 2020, 04:56:20 PM »
I'm not 100% sure but I believe RCPs use a 20-year running average/smooth and include anthropogenic aerosols(negative forcing).  Therefore endpoints or single years will have much higher CO2e than the 20 year average.  Lower pathways have less aerosols and less cooling.  Higher end RCPs: 6 & 8.5 have more cooling from aerosols.  Since all pathways begin at 2000 it takes a while for separation especially with inverse negative forcing/cooling in emission mitigation.

I don't believe the below graph has been posted yet and seems essential to the topic of this thread.

Assuming I'm reading this graph right we are well above RCP 8.5 at this point for CO2eq, as we are already above 450ppm CO2eq according to all of the numbers presented in this thread...

Also, I still haven't figured out how you get from ppb in CH4 to ppm in CO2eq if it's not using the GWP multiplier (some posters in this thread have claimed that GWP is not for atmospheric CO2 concentrations).
« Last Edit: February 03, 2020, 05:10:05 PM by wolfpack513 »

gerontocrat

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #56 on: February 03, 2020, 05:36:59 PM »
I'm not 100% sure but I believe RCPs use a 20-year running average/smooth and include anthropogenic aerosols(negative forcing).

Given the speed of change using a 20 year running average seems a bit out-of-date, and downright misleading. It reminds me of once a decade producing a new 30 year average of temperature, even though the climate in year 30 is now so much different from what it was in year 1.

The WMO in its recent report to the IPCC of THE GLOBAL CLIMATE 2015–2019 ,showed how much the average of 2015-2019 had changed from the average 2010-2014. i.e. the WMO used the change in 5 years to highlight what a rotten state the climate is and how quickly it is changing.

Executive summary
Quote
Compared to the previous five-year assessment period 2011–2015, the current five-year period 2015–2019 has seen a continued increase in carbon dioxide (CO2) emissions and an accelerated increase in the atmospheric concentration of major greenhouse gases (GHGs), with growth rates nearly 20% higher. The increase in the oceanic CO2 concentration has increased the ocean’s acidity.

The five-year period 2015–20191 is likely to be the warmest of any equivalent period on record globally, with a 1.1 °C global temperature increase since the pre-industrial period and a 0.2 °C increase compared to the previous five-year period.

Continuing and accelerated trends have also predominated among other key climate
indicators, including an acceleration of rising sea levels, a continued decline in the Arctic sea-ice extent, an abrupt decrease in Antarctic sea ice, continued ice mass loss in the glaciers and the Greenland and Antarctic ice sheets, and the clear downward trend in the northern hemisphere spring snow cover.

More heat is being trapped in the ocean; 2018 had the largest ocean heat content values on
record measured over the upper 700 meters.
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wdmn

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #57 on: February 03, 2020, 07:27:54 PM »
Thanks.

Not sure about the 20 year running average; as gerontocrat says it would be very misleading. I know that aerosols are included. They are also included in the numbers posted here from external sources. For example the 454ppm number in 2017.

Ken Feldman

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #58 on: February 03, 2020, 09:15:04 PM »
I don't believe the below graph has been posted yet and seems essential to the topic of this thread.

Assuming I'm reading this graph right we are well above RCP 8.5 at this point for CO2eq, as we are already above 450ppm CO2eq according to all of the numbers presented in this thread...

Also, I still haven't figured out how you get from ppb in CH4 to ppm in CO2eq if it's not using the GWP multiplier (some posters in this thread have claimed that GWP is not for atmospheric CO2 concentrations).

Keep in mind that the RCPs also include aerosols and land use (albedo) changes which have a cooling effect.  We've only been comparing the greenhouse gases on this thread. 

To get to a CO2eq you can take the measured concentration of a greenhouse gas in the atmosphere and calculate it's radiative forcing.  Then you can convert to CO2eq by finding the amount of CO2 that would have the same radiative forcing.  So you can get around the whole GWP 20 vs GWP 100 argument.

wdmn

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #59 on: February 03, 2020, 10:02:55 PM »
Thanks for the explanation re. GWP Ken.

As for the cooling effect of aerosols please see my last post ^^


mitch

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #60 on: February 03, 2020, 11:37:32 PM »
You don't actually get around the GWP20 vs GWP100 issue using Co2 equivalents.  Here is the NOAA website explaining how they calculate them:
https://www.esrl.noaa.gov/gmd/aggi/aggi.html

The CO2e depends on a calculation of forcing. 

wolfpack513

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #61 on: February 04, 2020, 01:09:55 AM »
I’m not a fan of 5-year averages gerontocrat.  2015-2019 was dominated by +ENSO.  2010-2014 which was weighted more -ENSO.  There has been some acceleration the last 40 years but majority of the last 5 years bump was internal variability.  The 20-year and 30-year trend are identical.  You can hardly see the red line overlaid the green line. 

wdmn

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #62 on: February 04, 2020, 02:33:46 AM »
You don't actually get around the GWP20 vs GWP100 issue using Co2 equivalents.  Here is the NOAA website explaining how they calculate them:
https://www.esrl.noaa.gov/gmd/aggi/aggi.html

The CO2e depends on a calculation of forcing.

Thanks, that had been my understanding.

I feel like a dog chasing his tail with this one, but I also feel that those of us making a clamour here are on to something.

Here's how I look at it: there's uncertainty attached to almost all of the numbers we're interested in. If we use RF there's a large uncertainty around aerosols.

So let's start with the things we can actually measure directly. To me that is atmospheric concentration. Yes, we have to find a way to make the different concentrations comparable and that is a problem... We can also measure GMSTA. Using those measurements we could potentially get clues about some of the areas where we lack certainty.

That's my reasoning.

edmountain

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #63 on: February 04, 2020, 05:30:51 PM »
I don’t think there’s any way to get around using time horizons when discussing CO2 equivalents. This is because the very definition of GWP is based on integration over time. From the IPCC AR5 report:

Quote
The Global Warming Potential (GWP) is defined as the time-integrated RF due to a pulse emission of a given component, relative to a pulse emission of an equal mass of CO2 (Figure 8.28a and formula).
Source: https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_all_final.pdf

The absolute GWPs (AGWP) of hypothetical gases are the areas under the curves red and green curves in Figure 8.28a from the same report as shown below. The AGWP for CO2 is the area under the blue curve. GWP for a gas is the AGWP for that gas divided by the AGWP for CO2.


CO2 equivalents are essentially a unit of measure of GWP (analogous to how meters are a measure of distance). As such, time horizons are inseparable from the definition of CO2 equivalents. I’m not sure how to interpret the instantaneous ratio of RF that Ken refers to other than being some measure of relative fluxes.

wolfpack513

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #64 on: February 04, 2020, 05:31:40 PM »
CMIP5 data in the IPCC 5th AR uses RCPs in 20-year centered periods: "Twenty-year AR5 climatologies and climatological anomalies are calculated for the averaging periods 2016-2035, 2046-2065, 2081-2100 for the CMIP5 scenario experiments rcp26, rcp45, rcp60 and rcp85."  So not exactly 20-year running averages. 

The 1998-2012 hiatus period is highlighted for issues with timescales of 15 years or less. Heat uptake is still occurring but internal variability may briefly slow GMST trends.  20-year period are long enough to average out most of this internal variability.  https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_Chapter09_FINAL.pdf


Thanks.

Not sure about the 20 year running average; as gerontocrat says it would be very misleading. I know that aerosols are included. They are also included in the numbers posted here from external sources. For example the 454ppm number in 2017.

nanning

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #65 on: February 04, 2020, 07:27:41 PM »
[rant]
"Where are we now in CO2e , which pathway are we on? "

I am fed up with these 'pathways'.
We are clearly on the pathway to catastrophy, to the end of life as we know it. Please talk to 'aware' children about that.

Forget those stupid budgets (a faraway point that 'the can' can be kicked to, and re-kicked) and 'informing decision makers' because nobody is listening (see COP25) and if anything is being done by some, it is far too little and far too late. How much more do you need to know to be certain of catastrophy? U.N.: Essential: Fundamental changes to our production/consumption systems.
Well, green BAU isn't it
.

People may wanna know precisely when 'it''ll happen to them? Well, it's already happening to millions of people elsewhere on this planet, i.e. the global poor south. It is here! People are dying!

I ask myself: Why study your own destruction in such detail? Putting all focus on analysis and modelling meanwhile the Earth is burning, drowing and sterilising and more and more humans (far away) are dying from it. Please see the big picture. It includes Africa. Africans are as much human as you and me.
[/rant]
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"It is preoccupation with what other people from your groups think of you, that prevents you from living freely and nobly" - Nanning
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sark

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #66 on: February 07, 2020, 08:10:42 AM »
Have we doubled the greenhouse effect?
I am not a scientist

wdmn

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #67 on: February 07, 2020, 08:52:14 AM »
Have we doubled the greenhouse effect?

The best answer comes from here: https://www.esrl.noaa.gov/gmd/aggi/aggi.html

and seems to be "no." The NOAA (IPCC) method gives us 496 ppm CO2e for 2018, so I guess somewhere around 500ppm for 2019. Growing at a rate of ~3.7 ppm/yr over the last six years, if that were to continue we would double in something like 20 years.

To understand how RF is calculated (i.e. how the constants used in table 1 above were derived), and so how the CO2eq is calculated, you would need to tackle the following:

Radiative Forcing of Climate Change, Chapter 6 in Climate Change 2001: The Scientific Basis

available here: https://www.ipcc.ch/site/assets/uploads/2018/03/TAR-06.pdf


« Last Edit: February 07, 2020, 09:40:47 AM by wdmn »

Tom_Mazanec

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #68 on: February 07, 2020, 11:42:23 AM »
Quote
Growing at a rate of ~3.7 ppm/yr over the last six years, if that were to continue we would double in something like 20 years.
But that rate of increase is itself slowly increasing, so more like 18 or 19 years.
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rboyd

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #69 on: February 07, 2020, 11:13:59 PM »
The NOAA CO2e calculation uses the 100-year CO2 equivalent for CH4.

CH4 is degraded out of the atmosphere over a 14 years period, with a 20-year CO2e of about 100, vs 34 for 100 years. Given that we are more than replacing the degraded CH4 every year (the atmospheric concentration keeps going up) we should be using at least the 20-year, if not the continuous, CO2e for CH4. Using the 20-year we are at about 620ppm CO2e - that is an accurate view of the current energy imbalance of the Earth System.

So we already doubled CO2e from pre-industrial (not taking into account climate dimming aerosols) and its only Earth System delayed responses (plus aerosols) which have stopped us from hitting the 2 degrees C increase already. The IPCC scientists assume that the CH4 will be reduced as NG use reduces, but thats not happening given the ongoing coal to NG switching and there is also the problem of natural CH4 emissions increasing as temperatures increase.

Thats how we get to be on the RCP8.5 scenario without the required level of anthropogenic CO2 emissions, the short-term effects of CH4 plus feedbacks fill the gap. If the Arctic Sea Ice goes then we will need a new scenario - RCP10 or perhaps RCP WAF (as in "we are f....").

wdmn

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #70 on: February 08, 2020, 04:28:14 AM »
Rboyd,

Does it say that somewhere on the NOAA site?

My understanding from reading the site was that they're first calculating RF for each GHG using numbers from lab experiments/models, and then they convert RF to CO2eq? They are able to do this because they have ppm CO2 and RF, so going from RF to ppm COe would be pretty simple. It seems to me they don't use a GWP multiplier at all, as Ken suggested earlier...

Stephan

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #71 on: February 08, 2020, 11:10:51 PM »
With the actual values of CO2, CH4, N2O and SF6 for October 2019 (see the individual threads) there is an annual increase (Oct 2019 vs. Oct 2018) of 3.08 ppm CO2 eq (20 y) or 2.87 ppm CO2 eq (100 y).
October 2019 vs. Sept. 2019 delivers an increase of 0.20 ppm CO2 eq (20 y) or 0.08 ppm CO2 eq (100 y)
It is too late just to be concerned about Climate Change

rboyd

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #72 on: February 11, 2020, 01:10:55 AM »
Rboyd,

Does it say that somewhere on the NOAA site?

My understanding from reading the site was that they're first calculating RF for each GHG using numbers from lab experiments/models, and then they convert RF to CO2eq? They are able to do this because they have ppm CO2 and RF, so going from RF to ppm COe would be pretty simple. It seems to me they don't use a GWP multiplier at all, as Ken suggested earlier...

2017 to 2018 rise for CO2 was 2.39ppm, which produced an increase in radiative forcing of 0.031
- 0.031 / 2.39 = radiative forcing per CO2 ppm = 0.01297


2017 to 2018 rise for NH4 was 8.27ppb = 0.00827ppm, which produced an increase in radiative forcing of 0.003
- 0.003 / 0.00827 - radiative forcing per NH4 ppm = 0.36276

An NH4 ppm produces a radiative forcing approximately 28 times that of a CO2 ppm, the 100-year equivalent amount according to the UN IPCC in 2011. The more recent 100-year value is 36. The 20-year value is 86 (direct forcing only).
« Last Edit: February 11, 2020, 01:16:09 AM by rboyd »

oren

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #73 on: February 11, 2020, 08:15:24 AM »
Thanks for the calculation rboyd. (NH4 should be CH4).
I note it does not include a timeframe (integration period) so I will take it as the instantaneous value I was looking for, which I would expect to be higher than 100-yr and 20-yr values as those include an assumption of CH4 concentration decay.
What I find weird is that the value of 28 is close to the 100-yr value and much lower than the 20-yr value. Are you sure there isn't some error in the calculation?

rboyd

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #74 on: February 11, 2020, 06:23:49 PM »
Oren, thanks for the correction, Ammonia is a very different thing!

I remember reading that NOAA was still using the outdated 28 multiplier for the CO2e of CH4, looked around a lot but couldn't find the reference. Neither any simple statement about the GPWP that NOAA. Thats why I did the calculation.

I really do think that they are using the 28 multiplier as a measure of RF, not even the GWP100 of CH4 which is more up to date. I did get a confirmation of this from AbruptSLR, but would definitely welcome information from somebody more in the know.

This is from the official NOAA website, they never mention the GWP20:

Quote
Methane plays an important role in the chemistry and radiative properties of the atmosphere. With a global warming potential of 28 over a 100-year horizon, methane is a potent greenhouse gas (IPCC, AR5). Atmospheric methane has a lifetime of about a decade, and it is ultimately oxidized to CO2. It is one of the greenhouse gases targeted by the Kyoto Protocol, and may well be regulated by the United States in the future. Controlling methane emissions also has implications for air quality, since oxidation of CH4 leads to tropospheric ozone formation in polluted environments.

https://www.esrl.noaa.gov/gmd/ccgg/carbontracker-ch4/

Ken Feldman

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #75 on: February 11, 2020, 10:56:01 PM »
The linked article discusses the global warming potential of SF6 and shows why reductions in CO2 and CH4 should be prioritized, even if it means slight increases in SF6 emissions in the next few decades.

http://theconversation.com/why-sf-emissions-from-the-renewable-energy-sector-should-not-be-considered-a-dirty-secret-130734

Quote
Why SF₆ emissions from the renewable energy sector should not be considered a ‘dirty secret’
February 10, 2020

How much does generating electricity using renewables boost global warming? You’d probably think not at all, but according to a BBC article published in September 2019, emissions of sulfur hexafluoride (SF₆), “the most powerful greenhouse gas known to humanity”, have been rising rapidly in recent years, and the likely culprit is “the green energy boom”.

SF₆ gas is used to insulate electrical installations like wind turbines and was quoted as the industry’s “dirty secret” in the BBC article. The article also claimed that SF₆ emissions to the atmosphere in 2017 had the same warming effect as adding an extra 1.3 million cars to roads across the UK and the EU.

Quote
The most important sentence in the BBC’s article is this:

    Concentrations in the atmosphere [of SF₆] are very small right now, just a fraction of the amount of CO₂ in the air.

Unfortunately, this critical point isn’t developed.

The global concentration of atmospheric CO₂ today is about 410 parts per million, whereas the global concentration of SF₆ is only about 10 parts per trillion. In other words, there is 41 million times more CO₂ in the atmosphere than SF₆.

But since SF₆ is 23,500 times stronger at trapping heat than CO₂, doesn’t this still mean it’s a bigger problem than CO₂ for the climate?

CO₂ is actually a very weak greenhouse gas and is much less efficient at trapping heat compared to other greenhouse gases, such as methane (CH₄) and nitrous oxide (N₂O). The reason why CO₂ has the largest impact on the climate is partly because, like SF₆, it is very long-lived. But mostly, it is because there is so much more CO₂ in the atmosphere than other greenhouse gases (except for water vapour, which is not the main driver of anthropogenic climate change because it is so short-lived).





Note that the article refers to Methane's GWP(200) as 28.  It has been updated to 34 as explained in the following reference.

https://ui.adsabs.harvard.edu/abs/2017AGUFM.A51N..08H/abstract

Quote
The global warming potential of methane reassessed with combined stratosphere and troposphere chemistry

    Holmes, C. D.; Archibald, A. T.; Eastham, S. D.; Søvde, O. A.

Abstract

Methane is a direct and indirect greenhouse gas. The direct greenhouse effect comes from the radiation absorbed and emitted by methane itself. The indirect greenhouse effect comes from radiatively active gases that are produced during methane oxidation: principally O3, H2O, and CO2. Methane also suppresses tropospheric OH, which indirectly affects numerous greenhouses gases and aerosols. Traditionally, the methane global warming potential (GWP) has included the indirect effects on tropospheric O3 and OH and stratospheric H2O, with these effects estimated independently from unrelated tropospheric and stratospheric chemistry models and observations. Using this approach the CH4 is about 28 over 100 yr (without carbon cycle feedbacks, IPCC, 2013). Here we present a comprehensive analysis of the CH4 GWP in several 3-D global atmospheric models capable of simulating both tropospheric and stratospheric chemistry (GEOS-Chem, Oslo CTM3, UKCA). This enables us to include, for the first time, the indirect effects of CH4 on stratospheric O3 and stratosphere-troposphere coupling. We diagnose the GWP from paired simulations with and without a 5% perturbation to tropospheric CH4 concentrations. Including stratospheric chemistry nearly doubles the O3 contribution to CH4 GWP because of O3 production in the lower stratosphere and because CH4 inhibits Cl-catalyzed O3 loss in the upper stratosphere. In addition, stratosphere-troposphere coupling strengthens the chemical feedback on its own lifetime. In the stratosphere, this feedback operates by a CH4 perturbation thickening the stratospheric O3 layer, which impedes UV-driven OH production in the troposphere and prolongs the CH4 lifetime. We also quantify the impact of CH4-derived H2O on the stratospheric HOx cycles but these effects are small. Combining all of the above, these models suggest that the 100-yr GWP of CH4 is over 33.5, a 20% increase over the latest IPCC assessment.


Publication:
    American Geophysical Union, Fall Meeting 2017

Also note that the Methane GWP already includes its impact on Ozone and Stratospheric Water Vapor, so it would be double-counting to include separate factors for those gases.
« Last Edit: February 11, 2020, 11:14:08 PM by Ken Feldman »

rboyd

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #76 on: February 17, 2020, 08:11:56 PM »
Looks like there are alternatives for SF6 in medium voltage uses, but not in high voltage ones. Looks like more research money needs to be spent on the HV applications. But definitely less of a issue that CO2 and CH4.

Quote
The rationale for this was that there was no viable alternative. However, as has been made clear this in this paper, this is no longer the case, at least not in the case of MV switchgear. There are alternatives which are technically and commercially viable. With EU regulation No 517/2014 due to be reviewed in 2020, policy makers should campaign for further legislation with the final aim of phasing out SF6. This will further invigorate the research and development of SF6 -free technologies, not only for MV switchgear, but also for HV applications. These measures will represent a significant step in the fight against climate change and also help reestablish Europe as a leader in cleantech

https://energypost.eu/why-the-eu-should-ban-sf6/

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #77 on: February 17, 2020, 10:35:15 PM »
In response to Ken Feldman's post ^^

Impacts of CH4 over 100 years are 24% of warming. This confirms my suspicion that considering a shorter timeframe CH4 could be responsible for most of the warming we see now.

This might sound crazy, but if cooling from anthro aerosols really is closer to -2W/m2 as a recent study suggests (or even if it is closer to -1.45 W/m2), then almost all of the warming from CO2 is being masked. Might this explain the hiatus? Didn't it occur during a time of flat methane emissions?

This is crazy speculation, which is why I've not said it before. But heck, here we go.

blumenkraft

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #78 on: February 18, 2020, 10:22:19 AM »
OMG  :-[
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Ken Feldman

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #79 on: February 18, 2020, 06:18:33 PM »
In response to Ken Feldman's post ^^

Impacts of CH4 over 100 years are 24% of warming. This confirms my suspicion that considering a shorter timeframe CH4 could be responsible for most of the warming we see now.

This might sound crazy, but if cooling from anthro aerosols really is closer to -2W/m2 as a recent study suggests (or even if it is closer to -1.45 W/m2), then almost all of the warming from CO2 is being masked. Might this explain the hiatus? Didn't it occur during a time of flat methane emissions?

This is crazy speculation, which is why I've not said it before. But heck, here we go.

There was no hiatus.  While temperatures vary from year to year, almost 93% of the extra heat in the climate winds up in the oceans.  Keep an eye on ocean heat content.

https://www.nodc.noaa.gov/OC5/3M_HEAT_CONTENT/


rboyd

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #80 on: February 18, 2020, 07:28:43 PM »
One of the reasons considered as causing the observed "hiatus" is that there were more La Nina events (with cold ocean surface), which pulled more heat from the atmosphere into the oceans. Also, atmospheric levels of CH4 flat-lined from 2000 to 2007 and China ramped up their coal production (the aerosol cooling is immediate while the CO2 effects take years to offset the aerosol cooling).

With the drive for clean air in China, now intensified by the actions taken to combat the virus, less aerosols to cool China.

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #81 on: March 06, 2020, 09:02:59 PM »
With the actual values of CO2, CH4, N2O and SF6 for November 2019 (see the posts in the individual threads) there is an annual increase (Nov 2019 vs. Nov 2018) of 2.81 ppm CO2 eq (20 y) or 2.60 ppm CO2 eq (100 y). Both values are in the lower end of what has been observed in the last year.

I plotted the annual increases of both (20 y / 100 y) CO2 eq. in a graph (see attached). The linear trend lines are increasing (= acceleration).
« Last Edit: March 06, 2020, 09:16:38 PM by Stephan »
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Re: Where are we now in CO2e , which pathway are we on?
« Reply #82 on: March 06, 2020, 09:55:25 PM »
With the actual values of CO2, CH4, N2O and SF6 for November 2019 (see the posts in the individual threads) there is an annual increase (Nov 2019 vs. Nov 2018) of 2.81 ppm CO2 eq (20 y) or 2.60 ppm CO2 eq (100 y). Both values are in the lower end of what has been observed in the last year.

I plotted the annual increases of both (20 y / 100 y) CO2 eq. in a graph (see attached). The linear trend lines are increasing (= acceleration).

With a hat tip to rboyd, why is it that the mean global annual rate of growth of atmospheric CO2 in 2019 of 3.08 +/- 0.08 ppm (see attached images from the linked NOAA website) is higher than your calculation for the difference of CO2-e for 2018 and 2019?

https://www.esrl.noaa.gov/gmd/ccgg/trends/gl_gr.html
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Stephan

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #83 on: March 06, 2020, 10:14:31 PM »
With the actual values of CO2, CH4, N2O and SF6 for November 2019 (see the posts in the individual threads) there is an annual increase (Nov 2019 vs. Nov 2018) of 2.81 ppm CO2 eq (20 y) or 2.60 ppm CO2 eq (100 y). Both values are in the lower end of what has been observed in the last year.

With a hat tip to rboyd, why is it that the mean global annual rate of growth of atmospheric CO2 in 2019 of 3.08 +/- 0.08 ppm (see attached images from the linked NOAA website) is higher than your calculation for the difference of CO2-e for 2018 and 2019?

Because I used the November 2019-November 2018 difference, which is the lowest individual difference observed in 2019. If I take all 12 values from Dec 2018 up to Nov 2019 I receive an average annual increase in CO2 eq of 3.47 ppm (20 y) or 3.29 ppm (100 y).
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Re: Where are we now in CO2e , which pathway are we on?
« Reply #84 on: March 06, 2020, 11:01:36 PM »
With the actual values of CO2, CH4, N2O and SF6 for November 2019 (see the posts in the individual threads) there is an annual increase (Nov 2019 vs. Nov 2018) of 2.81 ppm CO2 eq (20 y) or 2.60 ppm CO2 eq (100 y). Both values are in the lower end of what has been observed in the last year.

With a hat tip to rboyd, why is it that the mean global annual rate of growth of atmospheric CO2 in 2019 of 3.08 +/- 0.08 ppm (see attached images from the linked NOAA website) is higher than your calculation for the difference of CO2-e for 2018 and 2019?

Because I used the November 2019-November 2018 difference, which is the lowest individual difference observed in 2019. If I take all 12 values from Dec 2018 up to Nov 2019 I receive an average annual increase in CO2 eq of 3.47 ppm (20 y) or 3.29 ppm (100 y).

Thanks
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Stephan

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #85 on: March 06, 2020, 11:08:33 PM »
You're welcome.
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Stephan

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #86 on: April 06, 2020, 09:07:26 PM »
With the actual values of CO2, CH4, N2O and SF6 for December 2019 (see the posts in the individual threads) there is an annual increase (Dec 2019 vs. Dec 2018) of 3.16 ppm CO2 eq (20 y) or 2.99 ppm CO2 eq (100 y).
This increase is mainly driven (2.69 ppm) by CO2 itself.
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Re: Where are we now in CO2e , which pathway are we on?
« Reply #87 on: April 21, 2020, 06:52:56 PM »
New Study Says The North Pole Will Be Completely Ice-Free In Summer Before 2050, Even If We Curb Carbon Emissions

A new study in the journal Geophysical Research Letters forecasts a massive reduction in Arctic sea ice over the next three decades, predicting that the North Pole will experience its first ice-free summer before 2050. What’s particularly disquieting is that this eventuality appears likely for all climate models, including those that factor in rapid reductions in carbon dioxide emissions.

...

It is estimated that the world has a remaining carbon budget of around 1,000 gigatonnes of carbon dioxide, meaning that this is the absolute limit to our future emissions if we want to prevent a 2°C rise in global temperatures compared to pre-industrial levels. Yet after analyzing more than 40 different climate models, the study authors found that the Arctic will sometimes be ice-free in summer even if we stick to this budget.

https://www.iflscience.com/environment/new-study-says-north-pole-completely-ice-free-summer-before-2050-even-curb-carbon-emissions/

So if you do not reject this study this basically tells you we are on an unsafe trajectory.

It should have been 1C. This also means that not being on rcp 8.5 projections is not going to help and we can´t just let the markets do their thing.

PS: Another hint was permafrost becoming a source instead of a sink:

Arctic Shifts To a Carbon Source Due to Winter Soil Emissions

...

The earlier 2020 date (from some other research see link for details, k) triggered me because one of the goals always was to prevent things like this from happening and now it is already here.

Eyeballing Mauna Loa CO2 anything over 370 is bad. So that is an interesting challenge.


 
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Re: Where are we now in CO2e , which pathway are we on?
« Reply #88 on: April 21, 2020, 07:47:23 PM »
New Study Says The North Pole Will Be Completely Ice-Free In Summer Before 2050, Even If We Curb Carbon Emissions


The title is a tad sensational.

1) The study points to a likelihood, while the title implies certainty.

2) The study indicates the likelihood declines in lower emission scenarios, while the title implies its the outcome is out of human control.

3) The study is indicating the likelihood of BOE level loss (1M km2 at minimum) while the title indicates complete loss.

It would be more responsible for the journalists and the study authors to better highlight the correlation between emission scenarios and likelihood of BOE 2050.

The Walrus

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #89 on: April 21, 2020, 09:40:05 PM »
New Study Says The North Pole Will Be Completely Ice-Free In Summer Before 2050, Even If We Curb Carbon Emissions


The title is a tad sensational.

1) The study points to a likelihood, while the title implies certainty.

2) The study indicates the likelihood declines in lower emission scenarios, while the title implies its the outcome is out of human control.

3) The study is indicating the likelihood of BOE level loss (1M km2 at minimum) while the title indicates complete loss.

It would be more responsible for the journalists and the study authors to better highlight the correlation between emission scenarios and likelihood of BOE 2050.

I guess that is what happens when people read a pseudoscience website that publishes unproven and misleading information. 

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #90 on: April 22, 2020, 12:16:01 AM »
The title is a tad sensational.

We agreed to the Paris 2C thing to keep us safe. To prevent real world effects like losing the ice.

To point 1) do you like these odds? Do you have children? Etc.

If we aim for 2C we will overshoot that because that is how we roll. So you can safely assume the worse inputs

2) It is not out of our control we just don´t really do anything. This gap can be closed.

3) Editors always sort of botch headlines which is why you read the article and the science article it is about if it looks interesting.

Why do you focus on article formatting?

I guess that is what happens when people read a pseudoscience website that publishes unproven and misleading information.

Arctic Sea Ice in CMIP6

This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1029/2019GL086749

The whole point in preventing climate change was stopping the loss of Arctic ice (fail), permafrost feedbacks (fail) and keeping Iceland and Antarctica somewhat intact (guess).

There always was this tension between the carbon budget and the time lines people talked about and the time lines people actually commit too.




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The Walrus

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #91 on: April 22, 2020, 01:16:28 AM »
I think you misplaced the target of my post.  The article itself is fine.  I was referring to the website, which misrepresented an otherwise valid scientific paper.

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #92 on: April 22, 2020, 01:54:14 AM »
I am opposed to inaccurate messaging that induces people to give up hope.

For the benefit of people who might just be grazing in the thread, I thought it would be useful to explain that a superficial glance at the post is not necessarily reflecting the substance of the study.
« Last Edit: April 22, 2020, 02:30:11 AM by Phoenix »

Juan C. García

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #93 on: April 22, 2020, 02:08:59 AM »
New Study Says The North Pole Will Be Completely Ice-Free In Summer Before 2050, Even If We Curb Carbon Emissions


The title is a tad sensational.

1) The study points to a likelihood, while the title implies certainty.

2) The study indicates the likelihood declines in lower emission scenarios, while the title implies its the outcome is out of human control.

3) The study is indicating the likelihood of BOE level loss (1M km2 at minimum) while the title indicates complete loss.

It would be more responsible for the journalists and the study authors to better highlight the correlation between emission scenarios and likelihood of BOE 2050.
I don't have access to the study, but Dr. Dirk Notz is from Universität Hamburg, and they have also an internet page saying that:
Quote
"If we reduce global emissions rapidly and substantially, and thus keep global warming below 2 °C relative to preindustrial levels, Arctic sea ice will nevertheless likely disappear occasionally in summer even before 2050. This really surprised us" said Dirk Notz, who leads the sea-ice research group at University of Hamburg, Germany.
https://www.cen.uni-hamburg.de/en/about-cen/news/11-news-2020/2020-04-20-sea-ice-notz.html
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

Bruce Steele

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #94 on: April 22, 2020, 02:18:38 AM »
https://www.eurekalert.org/pub_releases/2020-04/uoh-nps042020.php
Says the low emissions pathways they used were IPCC 1-1.9 and IPCC 1-2.6 scenarios .
I thought we had already missed the bus on those two options.
 Maybe if the current Covid-19 lockdowns extended for decades we could still meet the IPCC 2.6
pathway ?
 Hard to find good news in the options remaining.

Juan C. García

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #95 on: April 22, 2020, 05:29:22 AM »
https://www.eurekalert.org/pub_releases/2020-04/uoh-nps042020.php
Says the low emissions pathways they used were IPCC 1-1.9 and IPCC 1-2.6 scenarios .
I thought we had already missed the bus on those two options.
And very important, even in these low emissions pathways:
Quote
"If we reduce global emissions rapidly and substantially, and thus keep global warming below 2 °C relative to preindustrial levels, Arctic sea ice will nevertheless likely disappear occasionally in summer even before 2050. This really surprised us" said Dirk Notz, who leads the sea-ice research group at University of Hamburg, Germany.
https://www.cen.uni-hamburg.de/en/about-cen/news/11-news-2020/2020-04-20-sea-ice-notz.html
they are finally acknowledging what we knew several years ago.
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

S.Pansa

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #96 on: April 22, 2020, 10:05:54 AM »
New Study Says The North Pole Will Be Completely Ice-Free In Summer Before 2050, Even If We Curb Carbon Emissions


The title is a tad sensational.

1) The study points to a likelihood, while the title implies certainty.

2) The study indicates the likelihood declines in lower emission scenarios, while the title implies its the outcome is out of human control.

3) The study is indicating the likelihood of BOE level loss (1M km2 at minimum) while the title indicates complete loss.

It would be more responsible for the journalists and the study authors to better highlight the correlation between emission scenarios and likelihood of BOE 2050.
I don't have access to the study, but Dr. Dirk Notz is from Universität Hamburg, and they have also an internet page saying that:
Quote
"If we reduce global emissions rapidly and substantially, and thus keep global warming below 2 °C relative to preindustrial levels, Arctic sea ice will nevertheless likely disappear occasionally in summer even before 2050. This really surprised us" said Dirk Notz, who leads the sea-ice research group at University of Hamburg, Germany.
https://www.cen.uni-hamburg.de/en/about-cen/news/11-news-2020/2020-04-20-sea-ice-notz.html
Here is a link to a freely available draft of the full paper. If anyone has use for it.
And below a pic of Table S4 from the supporting information.
And another one - figure 2 -  from the paper itself.

kassy

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #97 on: April 22, 2020, 02:30:26 PM »
I am opposed to inaccurate messaging that induces people to give up hope.

For the benefit of people who might just be grazing in the thread, I thought it would be useful to explain that a superficial glance at the post is not necessarily reflecting the substance of the study.

In this case false hope is much more dangerous.

And the question is what are we hoping for?

the objective of the IPCC is to provide governments at all levels with scientific information that they can use to develop climate policies. IPCC reports are also a key input into international climate change negotiations.

Very early on in the process the target was shifted from 1 to 1,5C for pure economic reasons. Then we slid to 2C because we did nothing in the meantime.

So you already see that the targets are not underpinned by science but politics.

As were the choices about the type of presentation made. Theoretically it would make sense to have a number of lines we should not cross (kickstarting irreversible melt in Arctic, Waking Antarctica, the permafrost, avoid losing mountain glaciers which quench our thirst etc) and let the best science on those produce constraints on the budget.

But no they cobbled together a bunch of scenarios in which the near term did not really matter. This choice in itself was once again political which you can clearly see if you read up on all the earth responses in the different categories.

And on that note...

For the benefit of people who might just be grazing in the thread

This is a specialist forum which means that if people graze a thread they are probably checking to see if new posts contain an interesting new article or just the running discussion or something like that.

If an article is interesting i will often read the science attached if it´s not paywalled. Then you think about it in relation to all the things you have already read.

When you discover ASIF the first time there is so much to delve into. How much and what people delve into varies.

An on topic response addressing a specific point in the study or something like that would arguably be of more benefit for people grazing the thread.

Hope is fine but we need action too. Whatever our state of despair we have only one (1) planet and nowhere else to go. Any long term problem we do not prevent will be harder and more costly to solve later on. We are acting irresponsibly and we should stop that.

Quote
It might be interesting to include other metrics like the carbon clock.

We only have a tiny real budget. Even if things are looking good for solar that does not mean it will happen fast enough. Plans are announced to be carbon neutral in 2050 (slow clap here) while the budget runs out in 2030. EVs and solar are only part of the carbon mix.

You can hope you brake in time before you go over the cliff or not drive towards that with your foot on the accelerator. We are still doing the latter while it is 2020.

Or a free variation on Curt & Kurt: Who needs action when you´ve got numbers?
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The Walrus

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #98 on: April 22, 2020, 04:14:00 PM »
Thank you kassy for that data and graph.  From their graph, Arctic sea ice area appears to fall below 1 km2 around 2075 under scenario SSP2-4.5.  Using their data, I calculated an average value of 2054 +/- 55 years.  I used average values, when they posted a range, and I suspect they treated those ranges differently.  Interestingly, in scenario SSP1-2.6, the sea ice reaches a minimum, and never falls below 1 km2.

kassy

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Re: Where are we now in CO2e , which pathway are we on?
« Reply #99 on: April 23, 2020, 06:02:58 PM »
Probably not good for that scenario.

Assuming they know more about what they are doing then someone plotting averages i would still go with their numbers.

Basically 2099 would stil be horrific. / -55 would yield 1999. We had other worries then.  ::)

Playing with numbers is nice but it is not going to help the planet. The extremely cynical way to read the research is that you have a decade left to argue data fits and then the 8 legged gompertz is going to win.

As a bonus:

In the linked 2017 RealClimate article Rahmstorf and Levermann make the case the global GHG emissions must peak by 2020.  I guess that we will all find out in a few years whether the global socio-economic system manages to meet/sustain that target/date:

Title: " Why global emissions must peak by 2020" by Stefan Rahmstorf and Anders Levermann

http://www.realclimate.org/index.php/archives/2017/06/why-global-emissions-must-peak-by-2020/comment-page-4/




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