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oren

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #100 on: January 22, 2021, 10:34:27 AM »
Coal in the US was largely replaced by natural gas, leading to reduced CO2 but higher methane. Solar and wind took up the increase in energy demand in the last few years, but did not replace existing demand - yet. In China and India coal has not been replaced at all - yet. There are good reasons to be optimistic about a transition in electricity production, as Ken Feldman and others (and Bob Wallace when he was active here) have been pointing out for quite some time. And yet, seeing is believing. I would rather see these changes taking place rather than understand that they are about to happen. I would like to see countries both developed and developing installing huge amounts of wind and solar and shutting down fossil fuel generation prematurely, so that fossil fuel use in electricity generation actually drops rather than plateaus.
As for other sectors the picture is much less rosy. In transportation we have an economic solution of EVs, currently more expensive but soon to reach parity with ICE cars. It's already being adopted by some consumers despite the cost, but globally the numbers are still minuscule.
Quote
Sales of electric cars topped 2.1 million globally in 2019, surpassing 2018 – already a record year – to boost the stock to 7.2 million electric cars. Electric cars, which accounted for 2.6% of global car sales and about 1% of global car stock in 2019, registered a 40% year-on-year increase.
It appears the economics are there for a fast transition to occur in global sales and later in global stock. But how fast is fast? I think it will take two decades at the least to replace most stock, and that it should take one decade at most.
A lot of industry can be shifted to electricity, but not all. Construction? Agriculture? Shipping? Some of these can be shifted by using cheap electricity to produce synthetic fuels. All this will take lots of time and lots of money. The electricity system should be transitioned very very fast, and result in very cheap prices for renewable electricity, to encourage the transition of the other industries. But mindsets change slowly and investment decisions affect results years ahead, so this may take at least another decade after transitioning of electricity, which itself could take two decades to mostly complete even if politicians across the globe do the right thing, which they often don't.
Some industries cannot be transitioned at all using current technology and economics.
In the meantime, warming accumulates, with natural feedbacks kicking in and taking up some of the slack in emissions. And summer Arctic sea ice will very probably disappear in the meantime, adding to the forcing due to a strong albedo feedback. Cleanup of energy will sharply reduce amount of aerosols, whether as a spike or as a long process doesn't matter too much for the end forcing result.
Should we be optimistic? Maybe. I think yes. Are we safely out of the woods? Hell no. The main ingredient here is time, which we don't have much of.

crandles

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #101 on: January 22, 2021, 12:53:57 PM »
I looked at the reference and could not find your graph please clarify where it is in the reference.

I cant be sure what is plotted because the vertical axis is not labeled.

The graph is just me drawing curves through PIOMAS volume data, which I have frequently done on this site. I have frequently said I don't believe the completely horizonal end of the curve as an extrapolation, it will trend down with increasing forcings like ghg levels but this shows you can fit the data without much of a decline in the current rate of loss of sea ice volume and it is tending to show that after a period of rapid loss it is curving flatter i.e. towards being harder to lose further ice volume.

(Maybe it will curve steeper again but that is just speculation not currently supported by the data or the science.)

jens

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #102 on: January 22, 2021, 01:17:41 PM »
Don't worry, people. Emissions will indeed go to zero, after the human civilization has collapsed.

gerontocrat

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #103 on: January 22, 2021, 02:20:01 PM »
I looked at the reference and could not find your graph please clarify where it is in the reference.

I cant be sure what is plotted because the vertical axis is not labeled.

The graph is just me drawing curves through PIOMAS volume data, which I have frequently done on this site. I have frequently said I don't believe the completely horizonal end of the curve as an extrapolation, it will trend down with increasing forcings like ghg levels but this shows you can fit the data without much of a decline in the current rate of loss of sea ice volume and it is tending to show that after a period of rapid loss it is curving flatter i.e. towards being harder to lose further ice volume.

(Maybe it will curve steeper again but that is just speculation not currently supported by the data or the science.)
You can find a curve to match the story you want
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crandles

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #104 on: January 22, 2021, 02:28:37 PM »

You can find a curve to match the story you want

Indeed you can but Tamino has shown a three straight line (6 parameter) fit is statistically justified. This is more like my shape and I only use 4 parameters.

Importantly the shape I suggest is also more like what models produce.

Yes you can produce curves that swing downwards in the extrapolation, but that isn't supported by data or by the shape that models produce so is basically just wild speculation.

oren

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #105 on: January 22, 2021, 05:17:55 PM »
We have the "When will the Arctic go ice free?" thread for in depth discussions and extrapolations on the subject.

interstitial

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #106 on: January 22, 2021, 07:54:32 PM »
I looked at the reference and could not find your graph please clarify where it is in the reference.

I cant be sure what is plotted because the vertical axis is not labeled.

The graph is just me drawing curves through PIOMAS volume data, which I have frequently done on this site. I have frequently said I don't believe the completely horizonal end of the curve as an extrapolation, it will trend down with increasing forcings like ghg levels but this shows you can fit the data without much of a decline in the current rate of loss of sea ice volume and it is tending to show that after a period of rapid loss it is curving flatter i.e. towards being harder to lose further ice volume.

(Maybe it will curve steeper again but that is just speculation not currently supported by the data or the science.)
So essentially in response to why would melting slow down something you say is shown by the science. You referenced a link to 166 pg pdf which may or may not say what is claimed but you do not indicate where. If the article were short I would read the whole thing but not something that long. If the whole article was a long explanation of the point that might work too but I could not find any supporting information. When questioned about it you ignored the question. The curve you show is some piomas data but you do not say whether it is 365 day average, monthly averages or what it is. the horizontal axis is labeled with years yet the horizontal axis for the curves is in days. The vertical axis has numbers which I can only guess the meaning of because you didn't say what they were but undoubtedly they are different for the curves and the jagged line.

Let me some up what I have so far. Your argument is a link to a long article about climate change but no indication how it relates to your article and a data points which I still don't know what they are fit with a clearly different axis manipulated in such a way as it appears like they data is related. You have made a claim that the science shows something and so far it seems what you have presented does not support your claim. I do not appreciate wasting my time with misdirection. If you do not want to back up a claim say so but do not insult me by trying to pass that off as a defense for your position. Please do not attack me for calling you out. If I am mistaken I will apologize if not stop the misinformation campaign.

kassy

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #107 on: January 22, 2021, 08:23:12 PM »
It is actually all mixed.

We're currently about 1.2 C (based on five year averages, 2020 was 1.25 C) above the baseline temperature for the IPCC 1.5C Report.  Global temperatures have been increasing by 0.2 C per decade.  With three decades before we get emissions close to net zero, we'll be at 1.8C.

The key is that once we achieve zero emissions, temperatures stabilize and then begin to decrease.  So an overshoot of 1.5C looks likely, but we can keep the temperature increase to under 2.0C.  The IPCC special report on 1.5C published in 2018 outlines the impacts of this temperature range.

So that at least gives us a time line.

Now if you take into account the current state of the ice. Some Mosaic pictures on the link:

https://thebarentsobserver.com/en/2020/08/mosaic-climate-expedition-shares-scary-photos-north-pole

Well that is not going to last 30 years. So we will get an extra bump from that.
Also that ensures that when we hit 1,8C on 2050 we would do so without most arctic ice.

Some people are looking at a rather specific range of reports and concluding that yay under 2.0C is a success while that is highly questionable.

The ice is important but the graphs won´t help that much. Lot´s of people are fixated with sept minimums but the problem will be open water in summer and autumn and the mixing that allows plus all the floating around that shattered ice does.

Also in the background of this discussion there is three decades of compound damage. Wildfires, ocean acidification etc. The loss of all tropical glaciers.

Some people just have a hard time being happy about an arbitrary line which ignores all that.


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ArgonneForest

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #108 on: January 22, 2021, 08:30:16 PM »
I really don't think you can make an argument that most Arctic ice will be gone by 2050, especially year-round, based on a few pictures

crandles

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #109 on: January 22, 2021, 08:36:05 PM »
I really don't think you can make an argument that most Arctic ice will be gone by 2050, especially year-round, based on a few pictures

You can't make a sensible argument for "Arctic ice will be gone by 2050 year-round" whatever you do, but only the most extreme of catastrophists would try to do so.

Arguing with a straw man doesn't help you.

El Cid

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #110 on: January 22, 2021, 08:49:07 PM »
I really don't think you can make an argument that most Arctic ice will be gone by 2050, especially year-round, based on a few pictures

noone does...people mostly talk about autumn/summer ice free...only you keep bringing up an all year around ice free state state - for the second time

The Walrus

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #111 on: January 22, 2021, 08:52:42 PM »
I really don't think you can make an argument that most Arctic ice will be gone by 2050, especially year-round, based on a few pictures

You can't make a sensible argument for "Arctic ice will be gone by 2050 year-round" whatever you do, but only the most extreme of catastrophists would try to do so.

Arguing with a straw man doesn't help you.

True, based on the data at least.  Referencing "year-round" has almost no chance.  Over the past four decades, the maximum Arctic sea ice extent has only decreased 10% (when referencing open water, extent or area is most relevant).  If that rate were to continue, we would lose another 10% at most.  The average annual sea ice extent has decrease a little more, 17%, such that an overall 30% decline is not unreasonable.  The September minimum has declined over 50%, such that the Arctic could be ice-free in another 30 years.  That is, if the ice maintains its long-term rate of decline.  Much has been said about whether that rate could continue, but I will not go into that now. 

Therefore, his statement about open water in summer and autumn has some merit, if he refines his definition to late summer and early autumn (i.e. the month of September).  Sea ice at the summer solstice has not decreased much (only 13%) compared to later in the year. 

crandles

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #112 on: January 22, 2021, 08:55:02 PM »
interstitial, it wasn't the best graph to choose just the one I found first and yes the lack of labelling was awful. I said it was PIOMAS data which is readily available and if you were familiar with the data you would readily recognise that it is September average volume in thousand km^3.

I quoted the relevant part. I also admit that searching for all of that or large chunks might fail due to deleted line numbers for readability but it is not too hard to select a couple of words and search for that. Or maybe looking at the contents and seeing "3.2.4. Surface albedo feedback" which together with my quote starting "The surface albedo feedback" might look worth investigating if you wanted to find it.

I didn't throw a lot of effort into finding lots of science to quote, I have done better on a more appropriate thread i.e. the when will arctic go ice free thread.

kassy

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #113 on: January 22, 2021, 09:06:05 PM »
The claim is not based on ice being gone year round in 2050.



Watch it go.

Watch the ice distribution.

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kassy

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #114 on: January 22, 2021, 09:27:55 PM »
To Argonne no we do not need to specify everything since that can not be done. If you have questions ask them. 
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ArgonneForest

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #115 on: January 22, 2021, 09:57:13 PM »
To Argonne no we do not need to specify everything since that can not be done. If you have questions ask them.

Kassy, I'm not asking you to specify everything, just that you're talking about summer ice loss when saying "most of the ice will disappear". It makes it sound like you're claiming the sea ice year-round will disappear. And I would appreciate it if whoever is deleting my posts would at least have the courtesy to inform me first
« Last Edit: January 22, 2021, 10:13:58 PM by ArgonneForest »

Sciguy

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #116 on: February 03, 2021, 01:10:17 AM »
A few focused Government initiatives could activate tipping points that accelerate the decarbonization of the global economy to achieve net-zero emissions by 2050.

https://www.tandfonline.com/doi/full/10.1080/14693062.2020.1870097

Quote
imon Sharpe & Timothy M. Lenton (2021) Upward-scaling tipping cascades to meet climate goals: plausible grounds for hope, Climate Policy, DOI: 10.1080/14693062.2020.1870097

ABSTRACT

Limiting global warming to well below 2°C requires a dramatic acceleration of decarbonization to reduce net anthropogenic greenhouse gas emissions to zero around mid-century. In complex systems – including human societies – tipping points can occur, in which a small perturbation transforms a system. Crucially, activating one tipping point can increase the likelihood of triggering another at a larger scale, and so on. Here, we show how such upward-scaling tipping cascades could accelerate progress in tackling climate change. We focus on two sectors – light road transport and power – where tipping points have already been triggered by policy interventions at individual nation scales. We show how positive-sum cooperation, between small coalitions of jurisdictions and their policymakers, could lead to global changes in the economy and emissions. The aim of activating tipping points and tipping cascades is a particular application of systems thinking. It represents a different starting point for policy to the theory of welfare economics, one that can be useful when the priority is to achieve dynamic rather than allocative efficiency.

Quote
In complex systems, change is often non-linear. Cause and effect need not be proportionate. Highly disproportionate change can be caused when a tipping point is crossed; that is, when a small perturbation triggers a large response from a system, sending it into a qualitatively different future state (Lenton, 2020; Lenton et al., 2008). At a tipping point, reinforcing (positive) feedbacks dominate the dynamics, propelling change. Tipping points have been observed in the climate, ecosystems, social, political, and economic systems, and in individual and collective behaviour (Lenton, 2020; Scheffer, 2009).

To bring a system to a tipping point typically requires some ‘forcing’ – i.e. a change in boundary conditions – in a direction that weakens balancing (negative) feedbacks maintaining the initial state and/or strengthens reinforcing (positive) feedbacks that amplify change. The change of state at a tipping point may be reversible or irreversible, depending on the strength of reinforcing feedbacks in the system, and whether the forcing can be rapidly reversed (Lenton et al., 2008). Importantly, in social systems, new feedbacks may evolve over time. Hence, transitions that are initially reversible may engender reinforcing feedbacks that make them increasingly difficult to reverse over time. For example, policy support triggering growth of a new technology sector and associated jobs can bring political irreversibility – a change of government that wants to reverse that support may find itself unable to do so.

Quote
As new technologies diffuse through markets and societies, they tend to benefit from multiple reinforcing feedbacks (Arthur, 1989). These include learning-by-doing (the more something is made, the better it can be made), economies of scale (the more it is made, the more cheaply it can be made), and the emergence of complementary technologies (the more something is used, the more technologies emerge that make it more useful). As a result, technology diffusion is self-generating, self-accelerating, and over time becomes increasingly difficult to reverse. Any tipping point that gives a new technology a substantial new advantage – e.g. greater market share, easier access to finance, or broader social acceptability – is likely to strengthen these reinforcing feedbacks, further amplifying its effect.

Quote
Solar and wind power provide only around 7% of global electricity generation (IEA, 2020), but they accounted for roughly two thirds of global generating capacity additions in 2019 (IRENA, 2020). The reinforcing feedbacks of diffusion are operating strongly, with rapid cost reductions persisting over decades, and the development of complementary technologies including batteries, demand-side response, and smart grids. The pace of growth of renewable power has consistently outperformed expectations, with global deployment of solar power in 2020 being over ten times higher than was projected fifteen years ago (Beinhocker et al., 2018). Meanwhile, coal power has experienced the opposite, with analysts’ expectations of its future growth prospects repeatedly revised downward (Bullard, 2020). Plans for nearly 900 GW of new coal plants have been cancelled within the last five years (Shearer, 2019).

Quote
Crossing these two tipping points at the national level resulted in a ∼75% reduction in coal use over ∼5 years (Figure 3b). Arguably this gave the UK government the confidence to launch a global campaign in 2017 to phase out unabated coal from the power sector – the Powering Past Coal Alliance (PPCA). Now with over a hundred members committed to this goal, covering more than a third of coal capacity in the OECD, the PPCA can reasonably claim to be influencing investor and policymaker expectations about the global future of coal power.

Solar and wind can already generate electricity more cheaply than fossil fuels, but the growth in their share of global power generation is held back by a range of factors – including vested interests, inertia in electricity market design and business models, inadequate grid infrastructure, and high financing costs – whose relative importance varies between countries. In many developing countries, the high financing costs of renewables are a significant barrier to investment (Schmidt, 2014). If the PPCA’s strengthening of negative investor expectations contributes to increasing the cost of capital for new coal plants, then together with measures to reduce the financing costs of renewables, it could help trigger a third tipping point in power systems around the world (Figure 4): the point at which in each market, the cost of capital for new renewable generation dips below that of coal.

kassy

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #117 on: February 05, 2021, 10:34:15 PM »
As a slight reality check i offer this shortened quote:

EU climate neutrality by 2050 is not Paris-compatible

The EU’s aim for net zero by 2050 is insufficient to meet the Paris Agreement and limit warming to 1.5°C. To avoid climate catastrophe, Europe needs to rethink auctions for renewable energy and reintroducing support for small scale supply, argue Hans-Josef Fell and Dr Thure Traber.

...

The EU’s Copernicus Climate Change Service finds that the atmospheric temperature in 2020 was already 1.25°C above the pre-industrial period. And calculations by the experts contributing to the Intergovernmental Panel on Climate Change (IPCC) show that global warming of 1.5°C can be expected as early as 2030.

Instead, the IPCC officially suggests to policymakers that only 1.3°C would be reached in 2030. This contradicts the model calculations of the IPCC’s own experts and misleads the public.

Based on the official IPCC statements, however, the political goal of climate neutrality by 2050 still foresees the use of fossil resources in Europe and elsewhere and thus further greenhouse gas emissions from 2030 onwards – i.e. after 1.5°C has been exceeded.

Such scenarios do not question the effectiveness of the target and lead to the erroneous assumption: effective climate protection can be achieved by pathways leading to climate neutrality by 2050.

Largely neglecting the necessity of climate protection, the European targets of 55% emission reduction compared to 1990 and of 32% renewable energy by 2030 only reflects this wrong narrative.

The example of Germany clearly shows that even if emissions were to be continuously reduced to zero from 2021 to 2050, almost another ten billion tons of German CO2 emissions would be emitted during this period alone.

This corresponds to about three times (factor 2.84) the amount indicated by the German Advisory Council on the Environment (SRU) on the basis of IPCC’s scientific – but not officially communicated – data as the upper German limit for achieving the 1.5°C target.

So, what would really be in store for Europe, if we adhere to the goal of climate neutrality by 2050? Not unlikely a climate catastrophe beyond 3°C, a Hothouse Earth scenario in which human civilisation as we know it today, may no longer be able to exist.

The proximity to such a (climate) catastrophic point of no return and the speed with which we are heading toward such point is widely not yet perceived or simply ignored on the political level, from the national parliaments to the European institutions, the media and to some extend even scientifically.

Those who claim, like the Commission, that the Paris Agreement could be met with the goal of climate neutrality by 2050 are knowingly or unknowingly deceiving the public.

Converting the economy by 2030 is possible but requires strong political will. It is technically and economically feasible, albeit with the greatest effort, to build a global zero-emissions economy combined with large natural carbon sinks by 2030.

https://www.euractiv.com/section/climate-environment/opinion/eu-climate-neutrality-by-2050-is-not-paris-compatible/

Aside from the quote above there are such nagging details such as the fact that we will build or maintain roads, will build more buildings. We still have to get on top of our wasteful plastic habits etc.

So we are far from done and we need more coordinated international action to move as much progress up to the 2030ies as we can. We don´t need to solve just cars or the grid but basically everything. Everything needs to be circular asap and we cannot use cheating with numbers because we can cheat ourselves and love doing so as long as it suits our narrative but Earth itself wont play.

This is not something just the markets will solve and the governments need to really pick up the pace and get to really concrete measures instead of pledging money which never arrives.

Optimism is cute but you cannot really base that on just some sectors doing well while  ignoring lots of other problems. Also can´t base it on what governments say only on what they manage to do. 

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El Cid

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #118 on: February 06, 2021, 10:21:42 AM »
We are already at +1,25 and during the last 20 yrs global temperatures rose cca 0,5 C. I see absolutely no chance of this stopping before +2 C. Emissions will be higher during 2020-40 than 2000-2020, there is also some lagging effect and then you have your Arctic feedback cycle. I think we will hit +2 C by 2040. Maybe we can limit this to +2,5 C. maybe. And then there are myriads of other problems as kassy said: plastics, soil erosion, loss of biodiversity, etc.
See attachement (3yr running mean of global temperatures), especially the last 10 years!

jai mitchell

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #119 on: February 06, 2021, 11:00:22 PM »
FWIW,

Hansen and Sato are on the record that the recent acceleration of warming (note some still want to argue that this acceleration is not yet proven!) is an indication of their long-held understanding that the Aerosol forcing is stronger than currently being modeled.  That the recent (last decade+) reduction of this pollution has caused the acceleration.

They state that the reason that the models being used today (and for this study showing a zero commitment) show a "too efficient" heat mixing model in the world's oceans, that this mixing does not play out as based on the 'reality check' of the ARGO buoy data.  They say that the models need to have a much lower aerosol forcing component because if they did not, the extra heat mixing in the ocean would invalidate hindcasts of temperature against the actual record, effectively blowing up the model's validity.

So, if they are right, and I firmly believe that they are, the aerosol forcing component is much stronger, the heat mixing into the oceans much smaller and the current top of atmosphere energy imbalance both stronger now and will be much more stronger as we continue to reduce aerosols AND the time lag for equilibrium temperature ALSO will take a bit longer, with other feedback mechanisms kicking in, (like the Dessler paper cloud effect and other studies on tropical and mid-latitude cloud effects)

This would mean that they have once again attempted to downplay the severity of the climate crisis in favor of current policy.
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Alexander555

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #120 on: February 07, 2021, 08:53:18 PM »
Emissions cause global warming. So if we stop emissions, will we end up with a new ice age ? Little by little the oceans will lose all their heat.

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #121 on: February 07, 2021, 09:19:38 PM »
Emissions cause global warming. So if we stop emissions, will we end up with a new ice age ? Little by little the oceans will lose all their heat.
CO2eq will have to go down first. This will probably take a whole Ice Age Cycle to occur.
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The Walrus

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #122 on: February 08, 2021, 01:03:55 AM »
Emissions cause global warming. So if we stop emissions, will we end up with a new ice age ? Little by little the oceans will lose all their heat.
CO2eq will have to go down first. This will probably take a whole Ice Age Cycle to occur.

The CO2eq would start falling immediately.  There is scant evidence  that it would propel us into another ice age, but temperatures would begin to fall concurrently.
« Last Edit: February 08, 2021, 02:20:08 AM by The Walrus »

kassy

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #123 on: February 08, 2021, 04:42:14 PM »
The first question is how quickly get we get to zero and what happens along the way.

The first problem we will encounter and will just have to swallow is that the reduction in pollution actually kicks the global temperatures up a bit.

Even going by the overly optimistic 2050 on the way we will lose a whole bunch of glaciers and the Arctic ice (you have to figure in the above mentioned temperature raise into extrapolations for SIVol because it occurs short term).

Then a part of our budget will be filled with feedbacks we should really have avoided such as permafrost carbon, forest fires, drying out forest and wetlands etc.

So it is hard to tell where we will end up temperature wise but we can be sure that it is quite a bit higher then today.

Another question is which target CO2 we need for a stable world? 350? Always seemed a good idea for an upper bound but we blew past that one. Maybe below 300. So that is a lot of CO2 to remove to actually bring temperatures down to regions were things don´t get worse.

Quote
Arctic Shifts To a Carbon Source Due to Winter Soil Emissions
https://eurekalert.org/pub_releases/2019-11/nsfc-ast110819.php

Researchers estimate a yearly loss of 1.7 billion metric tons of carbon from the permafrost region during the winter season from 2003 to 2017 compared to the estimated average of 1 billion metric tons of carbon taken up during the growing season.

That means early 2000 CO2 was enough to start this process so we have to target below that. Then there is this little detail...you can not just revert it so if you would want to stop this process with CO2 drawdown only you would need to get lower to where ice ages happen.

Long story short: we need to cut emissions ASAP worldwide.

Then there is another detail related to CO2eq but i will put that in a separate post.
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Alexander555

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #124 on: February 08, 2021, 05:31:44 PM »
Should these co2 levels go below some point first. Or is it a matter of having a small difference that keeps accumulating. Like you have today. Temperatures go up, heat is stored in the oceans, less ice on the poles, fires in Siberia, winters get shorter.......

oren

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #125 on: February 08, 2021, 06:05:49 PM »
IMHO temps would still continue to go up after CO2 starts going down (assuming it ever does), as long as the net forcing remains positive. By net forcing I mean the extra forcing since pre-industrial, less the increased outbound radiation due to the surface warming. When the net forcing becomes balanced, temps can start dropping. Apologies for using layman terms.

kassy

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #126 on: February 08, 2021, 06:31:41 PM »
Or being simple: how quickly would it go down? We know that the way up is constrained by the terrific amount of heat needed to melt ice. How would it work on the way down?
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Richard Rathbone

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #127 on: February 08, 2021, 07:07:12 PM »

Another question is which target CO2 we need for a stable world? 350? Always seemed a good idea for an upper bound but we blew past that one. Maybe below 300. So that is a lot of CO2 to remove to actually bring temperatures down to regions were things don´t get worse.


Depends what you mean by stable. If you ignore long term effects like ice sheets continuing to melt, bringing emissions to zero is good enough. If you don't ignore ice sheets and other effects that take more than a couple of decades to play out, then I think 350 is the current best guess, being the drop required to eliminate the current energy imbalance.

Sciguy

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #128 on: February 08, 2021, 07:18:50 PM »
FWIW,

Hansen and Sato are on the record that the recent acceleration of warming (note some still want to argue that this acceleration is not yet proven!) is an indication of their long-held understanding that the Aerosol forcing is stronger than currently being modeled.  That the recent (last decade+) reduction of this pollution has caused the acceleration.

They state that the reason that the models being used today (and for this study showing a zero commitment) show a "too efficient" heat mixing model in the world's oceans, that this mixing does not play out as based on the 'reality check' of the ARGO buoy data.  They say that the models need to have a much lower aerosol forcing component because if they did not, the extra heat mixing in the ocean would invalidate hindcasts of temperature against the actual record, effectively blowing up the model's validity.

So, if they are right, and I firmly believe that they are, the aerosol forcing component is much stronger, the heat mixing into the oceans much smaller and the current top of atmosphere energy imbalance both stronger now and will be much more stronger as we continue to reduce aerosols AND the time lag for equilibrium temperature ALSO will take a bit longer, with other feedback mechanisms kicking in, (like the Dessler paper cloud effect and other studies on tropical and mid-latitude cloud effects)

This would mean that they have once again attempted to downplay the severity of the climate crisis in favor of current policy.

Recent modelling indicates that the impact of aerosols is currently over-estimated.  This means that reducing pollution has less of an effect on additional warming than has been assumed in the past few years.  It also indicates that the high-sensitivity CMIP-6 models that rely on stronger aerosol cloud forcings in the future are not as accurate as lower sensitivity models in recreating past aerosol impacts on the observed climate trends in the 20th century.

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020GL091024?af=R

Quote
Wang, C., Soden, B., Yang, W., & Vecchi, G. A. (2021). Compensation between cloud feedback and aerosol‐cloud interaction in CMIP6 models. Geophysical Research Letters, 48, e2020GL091024. https://doi.org/10.1029/2020GL091024

 Abstract

The most recent generation of climate models (the 6th Phase of the Coupled Model Intercomparison Project – CMIP6) yields estimates of effective climate sensitivity (ECS) that are much higher than past generations due to a stronger amplification from cloud feedback. If plausible, these models require substantially larger greenhouse gas reductions to meet global warming targets. We show that models with a more positive cloud feedback also have a stronger cooling effect from aerosol‐cloud interactions. These two effects offset each other during the historical period when both aerosols and greenhouse gases increase, allowing either more positive or neutral cloud feedback models to reproduce the observed global‐mean temperature change. Since anthropogenic aerosols primarily concentrate in the Northern Hemisphere, strong aerosol‐cloud interaction models produce an interhemispheric asymmetric warming. We show that the observed warming asymmetry during the mid to late 20th century is more consistent with low ECS (weak aerosol indirect effect) models.

Sciguy

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #129 on: February 08, 2021, 07:49:16 PM »
The first question is how quickly get we get to zero and what happens along the way.

The first problem we will encounter and will just have to swallow is that the reduction in pollution actually kicks the global temperatures up a bit.

Even going by the overly optimistic 2050 on the way we will lose a whole bunch of glaciers and the Arctic ice (you have to figure in the above mentioned temperature raise into extrapolations for SIVol because it occurs short term).

Then a part of our budget will be filled with feedbacks we should really have avoided such as permafrost carbon, forest fires, drying out forest and wetlands etc.

So it is hard to tell where we will end up temperature wise but we can be sure that it is quite a bit higher then today.

Another question is which target CO2 we need for a stable world? 350? Always seemed a good idea for an upper bound but we blew past that one. Maybe below 300. So that is a lot of CO2 to remove to actually bring temperatures down to regions were things don´t get worse.

Quote
Arctic Shifts To a Carbon Source Due to Winter Soil Emissions
https://eurekalert.org/pub_releases/2019-11/nsfc-ast110819.php

Researchers estimate a yearly loss of 1.7 billion metric tons of carbon from the permafrost region during the winter season from 2003 to 2017 compared to the estimated average of 1 billion metric tons of carbon taken up during the growing season.

That means early 2000 CO2 was enough to start this process so we have to target below that. Then there is this little detail...you can not just revert it so if you would want to stop this process with CO2 drawdown only you would need to get lower to where ice ages happen.

Long story short: we need to cut emissions ASAP worldwide.

Then there is another detail related to CO2eq but i will put that in a separate post.

It's important to remember that the Arctic is just a small portion of the globe.  This 2020 update to the global carbon budget, which takes that study referred to in Kassy's post into account, indicates that the global carbon sinks are still 4.6 billion tons per year.

https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.15050

Quote
Terrestrial fluxes of carbon in GCP carbon budgets
Richard A. Houghton
First published: 26 February 2020
https://doi.org/10.1111/gcb.15050


Abstract

The Global Carbon Project (GCP) has published global carbon budgets annually since 2007 (Canadell et al. [2007], Proc Natl Acad Sci USA, 104, 18866–18870; Raupach et al. [2007], Proc Natl Acad Sci USA, 104, 10288–10293). There are many scientists involved, but the terrestrial fluxes that appear in the budgets are not well understood by ecologists and biogeochemists outside of that community. The purpose of this paper is to make the terrestrial fluxes of carbon in those budgets more accessible to a broader community. The GCP budget is composed of annual perturbations from pre‐industrial conditions, driven by addition of carbon to the system from combustion of fossil fuels and by transfers of carbon from land to the atmosphere as a result of land use. The budget includes a term for each of the major fluxes of carbon (fossil fuels, oceans, land) as well as the rate of carbon accumulation in the atmosphere. Land is represented by two terms: one resulting from direct anthropogenic effects (Land Use, Land‐Use Change, and Forestry or land management) and one resulting from indirect anthropogenic (e.g., CO2, climate change) and natural effects. Each of these two net terrestrial fluxes of carbon, in turn, is composed of opposing gross emissions and removals (e.g., deforestation and forest regrowth). Although the GCP budgets have focused on the two net terrestrial fluxes, they have paid little attention to the gross components, which are important for a number of reasons, including understanding the potential for land management to remove CO2 from the atmosphere and understanding the processes responsible for the sink for carbon on land. In contrast to the net fluxes of carbon, which are constrained by the global carbon budget, the gross fluxes are largely unconstrained, suggesting that there is more uncertainty than commonly believed about how terrestrial carbon emissions will respond to future fossil fuel emissions and a changing climate.

Quote
Terrestrial ecosystems have been recognized as a net carbon sink since the first construction of a global carbon budget in the early 1970s (Bacastow & Keeling, 1973). The total net terrestrial flux of carbon has traditionally been calculated by difference: total emissions from fossil fuels (and cement)—atmospheric growth—oceanic uptake. For the decade 2009–2018, the evaluation is:

Atmospheric Growth = Fossil fuel emissions - Oceanic Uptake - Land uptake
     4.9 (+/- 0.02)    =         9.5 (+/- 0.5)    -    2.5 (+/- 0.6) -  2.1  (+/- 0.7)

The net sink of 4.6 billion tons of carbon per year includes the emissions (and sinks) in the Arctic.  With a global carbon sink of 4.6 billion tons per year, we start seeing reductions in carbon concentrations well before we hit zero anthropogenic emissions.

Also, one of the benefits of looking at total carbon budgets is that the effects of a new source of carbon, or the lessening of an existing sink, is put in perspective.  We have very good measurements of the total concentrations of greenhouse gases in the atmosphere and thus a good knowledge of the "Atmospheric Growth" in the equation above.  So if a the Arctic became a source of carbon in the budget as hypothesized in the Natali et. al. 2019 study referenced by Kassy, then another sink must have been underestimated.  This is described in the Houghton 2020 global carbon budget article.

Quote
One implication of the uncertainty in gross fluxes is that the discovery of “new” emissions is not inconsistent with the requirement for a net land sink. Each discovery of gross emissions simply means that the gross removals required to balance the budget are larger than previously thought. For example, if thawing of permafrost has been releasing carbon, the processes removing carbon must also be larger than estimated by DGVMs. Again, there are few constraints on the magnitude of these gross fluxes.

crandles

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #130 on: February 08, 2021, 08:11:36 PM »
Should these co2 levels go below some point first. Or is it a matter of having a small difference that keeps accumulating. Like you have today. Temperatures go up, heat is stored in the oceans, less ice on the poles, fires in Siberia, winters get shorter.......


Another question is which target CO2 we need for a stable world? 350? Always seemed a good idea for an upper bound but we blew past that one. Maybe below 300. So that is a lot of CO2 to remove to actually bring temperatures down to regions were things don´t get worse.


Depends what you mean by stable. If you ignore long term effects like ice sheets continuing to melt, bringing emissions to zero is good enough. If you don't ignore ice sheets and other effects that take more than a couple of decades to play out, then I think 350 is the current best guess, being the drop required to eliminate the current energy imbalance.

Different things have different timescales e.g.
Ice sheets are very long term effects 1000 year plus. Oceans thermal inertia maybe up to 400 years. Ocean overturning cycle 1000 years. Glaciers decades +

Picking a single ghg level and expecting temperature to flatline without the slightest variation as these effects unwind is unrealistic (at least until a flatline temperature average has been maintained for 1000 years or so). Carefully adjusting the GHG target concentrations a little and somehow carefully keeping the GHG level close to these flexed targets to cope with unwind of these effects might get you close enough to a flatlining 30 year average temperature.

If the question is about stability of system rather than flatlining temperatures then it is unlikely there is a nearby GHG level that will cause long term runaway effects in carbon budgets. It is hard to rule out small short term effects like a Storegga Slide like event causing a short term effect. https://en.wikipedia.org/wiki/Storegga_Slide 

I don't think these are very frequent events. So generally for any particular nearby temperature level you want to stabilise at there will be a particular GHG level (given other forcings remain fairly stable) to achieve it. You may have to adjust this level a bit as various effects unwind. But basically the system is stable to perturbations. The system is of course keyed to GHG levels and the planets average albedo not to GHG emissions.

If you wanted a global average temperature well over 20C cooler than today, that would require both albedo changes and GHG level changes because the current albedo sets a black body temperature at about that level and greenhouse warming can only warm this not cool it. More ice would increase albedo so the limit of how much cooling we could get before hitting some limit or runaway effect would appear to be well below that. In the warming direction there is no nearby limit see Venus but make enough changes and eventually a run away effect might kick in but is very unlikely to be at a level close to where we are now.

Not really sure if this is what Alexander was asking.

« Last Edit: February 08, 2021, 08:20:46 PM by crandles »

crandles

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #131 on: February 08, 2021, 08:24:13 PM »
Should these co2 levels go below some point first. Or is it a matter of having a small difference that keeps accumulating. Like you have today. Temperatures go up, heat is stored in the oceans, less ice on the poles, fires in Siberia, winters get shorter.......

Another possible interpretation of this question might be? What causes most damage the rate of change of temperature or going above a particular temperature threshold?

Both cause damage of course but I don't have a good answer to which is worst.

Sciguy

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #132 on: February 08, 2021, 08:42:11 PM »
According to this recently published study, the Natali et. al (2019) study that determined the Arctic is now a net carbon source underestimated the growing season carbon sink by a factor of 3.  The study concludes that the Arctic is still a net carbon sink.

https://link.springer.com/article/10.1007/s40641-020-00169-5

Quote
Bruhwiler, L., Parmentier, FJ.W., Crill, P. et al. The Arctic Carbon Cycle and Its Response to Changing Climate. Curr Clim Change Rep (2021). https://doi.org/10.1007/s40641-020-00169-5

Abstract
Purpose of Review

The Arctic has experienced the most rapid change in climate of anywhere on Earth, and these changes are certain to drive changes in the carbon budget of the Arctic as vegetation changes, soils warm, fires become more frequent, and wetlands evolve as permafrost thaws. In this study, we review the extensive evidence for Arctic climate change and effects on the carbon cycle. In addition, we re-evaluate some of the observational evidence for changing Arctic carbon budgets.

Recent Findings
Observations suggest a more active CO2 cycle in high northern latitude ecosystems. Evidence points to increased uptake by boreal forests and Arctic ecosystems, as well as increasing respiration, especially in autumn. However, there is currently no strong evidence of increased CH4 emissions.

Summary
Long-term observations using both bottom-up (e.g., flux) and top-down (atmospheric abundance) approaches are essential for understanding changing carbon cycle budgets. Consideration of atmospheric transport is critical for interpretation of top-down observations of atmospheric carbon.

Quote
Current bottom-up estimates of the Arctic carbon budget show that the region is a sink of CO2 but a source of CH4. Model simulations suggest that the strong rise in arctic temperatures and the thaw of permafrost may turn the region into a net source of carbon, although current projections for the twenty-first century do not indicate a release of greenhouse gases that is larger than anthropogenic emissions [42, 163]. However, these projections are highly uncertain due to missing representation of thermokarst and key winter processes that may enhance arctic carbon loss. The risk of a large, uncontrolled, carbon cycle feedback from the Arctic remains a distinct possibility as long as anthropogenic emissions continue to rise and the amplified warming of the Arctic worsens.

Quote
Figure 7 shows annual net CO2 exchange and cold/warm season fluxes for latitudes north of 60° N estimated using top-down and bottom-up approaches. Results from two atmospheric inversion systems (CarbonTracker and CarbonTracker-Europe) suggest that the Arctic is taking up more CO2 than is respired over a year. The prior flux estimates used in these inversions are the CASA-GFED model for CarbonTracker [174, 175] and SiB-CASA for CarbonTracker-Europe [176], both dependent on remotely sensed NDVI for estimating GPP. In the annual mean, both priors are nearly annually balanced with uptake about equal to respiration. The SiB4 terrestrial ecosystem model [177, 178], which has prognostic phenology and does not use NDVI, produces annual net CO2 fluxes that are similar to the prior estimates. FLUXCOM’s annual net flux lies between the inversions and bottom-up models. During the warm season, FLUXCOM shows significantly less uptake than the other estimates and also less respiration during the cold season. Likewise, the inversions estimate less cold season respiration than their prior estimates or SiB4. During the cold season, emissions range from ~ 0.8 PgC/year for FLUXCOM to over 2.5 PgC/year for SiB4. The estimate of Natali et al. [107], 1.6 PgC/year, falls between the inversions and the priors; however, their calculated warm season uptake (~ − 1.0 PgC/year) is significantly smaller than the inverse estimates by at least a factor of 3. These results show the difficulty in interpretation of annual net CO2 fluxes since they are a balance of respiration and photosynthesis for which estimates from different methods can significantly diverge.


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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #133 on: February 08, 2021, 08:49:15 PM »

It's important to remember that the Arctic is just a small portion of the globe.  This 2020 update to the global carbon budget, which takes that study referred to in Kassy's post into account, indicates that the global carbon sinks are still 4.6 billion tons per year.
.....

Looked it up on wikipedia:
Arctic ocean is 4% of the global ocean surface
Arctic ocean is 1.3% of the global ocean volume.

Thus, in the context of the global carbon budget, the changes in the Arctic are negligible.

kassy

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #134 on: February 08, 2021, 11:16:54 PM »
And then add atmospheric physics...
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KiwiGriff

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #135 on: February 09, 2021, 08:21:31 AM »
See this.... !

Talking of net zero is meaningless when  this thing is still a upward curve.
It will continue to warm as long as our emissions are greater than Gaia's carbon sinks can absorb .

I have  been acutely aware of the reality of AGW for about fifteen years.
In that time we have only increased our emissions.

The impact of Atmospheric physics  does not end in 2100.
Earth System Sensitivity is far higher than the oft referenced ECS of 3C per doubling of CO2e. ESS means we are committed to warm for century's to come .
 Magic thinking ...
We do not have the technology to economically remove CO2 from the atmosphere to the extent  required by the low emission pathways used by the IPCC .

Thank fuck I have never breed I would not wish the inevitable dark future for humanity on any offspring of mine
Animals can be driven crazy by placing too many in too small a pen. Homo sapiens is the only animal that voluntarily does this to himself.
Notebooks of Lazarus Long.
Robert Heinlein.

Bruce Steele

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #136 on: February 09, 2021, 03:16:10 PM »
The amount of shelf is relatively large for the Arctic Ocean. The shelf and areas shallower than the carbonate compensation depth act as long term carbonate sinks and so long as the saturation horizon doesn’t shoal too much the Arctic Oceans shelf area may prove to be an important part of the earths long term carbon burial system when the ice recedes. However if the saturation horizon shoals to the surface the Arctic and other oceanic carbon sinks will fail. So even though the Arctic oceans surface area is small it’s relatively large shelf area may prove important to earths ability to sink carbon over the next hundred thousand years .

https://advances.sciencemag.org/content/7/4/eabd4876
Hat tip to Kassy

. The world's largest continental shelf extends 1,500 km (about 930 miles) from the coast of Siberia into the Arctic Ocean.
www.britannica.com › science › con...
Continental shelf | geology | Britannica

about 15% of the world's shelf seas (Menard and Smith 1966),
« Last Edit: February 09, 2021, 03:37:58 PM by Bruce Steele »

El Cid

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #137 on: February 09, 2021, 03:30:14 PM »

Thank fuck I have never breed I would not wish the inevitable dark future for humanity on any offspring of mine

Thank fuck I have. The future is always inevitably dark. Has been for millenia.

kassy

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #138 on: February 09, 2021, 04:27:49 PM »
According to this recently published study, the Natali et. al (2019) study that determined the Arctic is now a net carbon source underestimated the growing season carbon sink by a factor of 3.  The study concludes that the Arctic is still a net carbon sink.

https://link.springer.com/article/10.1007/s40641-020-00169-5

Thanks, quite a lot in that paper. I was planning to check out the follow ups to Natali et al mainly to figure out how they all go about calculating the budgets.

Basically it is a crude calculation.
It would be cool if we had an actual super accurate number for human CO2 pollution etc so we can work out the actual rest although we are moving in that direction (see my recent post in What is new in climate action).
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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #139 on: February 14, 2021, 11:18:48 PM »
https://www.esrl.noaa.gov/gmd/ccgg/ghgpower/

Hat tip to Stephan.

Some quotes i would like to highlight:

Quote
Table 3 shows that, although CO2 is responsible for 66% of the climate forcing by all greenhouse gases, its rate of increase during the last five years accounts for 82% of the total increase in forcing. From well-known chemistry of the carbonate system in the oceans we can estimate that, when the atmosphere and oceans are again in chemical equilibrium (after about 1000 years), ~83% of the excess CO2 resides in oceans and ~17% in the atmosphere. In the natural system, very slow calcium carbonate dissolution (which includes coral reefs) increases the alkalinity of the oceans allowing them to ingest the remaining 17% from the atmosphere, but that is expected to take between 3000 and 7000 years [Archer et al., 2009]. This is how long future generations will likely have to deal with the enhanced atmospheric CO2 unless ways will be found to pull the excess CO2 back out of the atmosphere and out of the oceans. Note that for this purely chemical estimate we assume that other factors, such as ocean circulation and ocean biology do not change, which is unlikely when the climate changes. If we would merely pull excess CO2 out of the atmosphere, the oceans would emit enough of its excess carbon back into the atmosphere to re-establish chemical equilibrium. The same could happen with the terrestrial biosphere, if the main reason for their current net uptake is fertilization by high CO2.

So if we would manage a slightly negative emissions there will still be a long long plateau.

Then the other greenhouse gasses, the novelties that we introduced to the atmosphere:

Quote
Radiative forcing from the sum total of observed changes of the industrial gases continues to increase. The abundances of gases included in the original Montreal Protocol on Substances that Deplete the Ozone Layer have declined, but other gases, some of them included in later amendments to the Montreal Protocol, are still increasing. The increased radiative forcing from the sum of the latter group more than compensates for the declines of the original group, so that climate forcing from all industrial gases continues to go up.

...

Back to the original MP gases, the decrease of CH3CCl3 was rapid (Figure 5) when its production stopped because of its relatively short lifetime of 5 years. The rate of decrease for most CFCs was slower than the rate one would expect for zero emissions, because of stored “banks” in insulation materials, equipment, etc., but very recently the rate of decrease of CFC-11 slowed down significantly further because of new production of the chemical [Montzka et al., 2018]. CCl4 is still being produced and emitted in large quantities, as its rate of decrease is much slower than would be expected from its chemical lifetime.

None of our measures of succes (EVs, easy parts of the energy transition) address those at all and if you check fig 3 you can see that their effects is quite large.

Bonus round or how may kettles?

Quote
How much energy are we talking about?
When we multiply the 2019 average heating intensity of 3.224 Watt m-2 by the surface area of the Earth we have 1644 TeraWatt (TW). For comparison, a large electrical power plant produces 1 GigaWatt (GW) of electrical power. One TW equals the output of one thousand of such 1 GW power plants. So the heat retention by greenhouse gases in 2019 equals the electrical output of 1.64 million large power plants. Global electricity production from all power plants in 2019 was 3.15 TW (extrapolated from 2018, BP Statistical Review 2019).

Let’s also compare 1644 TW with all the direct heat produced from all energy uses, the production of electricity including nuclear, transportation, heating/cooling of buildings, industrial processes, biofuels, waste. That total is 18.1 TW in 2019 [Ritchie, 2014]. Therefore, the excess heat retention by greenhouse gases in 2019 was 91 times larger than all the direct heat produced by humanity.

...

Now we will take a look at what 1644 TW could do in the climate system. If all of that energy were (hypothetically) directed into the Greenland ice cap, in one year it would heat up the ice, and then melt, 5.0% of the Greenland ice cap, which would raise global sea level by 36 cm, or 14”.

Alternatively, the energy could go toward heating the upper layers of the oceans. In one year the upper 100 m of all oceans would warm by 0.35 degree centigrade (°C , or 0.64 °F). If all of the energy could be aimed exclusively at the Great Lakes in North America (their water volume is ~22,600 km3), they would completely evaporate in 14 months.

I like these examples because they do show the scale of the problem in a way.
In the year 2000 we added 370 TW less.

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anthropocene

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Re: Global Warming Would Stop Quickly After Emissions Go To Zero
« Reply #140 on: February 15, 2021, 11:10:07 PM »
On Radio Ecoshock, interview with the author of the original paper which started this thread. Summary of the main points in digestible form and some of the questions posed here are raised in the interview.

https://www.ecoshock.net/downloads/ES_MacDougall_LoFi.mp3

Read the write up here:
https://www.ecoshock.org/2021/02/stop-the-ghastly-future.html