Environment & Energy
Related: About this forumThe temperature depends on how much carbon we burn, not how fast
Last edited Sat Nov 24, 2012, 02:49 AM - Edit history (2)
This is a crucial insight, it seems to me. The dwell time of CO2 in the atmosphere is measured in centuries and millennia. So if we really have 800 Gt of carbon or so in the ground, and we burn it all, we're going to get a temperature rise of at least +3.5C, no matter how fast or slowly we burn it.
In an effort to recover from my earlier data-driven gaffe, I've looked at the rate of increase of each of our three fossil fuels, and found something interesting. The rate of growth for oil and gas is essentially dead linear over the last 30 years. That means it should be relatively easy to at least keep their growth from going super-linear, and maybe even lower the slope a bit.
Coal is another story. At the moment its growth is decidedly super-linear, and that spells Trouble (right here in River City) over the next 50 or 60 years. As a first mitigation step, maybe we could bring the growth of coal back to a linear increase. It just might be possible to get global support for doing that when the funhouse ride I call "World of Hurt" begins around 2030. Unfortunately, even if we succeed it won't actually help in the long run. If we burn it all, we get the warming - it just takes a little longer.
I did the following two graphs (you knew there'd be more graphs, right?) to illustrate my point. I modeled the carbon emissions from oil and gas on their current linear slope from today until the reserves are exhausted in 2060. Then I modeled coal as rising exponentially as it is doing now until 2030, then dropping back to a linear growth rate until the world's coal reserves are exhausted (also, remarkably, in about 2060). We emit a total of about 800 Gt of carbon between now and 2060, and then everything just ... stops.
When I modeled the CO2 concentration I used historical carbon data from CDIAC going back to 1751 to establish the curves, and I used the observed data from Mauna Loa as a validation check. As you can see below, the model matches the observed levels exactly. CO2 levels rise until just after all the reserves are exhausted in 2060. In this simulation the CO2 concentration stabilizes at 643 ppm, a little over twice the pre-industrial level.
I assumed a climate sensitivity of +3.5C per doubling for this test. The temperature increase attributable to just CO2 (the green dashed line) rises from +0.8C today to just over +3.5C by the end of the century. In my model it also keeps rising slowly for about another 100 years, because the planet needs some time to stabilize after the CO2 shock.
The dashed red line simulates the various feedbacks that I expect to kick in once we pass +1.0C. Since they will be temperature-related, I used a feedback term that adds a cumulative 1% per year to the temperature rise. I have no way of knowing if that's even close the right value, but I'm convinced that the effect will be significant in the coming years. That drives the temperature up another couple of degrees by the end of the century. This line will keep rising as more and more methane is melted out of it's various hidey-holes over the coming millennia. Treat it as something to think about rather than any attempt at realistic prediction.
A number of messages fall out of this exercise:
- The decades from 2040 to 2060 could easily be the breaking point for civilization, as we warm the planet from two to three degrees in just two decades.
- We face a herculean task just to get coal use off its current acceleration and down onto a linear growth rate.
- Unless we can figure out how to leave carbon in the ground, we will warm the planet by 3 to 4 degrees at the very minimum.
- We have very little time we have left to do anything substantial. After burning fossil fuels for 250 years, we have just 18 years left (at the very most) in which to make mind-bendingly enormous changes to the way we use energy. The end of the track in now clearly in sight.
- Keep your eye on the north. What happens to Arctic methane in the next eight to ten years will spell the difference between a sliver of a chance and none at all.
That effect reduces the amount of useful work a civilization can do as the net energy declines, but it has less effect on CO2 emissions. The only thing that will reduce our emissions is slowing the rate at which we dig or pump the stuff out of the ground. Even if the rate at which we can dig the stuff up drops to a mere trickle at some point, as long as we keep doing it we'll keep warming the planet. Declining net energy may become an issue for us humans in the next 20 years, but unless we figure out how to stop digging it up, the planet will just keep on warming as the physics predicts.
joshcryer
(62,277 posts)As well as methane clathrates? We'll start seeing signs of both in about a decade (arctic sea ice being gone will have a major albedo impact on the arctic and sub-arctic).
GliderGuider
(21,088 posts)As such it would include both peat bog CO2 and methane clathrates. Both are temperature-dependent GHG mechanisms, so they're both in there. Is 1% compounded annually enough? Time will tell.
joshcryer
(62,277 posts)And no, it's not enough.
Who's the doomer now?
chervilant
(8,267 posts)at our species' imminent immolation. I strongly encourage you to view David Wasdell's presentation at the Tallberg Forum 2008, during which he notes the positive feedback loops already driving the catastrophic climate change we're witnessing. His presentation highlights the fact that we are now living in exponential times, and our species has not had time to adjust to this reality, much less look at it objectively.
In fact, your first graph appears to be exponential, with a discernible asymptote at about 2060. I wonder why you consider this a linear relationship...
Please take a moment to watch Wasdell's presentation:
http://www.democraticunderground.com/101744079
GliderGuider
(21,088 posts)Last edited Sat Nov 24, 2012, 01:37 PM - Edit history (1)
In my OP I had modified the carbon curve to be a linear from 2030 to 2060 just to show how little difference such an effort would make. Here's the same pair of graphs with the "unjiggered" carbon curve staying on the exponential it's been tracing since 1985. The party ends about 5 years earlier, but it makes no difference at all to the climate.
Thanks for the pointer to Wasdell. I'll watch him later this morning.
GliderGuider
(21,088 posts)I guess now we know what kind of stuff is going to turn up in AR5 to "scare the wits out of everyone."
That was a whole new level of education for me. Feedbacks on feedbacks in a metastable system, and we're living it right now. Amazing! I feel like such a rank novice.
Seriously, thank you!!!!!
chervilant
(8,267 posts)of our species' self-destructive hedonism was miring me in long stretches of bitter resignation, punctuated by white-hot rages. Siddha Yoga Meditation has helped me 'chill out' about these macro-level events over which I have no control. Now, I recognize the merit of witnessing these incredible events, and I feel that I've been 'destined' to see what's unfolding (even as I type this). Plus, I realized how arrogant it is for our species to presume that we'll have any lasting impact on this amazing planet. When Gaia has had enough of our puny infestation, she'll just roll over and scrape us off her backside. Maybe the next species up the evolutionary ladder will do a much better job than have we.
I think I told you before that I've positioned myself to be as self-sufficient as I possibly can be for the next two decades (if we last that long). I've been Vegan since February 29--getting physically fit, as well as building my stamina. I will have a bio-intensive garden this spring, and I hope to buy property with year-round running water in about three years (if the economy doesn't tank in 2015). I am blissed out every day, just watching autumn slide into winter in these beautiful mountains. This evening, I witnessed a breathtaking sunset, with the waxing moon rising over the mountain behind me. How lucky are we?!
I look forward to your posts, both here and on FB. Thanks for all that you share.
GliderGuider
(21,088 posts)When I woke up to what was going on, back in 2003 or so, I went through four years or so of utter, black despair, depression and rage. Like you, meditation and inner work pulled me back out of that Dark Night of the Soul. After a lot of poking around I settled on Jnana yoga or Advaita. I also recognize the enormous value of witnessing these events. There are times when I feel I chose to come here right at this point in time, but that's a chat for another time and place
Despite my realization I haven't done any serious prepping. I made a choice a few years ago simply to stay with my community, such as it is, and help with the psychological side of the change. Sometimes I think of my role as that of a psychopomp. Traditionally a psychopomp is a being whose responsibility is to escort newly deceased souls to the afterlife - not to judge them, but simply provide safe passage. I see those of us who are awake during this transition time as having that responsibility for our culture as well as for individuals. I guess it has something in common with taking a Bodhisattva vow.
I wrote this yesterday on Facebook, in a thread about this OP:
Learning and sharing are the two of the best reasons for staying alive.
Ghost Dog
(16,881 posts)I'd only offer one small quibble: You have:
"less net energy available for end users like you and me" --> "reduced amount of useful work a civilization can do"
But I'd suggest that a significant amount of the energy burned by the likes of you and me in the context of this 'civilisation' is pure waste, or even worse, dedicated to counter-productive and even self-destructive outcomes. I don't find it impossible to imagine a future very 'high' level of 'civilisation' based on much lower energy inputs (which need of course to be entirely CO2-neutral) operating at much more efficient 'civilisation'-positive utilisation levels than at present. For what size population, and under what type of social organisation will be, of course, not only for scientists, social scientists, financial controllers and associated politicians to decide, if current theories of the potential power of the vox populi indeed apply.
GliderGuider
(21,088 posts)Last edited Sat Nov 24, 2012, 01:24 PM - Edit history (1)
There is waste in every energy-using system - the laws of thermodynamics permit nothing else. Arguing for anything but "What Is" opens the door to the relative moralism of competing worldviews. There's nothing wrong with that competition of course, but in my opinion the simplest view is that what we've ended up doing is simply the way the dynamics of 7 billion people have balanced out. What's actually happening, and why, needs to be fully understood first.
One can profitably ask why we are apparently choosing a self-destructive path when the probably outcome is so easily visible. But that takes us off in the direction of the genetic and cultural components of human psychology. And that is an even less tractable field than energy consumption, especially given the time we have left. If there is a power to vox populi (and recent events indicate that there indeed is), we have to ask what the countervailing forces are, what direction the vox might take us us in the 20 years we have left, and whether it will make any difference at all to the climate.
wtmusic
(39,166 posts)The misperception that stabilizing carbon output = stabilizing temperature is about as widespread as the misperception that plants will somehow start sucking up all the excess carbon.
NoOneMan
(4,795 posts)But it seems like the current trend is cutting down profitable forests.
CRH
(1,553 posts)I think the level of CO2e concentrations in the atmosphere is much better understood than the other part of the global warming equation, that of climate sensitivity and the effects of radiative forcing. Without a better understanding, sensitivity skews the potential warming numbers over a wide range.
After reading of this for a couple of weeks, it is obvious scientists are very unsettled on sensitivity potentials, for many different reasons. For some it is the very function of the formulas, how 'right skewed distribution' might influence forcing with linear expectations to a different exponential interpretation. Others concede the lack of understanding of many of the component influences of radiative forcing.
The equation of forcing tries to be independent of the nature of the elements of forcing, whether they be specific GHGs and the reliability of the computations of a CO2e, or the settling location and distribution of gases in the atmosphere. But is that independence even possible, with so much unknown.
Still more controversy emerges with the effects of feed backs, albedoic and cloud influences, atmospheric and oceanic transference vectors in non stable and evolving patterns, solar luminosity and even cycles are being questioned in quest to understand climate sensitivity.
It is a debate that is far from settled, and as said earlier can swing computations from a 2*C warmer world to 6*C only by plugging in different sensitivity factors. I'm hoping the next IPPC report lends more clarity to the evolving and unsettled science.
Until then for me, more can be learned from projecting the effects of what I believe will be very disruptive and civilization threatening, lesser rises in global temperature.
2*C is a five time rise from present conditions, that has provided us with drought on five continents in the last several years, hurricanes that knock out the infrastructure and economy of cities, and a faltering agricultural base on a global level. Piling onto the environmental problem is a staggering global economy experiencing problems with debt, credit creation, and growth.
Now with 20 more years of drought sapping the supply of ground water, ocean acidification diminishing the yield of fisheries, world grain stocks entering deficit demand; and little recovery from already unsustainable, population, food sources, fresh water, employment and debt, will be sending civilization as we no it in unrecognizable stress and chaos.
We are beginning to enter into an environmental socioeconomic twilight zone that will challenge todays understanding of just what collapse is all about. Understanding these possible dynamics lends us insight into our best use of energy and resource, in adapting for the storm that threatens a large percentage if not all, of humanity.
So until the science has a better understanding of climate sensitivity and the resulting warming, for me the difference between 2*, 3.5*, or 6*C warming is a moot conversation. Best prepare for even the lesser storms we see now on the horizon, and they are formidable; worry about the worst when the data supports.
edit: a couple of words for clarity
GliderGuider
(21,088 posts)My only question is about your assertion that +2 is a 5x increase from current conditions. If we're at +0.8 that makes it 2.5x. But as you point out so well, it's all moot in the face of where we are and what we know is coming.
Thanks for the discussion of sensitivity.
CRH
(1,553 posts)it was based on what I felt was the most realistic scenario of a 4*C raise by 2070-2100. I need to make that correction in my notes, thanks for the catch.