Discussion > Leave Fossil Fuel in the Ground and We will Join it Very Soon
WOW!
Patrick Moore is a fan ^.^
Dung
To refine on my rather flippant comment, earlier in this discussion (Jun 9, 2015 at 1:22 PM), perhaps the high CO2 levels on Mars and Venus are indication that there is no life on these planets – and there never has been life on these planets!
As mooted by Dung and TinyCO2, perhaps the sequestering of CO2 into the rocks is one of the indications / drawbacks (choose your own) of life. The myriad of lifeforms that have created coral, chalk and limestone, as well as coal, oil and gas embedded within the Earth’s mantle, have extracted that carbon dioxide from the atmosphere, locking it in. Mother Earth/Nature/Gaia/call her what you will can only release that trapped carbon (dioxide) in fairly small dribs and drabs, through volcanoes, erosion, etc., so the efforts of humans could be a great benefit for all life on the planet. Get it out of the ground!
Radical Rodent
EM (Jun 12, 2015 at 1:46 PM): that is what it is: speculation. I have the suspicion that this was (it was in 2011) put forward as a ploy to help ratchet up the fear – “Look! CO2 caused mass extinction in the past! We do not want this to happen again – stop making CO2!”
Radical Rodent
RR
I am no expert but 'cycles' seem to run everything, why not assume that there must be a cycle that affects planetary life?
We look at Mars and think that it once had life so what stopped it?
I think Patrick Moore had it spot on and that we were close to an extinction situation and have luckily stumbled upon a way out.
Dung
Dung: I’m not sure that the cycles of Venus and Mars has ever included life. Someone, somewhere on this site, has pointed out that NASA has already declared that there is no evidence to suggest that there is and that there has ever been life on Mars, however, in order to keep its income stream flowing, and to make it sweet enough for the public (who actually pay for all this), they maintain the lie that maybe, perhaps, possibly we might find some – and we have to keep looking. Riiight. Why can we not keep it honest: we should keep exploring just for the thrill of exploring, as well as the information that we could find?
The hypothesis that I have suggested is that a planet that has such a high concentration of CO2 in the atmosphere has not, and has never had, any life on it.
Radical Rodent
Radical Rodent
Six years on from the speculation about the link between the Permean extinction, the Siberian Traps and increased CO2 we have this open access paper putting more flesh on the bones.
Dung
Regarding the carbon cycle, distinguish between the short term cycle ( driven by the biosphere and glacial cycles)
and the long term cycle driven by plate tectonics.
The former shuttles carbon in and out of short term storage on annual to millennial timescales. The total amount of carbon available remains relatively constant.The latter gradually locks up CO2 absorbed from the atmosphere by weathering into sedimentary rocks. Plate tectonics then gradually removes it from the system by subduction.
Venus lost its water early on, so weathering and plate tectonics stalled before much CO2 could be removed from the atmosphere, hence the 90bar pressure and high CO2 content.
Mars is a small planet which cooled quickly and its water froze. Weathering and plate tectonics stopped. The CO2 was not absorbed and the low gravity subsequently allowed most of the atmosphere to escape. Hence the thin, mostly CO2 atmosphere.
Earth has had weathering and plate tectonics right up to the present. Most of the primeval CO2 is now locked up in the crust or mantle. Hence the predominantly nitrogen/oxygen atmosphere and 1 bar pressure.
Entropic man
Life?
Venus probably got too hot too soon for life to appear locally, or be transferred from elsewhere.
Earth and Mars both had early conditions capable of supporting microbes. Earth had them and Mars may have had them too (no definite confirmation or falsification yet).
So far only Earth is confirmed to have an active carbon cycle.
Entropic man
EM
You wouldn't be trying to hide the pea by talking about the "carbon cycle" while the rest of us are talking specifically about "carbon dioxide", would you? I mean; perish the thought!.
CO2 is only one form of carbon, remember, and I'm not sure where plate tectonics come into it. Perhaps you would give us a link or explain yourself.
Mike Jackson
So, weathering and plate tectonics are water-dependent, then? Who knew?
Sorry, EM, but I think you are barking up the wrong tree, here. Yes, as far as we know, all life is dependent on water, but that is a red herring in these cases; my hypothesis is that the high concentration of CO2 in the atmosphere is indicative of there being no life, and there having been no life on the planet, as it is required that life remove the CO2 from the atmosphere, and lock it up into what will eventually become rock formations or fossil fuels. This is why there will be no chalk or limestone rocks on those planets, nor will there be fossil fuels, such as coal. Oil and natural gas may have other origins, so might exist.
Radical Rodent
RR
I think EM is saying (rightly) that plate tectonics needs heat so if the core cools then plate tectonics will stop.
Dung
Don’t be so sure about that, Dung:
Venus lost its water early on, so weathering and plate tectonics stalled…(Entropic man – Oct 16, 2015 at 12:59 AM).
Anyway, what do we know about the core temperatures of other planets?
Radical Rodent
From my point of view; I know that unless a planet's core is molten then plate tectonics can not exist .
Dung
Dung - I know the Earth's core is pretty hot - several millions of degrees (according to Al Gore).
How is the heat in the Earth's core generated? Radioactivity presumably, plus...?
Friction in tidal movements of the viscous material in the core?
Electric currents produced by movement of the Earth's core in its own magnetic field?
Anybody know? I imagine EM will know.
Martin A
Martin A
I believe that basically it is left over from the creation of the earth and remains because we have an atmosphere and we are close ish to the sun
Dung
On that principle, Dung, Venus is also likely to have a hot, perhaps molten, core, so plate tectonics may also exist, there; certainly, it is an option not to be discounted. How can we tell if there is such a thing on another planet? It might be a factor that is not yet possible to determine remotely; my understanding is that the only reason we know about tectonics on Earth is that we have sensors on the ground, and have been monitoring for quite a few years, now. Even so, when the idea was first mooted, it was ridiculed in much the same way as scepticism about AGW/ACC/call it what you will is, nowadays. Ho-hum… plus ça change…
Radical Rodent
You want me to go back to teaching you?
Put in " plate tectonics " or " carbon cycle" and the internet will give you lots of information.
Liquid cores? If you want to know if a rocky planet has a liquid iron core, look for a magnetic field. Venus and Earth both have strong magnetic field. Mars has a weak field.
What do you need for plate tectonics?
1) Convection in the mantle. Heat from the lower mantle causes molten rock to rise to the surface. It produces vulcanism and the lava solidifies into new surface which spreads out. When two spreading zones meet or the spreading hits a continent the rock sinks back into the mantle. Any sedimentary rocks on top get dragged down as well, including any carbon they contain. The sinking is called subduction.
2) Water
Liquid water drives weathering and lubricates subduction. Without it subduction stops and plate tectonics jams.
Venus now has a hot mantle but no water. Plate tectonics stopped on Venus when the water was lost to space. You still get vulcanism from the hot mantle, but with no subduction the lava just accumulates. There is no weathering to take CO2 out of the atmosphere and no subduction to carry it into the mantle.
Mars has water (now frozen) but has lost most of its internal heat (small planets cool faster). Convection in the mantle is slow, so vulcanism and new crust formation have stopped.
Earth has both. It is large enough to have held on to enough heat for a liquid core, mantle convention and volcanoes. It is for enough from the Sun to have held on to most of its water. Hence it still has plate tectonics.
CO2 in the atmosphere becomes carbonates when rocks weather. It ends up as sedimentary rocks which subduct. Given enough megayears some of the carbon returns to the surface via volcanoes. The rest remains in the mantle. Over deep time the amount of carbon available at the surface decreases.
Hiding the pea?
In the short term carbon cycle plants absorb CO2 by photosynthesis to form carbohydrates, fats and proteins. Animals respire the plants they eat back into CO2. Decomposition produces CO2 and methane. Long buried material cooks to hydrocarbons such as coal and oil.
Dissolved CO2 in water becomes carbonates and bicarbonates. Plankton use it to build calcium carbonates which become sedimentary rocks such as limestone and chalk.
CO2 is only one stage in these processes. Most carbon molecules spend most of the cyle in more complex molecules
Entropic man
Dung, Martin A
Core temperature for Earth is about 6000C. Part of the heat came from the kinetic energy delivered during the bombardment which formed the planet, the rest from radioactive decay.
Entropic man
EM
A genuine thanks for some stuff I did not know but can you tell me which bits of my posts at 12.35pm and 2.35 pm you have a problem with?
Dung
EM - thanks for that. 6000 degrees - how did you measure it?
Core temperature for Earth is about 6000C. Part of the heat came from the kinetic energy delivered during the bombardment which formed the planet, the rest from radioactive decay.
Didn't Lord Kelvin or someone work out that that put the age of the Earth at 44 million years - much longer than that and the original heat would have escaped completely? (Of course at that time radioactivity was not known about.)
Even though the temperature gradient can now only be a degree or so per mile, 4 billion years seems an awful long time for all of the original heat still not to have found its way out.
Liquid water drives weathering and lubricates subduction. Without it subduction stops and plate tectonics jams.
That's interesting as water is usually reckoned to be a pretty poor lubricant - if the transmission fluid cooler in your car's radiator leaks and you get water and antifreeze in the automatic gearbox you've got a trip to the car breaker's to look forward to - either taking the car there or in the hope of finding a working replacement gearbox.
Wouldn't graphite - or crude oil - do as a lubricant for plate tectonics?
Liquid cores? If you want to know if a rocky planet has a liquid iron core, look for a magnetic field. Venus and Earth both have strong magnetic field. Mars has a weak field.
Is there any reason to think that a *solid* metallic core would not also produce a strong magnetic field?
Martin A
Oct 16, 2015 at 7:25 PM | Unregistered CommenterEntropic man
This thread is about my suggestion that to leave fossil fuels in the ground will hasten the end of all life on earth apart from bacteria etc. and maybe even them.
Patrick Moore pointed out that levels of atmospheric CO2 have been falling for most of the 4.3 billion years of the earth's existence and that at (he says) 150 ppm all current vegetation will die and animal life will follow.
You know a great deal EM so please comment on that mate?
Dung
Dung
Nothing much to disagree on there.
I doubt that we will run out of CO2 without fossil fuels. There is a slow background release of CO2 from volcanoes, and considerable stored carbon in the permafrost. There is also a slow warming effect as the Sun moves towards the red giant stage. The last time we saw CO2 levels too low for plant photosynthesis was over 600 million years ago in the last snowball Earth episode. We may end up like Venus in a billion years, but losing the biosphere to reduced CO2 looks unlikely
Martin A
There is a dynamotheory for the origin of a planetary magnetic field.
Entropic man
Martin A
Lubrication is probably an oversimplification. IIRC water reduces the stiffness of subducting crust.
Entropic man
There is a dynamotheory for the origin of a planetary magnetic field.
EM - Theory or Hypothesis? :)
Actually, it seems hard to come up with any other explanation. What I was getting at is that it presumably would work with a solid (but electrically conductive) core so I was not sure why the existence of a planet's magnetic field implies its core is liquid as you asserted.
But thinking about it, if the planet is going to act as a self-excited dynamo, it will need to have parts that move differentially (equivalent to the rotor and the stator of a dynamo) so (unless it consisted of hollow solid concentric spheres rotating at different rates) it would need to have a liquid core to do that. So it does sound plausible that a strong magnetic field implies a liquid core - unless of course the core were a solid steel permanent magnet....
Martin A
EM
Thanks again for intelligent response mate :) However you are not explaining certain facts:
You said:
I doubt that we will run out of CO2 without fossil fuels. There is a slow background release of CO2 from volcanoes, and considerable stored carbon in the permafrost.
The background release of CO2 from Volcanoes and the CO2 stored in the permafrost has not so far stopped the ongoing reduction of levels of atmospheric CO2. The fall has happened despite those facts.
The only thing that has stopped the level of CO2 falling has so far been the burning of fossil fuels?
Dung
As a humorous aside: In 2006, the United Nations Food and Agricultural Organization (FAO) reported that livestock accounted for 18% of greenhouse gases, making livestock emissions “one of the most significant contributors to today’s most serious environmental problems.” However recently, Worldwatch Institute, a Washington D.C. environmental think-tank, reported that livestock emissions actually account for 51% of greenhouse gases. The USA and the UK are both aiming for an 80% reduction in CO2 emissions by 2050 ^.^