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Forum » SpaceEngine » Off-topic Discussions » General Global Warming / Climate Change Discussion (because a thread for this was long overdue)
General Global Warming / Climate Change Discussion
midtskogenDate: Sunday, 21.08.2016, 17:55 | Message # 151
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Quote steeljaw354 ()
What can we do stop Global warming/ climate change?

We can't and shouldn't stop climate change. We must rather ask how we can reduce our footprint in nature, like our waste into the ocean, land or air, and also be conscious about our land use. If we do that, any unnatural climatic effects will be avoided also.
Quote spacer ()
we can move to green energy. sun/wind/water.

The main source of energy must become nuclear. Building sun, wind and water power plants is raping nature, and must be minimised.





NIL DIFFICILE VOLENTI


Edited by midtskogen - Sunday, 21.08.2016, 17:59
 
spacerDate: Sunday, 21.08.2016, 19:17 | Message # 152
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Quote midtskogen ()
must become nuclear.

doesnt it pollute too with radioactive/nuclear waste?





"we began as wanderers, and we are wanderers still"
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midtskogenDate: Sunday, 21.08.2016, 20:12 | Message # 153
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Quote spacer ()
doesnt it pollute too with radioactive/nuclear waste?

No, unless there is a serious accident. But even the M9 Tōhoku earthquake in 2011 130 km from the aged and outdated Fukushima plant followed by a huge tsunami caused no casualties due to radiation, though a few workers received high radiation doses and have an elevated risk of cancer. Compare that to all the fatal accidents related to mining and drilling. Evacuation zones are good news for wildlife. And I think nature would prefer elevated radiation rather over oil spills.

There is much irrational fear related to radiation. The dangers exist, but it's so rarely a real problem. After the 2011 quake a nuclear scientist was interviewed on Norwegian TV and asked whether Norwegians in Tokyo should return back to Norway. Her answer was that they would receive more radiation during the flight than if they stayed. Which was funny, since I had just made the same remark to my wife.

Nuclear power is not a quick fix. It's complicated and expensive. But it gives the best promise to meet energy needs and to become cheap. If we don't use this technology, it wont improve either. One should think that the fear of rising CO2 levels would boost the development. Go figure.





NIL DIFFICILE VOLENTI


Edited by midtskogen - Sunday, 21.08.2016, 20:19
 
WatsisnameDate: Sunday, 21.08.2016, 21:04 | Message # 154
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Nuclear is a very good bridge toward a more sustainable energy future. And we know how to make a sustainable energy system in our generation with current technology. Which is an amazing thing. smile More and more in this field of study, we are finding that mitigating climate change, going to sustainable energy, and promoting further economic growth, all point in the same direction. Meaning we can do all of these things and be in good shape for the future.

It's also correct that we cannot stop climate change. Earth will continue to warm even if we stopped all emissions. But how much more it warms depends a lot on what we do. We can still implement reasonable policy decisions that stand a high likelihood of avoiding more than 2C of warming, if we make those decisions fast. And we can prevent more than 4C of warming if we move away from fossil fuels instead of burning through the rest of known reserves.





 
midtskogenDate: Sunday, 21.08.2016, 21:28 | Message # 155
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To stop climate change is absurd. It would either include things like changing the Earth orbit, stop continental drift, stop ocean circulations and another things which could have unseen side effects, or some method by which we could counter the changes which again is hard to imagine without side effects. But let's say we could actually stop climate change without any side effects. The climate today would be the same as in 100 years, in 10.000 years and in 10 million years. That would be totally unprecedented in the history of the earth, and I wonder how the ecosystems would react. How would evolution behave under such conditions?




NIL DIFFICILE VOLENTI
 
WatsisnameDate: Sunday, 21.08.2016, 21:53 | Message # 156
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Continental drift operates on a timescale of millions of years and I'm not even remotely worried about it. smile What I am worried about is multiple degrees C of warming on timescales of decades to centuries, since we are causing it and it affects us and our immediate descendants.

To do something about all climate change forever is a very different discussion than doing something about what's happening right now.





 
DoctorOfSpaceDate: Monday, 22.08.2016, 21:25 | Message # 157
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spacerDate: Monday, 22.08.2016, 21:53 | Message # 158
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https://www.co2.earth/monthly-co2





"we began as wanderers, and we are wanderers still"
-carl sagan

-space engine photographer


Edited by spacer - Monday, 22.08.2016, 21:54
 
WatsisnameDate: Monday, 22.08.2016, 22:56 | Message # 159
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Gone up 50ppm during my lifetime. That's 4x1014kg.

If that mass were as a solid cube with the density of lead, it would be 7km tall.

Correction, that should be 3km tall. Made a power of ten typo in Wolfram.
7km turns out to be the right answer if we take the 120ppm added since the industrial revolution and convert it into a cube with the density of standard rock. (2.65g/cm3). Which is a lot of CO2. Other comparisons:
It's close to a trillion (as in 1012) metric tons.
It's about 12 times the total biomass on Earth.

Actually, that last figure strikes me the most. We've put 12 times more organic carbon in the air than there is currently living organic matter on the planet.





 
spacerDate: Monday, 22.08.2016, 22:59 | Message # 160
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Watsisname, we are allready at 407ppm :(
7ppm in 3 years
so its not only growing but speeding





"we began as wanderers, and we are wanderers still"
-carl sagan

-space engine photographer


Edited by spacer - Monday, 22.08.2016, 22:59
 
WatsisnameDate: Monday, 22.08.2016, 23:18 | Message # 161
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Yeah, we did hit 407ppm a few months ago, but it's also dropping. There's a seasonal cycle of about 5ppm that peaks in May, since most plants are in the northern hemisphere. It would be more accurate to say we're at about 404ppm by the average of that cycle. The annual growth rate is about 2 to 2.5 ppm, which is faster than previous decades.






 
midtskogenDate: Tuesday, 23.08.2016, 07:45 | Message # 162
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So much talk. What if that time was spent in actual advances in technology instead...

Does anyone remember the forest dieback in the 80's? Science communication hasn't improved much.

Quote Watsisname ()
We've put 12 times more organic carbon in the air than there is currently living organic matter on the planet.

If 120 ppm is 12 times, the living organic matter equals 10 ppm, but the seasonal CO2 variation is 5 ppm, half of the living organic matter. Something doesn't add up. I'm assuming that you by "put into the air" mean the excess, not everything including what gets absorbed/goes back into the cycle.

It's difficult to sum the total living organic matter: There's a lot of trees out there, and bacteria, and animals are likely just a small portion. And do you only count the carbon of living matter, or the water and the rest as well?





NIL DIFFICILE VOLENTI


Edited by midtskogen - Tuesday, 23.08.2016, 07:57
 
WatsisnameDate: Tuesday, 23.08.2016, 12:14 | Message # 163
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Easier to make informed decisions about development with an understanding of where the climate is going. Or I suppose we could choose to be totally unprepared for what switching the world to an Eocene climate would be like.

Quote midtskogen ()
If 120 ppm is 12 times, the living organic matter equals 10 ppm, but the seasonal CO2 variation is 5 ppm, half of the living organic matter. Something doesn't add up.


This definition of biomass is the carbon component, and I am using the additional CO2 in the atmosphere by ppm, not the CO2 we emit. Of what we emit, about 1/2 remains in the atmosphere and the rest goes into the oceans, plants, and various other carbon sinks. At least one of which is still unknown!

Anyway, I'm pretty sure my calculation for the mass of 120ppm of CO2 is correct, but please feel free to check me on that part. I'm not infallible with math. smile And that was the motivation of the calculation originally. The comparison to biomass is a result from Wolfram Alpha. They say total biomass = 8x1013kg. Wolfram is usually pretty reliable so I didn't think to check it, but maybe they're using a weird definition or outdated estimate. So, let's check others.

https://en.wikipedia.org/wiki/Biomass_(ecology) says the total living biomass apart from bacteria is 560 billion tonnes, or 5.1x1014kg. In that case the mass of 120ppm C in CO2 is about 1.7 times that. They say the total mass could be as much as 4 trillion tons carbon, in which case the result is about a quarter, but the mass of bacteria is the hardest to quantify. For instance, a 2012 study found that we had been severely over-estimating the mass of microbes on the sea floor, and should be marked down from 300 billion tons to only 4 billion. This suggests reducing the total biomass on Earth by about 1/3, from a trillion tons. In which case the calculation should give 1.5 times as much CO2 as biomass, close to the result through wikipedia without bacteria. The CO2 molecule also weighs 3.67 times more than the carbon, so divide by that for a direct carbon to carbon comparison.

The biomass of trees is actually one of the easier ones to figure out, because trees in a given forest follow a well behaved distribution of sizes, often fractal. So measuring the mass of a forest can be done by measuring the distribution instead of every tree. This is pretty standard work for that field -- I don't have a citation offhand but I've seen a documentary about it which was pretty interesting.

So, looks like the result ought to be "within an order of magnitude" instead of "an order of magnitude more", but it's still pretty impressive. A trillion metric tons of CO2 is a lot of CO2. It's not totally surprising the amount of carbon stored in fossil fuels can be greater than that in the living biosphere, and we know that the amount of organic or inorganic carbon released in the atmosphere can be much greater because it has happened in previous climate changes. Those same climate changes are also associated with mass extinctions.





 
midtskogenDate: Tuesday, 23.08.2016, 13:22 | Message # 164
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Quote Watsisname ()
It's not totally surprising the amount of carbon stored in fossil fuels can be greater than that in the living biosphere

No, but the surprise here is that the seasonal CO2 variation, which is linked to plant growth, equals half of the living biomass. As if the living biomass doubles due to the NH spring.

But these comparisons aren't quite apples to apples. One thing is that you compare only the C of the biomass with CO2 (that is, both the C and the O), if I get you right. Yes, dividing by 3.67 is important. :)

Quote Watsisname ()
says the total living biomass apart from bacteria is 560 billion tonnes, or 5.1x10^14kg.

Not that it matters much, but if you count in inches, feet, tons etc, I suppose you get that number in kg, but in the civilised world a tonne is 1000 kg. ;)

According to this page there's 2.996×10^12 tonnes of CO2 in the atmosphere assuming 383 ppm. Correcting for 407 ppm and dividing by 3.67 to get the carbon, I get 867*10^12 kg of C in the atmosphere. 120 ppm then is 256*10^12 kg. If we for simplicity assume the biomass to be 1 trillion tonne, 10^15 kg, then it's 1/4 of the biomass, not 120 times. And the 5 ppm seasonal variation would be 1% of the biomass.

However, messing up maths like this is guaranteed since it's hard to guess what are reasonable numbers, so missing by a few orders of magnitude easily gets unnoticed. smile





NIL DIFFICILE VOLENTI


Edited by midtskogen - Tuesday, 23.08.2016, 20:18
 
WatsisnameDate: Tuesday, 23.08.2016, 21:53 | Message # 165
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Quote midtskogen ()
However, messing up maths like this is guaranteed since it's hard to guess what are reasonable numbers, so missing by a few orders of magnitude easily gets unnoticed.


Right? The estimates are fuzzy, and easy to botch the unit conversions and imperial/metric. tongue But it was good to have that sanity check from the seasonal variation.

Like I said I was originally going for the mass of additional CO2 in the air because I was curious to visualize it as an equivalent cube of solid matter. This calculation seems right and is pretty robust. Take the total mass of the atmosphere, break it up by composition to get the number of moles of equivalent molar mass, then multiply by the fraction of CO2 with its molar mass, giving 7.8x1012kg per ppm CO2, which agrees with the page you found. There's an assumption in there that we can use the parts per volume to get the moles of CO2, but this is reasonable since the air contains very small molecules of similar size. Result gives a cube many kilometers on a side, the exact number depending on what density we make it.

The 12 times biomass (not 120! Order of magnitude typos are easy, indeed biggrin ), stated from Wolfram Alpha did initially strike me as surprising but not too surprising since fossil fuels are built from many generations of biomass. But indeed it is too high. It makes me wonder where Wolfram's 8x1013kg came from. I tried various searches for the biomass with it but they don't parse correctly. I like Wolfram a lot and use it regularly, but this is a disappointing case where it's hard to know its sources.

It looks like we're getting a more reasonable estimate of "within an order of magnitude" of the biomass, which is probably as precise as we can be given uncertainty.





 
Forum » SpaceEngine » Off-topic Discussions » General Global Warming / Climate Change Discussion (because a thread for this was long overdue)
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