skepticalbip
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Hurricane Harvey and Climate Change
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That's harsh.
Elixir
Made in America
Okay.
It's not the difference in "a molecule" but rather a difference in the ratio of isotopes of CO2.
"Another, quite independent way that we know that fossil fuel burning and land clearing specifically are responsible for the increase in CO2 in the last 150 years is through the measurement of carbon isotopes. Isotopes are simply different atoms with the same chemical behavior (isotope means “same type”) but with different masses. Carbon is composed of three different isotopes, 14C, 13C and 12C. 12C is the most common. 13C is about 1% of the total. 14C accounts for only about 1 in 1 trillion carbon atoms.
CO2 produced from burning fossil fuels or burning forests has quite a different isotopic composition from CO2 in the atmosphere. This is because plants have a preference for the lighter isotopes (12C vs. 13C); thus they have lower 13C/12C ratios. Since fossil fuels are ultimately derived from ancient plants, plants and fossil fuels all have roughly the same 13C/12C ratio – about 2% lower than that of the atmosphere. As CO2 from these materials is released into, and mixes with, the atmosphere, the average 13C/12C ratio of the atmosphere decreases.
Isotope geochemists have developed time series of variations in the 14C and 13C concentrations of atmospheric CO2. One of the methods used is to measure the 13C/12C in tree rings, and use this to infer those same ratios in atmospheric CO2. This works because during photosynthesis, trees take up carbon from the atmosphere and lay this carbon down as plant organic material in the form of rings, providing a snapshot of the atmospheric composition of that time. If the ratio of 13C/12C in atmospheric CO2 goes up or down, so does the 13C/12C of the tree rings. This isn’t to say that the tree rings have the same isotopic composition as the atmosphere – as noted above, plants have a preference for the lighter isotopes, but as long as that preference doesn’t change much, the tree-ring changes wiil track the atmospheric changes.
Sequences of annual tree rings going back thousands of years have now been analyzed for their 13C/12C ratios. Because the age of each ring is precisely known** we can make a graph of the atmospheric 13C/12C ratio vs. time. What is found is at no time in the last 10,000 years are the 13C/12C ratios in the atmosphere as low as they are today. Furthermore, the 13C/12C ratios begin to decline dramatically just as the CO2 starts to increase — around 1850 AD. This is exactly what we expect if the increased CO2 is in fact due to fossil fuel burning. Furthermore, we can trace the absorption of CO2 into the ocean by measuring the 13C/12C ratio of surface ocean waters. While the data are not as complete as the tree ring data (we have only been making these measurements for a few decades) we observe what is expected: the surface ocean 13C/12C is decreasing. Measurements of 13C/12C on corals and sponges — whose carbonate shells reflect the ocean chemistry just as tree rings record the atmospheric chemistry — show that this decline began about the same time as in the atmosphere; that is, when human CO2 production began to accelerate in earnest.***
In addition to the data from tree rings, there are also of measurements of the 13C/12C ratio in the CO2 trapped in ice cores. The tree ring and ice core data both show that the total change in the 13C/12C ratio of the atmosphere since 1850 is about 0.15%. This sounds very small but is actually very large relative to natural variability. The results show that the full glacial-to-interglacial change in 13C/12C of the atmosphere — which took many thousand years — was about 0.03%, or about 5 times less than that observed in the last 150 years.?
CO2 produced from burning fossil fuels or burning forests has quite a different isotopic composition from CO2 in the atmosphere. This is because plants have a preference for the lighter isotopes (12C vs. 13C); thus they have lower 13C/12C ratios. Since fossil fuels are ultimately derived from ancient plants, plants and fossil fuels all have roughly the same 13C/12C ratio – about 2% lower than that of the atmosphere. As CO2 from these materials is released into, and mixes with, the atmosphere, the average 13C/12C ratio of the atmosphere decreases.
Isotope geochemists have developed time series of variations in the 14C and 13C concentrations of atmospheric CO2. One of the methods used is to measure the 13C/12C in tree rings, and use this to infer those same ratios in atmospheric CO2. This works because during photosynthesis, trees take up carbon from the atmosphere and lay this carbon down as plant organic material in the form of rings, providing a snapshot of the atmospheric composition of that time. If the ratio of 13C/12C in atmospheric CO2 goes up or down, so does the 13C/12C of the tree rings. This isn’t to say that the tree rings have the same isotopic composition as the atmosphere – as noted above, plants have a preference for the lighter isotopes, but as long as that preference doesn’t change much, the tree-ring changes wiil track the atmospheric changes.
Sequences of annual tree rings going back thousands of years have now been analyzed for their 13C/12C ratios. Because the age of each ring is precisely known** we can make a graph of the atmospheric 13C/12C ratio vs. time. What is found is at no time in the last 10,000 years are the 13C/12C ratios in the atmosphere as low as they are today. Furthermore, the 13C/12C ratios begin to decline dramatically just as the CO2 starts to increase — around 1850 AD. This is exactly what we expect if the increased CO2 is in fact due to fossil fuel burning. Furthermore, we can trace the absorption of CO2 into the ocean by measuring the 13C/12C ratio of surface ocean waters. While the data are not as complete as the tree ring data (we have only been making these measurements for a few decades) we observe what is expected: the surface ocean 13C/12C is decreasing. Measurements of 13C/12C on corals and sponges — whose carbonate shells reflect the ocean chemistry just as tree rings record the atmospheric chemistry — show that this decline began about the same time as in the atmosphere; that is, when human CO2 production began to accelerate in earnest.***
In addition to the data from tree rings, there are also of measurements of the 13C/12C ratio in the CO2 trapped in ice cores. The tree ring and ice core data both show that the total change in the 13C/12C ratio of the atmosphere since 1850 is about 0.15%. This sounds very small but is actually very large relative to natural variability. The results show that the full glacial-to-interglacial change in 13C/12C of the atmosphere — which took many thousand years — was about 0.03%, or about 5 times less than that observed in the last 150 years.?
JohnG
Senior Member
Yes, molecule was an inaccurate descriptor, but this is the data I was referring to. It's been awhile since I came across this research but this has been corroborated by climate and air quality scientists.
repoman
Contributor
I should have put it in quote marks, it is not "human activity" it is the coincidence that human activity has released the carbon dioxide (and methane). "Human activity" is the root cause and "carbon dioxide release" is the proximal cause.
But people (Rush Limbaugh has mastered this) make fun of saying human activity because they say that environmentalists have replaced moral sins against god (like having gay sex) with sins against mother earth. And the original sin for environmentalists is being human and people are evil.
I don't care about that nonsense, I am just running the numbers and looking at the carbon dioxide levels and can see there is some heavy shit coming down the pike, including irreversible sea level rise of 25 meters and counting. We as a species need to start moving now.
TSwizzle
Let's Go Brandon!!
Maybe it won't. Maybe it will and the effect will be negligible. It will require a lot more study. The science is far from settled no matter what Gore says.
Elixir
Made in America
Yeah, and "maybe" San Francisco Bay is made out of grape juice.
"Maybe" those lines will suddenly diverge for reasons beyond our feeble comprehension.
If those lines suddenly diverge, THAT will require a lot more study. Meanwhile, water is still wet and fire is hot...
Malintent
Veteran Member
Gravity requires far more study... we know almost nothing about the most important force affecting our everyday existence... except maybe the Strong (nucleic) Force that keeps matter from flying apart.... what can you tell the class about how that works?
So.... go jump off a bridge... maybe you'll fall to your death... but maybe not... because proof.
James Brown
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Shadowy Man
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Thanks for clearing that up. All I needed was the word isotope.
bilby
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bilby
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fromderinside
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Oh. So Irma was a category six event.
repoman
Contributor
So the oceans are absorbing most of the excess heat, which will make more storms
https://skepticalscience.com/graphics.php?g=46
https://skepticalscience.com/graphics.php?g=46
Shake
Senior Member
And here comes Maria:
Kharakov
Quantum Hot Dog
View attachment 12460
"Maybe" those lines will suddenly diverge for reasons beyond our feeble comprehension.
Not likely. GW causes CO2 emission from under the sea (ocean). Like totes.
repoman
Contributor
There is lag for the temperature to catch up with the CO2 in the atmosphere. The ocean is also heated. When the enough heat reaches reached methane clathrates global warming and oceanic oxygen starvation will go into overdrive. But before that the organic muck in the tundra will outgas from bacterial feeding frenzy on a couple million years of food.
repoman
Contributor
Is this run of hurricanes in so short a time out of statistical range? Don't they bleed off ocean heat? Is the ocean temp above average temp now also statistically pushing the limit?
The arctic has gotten the brunt of AGW so far.
The arctic has gotten the brunt of AGW so far.
skepticalbip
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You are confusing weather and climate. If hurricane number and intensity were due to global warming then it should be expected that we should be seeing a continuing increase in both over the years. We don't. What we actually see is the effect of the Atlantic multi-decadal oscillation, years with many hurricanes and years with few hurricanes - similar to the Pacific El Nino - La Nina cycle that was recognized as far back as the 1500s.
In 1950 there were 13 named storms, 11 of them hurricanes, and 8 of those hurricanes were "major" hurricanes. In 2013 there were only two hurricanes, neither of them were major hurricanes.
http://www.aoml.noaa.gov/hrd/tcfaq/E11.html
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Jimmy Higgins
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Two large hurricanes (one of which was less strength and more steering currents) and all of a sudden people think Climate Change is proven by it. The Middle East was hit by two hurricanes last year! While not unprecedented, that was rare. About as rare as the flooding in Texas. But yeah, weather v climate, not the same darn thing. Climate change is demonstrated by a tremendous number of observations made over a long period of time, not by a couple of storms.