In fact that is exactly what your own graph shows, the boom of the 20's had higher CO2 growth and a drop (before) the crash of 29'.
1933 is when things hit bottom, so not the end just the start of the recovery which took almost a decade. Again your own graph shows this with lower CO2 growth till ~1945, then it picks up as the war ends and production (globally) gets back to normal.
In the past deniers have tried to use WWII to claim there was no spike in CO2 of course this ignores some pretty basic issues, factories that would have been making things like cars and ordinary goods where retooled to war production so no 'spike' would be evident, and while Germany, U.S., U.K. and Russia where doing this the actual war was shutting down normal production across the rest of Europe, so why would there be a spike in CO2.
After the war global production picked up and then took off, and the CO2 record clearly shows that.
As for ice cores Trevor and gcnp58 are quite right they don't make good short term records and scientists have never tried to use them as short term records, the ice core record is a long term record.
Due to the nature of how ice forms, I note even Jim is admitting this one.
The modern CO2 sampling only starts in the 1950's so misses the great depression, but the modern record certainly shows a small dip in CO2 linked to the 2008 GFC, but that soon passed and CO2 is set to hit 400ppm this year. (currently sitting on 399ppm)
http://climate.nasa.gov/key_indicators#c...
Hi Mike,
You’ve been quiet of late, I trust that all is well.
I’ve now edited this answer since I first posted it (hopefully it makes more sense)
I managed to find some data for annual CO2 emissions and despite the severity of the Great Depression, the emissions of CO2 didn’t drop by much – perhaps 200 million tonnes per year in the US, in Europe and the rest of the world they held fairly steady
Atmospheric CO2 concentrations from 1900-1950 are from ice cores. Ice core CO2 measurements filter concentrations over a longer interval than covered by the Great Depression. It has to do with how long it takes the snow to compress enough to seal the air bubbles in the ice. Therefore the time resolution for ice core data can't be less than approximately decadal. If you google around you can find more details on this.
edit: The reference you want is Neftel et al., 1985, Nature, 315, 45-47. The averaging time for ice core measurements in the 20th century is 22 years. So any changes in CO2 concentration at shorter timescales won't show up unless they are huge.
> Wouldn't the years 1929-33 show up as at least a CO2 blip or deceleration?
Yes, and that seems to be what the graph shows. (The chart scale, and thickness of the line make it hard to see.) The decade of the 1920's shows a fairly steep rise, as does the decade of the 1940's. The decade of the 1930's shows a distinctly lower slope. CO2 did not decrease, but the rate of increase clearly slowed.
Interesting; thanks for pointing this out.
It would make sense if it did. Perhaps uncertainty in measurements are why such a blip is not apparent.
Ice core samples are not accurate to the year or even the decade. There can be a lot of mixing, so I guess I am not terribly surprised. I am surprised when scientists claim that the rise in temps is unprecedented throughout Earth's history as the measurements they use for paleoclimate data are not precise enough to determine this.
All non solids like smoke, exhaust, gases, co2, etc. that rise into the upper atmosphere separate by natures chemicals so the suns rays can warm earth as our planet rotates to grow plants to give food and oxygen so all species can survive. Global Warming ended in 2012, confirmed. Mike
Chem, it takes ice longer than that to form fern. I'm not sure where those numbers before 1950s came from.
I suspect that, since we were not taking direct measurements at that point (you'll see that those years were under "ice core data"), any reduction in emissions from the Depression were lost in the "noise". And, I'm not sure how exactly ice-core CO2 levels work, so it's possible that there was some "lag" between actual CO2 changes and what showed up in the ice, though you will notice that the line went from sharply increasing (to about the mid 20s) to much more slowly increasing ('til about the mid 40s).
Keep in mind, there's far more change in any one year from seasonal variation than there is from emissions. It's just that the seasonal variation is cyclic, while the emissions are additive.
Also, it's possible that other sources of CO2 emissions (power generation, cars, etc) were level or increasing even as industrial production dropped, and/or that the 40% drop in production didn't actually lead to a 40% drop in *emissions*, which would mean that there might not have been much of a drop or deceleration to even *see*.
It takes centuries for CO2 to cycle out of the atmosphere. You do see a slight reduction in the growth, though I don't think the ice core differences are so precise to fully trust the precision of the graph over one decade.
I didn't realize how much industrial production was curtailed due to the Great Depression. It dropped over 40% in both the US and Germany which were the top two producers.
Over the course of four years, I would have expected to see some sort of indication of this in the global atmospheric CO2 levels. However, I look at a chart like this and see nothing: http://www.cotf.edu/ete/images/modules/climate/GCcarbon1PICT2.gif
Wouldn't the years 1929-33 show up as at least a CO2 blip or deceleration?
Seems that climate science has been working backwards from their Mauna Loa records, since they can't accurately measure CO2 before that time. We know that GCM projections have been "way-off-base" when it comes to temperatures (projections are way too high). I think that there is a "consensus" among non-science people that climate science has no clue about a great many things when it comes to the climate.
