Wo there. We know that we are thus far mostly to blame for the current rise in atmospheric Co2 because we know how much we are emitting and how much deforestation we are causing. Of course we are not to blame for past increases. Other factors can cause an increase in co2 but right now during this time period we are clearly the culprit. The important bit of this is
Remember that the "fast increases of co2 and methane" from the holocene are much much slower and to a lesser degree than the increase we have seen over the last 100 years. Further it clearly links Co2 to increased temperature.
What am I missing? This seems to me to quite heavily support usgenic global warming.
Pretty sure our estimates, coming from theoretical assumptions or even mathematical applications of equations with some factual basis. . . . of "fast" changes in CO2 epochs ago, will be inadequate, so far as being a valid basis for measuring our "usgenic" impacts.
what don't we know? We don't know, we simply don't know.
We would need to look at a lot of things, perhaps some we haven't even considered or realized. . .
How well can we estimate even the things we can imagine about the past? We have some tools for making estimates, but no actual measurements. How do our methods and their correponding estimates vary from place to place? An ice core in the Antarctic or in Greenland? The ice in different places may give significantly different results. Antarctic ice covers no more than about fifty million years of our past, and obviously has a "bias" relating only the time when ice was accumulating, with lost info on the years when ice was being "lost". Our methods of dating ice are imprecise enough to leave some question about short intervals. . . .maybe a lot of them. . . .
same kind of questions about pollen cores in sediments anywhere. . . .
and then there are some large-scale issues like epochal volcanism, the fluxes in space "junk" including solar "wind" and whatever we may have been encourtering.. . .. which we have no possible way of measuring. We have local issues of hydrogen "clouds" in space, and maybe carbon dioxide or water or methane "clouds", as well as meteoric dusts or even larger meteors that could have caused catastropic impacts.. .. . atmospheric darkening. ... .
the volcanism we experience, along with perhaps our earthquakes, may be correlated to convection anomalies in the earth's core deriving from uranium and thorium "cycles" in concentrations. Or from changes in the plate tectonics on the surface. . . . here in the Great Basin, we have for some millions of years been "on the tectonic rack", being stretched out in a significant way, thinning the geologic "overburden" of huge masses of carbonate accumulations, resulting in a lot of volcanism, some of it fairly recent. Pretty certain there has been a lot of fixed carbonate deposits vaporized. . . .
still, the very idea that there has been a flux in dissolved carbon dioxide in the oceans over geological epochs is for most people just "too much information" when we think of "usgenic climate change".
I don't think we have proven we are the only significant actors on the stage, or even the most important ones.
global photosynthesis is bigger, volcanism is bigger, space junk is bigger. . . . and have larger variances than what we have done in the past hundred or 150 years. We have yet to prove we are even ten percent of the problem.