Just to nitpick, while commonly accepted, the idea that CO2 increase is anthropogenic is routinely disputed by climate skeptics [1].
The argument generally is that warming temperatures cause rising CO2. This in turn is a fact not disputed by climate scientists, only that it is not sufficient to explain the current rise in CO2.
Ya know, I saw this a year ago, and was curious if it actually held up. After all, the amount of CO2 released by humans is only about 4% of all CO2 released, on an annual basis (730 gigatons all sources, ~30 gigatons by humans).
But it's a pretty simple equation. We know the approximate mass of the atmosphere, and the number of molecules per weight. We know how many molecules are in a unit mass of CO2.
Thus we should be able to calculate out "how many gigatons of CO2 are necessary to increase atmospheric CO2 by 1ppm", and then given measurements of actual CO2 increases, how much CO2 is necessary to increase atmospheric levels by the amounts seen.
If the amount of CO2 required to yield the observed increase is greater than annual human emissions, then that's a strong signal that CO2 increase is NOT anthropogenic and something else is going on. If it's less, then that is a strong signal that humans are the primary culprit.
Anyway, I did out all the math and it takes about 8.8 gigatons to increase atmospheric levels by 1ppm, and we're netting an increase of about 17gt into the atmosphere per year, for an increase of ~2ppm annually. So it's pretty clear that this is anthropogenic.
If anyone wants to check my math I wrote it all up here [0]. Numbers are a couple years old at this point but the conclusion still stands.
That's not the same argument. Some people claim that CO2 increase does not cause temperature increase and therefore temperature increase is not anthropogenic (which is what your link is debunking), but nobody claims that the CO2 increase itself is not anthropogenic.
I’ve heard people (seemingly educated and intelligent) making arguments like volcanoes emit more (I wasn’t sure when they said it at the time but I looked it up and it’s nowhere near the amount - humans win by an overwhelming amount in CO2 emitted each year even if you look at the biggest eruptions ever).
Yes, the usual denial arguments I hear are on the form of "the climate has always been that way", "it's variance on the solar output" and "volcanoes are the ones emitting most of those gases".
It's also quite interesting window to thoughts of other people. I find it extremely mind-boggling that we live in times of detecting gravity waves, building particle accelerators etc. and some people live in reality where we don't know how much energy we're getting from the sun or co2 from volcanoes.
We can’t predict the weather more than 14 days into the future.
It seems like the opposite to me, it’s a no-brainer that predicting what will happen to an immensely complex system, and making all these assumptions about what will occur 50-100 years from now is going to be hotly debated.
Are you intentionally trying to conflate weather and climate? Is it hard to believe that short term trends (weather) are much harder to predict than long term trends (climate) because you’re smoothing out the chaos of the short term behavior?
A poor analogy is that you can’t predict where an atom is located and its speed due to quantum, yet when you average over a bunch of atoms you some pretty useful bounds on the shape of the problem.
Also, we already have plenty of data to evaluate the models - climate models are underpredicting the consequences (ie things are hotter and more volatile than climate models predicted). This indicates the models are conservative about the predictions in the wrong direction (you want to be predicting 20% worse than reality than 20% better because of it impacts planning). The reason they’re likely wrong is that we don’t have a full accounting of the ways in which human activity causes warming.
When we throw a tennis racket with spin about one specific axis we cannot predict the tumbling motion .. that's weather.
What we can do is predict the arc of motion of the centre of gravity .. that's climate.
It's a no-brainer that anybody who confuses the two and hasn't put in the work to raise their understanding to intermediate axis instability is below the bar for admission to grown up climate modelling discussions.
Yet, if you're living anywhere north of Mexico City, it's almost certain that 12 weeks from now it will be much hotter than 12 weeks ago. In fact, it is such a basic knowledge that our ancestors with stone tools figured it out.
What's impressive is that some people are so invested in not understanding climate that they reject the notion that larger trends can be bloody obvious before anyone can predict day-to-day variances. (Again, a basic principle that our stone tools ancestors figured out.)
That's an apples to oranges comparison. Weather is not climate. Meteorology is not climatology.
Obviously, meteorology doesn't work over a 50-100 years time frame -- "What's the temperature on January 20th 2064 and 9PM" is an impossible question to answer. But climatologists are not attempting to answer the same question as meteorologists. They're studying a much easier variable to predict, which is averages of phenomena, where all the short-term complicated meteorological noise cancels itself out due to the law of large numbers.
> The argument generally is that warming temperatures cause rising CO2. This in turn is a fact not disputed by climate scientists, only that it is not sufficient to explain the current rise in CO2.
It should also be noted that the type of C in CO2 matters:
> In addition, only fossil fuels are consistent with the isotopic fingerprint of the carbon in today’s atmosphere. Different kinds of carbon-containing material have different relative amounts of “light” carbon-12, “heavy” carbon-13, and radioactive carbon-14. Plant matter is enriched in carbon-12, because its lighter weight is more readily used by plants during photosynthesis. Volcanic emissions are enriched in carbon-13. The ratio of carbon-13 to carbon-12 in the atmosphere and the ocean are roughly the same. Since carbon-14 is radioactive, it decays predictably over time. Young organic matter has more carbon-14 than older organic matter, and fossil fuels have no measurable carbon-14 at all.
> As carbon dioxide concentrations in the atmosphere have risen over the past century or more, the ratio of carbon-13 to carbon-12 has fallen, which means that the source of the extra carbon dioxide must be enriched in "light" carbon-12. Meanwhile, the relative amount of carbon-14—radioactive carbon—has declined. The record of carbon-14 in the atmosphere is complicated by nuclear bomb testing after 1950, which doubled the amount of radioactive carbon in the atmosphere. After the nuclear test ban treaty in 1963, the excess atmospheric carbon-14 began to decline as it dispersed into the oceans and the land biosphere.
> In this “Grand Challenges” paper, we review how the carbon isotopic composition of atmospheric CO2 has changed since the Industrial Revolution due to human activities and their influence on the natural carbon cycle, and we provide new estimates of possible future changes for a range of scenarios. Emissions of CO2 from fossil fuel combustion and land use change reduce the ratio of 13C/12C in atmospheric CO2 (δ13CO2). This is because 12C is preferentially assimilated during photosynthesis and δ13C in plant-derived carbon in terrestrial ecosystems and fossil fuels is lower than atmospheric δ13CO2. Emissions of CO2 from fossil fuel combustion also reduce the ratio of 14C/C in atmospheric CO2 (Δ14CO2) because 14C is absent in million-year-old fossil fuels, which have been stored for much longer than the radioactive decay time of 14C.
It's weird to me that there's no mention of silicate weathering in that article as the big negative CO2-temperature feedback. If anything CO2 levels are fighting against a warming/wetting Earth which weathers more rock and captures it... although maybe on a very long timescale
I think the figure I saw was that if human emissions stopped tomorrow, silicate weathering would get rid of the excess carbon in something on the order of 10k years.
It is a high school lab experiment to watch CO2 absorb infrared and heat up.
There is no universe in which you can dig vast amounts of carbon, burn it, and not have things warm up. There are lots of hard questions but the fundamental fact that the globe has to warm is an unavoidable conclusion.
Yeah but your high school experiment has no feedback mechanisms, no oceans, water vapor, volcanos, solar cycles, plants, and so on. You’re also not putting in 0.04% CO2 vs 0.0395% CO2 and measuring anything meaningful because the scope and scale of the Earth’s atmosphere is unfathomably larger.
If you’ve ever owned a Fish Tank or taken High School Chemistry, you’d realize that even in the most simple environments things don’t always add up in a way that seems intuitive.
Where can I go or what can I read written by credible people (not autodidacts and conspiracy theorists from the internet) that makes the case against anthro-caused climate change, and puts the arguments in context with the pro-ACCC people?
The argument generally is that warming temperatures cause rising CO2. This in turn is a fact not disputed by climate scientists, only that it is not sufficient to explain the current rise in CO2.
[1] A pro-AGW debunking of the common argument https://skepticalscience.com/co2-lags-temperature.htm