Rohan Stevenson

[Rohan Stevenson @RohanEarth]

@jk_rowling The genius of your characters is that they are drawn from people who actually exist. I have known Snapes, and they are the kind of white middle class elitists one finds in schools and academia. It's cultural heritage which doesn't play with a black actor no matter how talented.

[Rohan Stevenson @RohanEarth]

@AtomsksSanakan @aumuaum @samzed94535545 @JunkScience @Tan123 Not wrong. These are temperature anomalies not absolute temp.

https://t.co/5TdmyC5XuY

[Rohan Stevenson @RohanEarth]

@JVinos_Climate @Janine511484078 3 pillars of truth - evidence, logic, reason. All are required.

Stomata density is direct response to CO2 which can be calibrated. It is preserved perfectly whereas CO2 in ice cores are not.

Supposition does NOT go into it, the response is very reliable from experiment.

[Rohan Stevenson @RohanEarth]

@JVinos_Climate @Janine511484078 Oh-we are way past arguing about Anthro CC. Nor does what I say about carbon cycle impact your work. But for the same reason's I was able to change my mind about CC, I was able to change about CO2cycle.

Ice cores are problematic, and there are no good arguments against stomata.

[Rohan Stevenson @RohanEarth]

@JVinos_Climate @Janine511484078 On top of which we add our contribution. But because GPP is CO2 dependent, the biosphere responds simply as if the planet had warmed slightly more than it had. GPP draws out transient CO2, some from long term stores, and then becomes part of annual flux.

[Rohan Stevenson @RohanEarth]

@JVinos_Climate @Janine511484078 The fact is the two process that emit and capture are different. One is dependent on temp, the other on available CO2. They run at v similar rates - but not exactly the same.

Processes acting on short term variblty also act on longer term stores. This accumulates in atmosphere.

[Rohan Stevenson @RohanEarth]

@JVinos_Climate @Janine511484078 Ins: 4% human, 96% natural
Outs: 0% human, 98% natural.
Atmospheric storage difference: +2%
(Ins = Outs + Atmospheric storage difference)
Balance = Atmospheric storage difference: 2%, of which:
Humans: 2% of 4% = 0.08%
Nature: 2% of 96 % = 1.92%
where 1.92% : 0.08% = 2400%

[Rohan Stevenson @RohanEarth]

@JVinos_Climate @Janine511484078 No, nature deposits more than it withdraws.

You can see this when humans stop depositing (albeit briefly). atmospheric CO2 continues to rise.

GPP is dependent on available CO2. More CO2 = expands. That means more CO2 released when it decays. The CO2 comes from long term stores.

[Rohan Stevenson @RohanEarth]

@JVinos_Climate @Janine511484078 Well it would be because the CO2 would not have had time to diffuse would it?
Over time, the CO2 trapped in snow bubbles out or reacts as the pressures and currents within the firn layer affect its chemistry. There are papers on this...

[Rohan Stevenson @RohanEarth]

@JVinos_Climate @Janine511484078 ...only on very long time scales. We do NOT know that they ARE net sinks. We assume that because we add more CO2 that is removed. But that is faulty thinking. The biosphere can remove (or add) more than 4 times our annual contribution.

[Rohan Stevenson @RohanEarth]

@JVinos_Climate @Janine511484078 To illustrate the uncertainties surrounding carbon cycle fluxes, this paper comes out pointing out that plants are absorbing 31% more CO2 than "previously thought". It's possible that the biosphere could absorb MORE than our contribution and CO2 levels could STILL rise.

[Rohan Stevenson @RohanEarth]

@JVinos_Climate @Janine511484078 2/ Ice cores have problems with diffusion and chemical reactions esp with impurities within the firn layer. Diffusion still occurs in the ice layers as well though not as strongly.

[Rohan Stevenson @RohanEarth]

@JVinos_Climate @Janine511484078 No - THAT is not correct. You have a shared account to which you contribute 4%, although you don't take anything out. Other account holders take money out and invest it to grow the account. The biosphere is the same, as it expands it produces more CO2 keeping levels higher.

[Rohan Stevenson @RohanEarth]

@JVinos_Climate @Janine511484078 Actually that "high freq" filter means they really only show timescales of centuries rather than decades. Ice cores and stomata agree well on timing of CO2 changes but not on extent. The problem with recent changes is that CO2 mixes in the firn layer. Also reacts with impurities.

[Rohan Stevenson @RohanEarth]

@JVinos_Climate @Janine511484078 Contradiction to which other techniques? You mean ice cores? They have their faults too, arguably more severe. The core argument does not require supposition. We aren't talking about a few ppm, we are talking ~100ppm difference. Can't just hand wave that away.