What's Really Warming the World?

> As a result, if we cut our carbon foot print to zero, we are still 100% at risk of extinction from climate change.

No, not in the comparable time frames. Please do see that https://xkcd.com/1732/ if you haven't.

> we don't have the necessary understanding, and models, needed to drive it in one direction or another.

No. We know that we drive it to very fast warming with filling the atmosphere with CO2.

https://www.youtube.com/watch?v=ujkcTZZlikg&t=4m24s

> we don't have one of those models.

We do. See above. See the bloomberg article to which we comment -- the effects are confirmed with the models.

> I haven't looked recently but the literature on what might be the factor behind the cycle of warm and cold cycles is still unknown.

Or maybe you haven't looked carefully enough? The cycles are, unsurprisingly, connected to how much the Sun warms the Earth (that's not a constant):

https://www.youtube.com/watch?v=ujkcTZZlikg&t=18m05s

Milankovitch was aware and slowly calculated the periods at the times when the computers didn't exist (he started some 100 years ago) knowing the exact astronomical behavior of the Earth. Now we can do it much easier.

https://en.wikipedia.org/wiki/Milankovitch_cycles

We have less exact models the further we move in the past, but that's irrelevant. It's like complaining that you don't know who was the wife of Socrates' second uncle, and that therefore we can't talk about the son-in-law of Donald Trump. You know less the more you move in the past, but it's not the argument to ignore what's going up now.

> there isn't a climate scientist out there who has ever gone on the record to say "do this and it will 'end' global warming."

It's completely the opposite. All the IPCC messages of all the world scientists were always "cut the CO2 emissions if you don't want huge increase in the average Earth temperature so fast like it never happened in the history of Earth, you are not going to like the effects." If anything IPCC reports are made to sound less "alarming" than they should be, given what we know. The most recent:

http://www.ipcc.ch/report/ar5/wg3/

Specifically:

http://www.ipcc.ch/pdf/assessment-report/ar5/wg3/WGIIIAR5_SP...

I just watched it: It has a lot of interesting stuff on time scales of some millions or billions of years. Yup, in particular, there have been some huge swings in temperature and CO2 concentrations and big effects in weathering rocks, the pH of the oceans, what plants have to do differently in their breathing in response to big CO2 concentration changes, etc.

He wants to claim "The Biggest Control Knob: Carbon Dioxide in Earth's Climate History".

It does appear that he argued that CO2 is a big indicator of temperature changes. He brings in some surprising ideas that with big changes in temperature from whatever cause, CO2 turns out to be nearly necessarily an indicator. Okay.

But, I'm not seeing that his interesting stuff says that CO2 is a control.

He discusses two big causes of big temperature changes, and neither is CO2:

His first cause is that some many millions of years ago, the sun gave the Earth about 30% less solar energy because the sun was cooler because it was burning more hydrogen, thus, converting it to helium and later got warmer because it had more helium. He does confess that we have poor data on how much cooler the sun was. But he goes on to say that it was clear that then the Earth had liquid water, and for this it needed to have the greenhouse effect of CO2 to keep the water from freezing. So, if believe that some many millions (some billions) of years ago the sun was significantly cooler, then maybe a CO2 greenhouse effect kept some of the water from freezing. Other ways to keep the water from freezing? Maybe volcanoes, radioactive decay of rocks, asteroid strikes, dust, water vapor, methane in the atmosphere, maybe more? But, okay, maybe in an extreme situation of a few billion years ago with an Earth atmosphere with a lot of CO2 (didn't yet have plants converting CO2 to O2), maybe also methane and water vapor, maybe clouds of dust, etc. the CO2 did help warm the Earth. But here the control was the cooler sun, not the CO2.

His second cause was some effects of the Earth's orbit or some such. So, that effect caused several periods of global cooling that can be seen in the ice core samples going back 800,000 years. He states clearly that CO2 did not cause that cooling, that as he mentioned the orbit did. But then he goes on to explain how with the cooling there got to be more CO2 and, then, some warming he attributes to the extra CO2. But, again, the control was the orbit, not the CO2.

His arguments are interesting, but his case is big swings in temperature and CO2 concentrations over millions of years with lots of big effects from the sun, the Earth's orbit, volcanoes, geology (weathering of rocks), pH of the oceans, huge changes in the oceans (e.g., lots of hydrogen sulfide), etc.

He's not really talking about some significant effect of Joe's gasoline powered lawnmower on the temperature in NYC in year 2050 thus justifying carbon taxes on Joe's gasoline.

Motivation is irrelevant if he makes a valid point.

No, the theory of evolution didn't have so much push back for so long because people thought "scientists are making this up just to get more grant money". It was because it went against mainstream religious belief of the time.

I love Randall's illustrations. And to be clear I don't have any argument at all with the data that shows humans dumping lots and lots of CO2 into the air. I wish it went back 40,000 years though.

My interest is about the systemic response of the planet to heat. Not CO2, heat. Because over time the planet has gone from very hot to very cold and back again. Richard Alley in that youtube video makes this point nicely where he points out that if Ice Ages were just caused by the tilt of the planet, you would expect they would either oscillate from pole to pole, or from equator to pole. And yet they don't, they take the whole planet with them. Why?

One of the papers I read discussed the notion of water vapor and its effect on global temperatures. Its hard to get right for the models since it doesn't leave a good footprint and it is difficult to evaluate using gas bubbles in ice cores.

In the current models if you add clouds to the stratosphere you get more warming (it traps heat) if you add clouds to the troposphere you get cooling. The basis for the nuclear winter argument is the obscuring of the troposphere.

So one of the big wild cards in climate science is this, as the atmosphere warms it can hold more water vapor, that is basic physics. But if that water vapor condenses in the troposphere it cools the planet, if it condenses in the stratosphere it warms the planet. So you can start the next ice age using the existing models of climate that we've built, by assuming a large fraction of the additional water vapor becomes clouds in the troposphere. Is that the future? Or is it desertification? Or is it something else?

To reiterate, I completely agree with every climate scientist who says you won't like the result, and that is what they say. You wrote it in your comment:

"cut the CO2 emissions if you don't want huge increase in the average Earth temperature so fast like it never happened in the history of Earth, you are not going to like the effects."

But they don't say "cut the CO2 emissions and the climate will moderate to a comfortable stability." Because from a systems perspective the climate always changes. Everyone who understands the argument understands humans are destabilizing the climate, but we haven't yet figured out how the Earth is going to react to that destabilization. I agree with you that "we're not going to like it."

And I mourn that when people talk about the climate it gets immediately politicized (by both sides). The Earth is an amazing system and we have a lot to learn about it, it is a shame that talking about what we know and what we wish to know sets up such emotional debate.