Commentary #6: Global Warming

[Chadillac]

Are you aware of the fact that there was a pre-Cambrian global glaciation event 850-630 mya when atmospheric CO2 was in excess of 6000 ppm? As well as other previous and subsequent global glacial events in the presence of 4-digit CO2? This statement "That is until the last ~100 years when atmospheric CO2 levels have gone from <300 to 417 ppm. In Earth’s timeframe this is a blink of an eye and basically represents a step (sic?) change in CO2 and is the only explanation for the current sudden increase in GMST." is both silly and indicative of nothing other than a lack of geological perspective. Global Mean Surface Temperature is not related to atmospheric CO2 levels, because CO2 is not a strong greenhouse gas.

A reminder:

You're talking about a timespan of 250 million years in which there were a series of ice ages and warming periods due to huge swings in CO2. These CO2 swings were caused by cycling between extreme periods of weathering (Carbonate–silicate cycle - Wikipedia) and volcanism.

Snowball Earth – Historical Geology

Water vapor is responsible for most of the greenhouse effect, but does not cause climate change. This is due to the fact that the atmosphere is physically limited on how much water vapor it can hold (saturation vapor pressure). However, since saturation vapor pressure is temperature dependent, water vapor amplifies the warming effect caused by other greenhouse gasses.

[golftdibrad]

What the study does conclude is:

PhanDA GMST exhibits a strong relationship with atmospheric CO2 concentrations (Fig. 4), demonstrating that CO2 has been the dominant forcing controlling global climate variations across the Phanerozoic.

you are making the critical error of reading the text and not looking at their data. Their data does not conclude this.

Just a moment...

I would clarify that this study does not show a direct linear relationship between atmospheric CO2 and global mean surface temperature (GMST), but rather concludes atmospheric CO2, as opposed to things like solar luminosity, has been the dominant control for GMST changes during the Phanerozoic.

No, it shows they correlate. When the ocean warms it releases CO2. This point is not disputed. The rise in temperature almost always (outside the industrial era) precedes the rise in CO2.

[Mark Rippetoe]

You're talking about a timespan of 250 million years in which there were a series of ice ages and warming periods due to huge swings in CO2.

How do you know that CO2 was the primary factor in the warming periods? Because it fits your belief system?

Water vapor is responsible for most of the greenhouse effect, but does not cause climate change. This is due to the fact that the atmosphere is physically limited on how much water vapor it can hold (saturation vapor pressure). However, since saturation vapor pressure is temperature dependent, water vapor amplifies the warming effect caused by other greenhouse gasses.

And the other "greenhouse" gasses obviously do not affect the climate, or there would have been no global glaciation with CO2 at 6000 ppm. Therefore, climate change is dependent on extra-atmospheric phenomena. Stop watching NBC News and begin to think, please.

[golftdibrad]

You're talking about a timespan of 250 million years in which there were a series of ice ages and warming periods due to huge swings in CO2. These CO2 swings were caused by cycling between extreme periods of weathering (Carbonate–silicate cycle - Wikipedia) and volcanism.

Snowball Earth – Historical Geology

Water vapor is responsible for most of the greenhouse effect, but does not cause climate change. This is due to the fact that the atmosphere is physically limited on how much water vapor it can hold (saturation vapor pressure). However, since saturation vapor pressure is temperature dependent, water vapor amplifies the warming effect caused by other greenhouse gasses.

Congratulations, this is the most idiotic thing I have read from someone defending AGW, and I have been exposed to some stupid shit.

In one sentence you managed to state a fact, and then immediately dismiss it. You then follow up with a rudimentary explanation of psychrometrics throwing out some sciencey sounding bullshit about saturation pressure limits. We know what humidity is - the grains of water the air can carry that varies with temperature and pressure, and it varies greatly over the globe at any given time. You going to try and tell us 'the science' can say that 250m years ago we knew what the humidity was with enough precision to tease a co2 signal out of that data AND attribute the GMST changes to this (generally much higher) co2 level? I'm going to not believe that without some very convincing evidence, and everything I've seen from the AGW pushers is junk.

[Chadillac]

you are making the critical error of reading the text and not looking at their data. Their data does not conclude this.

Yes it does. The r-values from the statistical analysis are listed right above Figure 4.

Correlation Coefficient | Introduction to Statistics | JMP

No, it shows they correlate. When the ocean warms it releases CO2. This point is not disputed. The rise in temperature almost always (outside the industrial era) precedes the rise in CO2.

The Ocean is a CO2 sink and releases less CO2 than it has absorbed. Phytoplankton absorb CO2 using photosynthesis and then some of that Carbon makes its way to the Ocean floor.

Please provide a reference that concludes a rise in global temperatures almost always precedes the rise in CO2.

How do you know that CO2 was the primary factor in the warming periods? Because it fits your belief system?

And the other "greenhouse" gasses obviously do not affect the climate, or there would have been no global glaciation with CO2 at 6000 ppm. Therefore, climate change is dependent on extra-atmospheric phenomena. Stop watching NBC News and begin to think, please.

No, it's because that's what the data shows. Determining dependency on a multi-variable system is not some crazy difficult thing to do (outside of colleting the data in this case). But study after study has shown that atmospheric CO2 is the main driver for global climate variations. This is not NBC news putting these studies together.

There are other greenhouse gasses that could affect climate, but I don't think it was cow farts that got us out of the last ice age. There is just way more CO2 than methane. Adding tens of billions of tons of CO2 to the atmosphere every year can make a big difference over time.

Climate change is not solely dependent on extra-atmospheric phenomena.

3.1 Changes in Solar Output and in the Earth’s Atmosphere – Environmental Geology

Congratulations, this is the most idiotic thing I have read from someone defending AGW, and I have been exposed to some stupid shit.

In one sentence you managed to state a fact, and then immediately dismiss it. You then follow up with a rudimentary explanation of psychrometrics throwing out some sciencey sounding bullshit about saturation pressure limits. We know what humidity is - the grains of water the air can carry that varies with temperature and pressure, and it varies greatly over the globe at any given time. You going to try and tell us 'the science' can say that 250m years ago we knew what the humidity was with enough precision to tease a co2 signal out of that data AND attribute the GMST changes to this (generally much higher) co2 level? I'm going to not believe that without some very convincing evidence, and everything I've seen from the AGW pushers is junk.

Climate change and the greenhouse effect are two different things. If there is a change in the global greenhouse effect then that can cause climate change. Water vapor is the primary greenhouse contributor in our atmosphere. Without water vapor in our atmosphere, our planet would basically be frozen. However, water vapor does not drive climate change because it's concentration in our atmosphere is physically limited. You're welcome to read about this "sciency sounding bullshit" here:

Vapour pressure of water - Wikipedia

The only way water vapor could contribute to long-term climate change is if there were changes to the atmospheric pressure or temperature. That is why water vapor is not a driver for climate change but can amplify the effects. For example, a rise in atmospheric CO2 => air temperatures increase => increased water vapor in the air => even higher air temperatures.

Why do we blame climate change on carbon dioxide, when water vapor is a much more common greenhouse gas? | MIT Climate Portal

[Subby]

Water vapor is responsible for most of the greenhouse effect, but does not cause climate change.

Can you elaborate on that please? explain like I'm 7.