Commentary #6: Global Warming

[Chadillac]

https://geoweb.princeton.edu/people/..._1999_copy.pdf

They use the typical misleading trick of putting zero, ie the present, at the far left of the graph. CO2 concentration responds to temperature, not vice versa.

From your reference:

Results from various climate simulations 39,40 make it reasonable to assume that greenhouse gases have, at a global scale, contributed significantly (possibly about half, that is, 2–3 C) to the globally averaged glacial–interglacial temperature change.

Ok, temperature is simply an indication of the energy deposited and retained by the sun. We know the suns output changes, we know the orbital path of earth changes, precession changes the amount of energy absorbed. We know concentration of ions that seed clouds (ie visible water vapor) from both the sun and the cosmos changes, which will greatly affect the amount of energy the surface of earth sees (ie albedo taken as a whole).

We KNOW this energy flux varies, causes temperatures to vary, and therefore water vapor's (recall even you said its the strongest greenhouse gas) ability to warm the planet. Why again are we a) so confident that we can tease a co2 effect signal out from the historical data on all these proxy measurements over water vapor, and b) make the further leap to conclude that this weak greenhouse gas is somehow the 'control knob' of earths temperature?

Because we can see that global temperatures have increased in the last several decades despite solar luminosity decreasing:

Is the Sun causing global warming? - NASA Science

Bonus question: if we are wrong it is still historically cold even within human evolutionary history; this is not disputable. Explain to me like I'm 7 why it would be bad if it were a couple degrees warmer over the next 100 years.

Climate change is gradual. I think latest estimates are an increase in average global temperatures around 3-7 degrees F by 2100 if we don't make significant changes and continue to live as we are. These are just by personal thoughts, but I know humans are adaptable and I think our species will survive for a very long time (if we don't kill ourselves in nuclear war). I think the chances of natural disasters, droughts, and wildfires will increase. We could see the pH level of the Ocean change and a decrease in some wildlife populations. Resources could become more sparse and the cost of living would continue to increase. Basically, the I don't think the world will be as nice for our grandkids and great-grandkids. But I really haven't spent much time studying what the impacts could be.

If I was king of the world, I'd replace all coal power plants with nuclear. That alone would make a huge difference. This probably makes me a hypocrite, but I don't want to give up my gas powered cars.

From your reference #4: https://web.archive.org/web/20111022...idt_etal_1.pdf

Yep. I agree. Like I said before, "...a rise in atmospheric CO2 => air temperatures increase => increased water vapor in the air => even higher air temperatures." It's the rise in CO2 that's the initiating event which leads to increased water vapor in the air and the total greenhouse effect becomes larger.

(I didn't know the allocation remains unchanged and basically CO2 and water vapor increase at the same rate. This is something new I learned.)

[Mark Rippetoe]

Because we can see that global temperatures have increased in the last several decades despite solar luminosity decreasing:

Are you satisfied with the quality of this temperature data? The location of the recording sites doesn't bother you?

[Chadillac]

Are you satisfied with the quality of this temperature data? The location of the recording sites doesn't bother you?

I trust it, especially after ~1980 when the two curves really start to diverge.

For solar luminosity, I believe satellites are able to measure this with an extremely high level of accuracy.

For global temperature, you’ll notice in that graph they don’t use an absolute temperature. Instead, they plot temperature anomaly off of a reference point. They’re measuring temperature changes over time.

If you’re continually measuring temperature trends at the same locations all over the world, with calibrated equipment, and the data is collected and analyzed by metrologists (not to be confused with meteorologists), then yes I trust it.

When absolute temperatures are used, there is often error bars around the data representing the calculated uncertainties in the measurements.

[Mark Rippetoe]

If you’re continually measuring temperature trends at the same locations all over the world, with calibrated equipment, and the data is collected and analyzed by metrologists (not to be confused with meteorologists), then yes I trust it.

Clarify this, please.

[Subby]

The Sun hits the Earth with an incredible amount of energy [1], about equivalent to the power of 170 billion nuclear reactors

That seems to be the driver of everything then. What would happen if the power received dropped to 160 billion nuclear reactors? Or rose to 180 billion?

Some of it is lost to space

what makes it be lost to space? Does the composition of the atmosphere affect that? And what would happen if less was lost to space?

Without any greenhouses gases in our atmosphere, our Earth's average temperature would be about -4F

Why are we reducing it again?

The Earth's average temperature has steadily been increasing the last ~100 years [5].

Not in my country, in fact our regime weather service was recently caught “homogenizing” past data to show a trend upwards to the present day. Previously the temperature records did not show warming.

The vast majority of scientists believes this increase in temperature is due to the rise of CO2 from human emissions and not because of solar variation [6]. Why do they believe CO2 is the cause of this climate change instead of water vapor, if water vapor has a stronger impact on our atmosphere's greenhouse effect?

How come in your first sentence you referred to CO2 and solar emissions, then answered a question relating to water vapour and CO2 emissions?

The amount of water vapor in our atmosphere stays relatively constant and there's almost nothing we can do to change it

What happens in an ice age to the amount of water in the atmosphere? What about when you travel to tropical rainforests?

because the water vapor will condense and be out of the atmosphere in a few days

If I understand you correctly, greenhouse gases trap heat in. And Water vapour is the largest contributor to the greenhouse effect, but because it’s gone in a few days it also doesn’t change the climate? How can it do two things at once? Does heat from the Sun take longer than a few days to warm the Earth?

I obviously didn’t go to MIT so naturally I have problems understanding the science. But I’m just getting stumped on the dual nature of water vapour, how it can contribute most of the greenhouse effect, but at the same time doesn’t contribute to climate change.

[Chadillac]

Clarify this, please.

The locations you’re gathering temperature data are stationary. Anyone that has ridden a motorcycle knows temperatures can change very quickly over short distances, even when on flat ground. Elevation obviously impacts temperature, so things like weather balloons that are mobile may be somewhat useful, but would have a much higher uncertainty for trying to measure things like global temperature changes. If the location you’re gathering your temperature data from is stationary, then it would be much easier determining what may be causing biases in the data.

[Mark Rippetoe]

The locations you’re gathering temperature data are stationary. Anyone that has ridden a motorcycle knows temperatures can change very quickly over short distances, even when on flat ground.

I'm glad you understand this. Anyone who rides a motorcycle is familiar with the "Heat Island" effect. Now, if you cleverly situate your temperature collection devices to bias your regional data -- as is done all over the world -- you will show warming unrelated to atmospheric variables. This is useful to you if your funding and subsistence is derived from the pseudoscience of "climate change."