Climate Change / Global Warming Discussion

[SageBrush]

Even so, why are they not 100% certain?

A host of reasons, although my impression is that the main ones are that recordings were less robust and incomplete in the past.

And "over half" implies 51%.

No, it means no less than 50.x percent

Why not 100%?

Because other cyclical forcings are in play that over a 30 year interval may be measured as net heating or cooling. If the cycles are discounted, CO2 forcing remains. Which is not surprising in the least since the greenhouse effect of CO2 is really well understood.

 

[Swampgator]

I was responding to: "Ice ages in the past when CO2 levels were 5X higher than today" Hard to tell what time period he's talking about. He wasn't interested in learning anyway.

Projecting much?

It was 35 million years ago when CO2 levels were estimated to be around 1600 ppm and the Earth entered a major Ice age in just under 100,000 years. OK, so you got me. CO2 was only 4X current levels. Even 5 million years later CO2 levels were still about 800 ppm.

 

[Swampgator]

Because there is uncertainty in climate science. As in many areas of human understanding.


.

How so? I thought the science was settled?

 

[SageBrush]

How so? I thought the science was settled?

We are at the 'extremely likely' level of confidence.

 

[SageBrush]

We are at the 'extremely likely' level of confidence.

Some more levels of confidence:

1. It is virtually certain that you will die. Not 100% certain, so I suppose you can say that is not 'settled' either.
2. My impression of you is that it is likely that you will gain no further understanding of probability before you die ... even after I include the possibility of your immortality.

 

[SageBrush]

Let's review a little stats with an analogy:

@Swampgator shows up at an attorney's office hot to sue somebody. The attorney says "if we sue for $1,000,000 we have at least a 95% likelihood of collecting no less than $500.000

Swampgator is disgusted, and walks away from the case since he concludes that he only has a 50:50 chance of winning some uncertain amount.

 

[ggr]

You do realize IPCC is a political body? It was formed for the express purpose of forming consensus as to anthropogenic attribution to climate change.
IPCC invented that term "extremely likely"when they couldn't sound alarmist enough with the terms THEY had defined prior to writing the AR5 (see below). Even so, why are they not 100% certain? And "over half" implies 51%. Why not 100%? The IPCC is not science.

View attachment 423533

I think you're being intentionally obtuse. They are "extremely likely" that at least half of the observed warming is anthropogenic. They are not saying that it's slightly more than a coin-toss. They are saying clearly that we ARE responsible for at least a majority of the factually observed results.

I wasn't going to engage but I'll refer to the chart you posted a few pages back. Note that according to that chart, for the last 20 million years the CO2 concentration was relatively stable around 300ppm. And yet, here we are in my own lifetime looking at 415ppm. Ignore, for a second, any talk of actual climate change, and answer one question for me. Where did that CO2 come from, if not us? I'll even save you the trouble of looking it up: volcanos don't come close.

Lastly the IPCC is not a political body. It's a bunch of scientists who find themselves stuck with having to convince politicians that something needs to be done.

 

[Swampgator]

Some more levels of confidence:

1. It is virtually certain that you will die. Not 100% certain, so I suppose you can say that is not 'settled' either.
2. My impression of you is that it is likely that you will gain no further understanding of probability before you die ... even after I include the possibility of your immortality.

I feel the same about your take on this issue. I would never presume to say that about YOU, as I do not know you. Only your rather rigid stance on this issue and inability to try and understand different ideas.

If you would, please answer these 3 simple questions that might trigger some actual critical thinking:

1. Are natural CO2 emissions always in balance with natural absorption?
2. How long (in years) has the earths temperature been warming up until present day?
3. What drives atmospheric CO2 increase the most, GMT or human CO2 emissions?

Then, I would be happy to answer any 3 simple questions from you as well. That's the best way to have a discussion and keep things from degenerating into ad hominum attack.

 

[Dr. J]

That's the best way to have a discussion and keep things from degenerating into ad hominum attack.

Now THAT is hilarious!

 

[Swampgator]

I wasn't going to engage but I'll refer to the chart you posted a few pages back. Note that according to that chart, for the last 20 million years the CO2 concentration was relatively stable around 300ppm. And yet, here we are in my own lifetime looking at 415ppm. Ignore, for a second, any talk of actual climate change, and answer one question for me. Where did that CO2 come from, if not us? I'll even save you the trouble of looking it up: volcanos don't come close.

The Co2 came from natural sources, and from us. IPCC even agrees with that. When temperature increases, CO2 levels increase lagging the temperature increase. Henry's law.

Lastly the IPCC is not a political body. It's a bunch of scientists who find themselves stuck with having to convince politicians that something needs to be done.

Oh, so the United Nations is not a political body? Just a bunch of governments getting together to help the planet, right?

Manufacturing consensus: the early history of the IPCC

 

[nwdiver]

The alternative hypothesis for what? That the earth is warming? Nobody debates that. The earth has cooled and warmed in regular cycles throughout it's history.

The primary driver for cooling and warming cycles throughout history is CO2. No other observed forcing comes anywhere near sufficient to explain the swings in temperature. What's driving the warming now? It's not the sun (we checked). It's not the Earths orbit (we should be cooling). What's causing the current warming if not the 40% increase in CO2???

The Co2 came from natural sources, and from us. IPCC even agrees with that. When temperature increases, CO2 levels increase lagging the temperature increase. Henry's law.

If the CO2 increase we're observing in the atmosphere is due to outgassing from the oceans... why are CO2 levels also increasing in the oceans? Plus... you realize that the ~40B tons per year that we're adding is equivalent to ~6ppm.... right? Just basic math proves that we're emitting more than enough to cause the rise in CO2 levels we're observing.

Mass of Anthropogenic CO2 Emissions (32E12kg) / Mass of Atmosphere (5.14E18kg) = 6.22ppm

 

[Swampgator]

The primary driver for cooling and warming cycles throughout history is CO2.

Totally false. The planet has been warming for several hundred years. CO2 did not start to increase significantly until the last century.

"It's not the Earths orbit (we should be cooling)."

We are:

 

[nwdiver]

"It's not the Earths orbit (we should be cooling)."

We are:

So.... why are sea levels rising? If it's not because of thermal expansion of the oceans... what's causing them to rise?

The planet has been warming for several hundred years.

Which is it? Are we cooling or are we warming???? If CO2 isn't the primary driver then what kicked us out of the last Ice age? CO2 levels increased from ~180 to 280. If it wasn't the increased radiative forcing what was it?

 

[Swampgator]

So.... why are sea levels rising? If it's not because of thermal expansion of the oceans... what's causing them to rise?

View attachment 423575




Which is it? Are we cooling or are we warming???? If CO2 isn't the primary driver then what kicked us out of the last Ice age? CO2 levels increased from ~180 to 280. If it wasn't the increased radiative forcing what was it?

They have been rising for the past 200 years. They have a long way to go at the current rate to reach levels seen in the past.
This is a direct quote from the IPCC AR5 report:

“There is very high confidence that maximum global mean sea level during the last interglacial period (129,000 to 116,000 years ago) was, for several thousand years, at least 5 meters higher than present, and high confidence that it did not exceed 10 meters above present.”

 

[nwdiver]

They have been rising for the past 200 years. They have a long way to go at the current rate to reach levels seen in the past.
This is a direct quote from the IPCC AR5 report:

“There is very high confidence that maximum global mean sea level during the last interglacial period (129,000 to 116,000 years ago) was, for several thousand years, at least 5 meters higher than present, and high confidence that it did not exceed 10 meters above present.”

And the rise has accelerated... A LOT. So you agree the Earth is warming? So why did you say we're cooling?

"It's not the Earths orbit (we should be cooling)."

We are:

Why is the Earth warming? Why has the warming accelerated? What's the alternative hypothesis to CO2?

 

[Swampgator]

We have been cooling since the El Nino of 2016. Look at the chart I posted above. It's from the UAH satellite data. It was warming from 1980 until that time. It had been cooling from 1940s until 1980. The Earth always warms and cools in cycles for the past 4.4 billion years .
At current levels of sea rise (3mm/yr) it will take quite some time to get to get to the 5 meters higher level the IPCC referenced above.

You say sea level rise is accelerating A LOT? Here is a chart for the past 24,000 years to help you with perspective.

 

[nwdiver]

We have been cooling since the El Nino of 2016. Look at the chart I posted above. It's from the UAH satellite data. It was warming from 1980 until that time. It had been cooling from 1940s until 1980. The Earth always warms and cools in cycles for the past 4.4 billion years .
At current levels of sea rise (3mm/yr) it will take quite some time to get to get to the 5 meters higher level the IPCC referenced above.

You say sea level rise is accelerating A LOT? Here is a chart for the past 24,000 years to help you with perspective.


View attachment 423587

There has not been any cooling since 2016; If there had been then sea level rise would not be accelerating. ~90% of thermal energy goes into the oceans. If this shifts to ~93% briefly this can be misinterpreted as 'cooling' if you're only counting land temperatures.

ok... so why is sea level rise accelerating now? Why is there a steep increase in the rate of sea level rise especially in the last 50 years?

 

[Mader Levap]

The question is the current warming unusual in a historical context. The answer to that is NO

This answer is a lie.

As far I know, there is no known period in Earth's history where rise in CO2 happened with such speed and in such short time. From 280ppm to 415ppm in few hundred years? Geologically it is blink in eye.

Extremely unusual.

 

[Swampgator]

This answer is a lie.

As far I know, there is no known period in Earth's history where rise in CO2 happened with such speed and in such short time. From 280ppm to 415ppm in few hundred years? Geologically it is blink in eye.

Extremely unusual.

You are conflating two issues, but I think you know that.
As for the rapid increase in CO2, the only reason why we think this is unprecedented because we have a resolution for measurement that is much better than the historical records (reconstructions)

But there is no doubt that CO2 levels have been MUCH higher in the distant past, and do not show much correlation with temperatures overall.

 

[Swampgator]