CO2 levels and the sun warming as it ages

[repoman]

Can anyone come up with a rough way to compare the past levels of atmospheric CO2 in the distant (million years+) past to the level of CO2 we have now and make get to with more fossil fuel burning?

I am trying to get a mostly linear relationship to say something like:

1 million years ago = "x" more ppm CO2 to have same temperature now at the sun's current output. The solar output vs time is reasonably well known and that will help to give a level of CO2 vs time for our recent preindustrial climate. I am just looking for a linear equation even if it is not as accurate as a more complex equation.

I get sick of people pulling out very old (tens or hundreds of MYA) records of high CO2 levels with mild or cold climates and saying that CO2 does not cause global warming.

 

[skepticalbip]

I don’t think you are going to find the correlation you are looking for because you seem to be starting with an incorrect assumption. CO2 is not THE greenhouse gas but A greenhouse gas. Water vapor is Earth's primary greenhouse gas with methane next in importance then there are others. Add to this that greenhouse gasses are only one of many determinants of climate and possibly a minor one compared to atmospheric and ocean circulation patterns, solar irradiance, mountain building, tectonic plate movement, plant coverage, etc., etc.

Granted, CO2 is a greenhouse gas and does affect climate but I doubt anywhere near the extent that you seem to believe. Mars would be a much warmer planet with much less day/night swings in temperature extremes if CO2 were as efficient at trapping heat as you seem to believe.

 

[Deepak]

I don’t think you are going to find the correlation you are looking for because you seem to be starting with an incorrect assumption. CO2 is not THE greenhouse gas but A greenhouse gas. Water vapor is Earth's primary greenhouse gas with methane next in importance then there are others. Add to this that greenhouse gasses are only one of many determinants of climate and possibly a minor one compared to atmospheric and ocean circulation patterns, solar irradiance, mountain building, tectonic plate movement, plant coverage, etc., etc.

Granted, CO2 is a greenhouse gas and does affect climate but I doubt anywhere near the extent that you seem to believe. Mars would be a much warmer planet with much less day/night swings in temperature extremes if CO2 were as efficient at trapping heat as you seem to believe.

How are you determining that methane is the next in importance? While in absolute terms methane has a strong contribution to the greenhouse effect, it also has quite a low half-life and concentration in the atmosphere. Water vapor is potent, not just in absolute terms but also because air is always saturated with water vapor.

I don't have figures offhand, but I seem to recall that while per-molecule methane produces an increased radiative forcing, when you look at the concentrations of gas in the atmosphere that carbon dioxide has a much larger effect.

 

[bilby]

On the scale of millions of years, continental drift is likely to have a large enough effect (via disruption of ocean circulation) to mask the other drivers of climate.

Just for one example, before the isthmus of Panama formed, the circulation pattern of the world's oceans would have been totally different from what they are with the Pacific and Atlantic circulations isolated as they are today.

 

[Perspicuo]

I don’t think you are going to find the correlation you are looking for because you seem to be starting with an incorrect assumption. CO2 is not THE greenhouse gas but A greenhouse gas. Water vapor is Earth's primary greenhouse gas with methane next in importance then there are others. Add to this that greenhouse gasses are only one of many determinants of climate and possibly a minor one compared to atmospheric and ocean circulation patterns, solar irradiance, mountain building, tectonic plate movement, plant coverage, etc., etc.

Granted, CO2 is a greenhouse gas and does affect climate but I doubt anywhere near the extent that you seem to believe. Mars would be a much warmer planet with much less day/night swings in temperature extremes if CO2 were as efficient at trapping heat as you seem to believe.

Off topic... I know I know, but my obsession insists: http://grammarist.com/usage/gases-gasses/

 

[skepticalbip]

I don’t think you are going to find the correlation you are looking for because you seem to be starting with an incorrect assumption. CO2 is not THE greenhouse gas but A greenhouse gas. Water vapor is Earth's primary greenhouse gas with methane next in importance then there are others. Add to this that greenhouse gasses are only one of many determinants of climate and possibly a minor one compared to atmospheric and ocean circulation patterns, solar irradiance, mountain building, tectonic plate movement, plant coverage, etc., etc.

Granted, CO2 is a greenhouse gas and does affect climate but I doubt anywhere near the extent that you seem to believe. Mars would be a much warmer planet with much less day/night swings in temperature extremes if CO2 were as efficient at trapping heat as you seem to believe.

Off topic... I know I know, but my obsession insists: http://grammarist.com/usage/gases-gasses/

Thank you. You taught me something today. I am always happy to learn even though grammar is low on my priority list, as is probably obvious from my posts.

 

[skepticalbip]

On the scale of millions of years, continental drift is likely to have a large enough effect (via disruption of ocean circulation) to mask the other drivers of climate.

Just for one example, before the isthmus of Panama formed, the circulation pattern of the world's oceans would have been totally different from what they are with the Pacific and Atlantic circulations isolated as they are today.

I gotta agree. Other than the Americas joining and changing ocean currents, Australia separating from Antarctica resulted in establishing a cold current around Antarctica which blocked warm currents from the equatorial regions – Antarctica developed its thick permanent ice cap locking up a great deal of Earth’s water. India colliding with Asia raised the Tibetan Plateau and Himalayas from the sea bed changing the world’s wind patterns. But continental drift also has shorter term affects on climate. It is the primary driver of volcanic activity. There are untold tons of emissions from volcanoes yearly and undersea volcanoes and vents warm deep sea waters.

The only thing I can think of that could have a greater affect on climate than continental drift is if the Sun’s output isn’t as stable over the long term as we assume. Unfortunately, variable stars are not that rare.

 

[repoman]

What i was trying to get was a correlation between the solar forcing increase of the sun vs time compared to now (the past is negative, present is zero and the future positive) to the forcing of CO2 levels compared to preindustrial.

Again, i don't care if it is even highly simplified or inaccurate.

 

[bilby]

What i was trying to get was a correlation between the solar forcing increase of the sun vs time compared to now (the past is negative, present is zero and the future positive) to the forcing of CO2 levels compared to preindustrial.

Again, i don't care if it is even highly simplified or inaccurate.

Oh, well if you don't mind highly simplified and inaccurate, then:

It was different back then to what it is now.

You're welcome.

 

[rjh01]

A good way to compare what is in the atmosphere in the past with today is to look at ice cores. These contain air bubbles trapped when the ice was formed.

 

[barbos]

Ice core does not go back enough to see solar flux change.
And methane is insignificant greenhouse gas. Most significant is water vapor and then C02.
as for sun, then yes there were less sun 2 billion years ago, but there were more C02, so yes, CO2 may have helped.

 

[Shadowy Man]

Unfortunately, variable stars are not that rare.

Well, certainly short term variability is observed in many stars, but we obviously haven't had the temporal baselines to study long-term output (centuries and up) variability in stars.

 

[fromderinside]

Unfortunately, variable stars are not that rare.

Well, certainly short term variability is observed in many stars, but we obviously haven't had the temporal baselines to study long-term output (centuries and up) variability in stars.

So you are assuming that in some trillions of trillions of view-able stars that all levels of star variability are not observable over shorter intervals and correlate-able into longer term predictions for star variability. Why the hell do we have networks of massive supercomputers then?

Yes. I understand there are limits to what I just wrote such as minimum observable variation required for observable change for very slow varying systems, but, that doesn't diminish the power of what I wrote very much when we combine multiple observations of many slow moving systems or fast varying systems for that matter. After all we do have a lot of observers.

Now back to the discussion.

 

[skepticalbip]

Unfortunately, variable stars are not that rare.

Well, certainly short term variability is observed in many stars, but we obviously haven't had the temporal baselines to study long-term output (centuries and up) variability in stars.

Absolutely. That is the reason for all the qualifiers leading up to the line you quoted. Astrophysics is a new field and there is a lot we don't know and we are finding that we were mistaken in some of what we thought we knew. We have models for how stars evolve but don't know for sure how accurate those predictions are. For example; we "knew" precisely the physics for an Ia supernova. We were so sure of our model that such supernovae were adopted as a "standard candle". Even though they may still be useful as a "standard candle" (or maybe not), the supernova, SN 2014J, this last January blew our model out of the water.

Certainly we have a model for how main sequence stars behave but, as you said, we don't centuries or millinnia of detailed observation to verify our model over the long term. I leave open the possibility that our Sun could surprise us.

 

[Underseer]

I don’t think you are going to find the correlation you are looking for because you seem to be starting with an incorrect assumption. CO2 is not THE greenhouse gas but A greenhouse gas. Water vapor is Earth's primary greenhouse gas with methane next in importance then there are others. Add to this that greenhouse gasses are only one of many determinants of climate and possibly a minor one compared to atmospheric and ocean circulation patterns, solar irradiance, mountain building, tectonic plate movement, plant coverage, etc., etc.

Granted, CO2 is a greenhouse gas and does affect climate but I doubt anywhere near the extent that you seem to believe. Mars would be a much warmer planet with much less day/night swings in temperature extremes if CO2 were as efficient at trapping heat as you seem to believe.

CO₂ is significant because it absorbs frequencies that many other greenhouse gases (such as water) let pass through.

Global temperature is a function of a lot of things, including the total amount of solar radiation, CO₂ and other things. The main problem with CO₂ is that we are dumping an awful lot of it into the atmosphere. There is no precedent for CO₂ increasing so rapidly over a sustained period of time, and unfortunately, CO₂ is part of a number of feedback loops.

We're probably a century or more from seeing any catastrophic effects, but we are at or very close to the tipping point of a runaway train that leads to catastrophic events in the future, and the longer we wait to try and fix the problem, the more expensive it will be to fix. If we start cutting back on CO₂ emissions now, we will have to cut back by much more in order to have the same impact on the environment we would have had if we started cutting back on CO₂ emissions immediately after the Kyoto Protocol was established. The longer we wait, the more we will have to cut back on CO₂ in order to achieve the same impact on the environment.

American conservolibertarians are not only making things worse for all of humanity with their lies, but they're making the problem more expensive to fix. And for what? So that they can believe in yet another wacky conspiracy theory? Don't they have enough conspiracy theories already?

 

[bleubird]

http://www.pmel.noaa.gov/co2/story/What+is+Ocean+Acidification?
Has there been a coral die off in the past?
I have seen estimates as high as 50% in the last 40 years.