|Why the cycle before the industrial revolution.13-10-2018 01:08|
|Hi, I understand why there are massive amounts of Co2 going into the atmosphere since the industrial revolution. I understand why it collects. I understand that graph that shows the correlation between the Co2 and the temperature back 4 cycles (450,000 years). I understand why there is a correlation. I understand why our increasing the Co2 38% higher than it ever was may just increase temperatures 38% higher than they ever were after all the world ice melts (yikes - if our highs are 100 now highs might get to 138 within 1,000 years maybe - or more if we keep increasing it - ouch).|
What I do not understand is why there is a cycle before the industrial revolution.
Maybe someone can enlighten me or point me to a web page that explains this. The only thing I can think of is a momentum in the ocean water flows. I am just curious. A real simple answer is all I need. I can use it to inform a friend.
The timing of glacial advances and retreats?
A real simple answer could be misleading. It's not really that simple.
A two-word answer: Milankovich cycles.
Small changes in insolation, in sunlight. Not so much the total amount of sunlight that the Earth receives in the course of a year, but exactly how and where it is distributed. The Earth's orbit is slightly elliptical and the amount of ellipticity varies in a regular way. Slightly, about 1% to 2%. Also, the Earth's axial tilt changes in a regular way. Two ways actually, both in direction (moves all the way around) and degree (just a little).
38% higher temperature? Where did that come from? Which temperature scale?
"I understand why our increasing the Co2 38% higher than it ever was may just increase temperatures 38% higher than they ever were"
Your understanding is flawed. In my view. Or at least very different from the conventional understanding.
A website to try: https://skepticalscience.com/
A textbook (not cheap but Amazon has it) Principles of Planetary Climate by R. Pierrehumbert
Also try The Warming Papers for a historical perspective going back to 1824 (Amazon also has)
|Thanks for your answer still learning". |
The 38% is from my calculation using the attached graph which I picked up somewhere on the web. It is a very rough calc. I took 411 parts per million which I gather is the current level and subtracted the highest amount which is 300 PPM then divided the difference by 300 to get 37% this time (my prior calc may have been a tiny bit different). So it made sense to me that we have within 50 to 100 years increased it by 38%. So my layman's conclusion is that the ice is what is causing temperature to not track this percentage rise in CO2 and that once it all melts in whatever time it takes the temperature will try to correlate with this rise just like the graph has been showing over 450,000 years.
Atmospheric physicists do it differently.
You'll find references to the term "climate sensitivity."
Quoting the Wikipedia article in the subject:"The climate sensitivity specifically due to CO2 is often expressed as the temperature change in °C associated with a doubling of the concentration of carbon dioxide in Earth's atmosphere."
There's both transient and equilibrium sensitivity.
Apparently the climate sensitivity for just a CO2 doubling without any "feedbacks" is fairly easily calculated and is only about 1 degree C. Lots of feedbacks though, positive and negative with tha actual Earth. Estimates of actual climate sensitivity seem to center at about 3 degrees C, plus or minus 1.5 C. Lots of uncertainty.
Just stumbled across this site, might be worth a look:https://atmos.washington.edu/~dennis/321/
|Thank you "Still Learning". These calculations are way over my head but I am not surprised that my calcs are incorrect. It is good to know that scientists believe that once the ice melts average temperatures will not go up by as much as I was thinking. |
The irony is if all lay people thought the way I think with my limited knowledge they would rush out and buy electric cars and solar panels out of fear and maybe even pressure Gov to do even more to reduce emissions. Sadly most do not and do nothing.
In the end the solution is bringing prices down (EV batteries and solar panels and wind mills). I watch this closely and I am encouraged by what I see. This is one thing everyone can understand.
...If you notice in the graph, a decline in CO2 levels will lag thousands of years behind atmospheric cooling. If the graph were longer but for the same time frame then the discrepancy would become more obvious.
John, remember that graph is obtained via ice cores and that there are several problems with that - they tend to be averaged over a great deal of time so you do not see the intermediate peaks and valleys. Also CO2 moves out through ice fairly easily during formation so that aside from the 200 year or so running average you have charted levels significantly lower than atmospheric levels. I can't remember now but I think that I pinned it down to about 30% below atmospheric levels.
So the long term temperature averaging is REALLY long term and the long term CO2 averaging suffers from violent fluctuations from outgassing from oceanic waters due to intermittent warm periods, you also have the normal 30% higher levels than you might see if everything were constant state.
Increasing CO2 levels causes pretty quick blooms of sea life. Since Oceans cover 70% of the globe increasing plant life very rapidly pulls excess surface levels of CO2 down. Atmospheric turnover brings the higher altitude CO2 down to surface levels. Then the lower levels of CO2 do the opposite and cause this 800 year or so lag in picking up or dropping.
So while your charts are indeed informative you have always to keep a skeptical eye towards how they are being interpreted.
On the whole, plant life absorbs CO2, dies and then rots releasing (actually generating C + O2 + energy from sunlight or chemical processes) the CO2 again. This is somewhat modified by a small percentage of this rotting not being completed before the rotting is covered over and sealed from these aerobic processes. In the sea, a tiny percentage avoids any of the chemical processes or animals feeding on it and drops into the ocean's depths.
Some fairly recent papers showed that there are anaerobic processes in the depths that also generate CO2.
But the point is that a tiny percentage of CO2 gets sealed into the Earth's crust and over time has led to the reduction of CO2 on a planetwide scale. This is where coal, oil and natural gas come from - the specific anaerobic processes that occur as this is sealed in the strata. Also continental drift has effects.
What your chart shows is an increasing temperature and consequent rising CO2 levels cause plant growth. Over millennia this slowly allows the plant life to reduce the CO2 to lower and lower levels. This causes, finally, there to be an ice age. Remember that it is PLANT growth and moisture in the atmosphere and not the CO2 directly that is causing atmospheric climate. Very low levels of CO2 but no processes to allow the carbon cycle. At this low temperature there is no plant growth hence lower and lower moisture interchanged with the atmosphere. The clouds disappear. When this happens the Earth's temperature rises fairly rapidly, clouds form, CO2 is released from the upper strata of the Oceans and the entire cycle begins again.
I suppose I should write a more comprehensive and understandable version of this but what the heck. At least it gives you something to think about.
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