"These go to 11" - Refuting a Common challenge to Climate Change

 Today's post is the final part of what ended up being a 3 part series on Greenhouse gas.  Our next posts will be about some other topics, as I'm sure no one wants to read about feedback anymore.  Today we will put forth and refute a classic Climate Change denier mantra.

Remember that Science and Math have no feelings, they simply are.  If reality differs from your model, you MUST adjust your model to account for this difference.  If your model accurately reflex reality then we try and build on this model to improve our understanding of what is going on.  If Climate scientists could one day discover that humans have no manageable affect on our environment it would be an incredible day.  We could use without worry, we could burn with no repercussions.  People attack scientists in the same way they attack ideologies, like physics and chemistry have some pride they are trying to protect - there is no pride however, just numbers and figures and facts.

Historical Temperature, CO₂ and Methane

I first need to make a correction to the previous post.  I stated that levels of Greenhouse gas are at an all-time high, which is technically untrue.  There are periods in earth’s past where greenhouse gasses were much higher than they are today (600+ppm) and earth’s average temperature was much higher.  For a long time CO₂ was too high to support any life, eventually settling down into what we have today.  This shows a couple CO₂ concentration models going back millions of years:

What I should have said was Greenhouse gasses are currently at an all-time high for the current glacial period, since we have started seeing 100,000 year temperature periods (Milankovitch).  This distinction does not invalidate what I wrote in the last blog post but is important later in this post.

The following graph shows change in temperature, Methane and CO₂ over the last 600,000 years

At this this scale it seems, as we expect, Greenhouse gasses and temperature are in lock step.  Even in today’s extreme case temperature change matches what we expect to find.  This data on the other hand says NOTHING about cause.  Data in itself never says anything about cause, it is simply a display of numbers.

If we scale down the above graph to only cover the 20 thousand years when temperatures make their large upswing we see something like this:

 

From this image we see that Antarctica’s temperature (from our ice core) actually increases first, then ~1000 years later CO₂ begins to rise, and finally global temperatures.  This is one of the places climate skeptics plant a huge flag – they say:

“If CO₂ and other Greenhouse gasses lag behind temperature change then you cannot say CO₂ causes climate change – climate change causes CO₂ change!”

Let’s debunk that Hot Garbage

Hopefully a couple of you, having read all my ramblings, can respond to the climate deniers statement with “… uhh what else would you expect” or “Yes and…”.  We have always admitted that the Milankovitch cycles have had a profound effect on the earth’s climate for millennia.  We are getting closer and further away from a heat source and have never claimed that CO₂ is the cause of large scale cooling and heating.  What we have said is as the earth warms, from whatever cause, it will affect things like deep ocean currents. If we think in the context of the last blog, deep ocean currents will affect the amount algae in the ocean.  As deep ocean currents change, the amount of algae in the ocean changes, then the amount of CO₂ in the atmosphere changes.  We said in our first blog post water in these currents can take up to 1000 years to resurface… matching our 1000 year lag time in CO₂ rates.  Finally we see that Global Temperature then lags CO₂ as CO₂ starts to rise and send earth’s heat back towards the surface.  All of this data matches exactly what we expect from our models.  We never said “In the past someone dumped a whole bunch of CO₂ in to the atmosphere and that caused Antarctica to heat up!”

What we have said is that the climate is a complex combination of inputs that are Amplified by Greenhouse gasses.  Remember all of the energy they add to our system comes from heat radiated from the planet earth.  Their absorption spectrums do no interact with sunlight at all – being closer to the sun would have no effect on a Greenhouse gas by itself.  The idea that parts of the earth heat up first, causing CO₂ to grow, causing sustained heating is exactly what the global warming model describes.

Imagine you had an amplifier and microphone pointed at each other.  We are going to record whatever we pick up in our mic and play it back through our amp.  If we turn the amp all the way down and then give a shout, the mic will simply record our shout. 

If we have the mic and amp some distance away and turn the amp on very low and give a shout the sound will enter the mic, come out the amp, and since the amp is so low may never make it back to the mic.  We still only record the shout.  Imagine now we start moving closer to the mic and but keep our shout the same volume.  Eventually we will get just close enough to the mic that the shout is loud enough to come out of the amp and reenter the mic.  If the amp is high enough the sound will then play back through the amp and back into the mic, over and over but at some stable volume, maybe growing slightly or waning slightly.

Now we start with our mic in the same spot, give the same shout that caused the feedback before except as the sound goes on we turn the amp up.  Now the first shout is recorded, and comes out of the amp, into the mic, out of the amp louder than the initial shout, into the mic, now louder than that previous shout—we keep turning up the amp, the sound gets louder and louder until the amp breaks or we blow a fuse!

In these examples the Milankovitch cycle is our body, getting closer or further from the microphone.  The microphone is the earth.  It receives the sound and relays that sound to the amp.  The amp is the greenhouse gas.  If we never got close enough to mic for the amp to replay the sound back strong enough nothing would ever happen.  We need the Milankovitch cycles to kick start this process.  If we always left the amp at its initial setting we would have to be very very close to the mic for the sound to build.  It may just have a couple loops and die out.  The setting of the amp, while it may not start the process, is what guarantees it continues.  It also tells us how loud the final volume will be.

For the last 600,000 years the earth has been able to turn down the amplifier.  Look at the first graph in this post; until the industrial revolution the Greenhouse gasses have always receded with the Milankovitch cycles, as you get further from the mic the amp starts to get turned down.  Now, this is not the case.  The earth cannot turn the amp down – humans are turning the amp up to 11… we are literally fighting to keep the amp as high as possible.

This also does not conclude that the earth will never be able to turn the amp down, start to remove all this excess CO₂, it did it millions of years ago maybe it can do it again – however it 100% points to trying to understand what affects this will have on our climate as the amplifier does not seem to be going anywhere. 

A Unique Departure

This part is not going to be super scientific since this blog tries to stay under 1,500 words.  I believe we are at a unique point in geological history.  In other millennia, when CO₂ was much higher, we can point to things like the sun being weaker or stronger, or the Milankovitch cycles being slightly different, or the earth’s masses all being placed differently causing the earth to be more or less reflexive; NONE of those things are shown to have a measurable effect on CO₂ currently.  We aren’t seeing unexpected radiation from the sun. The earth’s reflexivity is tracking with its temperature (it is getting lower but that is expected as the earth gets warmer).  We are seeing these huge anomalies in terms of Greenhouse gas, and average global temperature.  It will never matter whether the climate is generated via natural causes or not.  As long as humans have some appreciable effect on the climate it is worth looking into.  Our ecosystems and infrastructures have shown to be incredible fragile, why would we not want to attempt to preserve them.

Sources:

https://en.wikipedia.org/wiki/Carbon_dioxide_in_Earth's_atmosphere#/media/File:Phanerozoic_Carbon_Dioxide.png

http://www.realclimate.org/index.php/archives/2007/04/the-lag-between-temp-and-co2/

https://simpleclimate.files.wordpress.com/2012/04/figure2.jpg