Few realistic scenarios left to limit global warming to 1.5°C
No. No. No.<p>What are we doing?<p>I want to try to be kind, yet I have to admit I am growing increasingly frustrated with the nonsense being floated on a constant basis with regards to this matter.<p>Reality is never covered well by a single variable, so I won&#x27;t ascribe this to political effects.  I can&#x27;t even begin to list all the factors.  There are, for example, people and companies who are positioned to make a lot of money if the fear-mongering evolves into extreme action.  Like I said, hard to evaluate all the players and their motivations.<p>The truth about this issue is so ridiculously simple to explain and demonstrate that a high school kid with a ruler and some coaching could arrive at the inevitable conclusion:<p>We cannot affect significant change in anything that approximates a human time scale.<p>Prove it!<p>OK.  No problem.  Easy.<p>Don&#x27;t reply to my comment unless you have done the following:<p>Disclaimer:  Global warming is very real.  Deniers are delusional.  And so are zealots.  I feel like I have to proclaim this every time this is discussed because climate change has become a religion at both ends of the scale.<p>Step 1:  Go to this website...<p><a href="https:&#x2F;&#x2F;cdiac.ess-dive.lbl.gov&#x2F;trends&#x2F;co2&#x2F;ice_core_co2.html" rel="nofollow">https:&#x2F;&#x2F;cdiac.ess-dive.lbl.gov&#x2F;trends&#x2F;co2&#x2F;ice_core_co2.html</a><p>...and study this graph:<p><a href="https:&#x2F;&#x2F;cdiac.ess-dive.lbl.gov&#x2F;images&#x2F;air_bubbles_historical.jpg" rel="nofollow">https:&#x2F;&#x2F;cdiac.ess-dive.lbl.gov&#x2F;images&#x2F;air_bubbles_historical...</a><p>Focus on atmospheric CO2 and ignore the rest for now.<p>Step 2: Print the graph or open it with an image editing program of your choice.<p>Step 3: Fit lines to the down slopes on the graph; the periods of time of descending atmospheric CO2 concentration<p>Like this:<p><a href="https:&#x2F;&#x2F;i.imgur.com&#x2F;SW4tLGe.png" rel="nofollow">https:&#x2F;&#x2F;i.imgur.com&#x2F;SW4tLGe.png</a><p>Step 4: Draw vertical lines so we can estimate how long each descent phase took, like this:<p><a href="https:&#x2F;&#x2F;i.imgur.com&#x2F;37AKa8L.png" rel="nofollow">https:&#x2F;&#x2F;i.imgur.com&#x2F;37AKa8L.png</a><p>Step 5: Estimate how long each phase took.  This is what I get:<p>[80000, 25000, 33000, 40000, 50000, 60000, 50000, 100000] years<p>Step 6: Do a little math:<p>MIN: 25K years<p>MAX: 100K years<p>AVERAGE: 55K years<p>Step 6:  Think!<p>What does this mean?<p>Well, let&#x27;s start from the basis that this is highly accurate atmospheric data going back 800K years.  You can --as I did years ago-- dive into learning about why it is so accurate.  Google is your friend.<p>What does this data represent?<p>No, not the most obvious (atmospheric CO2 concentration across a very long span of time).  No, there&#x27;s something far more important and significant in there:<p>This shows us what the atmosphere and the planet did, how it behaved, WHEN HUMANS WERE NOT AROUND.  Or, if you want to be more accurate, when we were insignificant in the context of our contribution to the problem.  This is truly valuable and relevant insight.<p>What does it say?<p>It says that if humanity left the planet --if we all beamed-up to Mars and shut down all of our tech--, if we evaporated from earth tomorrow, it would take, on average, about 55000 years for atmospheric CO2 concentration to be reduced by about 100ppm.<p>Worst case:  100K years.  Best case: 25K years.<p>It also says something far more powerful:  WE CANNOT FIX THIS PROBLEM BY SUBTRACTION.<p>What do I mean by &quot;subtraction&quot;.  Shutting things down.  Not ever using petroleum for anything (which is impossible).  Going solar.  Going to wind power.  Going to 100% nuclear power.  Voluntarily destroying half the cities in the world and having half the population of the planet voluntarily commit suicide in the name of climate change.<p>Nothing --singularly or collectively-- compares favorably to the extreme case of all of humanity disappearing tomorrow.  Ergo, none of these proposals --singularly or collectively-- can perform better than the baseline case, or about 55K years for a 100ppm reduction of CO2.<p>We.  Cannot.  Fix.  This.<p>If we left the planet it would take tens of thousands of years.<p>Anyone proposing a solution that could fix the problem faster has to explain how it is they are going to improve from the no-humans-on-earth baseline while seven billion of us (and our cities, tech, etc.) are still on the planet.<p>It is pure hubris to think we can take a planetary scale process that takes tens of thousands of years and accelerate it to such a degree that the results would come in on a human time scale.  25 years?  Crazy!  50 years?  Nonsense.  100 years? Please stop.  Even a thousand years sounds insane.<p>There&#x27;s another principle here which everyone is glossing over.  And that&#x27;s the energy equation.  Without doing any math we can say that you cannot fix a problem like this with LESS energy than what it took to create it in the first place.  Impossible.  And, at a planetary scale, the mere suggestion of such a thing should have someone laughed off the stage.<p>What is far more likely to happen if we are not careful is that the zealots will push for ridiculous ideas and we are going to succeed at killing everything on the surface of this planet rather than fixing it.  Humanity&#x27;s history is full of examples of catastrophic unintended consequences such as the introduction of species A to erradicare species B from an ecosystem only to cause an even larger problem.  And we think we can engineer a rapid change of atmospheric CO2 at 1000x the natural rate?  Never mind mass extinction, I am not sure the energy and resources something like this would required is even available on earth on that time scale.<p>What to do then?<p>Start discussing this reality and have our brightest minds work on how humanity will deal with it.  In other words, work on solutions to the real problem rather than pushing religious belief in some superman-like solution.<p>This chart holds other secrets as well.  There are two very obvious questions one should ask:<p>1- What caused the increase in CO2 levels when humans were not around or insignificant?<p>2- How did CO2 decrease without human intervention?<p>The answer to the first question is easy:  Massive continental-scale fires.  While not the only contributor, it is easy to see this is just-about the only way this could have happened multiple times in 800,000 years.<p>The answer to the second question is equally simple:  Weather.  Storms.  Hurricanes.  Rain.  And the regrowth of vegetation.  These are natural carbon capture mechanism.  And, yes, they take a lot of time.  And energy.  You can&#x27;t fix a problem faster than it was created without expending more energy.  Since the energy per unit time available on earth is limited to what the sun provides, the reduction phases took longer.<p>This information is valuable because it helps us understand what we are seeing.  The planet has been reacting to atmospheric CO2 through weather.  And, in 50K to 100K years it will get things back down about 100ppm.<p>Yes, we made it worse.  We burned energy-dense materials that took millions of years to produce while consuming planetary-scale amounts of material (trees, animals, etc.) and energy from the sun.  We, effectively, released hundreds of thousands of years of CO2 in a short period of time, something that would not have happened naturally.  We now have to live with it.  We can&#x27;t fix it.<p>The earth will do what it does and we are along for the ride.<p>We need to focus on making that ride as benign to humanity as possible.  I can&#x27;t see how we can do anything else.  We are wasting valuable pretending we can fix this on a human time scale.