Emissions, Error and Innumeracy as a Guiding Policy

World leaders are now in a cleft stick.  How to cut CO2 emissions to a level they claim to believe will limit global warming to no more than 2C, or ideally 1.5C, above pre-industrial levels, and, at the same time keep their lights on.  Until recently, keeping the lights on didn’t seem to be that much of a problem – just keep throwing subsidies at supposedly cheap renewables to make them look less expensive and let the peasants cop it sweet.  But recent events in Europe and China must have given them pause, or some of them anyway. 

The Prime Minister claims the Coalition’s commitment to 2050 net zero CO2 emissions is being driven by events beyond our control – not a warming world (which we can do nothing about) but by pressure from financial institutions and big business. If we want the investment, we are told, we have to play by their rules.  There is some merit in Morrison’s justification but, on that very basis, the net zero commitment must logically be accompanied by a total rejection of any further government subsidies or grants for emerging technologies.  If the private sector is so convinced by these technologies, let them stump up the cash.  

Following the Copenhagen conference, optimists like me (as I was back then) thought its failure might buy us some time for clearer evidence to emerge that the world isn’t warming at anything like the rate the catastrophists claim.  I should have known that, as Michael Kile recently pointed out, sophistry is the lifeblood of the alarmists and any inconvenient ‘inconvenient truth’ can be rationalised away.

We are told we must get to net zero emissions by 2050 in order to achieve the target. Which is it, by the way, 1.5C or 2C?   But we are not told anything about the scientific basis for this plan.   I wrote about this in 2015 prior to the Paris conference. What we didn’t know then, and we still don’t know, is how much CO2 globally we need to mitigate.  Well, we do know, because it’s in the latest IPCC report.  It’s just that no politician ever talks about it.

What I am about to say is quite simplistic, but bear with me, and if I have made any gross errors, please call me out.  Everything we are being offered as justification for crippling our energy, transport and agricultural sectors is simplistic – we must cut our emission to net zero by 2050 to avoid 1.5C/2C of warming –  so I make no apologies for my approach.

If CAGW were a physical law, and not just an unproven hypothesis, it would be described by an equation not a suite of speculative and wildly inaccurate computer models.  That equation would provide a value for the property known as climate sensitivity, which is simplistically defined as the temperature change resulting from a doubling of atmospheric CO2 concentration.   According to Wikipedia:

Depending on the time scale, there are two main ways to define climate sensitivity: the short-term transient climate response (TCR) and the long-term equilibrium climate sensitivity (ECS), both of which incorporate the warming from exacerbating feedback loops. They are not discrete categories, but they overlap. Sensitivity to atmospheric CO2 increases is measured in the amount of temperature change for doubling in the atmospheric CO2 concentration.

From this, it is clear that climate sensitivity is a logarithmic function.  Every unit increase in temperature requires twice as much CO2 as the previous increase.  So, if the atmospheric CO2 concentration rises from 280ppm to 560ppm (an increment of 280ppm) and this causes a 1C rise in temperature, then it will take a further 560ppm to effect a further 1C temperature increase.  In theory there is a diminishing warming return on CO2 investment.  It’s a bit like heroin.

The latest IPCC report tells us:

The equilibrium climate sensitivity is an important quantity used to estimate how the climate responds to radiative forcing. Based on multiple lines of evidence21, the very likely range of equilibrium climate sensitivity is between 2°C (high confidence) and 5°C (medium confidence). The AR6 assessed best estimate is 3°C with a likely range of 2.5°C to 4°C (high confidence), compared to 1.5°C to 4.5°C in AR5, which did not provide a best estimate.

The interesting thing about the above is that this range for ECS (3C) has not narrowed in over forty years of ‘settled science’ research.  It’s just shifted 0.5C higher on the y axis.  This is explained below:

The CMIP6 models considered in this Report have a wider range of climate sensitivity than in CMIP5 models and the AR6 assessed very likely range, which is based on multiple lines of evidence. These CMIP6 models also show a higher average climate sensitivity than CMIP5 and the AR6 assessed best estimate. The higher CMIP6 climate sensitivity values compared to CMIP5 can be traced to an amplifying cloud feedback that is larger in CMIP6 by about 20%.

I find it passing strange that 40 years of research has not understood the concept well enough to narrow the range, but yet they can adjust it by 0.5C.

ECS is not that useful for predicting what might happen if we reduce our emissions to net zero by 2050 because it refers to the steady (or equilibrium) state climate that would result after net zero has been achieved and the amplifying feedbacks (eg increased water vapour) have had a chance to kick in and do their stuff.  This, we are told, could take centuries or even millennia.  So, it’s very convenient that climate scientists have not been able to narrow the range of ECS.  It allows them to postulate a possibly scary 5C rise somewhere in the future, long after they’ll be available to explain away why this was yet another climate disaster prediction that fails to materialize.

The more useful metric is the Transient Climate Response, defined in Wikipedia as:

The transient climate response (TCR) is defined as “is the change in the global mean surface temperature, averaged over a 20-year period, centered at the time of atmospheric carbon dioxide doubling, in a climate model simulation” in which the atmospheric CO2 concentration increases at 1% per year. That estimate is generated by using shorter-term simulations. The transient response is lower than the equilibrium climate sensitivity because slower feedbacks, which exacerbate the temperature increase, take more time to respond in full to an increase in the atmospheric CO2 concentration. For instance, the deep ocean takes many centuries to reach a new steady state after a perturbation during which it continues to serve as heatsink, which cools the upper ocean. The IPCC literature assessment estimates that the TCR likely lies between 1 °C (1.8 °F) and 2.5 °C (4.5 °F).

TCR is also a logarithmic function, but one which can be verified by actual observation — and that is why it is comparatively low and more precise than ECS.  And because we are three-quarters of the way towards our first CO2 doubling since the Industrial Revolution, we already have a good indication that the real TCR lies at the bottom of that range.  The IPCC tells us we have warmed 1.07C since 1850. And since, on a logarithmic scale, the rate of warming is highest at the beginning of the period and tapers off toward the end, it’s probable that TCR is about 1.5C.  And, in order to get to another 1.5C of warming we need to add another 560ppm.

The IPCC tells us that we likely emitted 2400 GtCO2 from 1850 to 2019.   So, we know that 2400 GtCO2 emitted results in 280ppm atmospheric concentration.  Therefore, in order to get an additional 560ppm we need to emit 4800 GtCO2.  At our current rate of emission – 50Gt pa – that will take 96 years.  The warming we have already experienced, whether it be natural or man-made, has been largely beneficial.  So, it’s hard to get too fussed about a further 1.5C.  

And further to that, the reason why climate sensitivity is logarithmic is that CO2 only blocks (absorbs) a certain range of infrared wavelengths.  Various sources tell us it absorbs infrared radiation (IR) in three narrow bands of wavelengths, which are 2.7, 4.3 and 15 micrometres (µM). This means that most of the heat-producing radiation escapes it. About 8% of the available black body radiation is picked up by these “fingerprint” frequencies of CO2.

So, at some, as yet unknown, atmospheric CO2 concentration, all of these frequencies will be fully absorbed.  From that time adding more CO2 will have no effect unless solar radiation increases.  We may already have reached that point. 

To summarize my thoughts to this point, it would seem to me we have little to fear, within our lifetime, or even that of our grandchildren, from a function that decays over time.   It seems a hard sell to me, at least.

It would be much more convenient for the IPCC to have a linear function to determine the relationship between CO2 and warming.  And what do you know, they do! It’s called the Transient Climate Response to Cumulative Carbon Emissions TCRE, which is the change in globally averaged surface temperature after 1000 GtC of CO2 has been emitted.  As such, it includes not only temperature feedbacks to forcing but also the carbon cycle and carbon cycle feedbacks.  It seems odd to me that we can have both a logarithmic and a linear relationship describing the same phenomenon, but no doubt some more qualified reader can set me straight on this.  If you look at the following graph in the IPCC Summary for Policymakers.

Figure SPM.10: Near-linear relationship between cumulative CO2 emissions and the increase in global surface temperature.

You will see that the rise in temperature over the 20^th century is linear only if you homogenize the temperature record to hide the fact that the 1930s was as hot as the present and that 1998 was hotter than today.  Absent this jiggery-pokery, the temperature rise in that graph would look a lot more logarithmic. You will notice that it is described in the caption as ‘near linear’.  This is like being a bit pregnant.  In a logarithmic relationship, growth in the y axis variable will decay over time until it effectively becomes zero.  In a linear relationship, it will go on forever, and that is the impression the IPCC appears to be striving for here.  The two are chalk and cheese.  It’s either linear or it’s not.  Global warming will either stop at some point or it will go on forever.  The big question, assuming you accept the ‘science’ (which I don’t) is this: will it stop at a benign level or a dangerous level?  All the indications so far are towards the former.

I could be wrong of course, but regardless of that we are stuck with the IPCC prognostications, which tell us:

This Report reaffirms with high confidence the AR5 finding that there is a near-linear relationship between cumulative anthropogenic CO2 emissions and the global warming they cause. Each 1000 GtCO2 of cumulative CO2 emissions is assessed to likely cause a 0.27°C to 0.63°C increase in global surface temperature with a best estimate of 0.45°C41. This is a narrower range compared to AR5 and SR1.5. This quantity is referred to as the transient climate response to cumulative CO2 emissions (TCRE). This relationship implies that reaching net zero42 anthropogenic CO2 emissions is a requirement to stabilize human-induced global temperature increase at any level, but that limiting global temperature increase to a specific level would imply limiting cumulative CO2 emissions to within a carbon budget.

As I understand it the essence of this is that not all CO2 emitted remains in the atmosphere – some is absorbed into the biosphere (hence the global greening we have observed) and some into the ocean.  

So, what we are basing our emissions cuts on is a carbon budget, which is the maximum amount of CO2 we may still emit and remain under some level of global warming.

The IPCC offers a number of budgets (GtCO2) offering different probabilities of keeping below the target temperature.  In summary:

What we don’t know is what target we are aiming for and what probability we are prepared to accept.  Are we shooting for 83 per cent probability of keeping to 1.5C?  Or are we prepared to accept a 33% chance of missing that target, whichever it is?

Let’s have a look at some of these scenarios, starting with the most extreme. If we want the best chance of keeping to 1.5C, the global budget remaining to us is 300 GtCO2.  How does that compare with current emissions?  Well, right now, global emissions are 50 GtCO2 per annum.  It is highly unlikely that, given the positions of China, India, Russia and the developing world, that figure is going to come down anytime soon.  So, in six year’s time (i.e. well before 2050) we will have exhausted that budget.  The Rolls Royce option requires not only Australia but the rest of the world to get to net zero by 2027.  We can forget that pipedream.  

Let’s look at a middle ground option, say 67% probability of keeping to 2C.  This, of course, implies that we are comfortable accepting a 33% chance of exceeding 2C.   The budget is 1150 GtCO2, or roughly half of what the IPCC estimates we have emitted since 1850.  At current emission rates we will exhaust that budget in 24 years, somewhat short of 2050.   Is there any mechanism by which countries are allocated a portion of this target?  Has Australia been given any guidance as to how much CO2 it may emit as part of this grand global scheme?  I think not.

China currently emits 10 GtCO2 per annum. Since 2017, China’s emissions have been growing at 3%.  If that growth were to continue until 2030 — and why shouldn’t it, Xi Jinping having made it quite clear he will do what he wants? — and then peak, China will have emitted a total of approximately 128 GTtCO2 by 2030 and 400 GtCO2 by 2050.

The best information I can find about India is that it emitted 2.5 GtCO2 in 2016, which was up 4.7% from the previous year.  So, let’s assume a growth rate of 4% until 2050.  By 2030, India would have emitted 34 GtCO2 and by 2050, 148 GtCO2.  

So, between them India and China would have emitted 548 GtCO2 or almost half our budget of 1150 GtCO2.  By my calculations, the rest of the developing world emits 22 GtCO2 per annum.  On the basis that most of them are even less likely to cut emissions than either India or China, until 2050 they too would emit another 660 GtCO2.  Let’s say they achieve a higher renewables penetration than developed countries, let’s be optimistic and limit their contribution to say 300 GtCO2 odd.   (In fact, if the poorest countries, especially in Africa, deployed widespread solar and wind power, that might make their lives a little easier but it would not lift them out of poverty.) That does not leave a lot of the budget remaining for the developed world.  It is likely my estimate of Third World and China emissions is on the low side.  This 67% probability scenario might be achievable if all the world started to go nuclear right now, but other than that it looks totally improbable.

Even as I write, a new UN report has come out castigating developed countries for their current commitments, claiming that, even if they were to be met, we would still be on track for 2.7C warming this century.  And it seems the target is, in fact, 1.5C.   According to my reckoning above, developed countries have a budget of only roughly 300 GtCO2 from which they can draw.  Currently, by my calculations, the developed world emits roughly 16 GtCO2 per annum.  In a business-as-usual scenario they would exhaust that budget by 2040.  To attain that level of reductions would require all developed countries to virtually ‘turn off the lights’ starting today.  It is totally implausible.

And what if we opted for the 1.5C target, as is being urged?  You can see from the IPCC budget above, that the only remotely plausible option (from a carbon budget point of view) is the 17% probability one.  How will St Greta and her spellbound admirers – Pope Francis, Prince Charles et alia – receive those glad tidings?

The point I’m trying to make is that if the global elite were serious about limiting global warming – rather than redistributing global wealth – they would have developed a plan based on one of the above scenarios and apportioned the associated budget accordingly, rather than leaving it up to individual countries to determine their own targets.  The reason they haven’t done this is because they know that if they revealed the fact that the only remotely possible budgets guarantee, at best, only a 67% chance of limiting warming to 2C, their own shock troopers – the mindless acolytes that they themselves have programmed – would go ballistic. Better to just waffle about current commitments not being enough and watch eager rent-seekers and their political lap dogs mindlessly destroy our way of life.  There is nothing scientific or rigorous about this process.

According to the IPCC there is nothing magic about getting to ‘net zero by 2050’.  All they stipulate is that the carbon budgets they have detailed above should not be breached.   Being a realist, I believe that none of the budgets above have snowflake’s chance in hell of not being breached.  And I’m sure even the most starry-eyed climate zealot must realize they are highly touch-and-go.  That being the case, it seems (from the global warmist elite’s point of view) highly irresponsible to adopt such as laissez faire attitude to reductions.  If they are to pull it off, this needs to be carefully planned and managed.  Daniel Andrews couldn’t do a worse job than they seem to be doing.

Put simply, Morrison has a ‘plan’ to get to net zero emissions by 2050, but to what aim?