Climate Necessity Defense for Minnesotan Valve Turners

Unlike the Michael Foster and other co-defendants is North Dakota, the Minnesotan Valve-Turners Emily Johnston and Annette Klapstein get their chance to present the Climate Necessity Defense. From (Hat tip Science Matters)

Klapstein, a retired lawyer, said they know of one case in which a judge allowed evidence about climate change but then told the jury to disregard it.

“It looks like we’re going to be able to bring in all our experts and present our evidence of how dire climate change is, so we’re pretty excited about that,” she said.

As a retired attorney, she perhaps should have read the criteria before responding.

In an order Friday, Clearwater County District Judge Robert Tiffany said the four defendants must clear a high legal bar.

In Minnesota, Tiffany wrote, a defendant asserting a necessity defense “must show that the harm that would have resulted from obeying the law would have significantly exceeded the harm actually caused by breaking the law, there was no legal alternative to breaking the law, the defendant was in danger of imminent physical harm, and there was a direct causal connection between breaking the law and preventing the harm.

The judge said it applies “only in emergency situations where the peril is instant, overwhelming, and leaves no alternative but the conduct in question.

This appears fairly clear. The Judge lays down four criteria to be met within an overriding one of emergency situations with no alternative. It is the legal equivalent of demanding that the positive impacts of an action greatly exceed the harms in very specific, very short-term, circumstances. Further, it is up to the defense to demonstrate that the circumstances apply, convincing the court in the face of cross-examinations.

There are a number of areas where I believe climate activists actions not only fails to meet these criteria, but does not even get anywhere close.

The timing issue

The emergency situations criteria are pretty immediate. An example is a police officer shooting dead a rampaging terrorist rather than maiming and performing an arrest. Another example might be destroying the car keys of someone who is drunk and intent on driving. The very short time scales of seconds or minutes exclude options that would take months or years to implement.  There are examples of where such an emergency situation does not apply to climate change policies.

If prominent climate activist Prince Charles was correct in saying in October 2009 that we have less than 100 months to save the planet, it would not have been considered an instant peril. With three months to go until the deadline, even that appears to be somewhat alarmist in the context of a lack of increase of signals of impending catastrophic consequences.

Another source is from the pinnacle of the climate establishment. The IPCC AR5 Synthesis Report gave a very rough guide to how much CO2 (or equivalent greenhouse gases) could be emitted to limit warming to less than 2°C. From 2012 it was about 1000 GtCO2e. This flowing is part of a presentation to summarize the IPCC AR5 Synthesis Report of 2014. Slide 33 of 35.

A more recent source is Miller et al 2017 Nature GeoScience. They estimate that 240 GtC (880 GtCO2e) from now will be needed to reach 1.5°C of warming. On the IPCC’s estimate then with slightly over 50GtCO2e of emissions per annum, the 2°C of warming would be reached sometime before 2032, when the climate experts are now saying the lower 1.5°C barrier will be reached sometime before 2035. Whichever you use as the barrier for breaching of dangerous climate change, that level will not be reached anytime soon according to the climate experts. There is plenty of time for a few more, tense, annual meetings with representatives of 195 nations to pontificate about mitigation policies.

So even if extreme climate alarmism is true, the expert opinion on policy strongly implies that the defendants were not “in danger of imminent physical harm”.

Finally, in 2008 the climate necessity defense was supported by James Hansen in a couple of British court cases. The detailed document prepared as written testimony for the Ratcliffe Nottingham trial is here and a 2011 commentary on the two cases by Hansen is here. As the supposed emergency in global emissions have not appeared in eight years between the testimony and the felony why should it be still considered a pressing problem? James Hansen, sometimes referred to as the Father of Climate Change after his 1988 Congressional Testimony pushed Global Warming to the fore of the political agenda, is likely to be the key witness in the necessity defence. He would have been the key witness at the trial of Micheal Foster in North Dakota last month if the necessity defense had been allowed. After the Foster Trial, Hansen wrote a long article, including arguments that will likely be presented at the Johnston and Klapstein Trail.

Indivisibility Issues

Many people in the United States believe that abortion is murder. Suppose a group managed to close down a busy abortion clinic by constant blockades and intimidation, throwing a number of people of work. An argument could be made that some of the women will not get abortions elsewhere, but will instead give birth to a child. The necessity defense criteria could, therefore, be operable. But with respect to global warming the evidence shows (and the science agrees) that it does not matter where in the world fossil fuels are burnt, the generated CO2 will be dispersed affecting the whole atmosphere. Otherwise, Eastern USA and Eastern China would have much higher concentrations of CO2 than in Africa, Antarctica or over the oceans that cover 70% of the earth’s surface.  Neither does that CO2 leave the atmosphere quickly but could remain in the atmosphere for many decades or even centuries. Therefore, the marginal impact delaying the transportation of one type of fossil fuel in one country for a few hours will have no significant impact on generations of people yet to come. As a rough estimate, the combined actions of the valve-turners (of which Micheal Foster on the Keystone Pipeline was by far the biggest contribution), was to delay the transportation of less than a million barrels of oil. That is to delay the transportation of around 1% of the daily global output of about 92 million barrels. A million barrels (140,000 tonnes) will produce around 400,000 tonnes of CO2. That is 0.4 million tonnes or 0.0004 billion tonnes. This 0.0004 GtCO2 is 0.00004% of the 1000 GtCO2e (million million) of emissions by the IPCC to breach the dangerous 2°C of warming barrier. The impact of Valve-Turners Emily Johnston and Annette Klapstein is somewhat less than this. The difference between “the harm that would have resulted from obeying the law” and “the harm actually caused by breaking the law” is infinitesimally small.

Local Harms, Wider Benefits

There is another set of harms to be considered.  That is the immediate costs of property damage and business disruption from the activists’ actions, along with the time and expense of law enforcement. Even if the action could be shown to have benefits exceeding the costs, for the actual persons or entities targeted that position will be reversed. So, hypothetically, if the benefits of stopping a few hundred thousand tonnes of emissions are even $100,000,000, and the immediate costs are just $1,000,000, the benefits are across the planet decades or centuries in the future and shared by tens of billions of people, whilst the costs are immediate and disproportionately borne by very few victims that the activists select. In reality, the benefits are likely far less, and the full costs somewhat more.

The catalyst effect of the action

As this was an act of climate activism, there was probably no intention that this act would stop climate change. Rather, that the act could serve as a catalyst for action to constrain emissions. It could serve as a wake-up call to policy-makers. A year later it is possible to see any impacts.

In the United States, less than a month after the valve turners did their deeds Donald Trump was elected President and subsequently has begun to rescind climate change policies. There appears to have been no impact on the Presidential elections. If it had, then criminal acts would have influenced the election, something that would have undermined the democratic process.

Another justification could be one of a catalyst for many more criminal actions. Again, there seems to be no surge in climate activism, whether through legal or illegal means does not seem to have happened. Further, lawyers might caution against using the catalyst argument in court to defend criminal acts.

So the catalyst defense (which may not be admissible under Judge Tiffany’s criteria) doesn’t seem to have worked out.

Non-exhaustion of legal policy initiatives

Judge Tiffany’s final specification was

leaves no alternative but the conduct in question.

Was there no alternative? There are two basic criteria necessary, but not sufficient, for the necessity defense to justify an otherwise illegal activity. First, that legal alternatives have been exhausted and second, that the illegal alternative has at least an expectation of being remotely effective. As already stated, the consensus believes that to prevent catastrophic climate change means permanently eliminating global greenhouse gas emissions. With respect to the burning of fossil fuels (about two-thirds of global GHG emissions), this is on the twin fronts of reducing global emissions to near zero and ensuring permanently leaving fossil fuels in the ground.

Possibilities for closing the policy gap

The global efforts to reduce global GHG emissions culminated in the Paris Agreement, written at the end of December 2015 and signed by most countries. The Adoption of the Paris Agreement proposal; Section II, Point 17 notes gives an indication of the gap between the aggregate impact of all the vague policy initiatives and the desired policy goal.

17. Notes with concern that the estimated aggregate greenhouse gas emission levels in 2025 and 2030 resulting from the intended nationally determined contributions do not fall within least-cost 2˚C scenarios but rather lead to a projected level of 55 gigatonnes in 2030, and also notes that much greater emission reduction efforts will be required than those associated with the intended nationally determined contributions in order to hold the increase in the global average temperature to below 2˚C above pre-industrial levels by reducing emissions to 40 gigatonnes or to 1.5˚C above pre-industrial levels by reducing to a level to be identified in the special report referred to in paragraph 21 below;

In a post last month I adapted a graphic produced by the UNFCCC in the run-up to Paris COP21 to show the gap between actual policy proposals and the Millar et al 2017 estimates to prevent 1.5˚C of warming being breached.

The aggregate impact of all policy ambitions if fully implemented fall a long way short of the targets. The majority is not due to the United States, or other Western Countries, failing to reduce emissions at a fast enough rate, but the developing countries increasing their emissions, rather than cutting emissions. When compared with  protests against President Trump’s policies (in a country with less than one-eighth of global emissions and a falling share of the total) there are no mass protests outside the embassies of Asian, Middle Eastern, African or South American countries, with over 80% if the global population and which collectively account for 100% of the growth in emissions between 1990 and 2012. Yet these countries have no expressed intention of reducing their emissions commensurate with the policy pathways. Criminal acts in the USA will do nothing to change this.

Leaving Fossil Fuels in the Ground

Arguments for targeting the output of Canadian tar sands include

(a) per unit of energy, it creates higher emissions than oil from say, Saudi Arabia.

(b) there are vast unproven reserves of oil in Canada that may exceed the current global proven reserves.

These aspects I will deal with in depth in a follow-up post. However, the two statements above are true. There are, however, wider policy aspects. Shutting down some of the global production of oil (and raising the price of oil) could increase the usage of coal instead. Push the price high enough and there will generate economic incentives to convert coal to liquids, a process that involves the generation of a number of times the CO2 emissions as from generating energy direct from oil alone.

The wider aspect is whether shutting down some proven reserves make available much less than the 1000 GtCO2e of emissions that would supposedly cause dangerous climate change. McGlade and Ekins 2015 (The geographical distribution of fossil fuels unused when limiting global warming to 2°C) estimate that the proven global reserves around 2900 GtCO2e. There is no clear breakdown by country, so I input their values of CO2 per unit into the BP’s estimates of global reserves of oil, gas and coal, coming up with a similar 2800 GtCO2e. These represent roughly 50 years of oil and gas supply and 120 years of coal supply at current usage rates. Taking into account other GHG emissions, to achieve the emissions target around 75% of proven reserves and 100% of any future discoveries must be left in the ground. I have produced a chart of the countries where these proven resources lie, measured in terms of CO2 produced from burning for energy.

McGlade and Ekins further estimate there are unproven but likely reserves of oil, gas and coal represent a further 8000 GtCO2e of emissions. Shutting down the Tar Sands permanently will not stop production of fossil fuels elsewhere in the world, particularly in the Middle East, Russia and other Asian countries.


There are a number of reasons that on their own ought to fail the necessity defense criteria laid down by Clearwater County District Judge Robert Tiffany last month. 

First, the climate experts at the UNIPCC, and the policy-promotors at the UNFCCC do not believe there is an imminent emergency. They estimate the threshold to dangerous climate change will not be crossed for over a decade.

Second, the cause of dangerous climate change is meant to the rise in global greenhouse levels, caused by global human greenhouse gas emissions. Shutting down fossil fuel emissions will not stop the harms in that area.

Third, the harms inflicted on the victims of the action are local, whereas any benefits in reduced emissions are global. But there is no evidence of the activists realizing this by campaigning for policy changes in other countries on anything like the level in the USA. The activist’s actions single out a particular source and are thus discriminatory.

Fourth, although the various actions on the same day stopped a vast amount of oil being moved, it was tiny in relation to oil the fossil being produced. Further, oil is only a minority source of all global greenhouse gas emissions.

Fifth, there is a large recognized global policy gap between forecast emissions if current policy proposals are fully enacted and the desired emissions pathways commensurate with 1.5°C or 2°C of warming. To meet these global pathways all countries must participate, but the evidence is that countries with over 80% of the global population have no expressed intention to get anywhere close to these policy criteria. Further, meeting the policy criteria would mean that the vast majority of proven reserves of fossil fuels are left in the group, along with any unproven reserves. Given the geographical dispersion of the proven reserves, this is not going to happen.

The principal theme that undermines the climate necessity defense is that the marginal impact of the action of shutting down a pipeline (or even a number of pipelines) is infinitesimally small compared to the required solution. For this reason, the necessity defense is still not valid even if (contrary to all the research to date) it can be proved beyond reasonable doubt that catastrophic climate changes will happen without rapid reductions in global emissions.

Kevin Marshall


The Policy Gap in Achieving the Emissions Goals

The Millar et al. 2017 has severe problems with the numbers, as my previous post suggested. But there is a more fundamental problem in achieving emissions goals. It is contained in the introductory paragraphs to an article lead author Richard Millar posted at Carbon Brief

The Paris Agreement set a long-term goal of limiting global warming to “well-below” 2C above pre-industrial levels and to pursue efforts to restrict it to 1.5C.

A key question for the upcoming rounds of the international climate negotiations, particularly when countries review their climate commitments next year, is exactly how fast would we have to cut emissions to reach these goals?

In a new paper, published in Nature Geoscience, we provide updated estimates of the remaining “carbon budget” for 1.5C. This is the total amount of CO2 emissions that we can still emit whilst limiting global average warming to 1.5C.

Our estimates suggest that we would have a remaining carbon budget equivalent to around 20 years at current emissions rates for a 2-in-3 chance of restricting end-of-century warming to below 1.5C.

This suggests that we have a little more breathing space than previously thought to achieve the 1.5C limit. However, although 1.5C is not yet a geophysical impossibility, it remains a very difficult policy challenge.

The problem is with the mixing of singular and plural statements. The third paragraph shows the problem.

In a new paper, published in Nature Geoscience, we provide updated estimates of the remaining “carbon budget” for 1.5C. This is the total amount of CO2 emissions that we can still emit whilst limiting global average warming to 1.5C.

In the first sentence, the collective “we” refers to the ten authors of the paper. That is Richard J. Millar, Jan S. Fuglestvedt, Pierre Friedlingstein, Joeri Rogelj, Michael J. Grubb, H. Damon Matthews, Ragnhild B. Skeie, Piers M. Forster, David J. Frame & Myles R. Allen.  In the second sentence, the collective “we” refers to approximately 7500 million people on the planet, who live about 195 countries. Do they speak for all the people in Russia, India, Nigeria, Iran, Iraq, China, Taiwan, North and South Korea, the United States and Australia for instance? What I would suggest is they are speaking figuratively about what they believe the world ought to be doing.

Yet the political realities are that even though most countries have signed the Paris Agreement, it does not commit them to a particular emissions pathway, nor to eliminate their emissions by a particular date. It only commits them to produce further INDC submissions every five years, along with attending meetings and making the right noises. Their INDC submissions are not scrutinized, still less sent back for “improved ambition” if they are inadequate in contributing to the aggregate global plan.

Looking at the substance of the Adoption proposal of the Paris Agreement, section II, point 17 notes gives an indication of the policy gap.

17. Notes with concern that the estimated aggregate greenhouse gas emission levels in 2025 and 2030 resulting from the intended nationally determined contributions do not fall within least-cost 2 ˚C scenarios but rather lead to a projected level of 55 gigatonnes in 2030, and also notes that much greater emission reduction efforts will be required than those associated with the intended nationally determined contributions in order to hold the increase in the global average temperature to below 2 ˚C above pre-industrial levels by reducing emissions to 40 gigatonnes or to 1.5 ˚C above pre-industrial levels by reducing to a level to be identified in the special report referred to in paragraph 21 below;

But the actual scale of the gap is best seen from the centerpiece graphic of the UNFCCC Synthesis report on the aggregate effect of INDCs, prepared in the run-up to COP21 Paris. Note that this website also has all the INDC submissions in three large Pdf files.

The graphic I have updated with estimates of the policy gap with my take on revised Millar et. al 2017 policy gaps shown by red arrows.

The extent of the arrows could be debated, but will not alter the fact that Millar et. al 2017 are assuming that by adjusting the figures and assuming that they are thinking for the whole world, that the emissions objectives will be achieved. The reality is that very few countries have committed to reducing their emissions by anything like an amount consistent with even a 2°C pathway. Further, that commitment is just until 2030, not for the 70 years beyond that. There is no legally-binding commitment in the Paris Agreement for a country to reduce emissions to zero sometime before the end of the century. Further, a number of countries (including Nigeria, Togo, Saudi Arabia, Turkmenistan, Iraq and Syria) have not signed the Paris Agreement – and the United States has given notification of coming out of the Agreement. Barring huge amounts of funding or some technological miracle most developing countries, with a majority of the world population, will go on increasing their emissions for decades. This includes most of the countries who were Non-Annex Developing Countries to the 1992 Rio Declaration. Collectively they accounted for just over 100% of the global GHG emissions growth between 1990 and  2012.

As some of these Countries’ INDC Submissions clearly state, most will not sacrifice economic growth and the expectations of their people’s for the unproven dogma of politicalized academic activists in completely different cultures say that the world ought to cut emissions. They will attend climate conferences and be seen to be on a world stage, then sign meaningless agreements afterward that commit them to nothing.

As a consequence, if catastrophic anthropogenic global warming is true (like the fairies at the bottom of the garden) and climate mitigation reduction targets are achieved, the catastrophic climate change will be only slightly less catastrophic and the most extreme climate mitigation countries will be a good deal poorer. The non-policy countries will the ones better off. It is the classic free-rider problem, which results in an underprovision of those goods or services. If AGW is somewhat milder, then even these countries will be no worse off.

This is what really irritates me. I live in Britain, where the Climate Change Act 2008 has probably the most ludicrous targets in the world. That Act was meant to lead the world on climate change. The then Environment Secretary David Miliband introduced the bill with this message in March 2007.

From the graphic above COP21 Paris showed that most of the world is not following Britain’s lead. But the “climate scientists” are so stuck in their manipulated models, they forget that their models and beliefs of their peers are not the realities of the wider world. The political realities mean that reduction of CO2 emissions are net harmful to the people of Britain, both now and for future generations of Britains. The activists are just as wilfully negligent in shutting down any independent review of policy as a pharmaceutical company who would push one of its products onto the consumers without an independent evaluation of both the benefits and potential side effects.

Kevin Marshall

Nature tacitly admits the IPCC AR5 was wrong on Global Warming

There has been a lot of comment on a recent paper at nature geoscience “Emission budgets and pathways consistent with limiting warming to 1.5C” (hereafter Millar et. al 2017)

When making a case for public policy I believe that something akin to a process of due diligence should be carried out on the claims. That is the justifications ought to be scrutinized to validate the claims. With Millar et. al 2017, there are a number of issues with the make-up of the claims that (a) warming of 1.5C or greater will be achieved without policy (b) constraining the emissions  

The baseline warming

The introduction states
Average temperatures for the 2010s are currently 0.87°C above 1861–80,

A similar quote from UNIPCC AR5 WG1 SPM page 5

The total increase between the average of the 1850–1900 period and the 2003–2012 period is 0.78 [0.72 to 0.85] °C, based on the single longest dataset available.

These figures are all from the HADCRUT4 dataset. There are three areas to account for the difference of 0.09°C. Mostly it is the shorter baseline period. Also, the last three years have been influenced by a powerful and natural El-Nino, along with the IPCC using an average of the last 10 years.

The warming in the pipeline

There are valid reasons for the authors differing from the IPCC’s methodology. They start with the emissions from 1870 (even though emissions estimates go back to 1850). Also, if there is no definite finish date, it is very difficult to calculate the warming impact to date. Consider first the full sentence quoted above.

Average temperatures for the 2010s are currently 0.87°C above 1861–80, which would rise to 0.93°C should they remain at 2015 levels for the remainder of the decade.

This implies that there is some warming to come through from the impact of the higher greenhouse gas levels. This seems to be a remarkably low and over a very short time period. Of course, not all the warming since the mid-nineteenth century is from anthropogenic greenhouse gas emissions. The anthropogenic element is just guesstimated. This is show in AR5 WG1 Ch10 Page 869

More than half of the observed increase in global mean surface temperature (GMST) from 1951 to 2010 is very likely due to the observed anthropogenic increase in greenhouse gas (GHG) concentrations.

It was after 1950 when the rate largest increase in CO2 levels was experienced. From 1870 to 1950, CO2 levels rose from around 290ppm to 310ppm or 7%. From 1950 to 2010, CO2 levels rose from around 310ppm to 387ppm or 25%. Add in other GHG gases and there the human-caused warming should be 3-4 times greater in the later period than the earlier one, whereas the warming in the later period was just over twice the amount. Therefore if there is just over a 90% chance (very likely in IPCC speak) of over 50% of the warming post-1950 was human-caused, a statistical test relating to a period more than twice as long would have a lower human-caused element of the warming as being statistically significant. Even then, I view the greater than 50% statistic as being deeply flawed. Especially when post-2000, when the rate of rise in CO2 levels accelerated, whilst the rise in average temperatures dramatically slowed. There are two things that this suggests. First, the impact could be explained by rising GHG emissions being a minor element in temperature rise, with natural factors both causing some of the warming in the 1976-1998 period, then reversing, causing cooling, in the last few years. Second is that there is a darn funny lagged response of rising GHGs (especially CO2) to rises in temperature. That is the amount of warming in the pipeline has increased dramatically. If either idea has any traction then the implied warming to come of just 0.06°is a false estimate. This needs to be elaborated.

Climate Sensitivity

If a doubling of CO2 leads to 3.00°C of warming (the assumption of the IPCC in their emissions calculations), then a rise in CO2 levels from 290ppm to 398 ppm (1870 to 2014) eventually gives 1.37°C of warming. With other GHGs this figure should be around 1.80°C. Half that warming has actually occurred, and some of that is natural. So there is well over 1.0°C still to emerge. It is too late to talk about constraining warming to 1.5°C as the cause of that warming has already occurred.

The implication from the paper in claiming that 0.94°C will result from human emissions in the period 1870-2014 is to reduce the climate sensitivity estimate to around 2.0°C for a doubling of CO2, if only CO2 is considered, or around 1.5°C for a doubling of CO2, if all GHGs are taken into account. (See below) Compare this to AR5 WG1 section D.2 Quantification of Climate System Responses

The equilibrium climate sensitivity quantifies the response of the climate system to constant radiative forcing on multicentury time scales. It is defined as the change in global mean surface temperature at equilibrium that is caused by a doubling of the atmospheric CO2 concentration. Equilibrium climate sensitivity is likely in the range 1.5°C to 4.5°C (high confidence), extremely unlikely less than 1°C (high confidence), and very unlikely greater than 6°C (medium confidence).

The equilibrium climate sensitivity ECS is at the very bottom of the IPCC’s range and equilibrium climate response is reached in 5-6 years instead of mutlicentury time scales. This on top of the implied assumption that there is no net natural warming between 1870 and 2015.

How much GHG emissions?

With respect to policy, as global warming is caused by human greenhouse gas emissions, to prevent further human-caused warming requires reducing, and possibly eliminating global greenhouse emissions. In conjunction with the publication of the AR5 Synthesis report, the IPCC produced a slide show of the policy case laid out in the three vast reports. It was effectively a short summary of a summary of the synthesis report. Approaching the policy climax at slide 30 of 35:-

Apart from the policy objective in AR5 was to limit warming from 2°C, not 1.5°C, it also mentions the need to constrain GHG emissions, not CO2 emissions. Then slide 33 gives the simple policy simplified position to achieve 2°C of warming.

To the end of 2011 1900 GTCO2e of GHGs was estimated to have been emitted, whilst the estimate is around 1000 GTCO2e could be emitted until the 2°C warming was reached.

The is the highly simplified version. At the other end of the scale, AR5 WG3 Ch6 p431 has a very large table in a very small font to consider a lot of the policy options. It is reproduced below, though the resolution is much poorer than the original.

Note 3 states

For comparison of the cumulative CO2 emissions estimates assessed here with those presented in WGI AR5, an amount of 515 [445 to 585] GtC (1890 [1630 to 2150] GtCO2), was already emitted by 2011 since 1870

The top line is for the 1.5°C of warming – the most ambitious policy aim. Of note:-

  • The CO2 equivalent concentration in 2100 (ppm CO2eq ) is 430-480ppm.
  • Cumulative CO2 emissions (GtCO2) from 2011 to 2100 is 630 to 1180.
  • CO2 concentration in 2100 is 390-435ppm.
  • Peak CO2 equivalent concentration is 465-530ppm. This is higher than the 2100 concentration and if for CO2 alone with ECS = 3 would eventually produce 2.0°C to 2.6°C of warming.
  • The Probability of Exceeding 1.5 °C in 2100 is 49-86%. They had to squeeze really hard to say that 1.5°C was more than 50% likely.

Compare the above to this from the abstract of Millar et. al 2017.

If COemissions are continuously adjusted over time to limit 2100 warming to 1.5C, with ambitious non-COmitigation, net future cumulativCOemissions are unlikely to prove less than 250 GtC and unlikely greater than 540 GtC. Hence, limiting warming to 1.5C is not yet a geophysical impossibility, but is likely to require delivery on strengthened pledges for 2030 followed by challengingly deep and rapid mitigation.

They use tonnes of carbon as the unit of measure as against CO2 equivalent. The conversion factor is 3.664, so cumulative CO2 emissions need to be 870-1010 GtCO2 range. As this is to the end of 2015, not 2011 as in the IPCC report, it will be different. Subtracting 150 from the IPCC reports figures would give a range of 480 to 1030. That is, Millar et. al 2017 have reduced the emissions range by 75% to the top end of the IPCC’s range. Given the IPCC considered a range of 1.5-1.7°C of warming, this seems somewhat odd to then say it related to the lower end of the warming band, until you take into account that ECS has been reduced. But then why curtail the range of emissions instead calculating your own? It appears that again the authors are trying to squeeze a result within existing constraints.

However, this does not take into account the much higher levels of peak CO2 equivalent concentrations in table 6.3. Peak CO2 concentrations are around 75-95ppm higher than in 2100. Compare this to the green line in the central graph in Millar et. al 2017. 

 This is less than 50ppm higher than in 2100. Further in 2100 Millar et. al 2017 has CO2 levels of around 500ppm as against a mid-point of 410 in AR5. CO2 rising from 290 to 410ppm with ECS = 3.0 produced 1.50°C of warming. CO2 rising from 290 to 410ppm with ECS = 2.0 produced 1.51°C of warming. Further, this does not include the warming impact of other GHGs. To squeeze into the 1.5°C band, the mid-century overshoot in Millar et. al 2017 is much less than in AR5. This might be required in the modeling assumptions due to the very short time assumed in reaching full equilibrium climate response.

Are the authors playing games?

The figures do not appear to stack up. But then they appear to be playing around with figures, indicated by a statement in the explanation of Figure 2

Like other simple climate models, this lacks an explicit physical link between oceanic heat and carbon uptake. It allows a global feedback between temperature and carbon uptake from the atmosphere, but no direct link with net deforestation. It also treats all forcing agents equally, in the sense that a single set of climate response parameters is used in for all forcing components, despite some evidence of component-specific responses. We do not, however, attempt to calibrate the model directly against observations, using it instead to explore the implications of ranges of uncertainty in emissions, and forcing and response derived directly from the IPCC-AR5, which are derived from multiple lines of evidence and, importantly, do not depend directly on the anomalously cool temperatures observed around 2010.

That is:-

  • The model does not consider an “explicit physical link between oceanic heat and carbon uptake.” The IPCC estimated that over 90% of heat accumulation since 1970 was in the oceans. If the oceans were to belch out some of this heat at a random point in the future the 1.5°C limit will be exceeded.
  • No attempt has been made to “calibrate the model directly against observations”. Therefore there is no attempt to properly reconcile beliefs to the real world.
  • The “multiple lines of evidence” in IPCC-AR5 does not include a glaring anomaly that potentially falsifies the theory and therefore any “need” for policy at all. That is the divergence in actual temperatures trends from theory in this century.


The authors of Millar et. al 2017 have pushed out the boundaries to continue to support climate mitigation policies. To justify constraining emissions sufficient stop 1.5°C of warming the authors would appear to have

  • Assumed that all the warming since 1870 is caused by anthropogenic GHG emissions when there is not even a valid statistical test that confirms even half the warming was from this source.
  • Largely ignored any hidden heat or other long-term response to rises in GHGs.
  • Ignored the divergence between model predictions and actual temperature anomalies since around the turn of the century. This has two consequences. First, the evidence appears to strongly contradict the belief that humans are a major source of global warming and by implication dangerous climate change. Second, if it does not contradict the theory, suggests the amount of warming in the pipeline consequential on human GHG emissions has massively increased. Thus the 1.5°C warming could be breached anyway.
  • Made ECS as low as possible in the long-standing 1.5°C to 4.5°C range. Even assuming ECS is at the mid-point of the range for policy (as the IPCC has done in all its reports) means that warming will breach the 1.5°C level without any further emissions. 

The authors live in their closed academic world of models and shared beliefs. Yet the paper is being used for the continued support of mitigation policy that is both failing to get anywhere close to achieving the objectives and is massively net harmful in any countries that apply it, whether financially or politically.

Kevin Marshall

Commentary at Cliscep, Jo Nova, Daily Caller, Independent, The GWPF

Update 25/09/17 to improve formatting.