Methane and the disturbed Carbon Cycle

A look at recent studies in climate science

By Phil Harris, originally published by Cassandra’s legacy

  • May 1, 2012

“Ugo… At least I should try. If we understand sufficiently the science story, we should teach and encourage others to enquire.
The importance of the non-condensing gases becomes clearer.
Through our own intellectual struggle we occasionally find a dawning reality.
The mental act of adding modern CO2 and CH4 numbers on to that figure of Hansen & Sato’s was such a moment for me.
It also prepared me for The Kilda Basin Conjecture.
We are becoming already an exhaling ‘Kilda Basin’?
This stuff got a ‘human reaction’ from me, which might be communicable.”

Recently Ugo Bardi raised the matter of methane and the fact that compared with geological history, the present level in the atmosphere of this potent ‘greenhouse-gas’ is exceptionally high. We see methane bubbling from the arctic margins. We know the present level is around 1800 parts per billion (1.8ppm); more than 2.5-fold the pre-industrial level. We know this rise has been sudden and that most of it occurred in the 20thC up to about year 1990, and that interestingly for a rapidly oxidised molecule, this high level has been sustained, and lately has begun to increase again.  After a brief discussion with Ugo, I decided to attempt an update of my own knowledge. I needed also to integrate knowledge of methane with understanding the role of the chief non-condensing ‘greenhouse-gas’, carbon dioxide.

What I have experienced in the last few weeks has not been exactly a ‘Damascene’ moment, but as we all know, if we struggle hard enough intellectually then a new awareness of reality can dawn. Twenty and more years ago I had collected scientific papers that addressed the importance of atmospheric methane. This gas was already well understood to be part of the more general human-induced inflation of radiative forcing in the climate. We have dramatically increased the non-condensing ‘greenhouse’ gases in the earth’s atmosphere. It is a matter of fact that we experience extra radiative forcing (net trapped sunlight) because of these ‘trace’ gases released by industrialisation and in the case of methane also arising from the recent large extension of agriculture. We have for decades been able to watch the ongoing rise of carbon dioxide (CO2) measured continuously by NOAA Observatory in Hawaii. Methane (CH4), the second most important of the non-condensing gases was known to have increased even more dramatically from pre-industrial levels. All this we knew decades ago. And, already twenty years ago the ice and sediment records were beginning to tell their stories of past climates.

Where has the relevant science gone over the intervening 20 years? Can I interest you, the reader, in my recent journey of discovery, and particularly in what for me were the illuminating and I hope insightful moments?

I wrote a longer article in order to convince myself that I had sufficiently grasped the later scientific evidence and scientific arguments, and I used many quotes from and references to scientific papers: this longer article is available at the ASPO website if you want to engage more with the details. I would value additions, comments and corrections.

Toward the end of this present shorter article I draw your attention tothe ‘Kilda Conjecture’. Nisbet et al Nature 2009, see below, make the case that repeated exhalations of methane and carbon dioxide from an ancient ocean basin they name ‘Kilda’, could 55 million years ago, have kick-started the profound disorder in the carbon cycle seen in the geological record; a disorder known to have lasted about 100,000 years, the PETM. These authors draw parallels with the present extended exhalations of greenhouse gases from modern human society.

Firstly I familiarised myself again with the carbon cycle (‘sources and sinks’) and then with the way it has changed over geological time, so that I could better place in this context the vast “meta-stable” reserves of solid methane gas hydrates, otherwise known as ‘clathrates’. These are sequestered but potentially gaseous carbon deposits, which have been part of the earth’s carbon cycle for hundreds of millions years; maintained possibly continuously, if dynamically, over this unimaginably long history. More recently, clathrates have been part of a relatively stable, though oscillating, carbon cycle and climate[1]. These oscillating cycles have been ‘normal’ for a million or more years. As the climate oscillates, so does the carbon cycle along with the consequent hydrological cycle. The earth during this period has oscillated from glacial era to part-glacial era and correspondingly the sea level has gone up and down by some 120 to 130m. Our kind has become used to the latest extended warm period since the sea level last rose by about 120m about 10,000 years ago.

 We can ask, though, how the great stores of methane clathrates have interacted with climate changes not only in the last million years, but also much further back. What do we know from the records of longer geological time? Calculations have revealed that even a small fraction of the probable reserves if they were suddenly released into the atmosphere could overwhelm the photo-oxidation (OH’) capacity of the atmosphere and thereby persist for long enough to cause a great pulse of warmth from trapped sunlight. Indeed it was a long time ago, about 55 million years ago, but something like this actually seems to have happened. The result then was to initiate a disordered carbon cycle that lasted 100,000 years and a ‘thermal maximum’ climate we would not recognise – the PETM[2].

1st personal insight: comparability of the present day ‘trace’ gases with the remote geological past

During the PETM both CO2 and CH4 were maintained over millennia at very high concentrations; methane at perhaps 5 to 10-fold those of the recent pre-industrial concentrations. Numbers matter. To recapitulate; CH4 levels in the last few decades are sustained 2.5-fold higher than pre-industrial concentrations. I will return to the PETM but let me introduce another ‘moment’ that was for me one of increased clarity.

2nd: the importance of the non-condensing ‘trace’ greenhouse gases becomes clearer.

Snowball Earth and the non-condensing gases

There was, a very long time ago, a Snowball Earth; a period that ended around 635Ma. Gas hydrate releases are mentioned as one of putative positive feedback mechanisms that brought this phenomenon to an end.

[i] Hypotheses accounting for the abruptness of de-glaciation include ice albedo feedback, deep-ocean out-gassing during post-glacial oceanic overturn or methane hydrate destabilization.

Scientific discussion continues about this interesting period, but for our purposes it is worth noting the reasons why we do not have a snowball earth.

[ii]  Ample physical evidence shows that carbon dioxide (CO2) is the single most important climate-relevant greenhouse gas in Earth’s atmosphere. This is because CO2, like ozone, N2O, CH4, and chlorofluorocarbons, does not condense and precipitate from the atmosphere at current climate temperatures, whereas water vapour can and does. Non-condensing greenhouse gases, which account for 25% of the total terrestrial greenhouse effect, thus serve to provide the stable temperature structure that sustains the current levels of atmospheric water vapour and clouds via feedback processes that account for the remaining 75% of the greenhouse effect. Without the radiative forcing supplied by CO2 and the other non-condensing greenhouse gases, the terrestrial greenhouse would collapse, plunging the global climate into an icebound Earth state (emphasis added).

Methane is only a transient ‘trace’ gas, but we know that in recent decades it supplies about 20% of the extra net radiative forcing that results from ‘our’ extra greenhouse gases in the atmosphere; a significant addition to the total greenhouse effect.

3rd: the enormity of the last few decades

Glacial and Inter-Glacial Periods over the last 800,000 years

Before our present Holocene interglacial there was the previous warmer Eemian (+1°C, 125,000 years ago), and before that the also warmer Holsteinian (400,000 year ago). Greenhouse gases in the atmosphere rose then to levels similar to recent pre-industrial Holocene levels.

Figure 1 800,000 years of CO2 and CH4 concentrationscorrespond with timing of glacial/interglacial temperature fluctuations; from Hansen & Sato, 2011; Reference iv below

Personally, I only get the enormity of what has happened in the last few decades if I superimpose present CO2 and CH4 concentrations (respectively 392ppm and approximately 1800ppb[iii]) on the end of the above figure (Hansen & Sato,2011[iv]). Methane immediately after the end of the Younger Dryas event was at ~700ppb; dropped to ~600ppb by 5000 years ago; climbed to >700 again by the year 1750.)

I encourage you to re-enact my mental process and superimpose your own visualisation.

4th: comparisons over 5 million years are valid enough

A mere 5 million years ago in the Pliocene the ocean was about 25m higher than today, but temperatures were not greatly higher than those in the inter-glacial Eemian 125,000 years ago, or those just now. However, CO2 levels back then in the Pliocene were higher than in the more recent one million year glacial period; i.e. higher than pre-industrial levels in our Holocene (280ppm), but probably comparable with those of the last 10 years at 380ppm. (See discussion in Hansen & Sato, 2011 ref. iv). Quote:  

And regardless of the precise temperatures in the Pliocene, the extreme polar warmth and diminished ice sheets are consistent with the picture we painted above. Earth today, with global temperature having returned to at least the Holocene maximum, is poised to experience strong amplifying polar feedbacks in response to even modest additional global mean warming.

This is our world as it is emerging. ‘Our’ CO2, though, has the potential to go much higher than Pliocene levels, and is coupled at the same time with a sustained exceptional methane level.

….  ******  ….

I have collected a number of up-to-date studies that look at abrupt (millennial scale) warm and cold climate events that occurred both during and at the termination of the last glacial maximum. These studies consider the raised level of methane (see again Figure 1, above), that accompanied both the earlier warmer excursions and, finally, the glacial termination. The studies include an assessment of the stability of marine clathrates and whether sudden release of methane might have initiated the warm periods. Details are in my longer article located here. Despite conjectures about the ‘Clathrate Gun’ (a sudden instability of very large clathrate deposits) having initiated positive feed-back changes and thus acted as a prompt cause of rapid climate warming events, marine hydrates actually appear to have been generally stable during the glacial and inter-glacial periods of the Pleistocene. Nevertheless, clathrates over this time have been to a degree dynamic, especially in the Arctic. They either form or are released in response to changing pressure/temperature combinations as the temperatures of both ground and ocean adjust to the prevailing cooling or warming trend and as the sea level falls or rises; … I quote from my longer article:

There is much of interest discussed [refs.], but the take-home point just now might be that although past thermal shocks must have gradually de-stabilised some CH4 gas hydrates, thus both increasing chronic methane release and adding to warming events during de-glaciations, these shocks did not cause sustained runaway temperatures during the subsequent inter-glacial periods. Further methane-induced positive feedback did not happen. Vast reserves of CH4 and other near-surface carbon still remained. For example; the previous Eemian inter-glacial 125,000 years ago achieved a greater global warmth (about +1°C with reference to year 2000, according to ocean cores, see Hansen & Sato above), high enough to entail a 5m higher sea level than at present, but did not provoke a self-stoking methane/CO2 release sufficient to prevent later re-glaciation. In the last very few decades, however, humanity is administering a powerful thermal shock to a still warm inter-glacial by inducing concentrations of non-condensing greenhouse gases that are higher by a margin not seen in the past 2 – 5 million or more years.

For those readers who are interested in arctic methane and the basis for future studies, there is also in my longer article an introductory discussion of a very recent publication: “Gas Hydrate Formation and Dissipation Histories in the Northern Margin of Canada”, 2012. I have even more recently read this paper “On carbon transport and fate in the East Siberian Arctic land–shelf–atmosphere system”, 2012, which makes a strong case for future monitoring of these processes. As a ‘lay person’ I heartily endorse the authors’ case. Earlier papers by Nisbet, 2002, and Archer, 2007, are also worth reading and links are in my longer article.

….  ******  ….

5th: atmospheric methane levels, and their impacts, depend on the rate of release not on reserves

In my longer article I comment in more detail on the calculations and thesis accompanying the ‘Kilda conjecture’ published in the journal Nature Geoscience; Nisbet, 2009 [Ref V below].

Recent calculations have assessed the quantities and the rate of release that would be needed for a sustained methane-induced thermal shock to the climate, large enough to lead to a runaway effect. The present dissipation of clathrates (or other near surface organic sources of methane) to the air, is more likely to remain chronic and will probably contribute to sustaining the high man-made level of atmospheric methane, rather than, on its own, initiate runaway ‘positive feedback’. (It can be assumed that in the absence of very high sustained ‘natural’ levels, future atmospheric CH4 levels would rapidly reduce if methane release from fossil fuels was to stop.)

[v]The period between gas release events (repeat time) needs to be comparable to, or shorter than, the atmospheric residence time of the warming gas, otherwise the warming effect of one release event will fade before the next event occurs. [Emphasis added.]

The snag, though, it seems is the continuing very large man-made releases of both CH4 and CO2, particularly from remaining fossil fuels, and the raised CO2 concentrations that will continue long after most fossil fuels have been burned.

6th: requirements for a disrupted carbon cycle and sustained climate disorder can be described; for example, the Kilda conjecture

A massive climate impact, such as the start of a disordered carbon cycle of the size-order of the Paleocene/Eocene Thermal Maximum, PETM, would require a very large and sustained release of greenhouse gases.

Ibid ref V a recurrent release of greenhouse gases is therefore required to explain the much longer-term warming in the PETM. …

Even a large release from a single deep ocean clathrate deposit, perhaps if it occurred because of volcanic action unrelated to climate change, would not be enough to firstly interrupt and then promote self-sustaining disorder of the carbon cycle. I quote from my own longer article:

“In particular, single event methane releases have been examined [by Nisbet et al. ref V] as putative trigger events for a cascade leading to sustained high levels of atmospheric non-condensing gases. Single releases from sources such as ocean floor hydrates were/are not, individually, sufficiently large, nor did they recur frequently enough, to act as trigger events for subsequent self-sustaining high atmospheric concentrations, and these sources are rejected as explanations for the ‘PETM trigger’. The authors, though, identify one possible singular source of methane, the geologically brief Kilda Basin 55Ma. This basin apparently has no large modern parallel although some modern Rift Valley conditions provide qualitative parallels. The ancient Kilda Basin could have provided a single source large enough to suddenly overwhelm the atmospheric OH’ oxidising sink and thus prolong for many decades the atmospheric residence time of a massive methane release. Hence, the release could have been big enough to promote a subsequent very prolonged period of both high CO2 and CH4 concentrations. (It is possible that the Kilda Basin might have produced recurrent exhalations). Plausibly the trajectory to the inevitable PETM was begun in this way. The authors speculate:

Ibid ref V Unlike other suggested triggers, bursts of methane and carbon dioxide from Kilda could have been large enough, and could have been repeated frequently enough, to initiate the persistent global warming throughout the PETM. Could the comparable injection of modern anthropogenic emissions induce the same response from the planet? [Emphasis added.]

Remaining queries:

Thus, for now, my remaining query will be: Are ‘we’ the modern ‘Kilda Basin’?

Could ‘we’ be an initiating trigger like Kilda?

There are already signs of a disrupted carbon cycle as we lower the pH in the ocean.

Modern rising CO2 levels are rising more rapidly and changing the ocean more quickly than the slow changes recorded for the Pliocene a mere 5 million years ago when CO2 was last near 390ppm in the atmosphere. [See footnote[3] and ref[vi]]

The configuration of the continents, mountain ranges and ocean connections are different from those 55 million years ago. The PETM took (several) thousands of years to reach a maximum. We can hope our descendents are spared.

Personally I do not wish to even think about a future PETM equivalent, even if it is not imminent for a thousand years. The current human-induced mass extinction of biota and the emergence of a ‘New Climate’ are bad enough to contemplate, even with scientific caveats about uncertainty. There was a symposium in London at the Royal Society of Chemistry, Burlington House, November 2-3, 2010, and abstracts are available on-line. Presentations reviewed past Carbon Isotope Excursions, CIE’s, particularly the Palaeocene Eocene thermal maximum (PETM, 55Ma), when discussion centred on these past ‘greenhouse worlds’ and mass extinction events as analogues for future events and ecologies. I refer you to the set of symposium abstracts[4] and leave you with the safety instructions for Burlington House displayed prominently at the end of the programme ’flyer’;

If you hear the Alarm

Alarm Bells are situated throughout the building and will ring continuously for an evacuation. Do not stop to collect your personal belongings.

Notes 1 – 5 were added 2012; links are not functional 2020

[1] In remote geological time carbon became sequestered in very large persistent sinks of carbonaceous rock and in petroleum and gas deposits. Weathering, tectonic movement and volcanic activity release carbon from rocks, and seepage occurs from trapped “fossil fuels” and buried organic material, but since the last 10s of millions of years, the earlier sequestration has had the net ongoing effect of a reduced carbon gas level maintained in the atmosphere. Thus, more recent geological ages have experienced much lower levels of free CO2 and CH4 than those remote epochs when the largest ancient carbon stores were laid down.

[2] PETM: Palaeocene/Eocene Thermal Maximum. Configurations of continents mountain ranges and oceans have changed since then and the world now could have a different reaction to ‘trigger events’.

[3] I refer you to recent FAQs and programmes of research on ocean acidification; here.

[4] Past CIEs and future ecologies; Burlington House, London, 2-3 November 2010 ABSTRACTS HERE

References i to vi The link to Hansen & Sato is valid. I am indebted to the authors for the use of the image in Figure 1 above: atmospheric CO2 & CH4 over 800k years. The link in Ref. vi to the Abstract is also valid

[i]  Snowball Earth termination by destabilization of equatorial permafrost methane clathrate;

Kennedy M, Mrofka D, von der Borch C. Nature, 2008 May 29; 453(7195):642-5.

[ii]   Atmospheric CO2: principal control knob governing Earth’s temperature; Lacis A.A. et al. Science. 2010 Oct 15;330 (6002):356-9.

[iii] Global atmospheric methane: budget, changes and dangers; Dlugokencky EJ, et al. Philos Transact A Math Phys Eng Sci. 2011 May 28; 369(1943):2058-72.

[iv] Paleoclimate Implications for Human-Made Climate Change, Hansen & Sato, 2011, submitted for publication. FULL PAPER

[v] Kick-starting ancient warming;  E. G. Nisbet et al.; 2009, Nature Geoscience 2, 156 – 159 (2009)

[vi] The Geological Record of Ocean Acidification, Bärbel Hönisch et al, Science2 March 2012:335 no. 6072 pp. 1058-1063 ABSTRACT

Nostalgia for 2012? Methane, Optimism, Pessimism, Low Tech and the Engineers

Nostalgia for 2012? Sounds a bit odd, but old age is like that it seems.

Reposted from

I am glad to see that my tour of the methane horizon from 2012 is still hosted by Resilience.   Nice picture they put up, by the way …

If the methane gas released each year is not destroyed at a fast enough rate by the atmosphere, it accumulates.  Prompted by Ugo Bardi it was a chance in 2012 to make an appraisal of the effects of likely upper and lower estimates of the combination of fossil fuel emissions and ‘positive feedback’ in the  natural environment, and to contemplate that key context for life ”The Carbon Cycle’. ‘Pessimism’ and ‘Optimism’, if you like. There was a lull in the CH4 accumulation when I was writing back then.

In 2012 despite the ‘Kilda Conjecture’ as a possible cause of the PETM carbon-cycle collapse about 55 million years ago, I judged that industrial civilisation’s version of the  ‘methane bomb’ was not likely to trigger a similar collapse within the human future.  The accumulation of atmospheric methane had stabilised during 2000 – 2006. Since then there has been a 9% increase but I still do not think this presages a ‘new PETM’. There remains of course within the limits of present knowledge an unknown risk  of a seriously de-stablised carbon cycle over the next centuries. Nevertheless, for now environmental ‘positive feedback’ seems a lesser part of the yearly CH4 release. Quote: “The [decadal] increase was primarily fueled by human activities—especially agriculture and fossil fuels,”   

The reality of Climate Change is ongoing, but there is more, much more, going on in the  immediate future it seems, that is also mostly promoted by industrial growth. There is a present enthusiasm in richer countries for the ‘next big thing’; the electrification of transport along with substitution for all fossil fuels via solar energy, which could perhaps enable the hydrogen economy and all the Hi-Tech to go with it. This vision is in my view arguably the most dangerous utopian fantasy yet! Net zero carbon enthusiasts please note.

Listen to the engineers! A recent key-note text is published in the anglophone world. It needed to be translated from the French. Many thanks go to Professor Chris McMahon for seeing the need and for doing it.  There is an interesting review at the publisher’s site under ‘Media’, with the link  

I hope to extend an archive of links to less well known studies such as those by Philippe Bihouix and Chris McMahon, and to sites created or read by members of a private discussion group. The site was started in response to the formation of this eclectic discussion group in what is still known as The British Isles. The site was called ‘Ecosophic Isles’ by the group. I don’t think the group do much in the way of ‘prediction’, and mostly take the reference to ‘Eco Wisdom’ with a pinch of salt!😉 There is also currently archived there a copy of a letter from some other  engineers to the UK Statutory Committee on Climate Change on the constraints surrounding electrification, which some of us found instructive.


Phil H

Natural History Museum letter to UK statutory Committee on Climate Change – June 2019 – copy

3rd June 2019

Committee on Climate Change

7 Holbein Place,



Dear Committee Members,

Re: Reaching net zero emissions in the UK by 2050

In the Committee on Climate Change’s May 2019 report1 the key conclusion is ‘that net-zero is necessary, feasible and cost-effective’. The report is laudable but we attest is only likely to be feasible if considerations are made on the resource implication of what is needed to achieve that goal.

A key component of the net zero attainment is for ‘all cars and vans to be electric by 2050’.  This further requires ‘all sales to be pure battery electric by 2035 at the latest’.  In the report the need for vehicle charging facilities and infrastructure to support this change are acknowledged, but it entirely omits the challenge of the metal resources needed to produce the vehicles that will lead to this revolution. 

There are currently 31.5 million cars on the UK roads. Between them they cover 252.5 billion miles per year2. In 2017 electric and hybrid cars accounted for about 0.2% of the UK fleet, so that clearly needs to change rapidly for this to reach 100% by 2050.  The stated challenge for all sales to be pure battery by 2035 is also a steep ask, given projections for vehicle sales, set to be around 2.5 million new vehicles per year.

Electric vehicles are resource hungry.  Although the body and chassis are largely constructed from the same materials as internal combustion engine vehicles, the drive train and fuel (comprising stored electricity in the form of batteries) demand a new range of metals.  An average battery electric vehicle with the next generation, low cobalt, NMC811 battery, will demand 6.6 kg cobalt and 8.4 kg of LCE (lithium carbonate equivalent)3.  In addition, the electric drive chain contains between 1-2 kg of neo-magnets, containing around 0.2kg neodymium and 0.03kg dysprosium.  Electric vehicles also need, on average, 90kg of copper for wiring to connect the battery and drive train.  It should be noted that a conventional car currently contains between 9 and 25 kg copper along with minor cobalt in structural steel elements and minor rare earths for the electrical systems.

To replace all these UK-based vehicles today with electric vehicles (not including the LGV and HGV fleets), assuming they use the most resource-frugal next-generation NMC 811 batteries, it would take 207,900 tonnes cobalt,  264,600 tonnes of lithium carbonate (LCE), at least 7,200 tonnes of neodymium and dysprosium, in addition to 2,362,500 tonnes copper.  This represents, just under two times the total annual world cobalt production, nearly the entire world production of neodymium, three quarters the world’s lithium production and at least half of the world’s copper production during 2018. Even ensuring the annual supply of electric vehicles only, from 2035 as pledged, will require the UK to annually import the equivalent of the entire annual cobalt needs of European industry.

If we are to extrapolate this analysis to the currently projected estimate of 2 billion cars worldwide1, based on 2018 figures, annual production would have to increase for neodymium and dysprosium by 70%, copper output would need to more than double and cobalt output would need to increase at least three and a half times for the entire period from now until 2050 to satisfy the demand.

This choice of vehicle comes with an energy cost too.  Energy costs for cobalt production are estimated at 7000-8000 kWh for every tonne of metal produced4 and for copper 9000 kWh/t5.  The rare earth energy costs are at least 3350 kWh/t6, so for the target of all 31.5 million cars that requires 22.5 TWh of power to produce the new metals for the UK fleet, amounting to 6% of the UK’s current annual electrical usage7.  Extrapolated to 2 billion cars worldwide, the energy demand for extracting and processing the metals is almost 4 times the total annual UK electrical output.

Furthermore there are serious implications for the electrical power generation in the UK needed to recharge these vehicles. Using figures published for current EVs (Nissan Leaf, Renault Zoe), driving 252.5 billion miles uses at least 63 TWh of power. This will demand a 20% increase in UK generated electricity.  If wind turbines are chosen for this extra capacity, each GW of added power capacity for new generation wind turbines uses 4700t copper, 200t neodymium and 13t dysprosium8. Data shows that wind farms in the UK operate at about 40% of their nominal capacity9, so for the 63 TWh needed annually to fuel the EV fleet, 18GW of new installed capacity is needed.  Equating to 6000 wind turbines of 3MW capacity, these demand an additional 84,600t of copper, 3600t of neodymium and 234t of dysprosium.  If we are to power all of the projected 2 billion cars at UK average usage, this requires the equivalent of a further years’ worth of total global copper supply and 10 years’ worth of global neodymium and dysprosium production to build the windfarms. The solar alternative to wind is also resource hungry; all the photovoltaic systems currently on the market are reliant on one or more raw materials classed as “critical” or “near critical” by the EU and/ or US Department of Energy 10 (high purity silicon, indium, tellurium, gallium) because of their natural scarcity or their recovery as minor-by-products of other commodities. With a capacity factor of only ~10%11, the UK would require ~72GW of photovoltaic input to fuel the EV fleet; over five times the current installed capacity. If CdTe-type photovoltaic power is used, that would consume over thirty years of current annual tellurium supply.  Both these wind turbine and solar generation options for the added electrical power generation capacity have substantial demands for steel, aluminium, cement and glass which has been highlighted by previous authors12

It is clear that our move to a lower-CO2 society and industry has a significant resource footprint, such that the availability (and price) of raw materials will likely be a major limiting factor. The UK’s industrial  and environmental strategies will depend not just on novel technologies for energy generation, but on the discovery of new mineral resources, and more efficient extraction of a greater diversity and amount of elements and minerals from our mines.  This has to be achieved while reducing the environmental impacts and energy consumption of those extractive industries. Researchers in the UK are engaged in research to do just this – the recent “Security of Supply” programme funded jointly by NERC, EPSRC, Newton and FAPESP ( focussed on improving our understanding of how particular scarce elements become concentrated in particular ore deposits, and how we can better extract them. Across the programme, our research has identified potential sources for cobalt, rare earths, tellurium and more; modelled the impacts of mining seabed resources; calculated the environmental and energy footprints of competing REE resources; piloted cobalt extraction through novel bio-processing; and developed new “deep eutectic” solvents capable of recovering a suite of metals with low energy inputs and water consumption.

This research represents the tip of the iceberg. Over the next few decades, global supply of raw materials must drastically change to accommodate not just the UK’s transformation to a low carbon economy, but the whole world’s. It is essential to have timely and sustainable supplies of raw materials in quantities greatly exceeding current global mining and processing capacity. There is space for us to look again at the our own local mineral endowment; Europe has great potential for many of these commodities but the current economics, socio-political framework and export of mining from the developed world have led the world’s mining industry to seek minerals in more permissive tracts, a move that has itself led to risks in the supply chain13.  The UK itself has potential for some of the metals needed for these new vehicles, but currently we do not have a a clear measure of that local potential.  Society needs to understand that there is a raw material cost of going green and that both new research and investment is urgently needed for us to evaluate new ways to source these, potentially considering sources much closer to where the metals are to be used. 

We would welcome the opportunity to discuss the contents of our letter with the committee and work with interested parties to build on the useful research started through the SoS MinErals programme and seek solutions for the resource supply challenge that a ‘Net Zero’ pledge raises.

Yours sincerely,

Professor Richard Herrington, Head of Earth Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD Email: (corresponding author)

Professor Adrian Boyce, Professor of Applied Geology at The Scottish Universities Environmental Research Centre

Paul Lusty, Team Leader for Ore Deposits and Commodities at British Geological Survey

Dr Bramley Murton, Associate Head of Marine Geosciences at the National Oceanography Centre

Dr Jonathan Naden, Science Coordination Team Lead of NERC SoS MinErals Programme, British Geological Society

Professor Stephen Roberts, Professor of Geology, School of Ocean and Earth Science, University of Southampton

Associate Professor Dan Smith, Applied and Environmental Geology, University of Leicester

Professor Frances Wall, Professor of Applied Mineralogy at Camborne School of Mines, University of Exeter


  1. Net Zero – The UK’s contribution to stopping global warming, 2019, report, UK Parliamentary Committee on Climate Change, London, May 2019, 275pp
  2. RAC Foundation
  3. McKinsey & Co Metals and Mining June 2018 Report
  4. Dai et al. 2018
  5. Energy Use in Copper Production, Rankin 2012
  6. Piero and Mendez (2013) 10.1007/s11837-013-0719-8
  7. Energy consumption in the UK, 2015, UK Department of Energy & Climate Change
  8. Ayman Elshkaki and T.E. Graedel, 2014, Dysprosium, the balance problem, and wind power technology, Applied Energy, 136, 548-559
  9. Energy Numbers Info
  10. Hayes & McCullough, Critical minerals: A review of elemental trends in comprehensive criticality studies, Resources Policy, V. 59, 2018
  11. Hemingway, James (2013). “Estimating generation from Feed in Tariff installations” (pdf). Energy Trends. Department of Energy & Climate Change.
  12. Vidal et al. (2013)
  13. Herrington (2013)