Category Archives: greenhouse gas emissions

Simple approximations can link emissions and temperature rise

Some simple indicators based on stylised emissions tracks help show clearly the consequences of different rates of emissions reductions.

A simple relationship allows the overall objectives – limiting temperature rises and reducing emissions – to be linked in a straightforward way[i]. Over relevant ranges and timescales temperature rise varies approximately linearly with cumulative emissions of CO2, after adjusting for the effect of other greenhouse gases.  Specifically, for every 3700 GtCO2 emitted (1000GtC) the temperature will rise by about 2.0 degrees[ii] (with estimates in the range 0.8 to 2.5 degrees)[iii].  This is the transient climate response to cumulative emissions (TCRE).

There has been around a 1.0 degree rise in temperatures to date[iv].  This means the remaining total of cumulative emissions (“carbon budget”) needs to be small enough to keep further temperature rises to around 0.5 to 1.0 degrees if it is to meet targets of limiting temperature rises to 1.5 to 2.0 degrees.

The remaining carbon budget for meeting a 1.5 degree target (with 50% probability) is around 770 GtCO2.  The remaining carbon budget for meeting a 2 degree target (again with 50% probability) is 1690 GtCO2[v].  This is illustrated in Chart 1, which shows temperature rise (median estimates) against additional emissions from 2018.

There are many uncertainties in the estimates of the remaining carbon budget.  These include different estimates of the climate sensitivity, variations in warming due non-CO2 pollutants, and the effect of additional earth system feedbacks, including melting of permafrost.  These can each change the remaining carbon budget by around 200GtCO2 or more.

Chart 1: Temperature rise from additional emissions

 

Source: adapted from Table 2.2 in http://report.ipcc.ch/sr15/pdf/sr15_chapter2.pdf

To look at the implications of this simple relationship we can make the following assumptions about future levels of emissions.  These are simplistic, but like all useful simplifications, allow the essence of the issue to be seen more clearly.

  1. Net emissions continue approximately flat at present levels (of around 42 GtCO2a.[vi]) until they start to decrease.
  2. Once net emissions start decreasing they continue decreasing linearly to reach zero – when any continuing emissions are balanced by removals of COfrom the atmosphere. They then continue at zero. There are of course many other emissions tracks leading to the same cumulative emissions.  For example, many scenarios include negative total emissions, that is net removal of carbon dioxide from the atmosphere, in the second half of the century.
  3. Relatively short-lived climate forcings, such as methane, are also greatly reduced, so that they eventually add about 0.15 degrees to warming[vii].

Chart 2 shows various temperature outcomes matched to stylised emissions tracks.  Cumulative emissions are the areas under the curvesTo limit temperatures rises to 1.5 degrees, emissions need to fall to zero by around 2050 starting in 2020, consistent with the estimates in the recent IPCC report[viii].

For limiting temperature rises to 2 degrees with 50% probability, zero emissions must be reached around 2095To reach the 2 degree target with 66% probability emissions need to be reduced to net zero about 20 years earlier – by around 2075 from a 2020 start.  |To reach a target of “well below” 2 degrees is specified in the Paris Agreement emissions must be reduced to zero sooner.

Chart 2: Stylised emissions reduction pathways for defined temperature outcomes (temperatures with 50% and 75% probability)

This simplified approach yields some useful rules of thumb.

Each decade the starting point for emissions reductions is delayed (for example from 2020 to 2030) adds 0.23 degrees to the temperature rise if the subsequent time taken to reach zero emissions is the same (same rate of decrease – i.e. same slope of the line) – see Chart 3 below. This increase is even greater if emissions increase over the decade of delay.  This is a huge effect for a relatively small difference in timing.

Delaying the time taken to get to zero emissions by a decade from the same starting date (for example reaching zero in 2070 instead of 2060) increases eventual warming by 0.11 degrees.

Correspondingly, delaying the start of emissions reductions increases the required rate of emissions reduction to meet a given temperature target.  For each decade of delay in starting emissions reductions the time available to reduce emissions to zero decreases by two decades.  For example, tarting in 2020 gives about 75 years to reduce emissions to zero for a 2 degrees target.  Starting in 2030 gives only 55 years to reduce emissions from current levels to zero once reductions have begun, a much harder task.

Chart 3: Effect of delaying emissions reductions (temperatures with 50% probability)

These results are, within the limits of the simplifications I’ve adopted, consistent with other analysis (see notes at the end for further details)[ix].

How realistic are these goals? Energy infrastructure often has a lifetime of decades, so the system is slow to change.  Consistent with this, among major European economies the best that is being achieved on a sustained basis is emissions reductions of 10-20% per decade.  While some emissions reductions may now be easier than they were, for example because the costs of renewables have fallen, deeper emissions cuts are likely to be more challenging.  This implies many decades will be required to get down to zero emissions.

All of this emphasises the need to start soon, and keep going. The recent IPCC report emphasised the challenges of meeting a 1.5 degree target.  But even the target of keeping temperature rises below 2 degrees remains immensely difficult.  There is no time to lose.

Adam Whitmore – 23rd October 2018

Notes

[i] This analysis draws on previous work by Stocker and Allen, which I covered a while back here: https://onclimatechangepolicydotorg.wordpress.com/2013/12/06/early-reductions-in-carbon-dioxide-emissions-remain-imperative/

[ii] This is the figure implied in Table 2.2 in http://report.ipcc.ch/sr15/pdf/sr15_chapter2.pdf.  All references to temperature in this post are to global mean surface temperatures (GMST).

[iii] IPCC Fifth Assessment Report, Synthesis Report, Section 2.2.4 for the range.  The central value is that which appears to have been used to construct Table 2.2 of http://report.ipcc.ch/sr15/pdf/sr15_chapter2.pdf

[iv] The IPCC quotes 0.9 degrees by 2006-2015, which is consistent with 1.0 degrees now.

[v] Table 2.2 of http://report.ipcc.ch/sr15/pdf/sr15_chapter2.pdf

[vi]  http://report.ipcc.ch/sr15/pdf/sr15_spm_final.pdfC1.3

[vii] See IPCC 1.5 degree report Chapter 2 for details.

[viii] http://report.ipcc.ch/sr15/pdf/sr15_spm_final.pdf summary for policy makers, see charts on p.6

[ix] See for example work by Climate Action Tracker https://climateactiontracker.org/global/temperatures/, and and the Stocker and Allan analysis cited as reference (i) above.  The recent IPCC report Chapter 2 Section C1, concludes:  In model pathways with no or limited overshoot of 1.5°C, global net anthropogenic CO2 emissions decline by about 45% from 2010 levels by 2030 (40–60% interquartile range), reaching net zero around 2050 (2045–2055 interquartile range). For limiting global warming to below 2°C CO2 emissions are projected to decline by about 20% by 2030 in most pathways (10–30% interquartile range) and reach net zero around 2075 (2065–2080 interquartile range). Non-CO2 emissions in pathways that limit global warming to 1.5°C show deep reductions that are similar to those in pathways limiting warming to 2°C.”  References in this paragraph to pathways limiting global warming to 2C are based on a 66% probability of staying below 2C.

 

 

Satellite data can help strengthen policy

Advancing satellite technology can improve monitoring of emissions.  This will in turn help make policies more robust.

There are now around 2000 satellites in earth orbit carrying out a wide range of tasks.  This is about twice as many as only a decade ago[i].   Costs continue to come down, technologies are advancing and more organisations are making use of data, applying new techniques as they do so.   As progress continues, satellite technologies are positioned to make a much larger contribution to monitoring greenhouse gas emissions.

Tracking what’s happening on the ground

Satellites are critical to tracking land use changes that contribute to climate change, notably deforestation.   While satellites have played an important role here for years, the increasing availability of data is enabling organisations to increase the effectiveness of their work.  For example, in recent years Global Forest Watch[ii] has greatly increased the range, timeliness and accessibility of its data on deforestation.  This in turn has enabled more rapid responses.

This is now extending to other monitoring.  For example, progress on construction projects can be tracked over time.  This enabled, for example, monitoring the construction of coal plant in China, which showed that construction of new plants was continuing[iii].

Monitoring operation and emissions

As the frequency with which satellite pictures are taken increases, it becomes possible to monitor not only construction and land use changes, but also operation of individual facilities.  For example, it is now becoming possible to track operation of coal plant, because the steam from cooling towers is visible[iv].  This can in turn allow emissions to be estimated.

More direct monitoring of emissions continues to develop.  Publicly available data at high geographic resolution on NOx, SOx, particulates and in the near future methane[v] are becoming increasingly available[vi].   For example, measuring shipping emissions has traditionally been extremely difficult, but is now becoming tractable, at least for NOx.

Measuring methane is especially important.  Methane is a powerful greenhouse gas with significant emissions from leakage in natural gas systems.  Many of these emissions can easily be avoided at relatively low cost, leading to highly cost-effective emissions reduction.

Monitoring CO2

CO2 is more difficult to measure than other pollutants, in part because it disperses and mixes in the atmosphere so rapidly.  However, some of the latest satellites have sophisticated technology able to measure CO2 concentrations very accurately[vii].  These cover only quite small areas at the moment but are expected to scale up and allow more widespread direct monitoring.  The picture below shows a narrow strip of the emissions from a coal plant in Kansas, based on data from the Orbiting Carbon Observatory 2 (OCO‐2) satellite.  These estimates conform well with reported emissions from the plant.

Figure 1:  Satellite data showing CO2 emissions for a power plant in Kansas

Note: the red arrow shows prevailing wind direction.

Space agencies around the world are now exploring how such monitoring can be taken further.  For example, the EU has now asked the European Space Agency to design a satellite dedicated to monitoring CO2.  It is expected to be operational in the 2020s.[viii]

Work is also underway to improve data analysis, so that quantities of emissions can be attributed to individual plants.  Machine learning holds a good deal of promise here as a way of finding and labelling patterns in the very large amounts of data available.  It is likely soon to be possible to monitor emissions from an individual source as small as a medium size coal plant, taking account of wind speed and direction and so forth.

Implications

These developments will make actions much more transparent and subject to inspection internationally.  Governments, scientists, energy companies, investors, academics and NGOs can monitor what is going on.  Increasingly polluters will not be able to hide their actions – they will be open for all to see.  This is turn will make it easier to bring pressure on polluters to clean up their act, potentially including, for example, holding countries to account for their Nationally Determined Contributions (NDCs) under the Paris Climate Agreement.

Improved transparency and robust data are not in themselves solutions for reducing climate change.  Instead, they play an important role in an effective policy architecture.  And the do so with ever increasing availability and quality.  This gives cause for optimism that policies and their implementation can be made increasingly robust.

Adam Whitmore – 12th September 2018

Thanks to Dave Jones for sharing his knowledge on the topic .

[i] https://www.ucsusa.org/nuclear-weapons/space-weapons/satellite-database#.W5Y-7ZNKhcA, https://allthingsnuclear.org/lgrego/new-update-of-ucs-satellite-database,

[ii] https://www.globalforestwatch.org/about

[iii] See here http://www.climatechangenews.com/2018/08/07/china-restarts-coal-plant-construction-two-year-freeze/ for examples

[iv] https://twitter.com/matthewcgray/status/1032251925515968512

[v] http://www.tropomi.eu/data-products/methane

[vi] https://www.scientificamerican.com/article/meet-the-satellites-that-can-pinpoint-methane-and-carbon-dioxide-leaks/

[vii] https://agupubs.onlinelibrary.wiley.com/doi/10.1002/2017GL074702

[viii] https://www.bbc.co.uk/news/science-environment-43926232

 

Five years on

The past five years have given many reasons for optimism about climate change

I have now been writing this blog for just over five years, and it seems timely to step back and look at how the climate change problem appears now compared with five years ago.

In some ways it is easy to feel discouraged.  In the last five years the world has managed to get through about a tenth of its remaining carbon budget, a budget that needs to last effectively forever.

However, in many ways there seem to be reasons for much greater optimism now than five years ago.  Several trends are converging that together make it appear that the worst of the risks of climate change can be avoided.

There is increasing action at the national level to reduce emissions, reinforced by the Paris Agreement …

Legislation is now in place in 164 countries, including the world’s 50 largest emitters.  There are over 1200 climate change and related laws now in place compared with 60 twenty years ago[i].  And this is not restricted to developed countries – many lower income countries are taking action.  Action at national level is being supported around the world by action in numerous cities, regions and companies.

This trend has now been reinforced by the Paris Agreement, which entered into force in November 2016, and commits the world to limiting temperature rises and reducing emissions.

There is increasing evidence of success in reducing emissions …

Many developed countries, especially in Europe, have shown since 1990 that it is possible to reduce emissions while continuing to grow their economies.  Globally, emissions of carbon dioxide from energy and industry have at least been growing more slowly over the past four years and may even have reached a plateau[ii].

Carbon pricing is spreading around the world  …

Among the many policies put in place, the growth of carbon pricing has been especially remarkable.  It has grown from a few small northern European economies 15 years ago to over 40 jurisdictions[iii].  Prices are often too low to be fully effective.  However, carbon pricing has also been shown to work spectacularly well in the right circumstances, as it has in the UK power sector.  And the presence of emissions caps in many jurisdictions gives a strong strategic signal to investors.

Investors are moving out of high carbon sources and in to lower carbon opportunities …

Companies are under increasing pressure to say how their businesses will be affected by climate change and to do something about reducing emissions.  And initiatives such as the Climate Action 100+, which includes over two hundred global investors controlling over $20 trillion of assets, are putting pressure on companies to step up their action.  This will further the trend towards increasing investment in a low carbon economy.  Meanwhile, many funds are divesting from fossil fuels, and vast amounts of capital are already going into low carbon investments.

Falling costs and increasing deployment of renewables and other low carbon technologies …

Solar and wind power and now at scale and continuing to grow very rapidly.  They are increasingly cost-competitive with fossil fuels.  The decarbonisation of the power sector thus looks likely to proceed rapidly, which will in turn enable electrification to decarbonise other sectors.  Electric vehicle sales are now growing rapidly, and expected to account for the majority of light vehicle sales within a couple of decades.  Other technologies, such as LED lighting are also progressing quickly.

This is not only making emissions reductions look achievable, it is making it clear that low carbon technologies can become cheaper than the high carbon technologies they replace, and can build whole new industries as they do.  As a reminder of just how fast things have moved, in the last five years alone, the charts here show global generation from wind and solar since 2000.

Falling costs of low carbon technologies, more than anything else, gives cause for optimism about reducing emissions.  As lower carbon alternatives become cheaper the case for high carbon technologies will simply disappear.

Charts: Global Generation from Wind and Solar 2000 – 2017

Sources:  BP Statistical Review of World Energy, Enerdata, GWEC, IEA

Climate sensitivity looks less likely to be at the high end of the range of estimates …

The climate has already warmed by about a degree Celsius, and some impacts from climate change have been greater than expected.  However, the increase in temperature in response to increasing concentrations of greenhouse gases has so far shown few signs of being towards the top end of the possible range, although we can never rule out the risk of bad surprises.

Taking these trends together there is reason to be cautiously optimistic …

There will still be serious damage from climate change – indeed some is already happening.  And it is by no means clear that the world will act as quickly as it could or should.  And there could still be some nasty surprises in the earth’s reaction to continuing emissions.  Consequently, much effort and not a little luck is still needed to avoid the worst effects of climate change.

But compared with how things were looking five years ago there seem many reasons to believe that things are beginning to move in the right direction.  The job now is to keep things moving that way, and to speed up progress.

Adam Whitmore – 10th April March 2018 

[i] http://www.lse.ac.uk/GranthamInstitute/publication/global-trends-in-climate-change-legislation-and-litigation-2017-update/

[ii] http://www.pbl.nl/sites/default/files/cms/publicaties/pbl-2017-trends-in-global-co2-and-total-greenhouse-gas-emissons-2017-report_2674.pdf

[iii] https://openknowledge.worldbank.org/handle/10986/28510

Economic growth and emissions cuts can go together

There is often said to be a trade-off between growth and decarbonisation, but the evidence shows that advanced economies can combine large emissions cuts with continuing economic growth.

Policy on greenhouse gas emissions reductions is often framed as a trade-off between greater emissions reductions and greater economic growth.  However, while emissions clearly can’t be reduced to zero immediately, faster emissions reductions can be accompanied by robust economic performance.  The clearest example of this is the UK.  Since 1990 the UK has cut its total greenhouse gas emissions much more rapidly than other G7 countries, while growing its economic output per capita more than the average.  This is illustrated in Chart 1.

Chart 1: UK per capita GDP growth and greenhouse gas emissions compared with the G7 average[i]

The extent by which the UK has cut its per capita emissions relative to other countries is emphasised in the following charts, which show that the UK has achieved by far the largest reductions in per capita CO2 emissions.

Chart 2: CO2 emissions per capita in 2016 and 1990 for G7 countries[ii]

Note: Japanese emissions rose by 0.4 tonnes per capita over the period (not shown)

Chart 3: Change in per capita and total CO2 emissions 1990 to 2016 for G7 countries

Note: Data in these charts is for CO2 only, excluding other greenhouse gases.

Of course, some of the relative changes reflect circumstances.  The UK started with relatively high emissions, including extensive use of coal in power generation.  In contrast, France already had a low carbon power sector in 1990, and in 2016 France’s per capita emissions remained about 8% below those of the UK, even though UK emissions had fallen much more from their 1990 levels.

Germany has also achieved significant reductions, having benefitted from reductions in emissions in the former East Germany and installing large amounts of renewables.  However it has been hampered by continuing extensive use of coal and lignite for power generation.  The USA has accommodated significant population growth with only a small rise in emissions, but this is clearly nowhere near enough if it is to make an appropriate contribution to global reductions.  Emissions remain at almost three times UK levels.  Canadian emissions are also high and have increased in absolute terms.  Japan’s emissions have grown slightly over the period.

Some falls in emissions in G7 economies may reflect a shift in the global pattern of emissions, with reduced emissions from industry in the G7 economies balanced by increases in China and elsewhere.  However this can’t account for all of the reductions that have been achieved, or the vast differences in reductions between countries.

Policy has certainly also played its part.  UK policy has successfully targeted relatively low cost emissions reduction, notably reducing coal use in the power sector.  Above all the Climate Change Act (2008) has provided a consistent and rigorous policy framework.

And whatever the reason, one thing is clear.  Cutting emissions more can accompany growing the economy more.

Adam Whitmore – 8th March 2018

 

 

[i]https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/651916/BEIS_The_Clean_Growth_online_12.10.17.pdf

[ii] http://www.pbl.nl/en/publications/trends-in-global-co2-and-total-greenhouse-gas-emissions-2017-report

There should be few reservations about auction reserve prices

The auction reserve price in California has proved successful in maintaining a minimum carbon price.  However it shows the importance for an emissions trading system of political commitment and stability. 

This is the second of two posts looking at experience of carbon price floors.  My previous post looked at UK carbon price support, which guarantees a minimum price by means of a tax.   This post looks at an alternative approach, which is used in California  and the other Western Climate Imitative systems, Quebec and Ontario.  Here, instead of imposing a tax, the floor is set by specifying a reserve price in auctions of allowances.  If bids in auctions stay below the reserve price the allowances are not sold.  Reserve prices such as this are common in practice in many commercial auctions, including those held by major auction houses and online.

Reserve prices give what is often called a “soft” floor.  The market price can go below the auction reserve, but eventually the need to buy allowances at auction is likely to ensure that the price recovers.

The chart below shows the auction reserve price in the California system (green line), which started at $10/tonne in 2012 and is increased each year by 5% plus the rate of inflation.  The California market price (blue line) has generally stayed above this level.  However it did dip below the reserve price for a while in 2016, illustrating that the floor is soft.  This price dip reflected a combination of legal challenges to the system, and political uncertainty about the continuation of the system after 2020, which together reduced the demand for allowances.  Once those uncertainties were resolved the market price recovered.

Chart: Auction reserve prices and market allowance prices in the California cap-and-trade system to end of 2017

Source:  http://calcarbondash.org/ and CARB

The Regional Greenhouse Gas Initiative (RGGI) has similar arrangements but with a much lower reserve price, and there too the price has been above the floor.

The environmental effectiveness of price containment mechanisms depends in large part on what eventually happens to any unsold allowances.  In the case of California this issue particularly affects the upper Price Containment Reserve, from which allowances are released if prices go above defined thresholds.  Allowances from this reserve appear most unlikely to be required in the current phase, as prices seem highly unlikely to reach the threshold levels.  If these unsold allowances in the reserve are cancelled, or otherwise put beyond use, cumulative emissions will be lower.  However if they eventually find their way back into the system, and enable the corresponding quantity of emissions to take place, the environmental benefit may not be realised, or at least not it full.  Some sort of cancellation mechanism is therefore needed, for example cancelling allowances that have been in the reserve for more than a specified number of years.

So price floors can work, however in the case of the California system at least two things need to be agreed as the rules for the system after 2020 are debated this year.

First, continuation of the escalation of the floor price needs be confirmed at least at the current rate, and ideally the rate should be increased.

Secondly, rules for cancelling unsold allowances from the Price Containment Reserve need to be defined.  The cancellation of allowances from the Market Stability Reserve included in the recent reforms to the EUETS sets a valuable precedent in this respect.

The theoretical advantages of a floor price in an ETS are well known.  The experience of auction reserve prices now proving effective in practice over a number of years should encourage other jurisdictions, especially the EU, to introduce similar arrangements.  And those jurisdictions such as California where they are already in place need to continue to develop and enhance them.

Adam Whitmore – 15th February 2018

Emissions reductions from carbon pricing can be big, quick and cheap

The UK carbon tax on fuel for power generation provides the most clear-cut example anywhere in the world of large scale emissions reductions from carbon pricing.   These reductions have been achieved by a price that, while higher than in the EU ETS, remains moderate or low against a range of other markers, including other carbon taxes.

The carbon price for fuels used in power generation in the UK consists of two components.  The first is the price of allowances (EUAs) under the EUETS.  The second is the UK’s own carbon tax for the power sector, known as Carbon Price Support (CPS).  The Chart below shows how the level CPS (green bars on the chart) increased over the period 2013 to 2017[i].  These increases led to a total price – CPS plus the price of EUAs under the EUETS (grey bars on the chart) – increasing, despite the price of EUAs remaining weak.

This increase in the carbon price has been accompanied by about a 90% reduction in emissions from coal generation, which fell by over 100 million tonnes over the period (black line on chart).   Various factors contributed to this reduction in the use of coal in power generation, including the planned closure of some plant and the effect of regulation of other pollutants.  Nevertheless the increase in the carbon price since 2014 has played a crucial role in stimulating this reduction in emissions by making coal generation more expensive than gas[ii].  According to a report by analysts Aurora, the increase in carbon price support accounted for three quarters of the total reduction in generation from coal achieved by 2016[iii].

The net fall in emissions over the period (shown as the dashed blue line on chart) was smaller, at around 70 million tonnes p.a. [iv] This is because generation from coal was largely displaced by generation from gas. The attribution of three quarters of this 70 million tonnes to carbon price support implies a little over 50 million tonnes p.a. of net emission reductions due to carbon price support.   This is equivalent to a reduction of more than 10% of total UK greenhouse gas emissions.  The financial value of the reduced environmental damage from avoiding these emissions was approximately £1.6 billion in 2016 and £1.8 billion in 2017[v].

Chart:  Carbon Prices and Emissions in the UK power sector

The UK tax has thus proved highly effective in reducing emissions, producing a substantial environmental benefit[vi].  As such it has provided a useful illustration both of the value of a floor price and more broadly of the effectiveness of carbon pricing.

This has been achieved by a price that, while set at a more adequate level than in the EU ETS, remains moderate or low against a range of other markers, including other carbon taxes.  CPS plus the EUA price was around €26/tCO2 in 2017 (US$30/tCO2).  The French the carbon tax rose from €22/tCO2 to €31/tCO2 over 2016-2017. In Canada for provinces electing to adopt a fixed price the carbon price needs to reach CAN$50/tCO2 (€34/tCO2) by 2022[vii].  These levels remain below US EPA 2015 estimates of the Social Cost of Carbon of around €40/tCO2 [viii].

This type of low cost emissions reduction is exactly the sort of behaviour that a carbon price should be stimulating, but which is failing to happen as a result of the EU ETS because the EUA price is too low.  More such successes are needed if temperature rises are to be limited to those set out in the Paris Agreement.  This means more carbon pricing should follow the UK’s example of establishing an adequate floor price.  This should include an EU wide auction reserve for the EUETS.  The reserve price should be set at somewhere between €30 and €40/t, increasing over time.  This would likely lead to substantial further emissions reductions across the EU.

Adam Whitmore – 17th January 2018

Notes:

[i] Emissions date for 2017 remains preliminary.  UK carbon price support reached at £18/tCO2 (€20/tCO2) in the fiscal year 2015/6 and was retained at this level in 2016/7.  In 2013/4 and 2014/5 levels were £4.94 and £9.55 respectively.  This reflected defined escalation rates and lags in incorporating changes in EUA prices. https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/293849/TIIN_6002_7047_carbon_price_floor_and_other_technical_amendments.pdf and www.parliament.uk/briefing-papers/sn05927.pdf

[ii] http://www.theenergycollective.com/onclimatechangepolicy/2392892/when-carbon-pricing-works-2

[iii] https://www.edie.net/news/6/Higher-carbon-price-needed-to-phase-out-UK-coal-generation-by-2025/

[iv] Based on UK coal generation estimated weighted average emissions intensity of 880gCO2/kWh, and 350gCO2/kWh for gas generation.

[v] 50 million tonnes p.a. at a social cost of carbon based on US EPA estimates of $47/tonne (€40/tonne).

[vi] There is a standard objection to a floor in one country under the EUETS is that it does not change of the overall cap at an EU level so, it is said, does not decrease emissions.  However this does not hold under the present conditions of the EUETS, and is unlikely to do so in any case.  A review of how emissions reductions from national measures, such as the UK carbon price floor, do in fact reduce total cumulative emissions over time is provided was provided in my recent post here.

[vii] The tax has now set at a fixed level of £18/tonne.  It was previously set around two years in advance, targeting a total price comprising the tax plus the EUA price.  There was no guarantee that it would set a true floor price, as EUA prices could and did change a good deal in the interim.  Indeed, in 2013 support was set at £4.94/tCO2, reflecting previous expectations of higher EUA prices, leading to prices well below the original target for the year of £16/tCO2 in 2009 prices (around £17.70 in 2013 prices). See https://openknowledge.worldbank.org/handle/10986/28510?locale-attribute=en.  The price is also below the levels expected to be needed to meet international goals (see section 1.2), and below the social cost of carbon as estimated by the US EPA (see https://onclimatechangepolicydotorg.wordpress.com/carbon-pricing/8-the-social-cost-of-carbon/ and references therein).

[viii] Based on 2015 estimates.

The case for additional actions in sectors covered by the EUETS is now even stronger

Recently agreed reforms to the EUETS mean that excess allowances in the MSR will be cancelled.  This further strengthens the case for actions such as phase-out of coal plant, increasing energy efficiency and deploying more renewables.

About a year ago I looked at whether additional actions to reduce emissions in sectors covered by the EUETS do in practice lead to net emissions reductions over time [i].

It is sometimes claimed that total emissions are always equal to the fixed cap.  By implication additional actions do not reduce total emissions, because if emissions are reduced in one place there will be a corresponding increase elsewhere.  This is sometimes called the “waterbed hypothesis” by analogy – if you squeeze in one place there is an equal size bulge elsewhere.

Although often repeated, this claim is untrue.  Under the EU ETS at present the vast majority of emissions reductions from additional actions will be permanently retained, reflecting the continuing surplus of allowances and the operation of the MSR.  Furthermore, over the long term the cap is not fixed, but can respond to circumstances.  For example, tighter caps can be set by policy makers once emissions reductions have been demonstrated as feasible.

When I last looked at this issue, the fate of additional allowances in the MSR remained necessarily speculative.  It was clear that additional excess allowances would at least not return to the market for decades.  It also seemed likely that they would be cancelled.  However, no cancellation mechanism was then defined.

This has now changed with the trilogue conclusions reached last week, which include a limit on the size of the MSR from 2023.  The limit is equal to the previous year’s auction volume, and is likely, given the size of the current surplus, to lead to large numbers of allowances being cancelled in the 2020s.

With this limit in place there is a very clear pathway by which allowances freed up by additional actions, such as reduced coal burn or increased renewables, will add to the surplus, be transferred to the MSR then cancelled (see diagram).  Total emissions under the EUETS will be correspondingly lower.

There is now a clear mechanism by which additional actions reduce total emissions

Modelling confirms that with the limit on the size of the MSR in place a large majority of reductions from non-ETS actions are retained, because additional allowances freed up almost all go into the MSR, and are then cancelled.  This is shown in the chart below for an illustrative case of additional actions which reduce emissions by 100 million tonnes in 2020.  Not all of the allowances freed up by additional actions are cancelled.  First there is a small rebound in emissions due to price changes (see references for more on this effect).  Then, even over a decade, the MSR does not remove them all from circulation.  This is because it takes a percentage of the remainder each year, so the remainder successively decreases, but does not reach zero.  If the period were extended beyond 2030 a larger proportion would be cancelled, assuming a continuing surplus.  Nevertheless over 80% of allowances freed up by additional actions are cancelled by 2030.

The benefit of additional actions is thus strongly confirmed.

The large majority of allowances freed up by additional actions are eventually cancelled

Source: Sandbag

When the market eventually returns to scarcity the effect of additional actions becomes more complex.  However additional actions are still likely to reduce future emissions, for example by enabling lower caps in future.

Policy makers should pursue ambitious programmes of additional action in sectors covered by the EUETS, confident of their effectiveness in the light of these conclusions.  Some of the largest and lowest cost gains are likely to be from the phase out of coal and lignite for electricity generation, which still accounts for almost 40% of emissions under the EUETS.  Continuing efforts to deploy renewables and increase energy efficiency are also likely to be highly beneficial.

Adam Whitmore – 15th November 2017

[i] See https://onclimatechangepolicydotorg.wordpress.com/2016/10/21/additional-actions-in-euets-sectors-can-reduce-cumulative-emissions/  For further detail see https://sandbag.org.uk/project/puncturing-the-waterbed-myth/ .  A study by the Danish Council on Climate Change reached similar conclusions, extending the analysis to the particular case of renewables policy.  See Subsidies to renewable energy and the european emissions trading system: is there really a waterbed effect? By Frederik Silbye, Danish Council on Climate Change Peter Birch Sørensen, Department of Economics, University of Copenhagen and Danish Council on Climate Change, March 2017.