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

 

Fixing the starting price of allowances in an ETS

Fixed price allowances can be a useful way of establishing emissions trading gradually.

I have previously looked at the relative advantages of carbon taxes and emissions trading systems (ETSs), including in the videos on this site.

Among the drawbacks of emissions trading systems is that they tend to be more complex to administer than carbon taxes.  An emissions trading system requires surrender of allowances, which need to be issued, often by both auction and free allocation, and tracked as they are traded.  There is a range of administration needing for this, including maintaining a registry of allowances and ownership.  In contrast, a tax simply requires a payment to be made per tonne emitted.

The administrative cost of emissions trading is unlikely to be a significant proportion of the costs of a system for a large jurisdiction with high administrative capacity, for example the EU.  However it can be daunting for smaller jurisdictions with more limited administrative capacity.  Even a large jurisdiction may be concerned about the time needed to establish an emissions trading system.

There may also be concern about the economic the risks.  For example, there will always be uncertainty about price when the cap is first set.

These difficulties can be reduced by including an initial phase of fixed price allowances.  Under this approach emitters pay a fixed price per tonne.  However rather than simply paying a tax they are required to surrender allowances.  An unlimited number of allowances is available from the regulatory authorities at a fixed price.

This approach has the advantage that it puts in place much of the administrative infrastructure necessary for emissions trading.  Allowances are issued and a registry is established.  From there it is a more straightforward path to limiting the number of allowances to impose a cap, and allowing them to be traded.

It has the further advantage that it can introduce a carbon price, perhaps gradually through and escalating price, and the effect of this can be assessed when setting  a subsequent the cap.  The additional information can further reduce risks.

The Australian example

This approach of issuing fixed price allowances was implemented in Australia, starting in 2012.  An initial 3 year phase was originally planned with emitters required to surrender allowances.  An unlimited number of allowances was available each year at a fixed price.  This was AU$23/tonne in the first year, escalating at 2.5% plus the rate of inflation each year. This was intended to be followed by a transition to an emissions trading system with a cap and a price floor.

The chronology in practice was as follows.  Legislation to introduce carbon pricing was passed in 2011.  The fixed price came into effect ion 1st July 2012, with unlimited allowances available at AU$23/tonne.  Full trading was originally scheduled to being in 2015.  In 2013 it was announced this would be brought forward a year to 2014.  However this did not happen, as the incoming Abbott government, which took office in September 2013, repealed the carbon pricing scheme with effect from July 2014.

In the Australian political context that prevailed at the time the similarity to a tax was seen as a drawback politically.  It allowed the opposition to label it a tax, which the previous government had committed not to introduce.  A very sensible approach was therefore abandoned.  However this was a feature peculiar to Australian politics at the time, and not a more general problem.

The EU and the Western Climate Initiative have both shown that it is possible to establish emissions trading systems directly, without the need to go through an initial fixed price phase (the WCI systems were delayed by a year from their originally intended start date, but have generally worked well since).  And some jurisdictions will choose a tax in any case.

Nevertheless, if there is a desire to put an ETS in place in a way which lowers the initial administrative burden and some of the risks of establishing an ETS, then transitioning to an ETS through issuing fixed price allowances can be a valuable approach.

Adam Whitmore – 13th June 2018

New Video on Carbon Pricing and Industrial Competitiveness

Today I have posted the fourth video in my series about carbon pricing.  This one looks at ways of safeguarding industrial competitiveness, including free allocation of allowances and border adjustments.

Copies of the slides and a transcript of the talk are also available.

This and the other videos in the series can be found on the video tab of this site and this link.

https://onclimatechangepolicydotorg.wordpress.com/videos/

Adam Whitmore – 8th June 2018

 

Capturing carbon dioxide is a massive problem (literally)

Assessing the potential contribution of carbon capture and storage (CCS) to limiting climate change must take into account the huge physical scale of the materials being captured and transported.

In my previous post I looked at the slow growth of carbon capture and storage (CCS) and carbon capture and use (CCU).  In this post I look at the scale of CO2 that needs to be captured to make a material difference to the climate, and some of the implications of this.

As reference points, the chart below shows annual production of major commodities. The mass of fossil fuels produced and consumed each year is huge – about 12 billion tonnes every year, over one and a half tonnes for each person in the world.  That is much more than other major commodities.  Wheat is less than a billion tonnes per annum, the iron ore for the world’s iron and steel industry is a little over two billion tonnes, and cement is something over four billion tonnes.

However the CO2 produced from energy and industry (so excluding land use), is much greater still – about 36 billion tonnes.  The vast majority of this comes ultimately from the world’s fossil fuels.  Very simply, the mass of the fossil fuels is mainly carbon, and burning this carbon adds two atoms of oxygen to each atom of carbon, more than tripling the mass, hence the scale of the mass of CO2 produced relative to fossil fuels.

Chart: annual production of major commodities[i]

Even capturing and transporting around a third of current emissions would involve dealing with masses as large as the current fossil fuel system, which has required, cumulatively, tens of trillions of dollars of investment over many decades. Many low carbon technologies have faced similar challenge of scale.  For example, it has taken decades to get wind power to the scale where it is making a material difference to emissions.

The problem gets even worse for any process of CO2 capture from the air that involves use of a solid to bind the CO2.  This is because binding CO2 as a solid inevitably involves adding mass.  For example, if theCO2 were eventually to end up as limestone (CaCO3) the limestone would have more than double the mass of the captured carbon dioxide.

This is especially important for some of the proposals for removing carbon dioxide from the atmosphere by direct air capture into solid form.  To make any worthwhile reduction in atmospheric concentration hundreds of billions of tonnes of solid material will be eventually be generated.   For this reason it is often considered that air capture is best located the source of the scrubbing mineral and where it can be easily disposed of, but the masses involved are nevertheless huge and handling remains a huge problem.

The challenges raised by the mass of CO2 produced by energy use extends to the development of more localised technologies.  Suppose, for example a new technology were invented for carbon capture, capable of cheaply absorbing and binding in solid form CO2 produced by a standard domestic heating boiler.  A typical UK household burns about 16,500 kWh of gas per annum[ii], which generates about 3.3 tonnes of CO2.  Any attempt to capture this would produce many tonnes of material a year to be disposed of.  This compares with current total waste per household at present of around 1 tonne per household.  Alternatively, if household CO2 capture were based around solvents to regenerated while the CO2 is piped away, this would require huge amounts of new pipeline infrastructure.  This is unlikely to be practical.  Instead any CCS is likely to be deployed centrally, for example as part of low carbon hydrogen production, with the hydrogen burnt to produce heat, or for production of low carbon electricity.

The vast scale of CO2 emissions has several implications. First, it will usually be much better to avoid creating the CO2 in the first place than to try to deal with it as a waste problem.  The waste problem is already too big to handle, so adding more in the hope of being able to deal with it is not likely to be the best option.

Second, any system that does make a material contribution to reducing climate change will take vast investment and many years to build – which is a good reason for starting now.

Third, making CCS and CCU more economically viable would help, and this is one of many reasons that higher carbon prices are desirable.

There are however two important caveats to this.  One is that land use does have an important contribution to make.  The scale of release of CO2 from land use and, correspondingly, the potential benefits from reducing deforestation and improving management of biological sinks are large.  However, as I’ve previously noted, there are limits on the availability of biofuels.

The other caveat is that all contributions to reducing emissions are welcome, and there may be cases, especially in industry, where there are few if any alternatives to capture.    Reducing emissions will require a very large range of technologies to be deployed.  Nothing I’ve said in this post should be taken as a reason for not proceeding with CCS or CCU.

As I noted in my previous post CCS continues to look necessary in a range of applications.  And building an industry at the scale required will take decades, and there is an urgent need for progress.  It is imperative to recognise just how large the physical scale of the challenge is, even relative to other economic activities such as iron and steel production often (rightly) thought to be very large scale.

Adam Whitmore – 21st  May 2018

[i] Based on data in the BP statistical review of world energy, UN Food and Agriculture organisation, EDGAR database, USGS, http://www.worldcement.com.  The ratio of fuels to carbon dioxide is not exactly the same as the ratio of the masses of carbon to CO2, which is 3.7, because of the other components in fossil fuels.  The CO2 total includes emissions from industrial processes in addition to combustion.  However many non-combustion emissions, such as the use of carbon in anodes from aluminium smelting, and (depending on your definition of combustion) the use of coke in blast furnaces also use fossil fuels as their source of carbon.

[ii] Source Ofgem

A limited but important medium term future for CCS

CCS has not yet been implemented on a scale needed to make a substantial difference to climate change.  However it continues to look necessary for the longer term, with more projects necessary to get costs down.

A decade or so ago many people expected rapid development of Carbon Capture and Storage (CCS) as a major contributor to reducing global emissions.  I was one of them – at the time I was working on developing CCS projects.  However, the hoped-for growth has not yet happened on the scale needed to make a material difference to global emissions.

The chart below shows total quantities captured from large CCS projects, including 17 that are already operational and a further 5 under construction.  The quantity of emissions avoided are somewhat lower than the captured volumes shown here due to the CO2 created by the process itself.[i]

Between 2005 and 2020 capture will have grown by only around 25 million tonnes p.a..  This is only 0.07% of annual global CO2 emissions from energy and industry.  In contrast the increase in wind generation in 2017 alone reduced emissions by around 60 million tonnes[ii], so wind power reduce annual emission more from about 5 months’ growth than CCS will from 15 years’ growth – though it took wind power several decades to get to this scale.    

Chart 1: Growth of large CCS projects over time

Source: Analysis based on Global Carbon Capture and Storage Institute database[iii]

The picture gets even less promising looking at the types of projects that have been built.  The chart below shows the proportion of projects, measured by capture volume, in various categories.  The largest component by some distance is natural gas processing – removing the CO2 from natural gas before combustion – which accounts for over 60% of volumes.  This makes sense, as it is often a relatively low cost form of capture, and is often necessary to make  natural gas suitable for use.  However, it will clearly not be a major component of a low carbon energy system.  Much of the rest is chemicals production, including ethanol and fertiliser production.  These are helpful but inevitably small. There are just two moderate size power generation projects and two projects for hydrogen production, which is often considered important for decarbonising heat.

Furthermore, most of the projects separate out CO2 at relatively high concentrations or pressures.  This tends to be easier and cheaper than separating more dilute, lower pressure streams of CO2.  However it will not be typical of most applications if CCS is to become more widespread.

Chart 2:  Large CCS projects by type (including those under construction) 

Source: Analysis based on Global Carbon Capture and Storage Institute database

This slow growth of CCS has been accompanied by at least one spectacular failure, the Kemper County power generation project, which was abandoned after expenditure of several billion dollars.  Neither the circumstances of the development or the technology used on that particular plant were typical.  For example, the Saskpower’s project at Boundary Dam and Petra Nova’s Texas project have both successfully installed post combustion capture at power plants, rather than the gasification technologies used at Kemper County.  Nevertheless, the Kemper project’s failure is likely to act as a further deterrent to wider deployment of CCS in power generation.

There have been several reasons for the slow deployment of CCS.  Costs per tonne abated have remained high for most projects compared with prevailing carbon prices.  These high unit costs have combined with the large scale of projects to make the total costs of projects correspondingly large, with a single project typically having a cost in the billions of dollars.  This has in turn made it difficult to secure from governments the amount of financial support necessary to get more early projects to happen. Meanwhile the costs of other low carbon technologies, notably renewables, have fallen, making CCS appear relatively less attractive, especially in the power sector.

The difficulties of establishing CCS have led many to propose carbon capture and utilisation (CCU) as a way forward.  The idea is that if captured CO2 can be a useful product, this will give it a value and so improve project economics.  Already 80% by volume of CCS is CCU as it includes use of the CO2 for Enhanced Oil Recovery (EOR), with project economics supported by increased oil production.

Various other uses for CO2 have been suggested.  Construction materials are a leading candidate with a number of research projects and start-up ventures in this area.  These are potentially substantial markets.  However the markets for CO2 in construction materials, while large in absolute terms, are small relative to global CO2 emissions, and there will be tough competition from other low carbon materials. For example, one study identified a market potential for CCU of less than two billion tonnes p.a. (excluding synthetic fuels) even on a highly optimistic scenario[iv], or around 5% of total CO2 emissions.  It is therefore difficult to be confident that CCU can make a substantial contribution to reducing global emissions, although it may play some role in getting more early carbon capture projects going, as it has done to date through EOR.

Despite their slow growth, CCS and CCU continue to look likely to have a necessary role in reducing some industrial emissions which are otherwise difficult to eliminate.  The development of CCS and CCU should be encouraged, including through higher carbon prices and dedicated support for early stage technological development.  As part of this it remains important that more projects CCS and CCU projects are built to achieve learning and cost reduction, and so support the beginnings of more rapid growth.  However in view of the lead times involved the scale of CCS looks likely to continue to be modest over the next couple of decades at least.

Adam Whitmore – 25th April 2018

[i] CO2 will generally be produced in making the energy necessary to run the capture process, compression of the CO2 for transport, and the rest of the transport and storage process.  This CO2 will be either emitted, which reduces the net gain from capture, or captured, in which case it is part of the total.  In either case the net savings compared with what would have been emitted to the atmosphere with no CCS are lower than the total captured.

[ii] Wind generation increased by a little over 100 TWh between 2016 and 2017 (Source: Enerdata).  Assuming this displaced fossil capacity with an average emissions intensity of 0.6 t/MWh (roughly half each coal and gas) total avoided emissions would be 60 million tonnes.

[iii] https://www.globalccsinstitute.com/projects/large-scale-ccs-projects

[iv] https://www.frontiersin.org/articles/10.3389/fenrg.2015.00008/full

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