Category: Scenarios

Reflecting on the IPCC Synthesis Report through new Shell scenarios

March 23, 2023

After a year of work, with a few hints along the way offered via this blog, the Shell scenarios team launched The Energy Security Scenarios this week. This is the team I am proud to be a member of and our new scenarios offer a very different perspective on the world in a time of challenging circumstances. With an almost identical release date, the IPCC 6th Assessment Synthesis Report also landed this week. The scenarios also offer a new lens through which to view the IPCC findings.

The Energy Security Scenarios are built on the foundation of a world in which a security mindset is becoming pervasive, be it national security based on military threats, energy security following a year of supply disruption and price volatility, economic security as we watch the banking system being challenged by some defaults or climate security as the global average surface temperature continues to rise and impacts are becoming more visible. How countries respond to energy price volatility and supply disruption is highly variable, but nevertheless a pattern has emerged that ties together disparate responses such as India buying Russian crude oil and the USA pumping billions of dollars into direct air capture. These behaviours form part of an archetype framework that underpins our new scenarios. This foundation also offers some colour to the energy story we tell, with our archetypes classified as Innovation Wins, Green Dream, Surfers and Great Wall of Change.

Two key drivers shape the stories that we explore, notably the call at COP26 in Glasgow to deliver net-zero emissions globally by 2050 and deep cuts in emissions by 2030 and the response to the Russian invasion of Ukraine which has stressed the global energy system over the past twelve months. As a result, two new scenarios emerge which embrace both drivers, but prioritise them differently as the world moves forwards. We look out not just to 2030 or 2050, but all the way to 2100 and even draw one surprising conclusion about what the 22nd century has to offer. These are stories that describe a world locked in an energy transition not only driven by cooperative change as called for by many, but instead trending towards a world of more intense competition as countries seek to shore up their energy system for the 21st century. The scenarios are Sky 2050 and Archipelagos. Both scenarios see the energy transition accelerating, but at different paces. In Sky 2050 climate security is the priority, whereas in Archipelagos there is more attention to ongoing energy security.

Highlighting the increasing pace of the transition is the recognition of an inflection point in this decade as fossil fuels begin to lose market share in primary energy, finally shifting away from the 80% role they have played for many decades. The pace in Sky 2050 is about twice that of Archipelagos, but both represent a trend break.

Meanwhile, the IPCC is very focussed on the diminishing carbon budget and the rapidly narrowing opportunities for limiting warming to 1.5°C. In the Synthesis Report they broadly conclude that action will be insufficient to contain warming below 1.5°C in the near term, which points to an overshoot outcome and therefore the need to recover the situation later in the century. This is similar to the pathway visible in Sky 2050, which does see global emissions start to fall in the 2020s and net-zero emissions reached in 2050, but nevertheless the surface temperature rises above 1.5°C in the mid-2030s. However, a burgeoning new direct air capture industry, borne out of initiatives such as the Inflation Reduction Act in the USA, appears in Sky 2050. It grows to such an extent than in combination with extensive change in land management practices, from forestry to farming, as much carbon dioxide is removed from the atmosphere between 2050 and 2100 as has been added from now to 2050. The result is that by 2100 surface temperature warming in Sky 2050 has returned to today’s levels, with the potential for climate restoration during the 22nd century.

The IPCC make the case that only a drastic reduction in near term emissions can avoid passing 1.5°C, with CO2 emissions needing to fall by 48% by 2030 relative to 2019 levels. These numbers will become higher with each passing day that emissions do not reduce. The table below comes from the Synthesis Report released on Monday and outlines what must happen in the seven years to 2030, then to 2035, 2040 and 2050.

Source: IPCC 6th Assessment Report – Synthesis

In The Energy Security Scenarios we do not see the scope for such large near term action reductions, with Sky 2050 achieving a reduction of around 12% by 2030. In Archipelagos emissions are higher in 2030 than in 2019. Although the Synthesis Report calls for immediate reductions, the IPCC note that of their modelled scenarios, only a small number of the most ambitious global modelled pathways limit global warming to 1.5°C by 2100 without exceeding this level temporarily. The IPCC state the following:

Global warming will continue to increase in the near term (2021-2040) mainly due to increased cumulative CO2 emissions in nearly all considered scenarios and modelled pathways. In the near term, global warming is more likely than not to reach 1.5°C even under the very low GHG emission scenario (SSP1-1.9) and likely or very likely to exceed 1.5°C under higher emissions scenarios. In the considered scenarios and modelled pathways, the best estimates of the time when the level of global warming of 1.5°C is reached lie in the near term.

In the case of overshoot, i.e. temporarily exceeding 1.5°C, they also note that the application of large scale carbon dioxide removal (CDR) technologies and practices is required to progressively reverse the overshoot situation. However, they also note that any overshoot brings with it the added risk of long term irreversible changes in the global ecosystem.

In short, the Synthesis Report paints a concerning picture of the world exceeding 1.5°C and taking on the associated climate risks. While the report makes every attempt to say that the possibility of not doing so still exists, there is little solid content to argue that this is achievable, a finding backed up by the analysis presented in The Energy Security Scenarios. The temperature outcomes for Sky 2050 and Archipelagos are presented below. The assessments were made by the MIT Joint Program using their climate model and also reported with the release of the Shell scenarios. You can also explore the scenario data here.

The Energy Security Scenarios complement the IPCC Synthesis Report well in that Sky 2050 sets out a very clear and unambiguous pathway to 2100, that both recognises the near term prospect of overshoot and the steps to take to more than redress the situation. By contrast, Archipelagos sets out a plausible pathway forward based on current tensions, but also shows that even under trying circumstances the world may find that 2.2°C is now the upper maximum for warming. While 2.2° is not considered safe territory by IPCC, the Archipelagos outcome is well positioned at the lower end of the range of outcomes that IPCC consider, which exceed 4°C in the worst case. Archipelagos is a story of global political headwinds buffeting the transition, but not to the extent that it slows in comparison with today. Quite the opposite – the pace increases as security concerns and competition drive the system away from fossil fuels.

You can find more on The Energy Security Scenarios here, which I would encourage readers to explore. But if you don’t have the time right now, this short video introduction may be of interest.

Plunging into Islands?

March 13, 2022

I, no doubt like you, am deeply concerned about Russia’s war against Ukraine and horrified at the resulting loss of life and humanitarian crisis enveloping millions of people. The protection of people should be everyone’s primary focus. But we are also seeing the impact of the situation on the world’s energy supply.

Just over a year ago the Shell Scenarios team launched the Energy Transformation Scenarios. The set of scenario stories looked at three possible pathways forward, built on societal trends that we saw emerging from the pandemic in our earlier work, Rethinking the 2020s. Those trends, illustrated below, were Wealth First, Security First and Health First, described as follows;

  • Wealth first: A focus on wealth and economic recovery, but this results in a late start to the rapid transition required to reach net-zero emissions around the middle of the century. Rather, the energy required to support growth in the 2020s comes from conventional sources. This led to the Waves scenario.
  • Security first: National sentiment shifts inwards and security issues prevail. The transition slows along with economic growth. Domestic energy resources prevail and while some countries proceed with a transition, the global pace of change required for the Paris Agreement just isn’t there. This thinking underpins the Islands scenario.
  • Health first: The pandemic leads to structural change across society, significant green investment and a realization that the broader health and well-being of society is fundamental. In this context the goals of the Paris Agreement are met under the Sky 1.5 scenario.
Shell Energy Transformation Scenarios

Islands always struck me as being a rather dystopian view of the world, but it emerged from a robust scenario development process as a very possible world. In more recent publications, such as our Singapore Sketch, it has been featured and discussed but not particularly emphasized. Both Waves and Sky 1.5 seemed more in tune with the times. Yet here we are, looking at the prospect of a world becoming very distracted from the energy transition by security issues.

While Islands is framed in the context of the pandemic and how it is dealt with, it nevertheless points to trends that are becoming visible in the world order as each day passes. As a nationalistic islands-type mentality takes hold in the scenario, growth in the global economy begins to stagnate, and efforts to address the climate challenge slow. Islands involves the triumph of the nation state and nationalism, while the forces behind globalization weaken. It is a more challenging economic environment where technology innovation and its diffusion are slow, and efforts to address climate change fragment. Geopolitics are re-calibrated and shift in tandem with increasing attention on national security and trade barriers. Security of energy supply and domestic socio-economics dominate agendas.

Even in Europe, with its strong focus on climate action, efforts to reduce emissions slow in Islands, particularly compared to Sky 1.5. Coal in primary energy remains high through to 2050 and the electric vehicle revolution stalls badly with no significant uptake until the late 2030s.

These trends may feel extreme in that, for example, there is already a visible shift towards electric vehicles in Europe. But scenarios are designed to push thinking to extremes, not forecast the future. Importantly, because they aren’t forecasts, we shouldn’t sit back and just imagine that Islands in now inevitable. Rather, we should take heed of the signals it is giving. There is the very real possibility of domestic security issues enveloping the world and slowing the energy transition, particularly if governments choose a path of rearming and shoring up their own borders. But other outcomes are also possible.

Sky 1.5 is built on strong international cooperation, which could be a possible silver lining in the current crisis. We imagined when developing the story that such cooperation emerged through actions related to the pandemic, but actions in response to the Russian invasion of Ukraine could also bolster the focus required for a major energy transition. What is hard to imagine is a rapid energy transition when governments are also deeply focused on security matters. That is perhaps the underlying Islands story.

Creating a 21st century energy hub in Singapore

February 17, 2022

About a year ago the Shell Scenario Team released the Energy Transformation Scenarios, which looked in detail at possible pathways the world might take in this century as society responds to climate change and other pressures. The scenarios were built on earlier work that focused on the more immediate changes that society could see in the 2020s as a result of the pandemic. But the global story is just the tip of the iceberg; there is a wealth of national and regional detail below the surface of the Energy Transformation Scenarios thanks to the team’s energy modelling capacity.

One region that is of particular importance to the energy system is Asia and within the region Singapore is a key oil products supply and distribution hub. Given its unique geographical location and history as a major trading port, Singapore supplies some 20% of global marine bunkers, 3% of aviation fuel and exports a sizeable portion of the oil products used throughout the region.

Singapore is a major oil products supply hub today (Source: Shell analysis of various data sources)

But as the energy system shifts and oil products are replaced with electricity and fuels such as hydrogen, how might Singapore adapt to the transformation and what might this mean for its role as an oil products supply and distribution hub? To help people think about these key questions for Singapore, Shell has released a new Scenario Sketch, Singapore: A 21st Century Energy Hub. The Sketch makes extensive use of the regional and country data within the Energy Transformation Scenarios, setting out three possible scenarios for the region.

These scenarios are not forecasts, predictions or plans, but possible pathways that could emerge if certain trends take hold. Only one scenario meets the goals of the Paris Agreement, which implies that very deliberate steps will need to be taken to ensure the goals are met. Scenarios can help craft our thinking about the future and catalyse the actions required to shape a particular outcome.

The three scenarios are known as Waves, Islands and Sky 1.5 and they reflect the underlying trends that can be seen across society as a result of the pandemic.

  • Waves: A focus on wealth and economic recovery, but this results in a late start to the rapid transition required to reach net-zero emissions around the middle of the century. Rather, the energy required to support growth in the 2020s comes from conventional sources. The transition is rapid from the 2030s, with a clear focus on ending fossil fuel use rather than directly managing emissions. Net-zero emission is reached around the end of the century.
  • Islands: National sentiment shifts inwards and security issues prevail. The transition slows along with economic growth. Although the transition eventually takes hold, net-zero emissions is not reached until well into the 22nd century.
  • Sky 1.5: The pandemic leads to structural change across society, significant green investment and a realisation that the broader health and well-being of society is fundamental. In this scenario the goals of the Paris Agreement are met.

All three scenarios see the role of electricity expanding, for example in transport, the further emergence of biofuels and the introduction of hydrogen as an energy carrier for certain applications.  But the time lines are very different. However, these shifts in the energy system all challenge the supply and distribution model that Singapore has established for oil products and tend to favour local production. This is certainly the case for electricity, but may also be true for biofuels where feedstocks are available on a local level and hydrogen should electrolysers become the preferred mode of production. However, hydrogen supply may also lend itself to a distribution model if significant renewable electricity is available in a particular area, although this is not currently the case for Singapore.

The more immediate change for Singapore comes in the aviation and marine sectors, where airlines and shipping companies are beginning to plan and implement strategies to make use of sustainable fuels and develop possible roadmaps for hydrogen as a future energy carrier. Although progress is slow in Islands, both Waves and Sky 1.5 see early developments. This opens up the prospect of Singapore leading the way in supplying such fuels, maintaining its role as a supply hub.

In Sky 1.5 another opportunity emerges for Singapore through Article 6 of the Paris Agreement. A feature of Sky 1.5 is significant activity to develop carbon removals, both through reforestation and carbon capture and storage technologies. The use of removals to balance continued use of fossil fuels in some sectors is an important part of the global strategy for limiting warming to below 1.5°C in 2100, but catalysing the investment required for removals and directing the benefit to emitters requires a carbon trading market to emerge. With it’s strong history as a commercial and financial centre, Singapore could lead the way here, particularly as the region holds significant opportunity for removals and Singapore itself is a centre for the two sectors that may make greatest use of them, namely aviation and marine.

Singapore could become a major carbon trading hub

A feature that does emerge across the stories is just how long Singapore may find itself as an important regional distributer of oil products, even as the transition gather pace. The Asian region is still developing rapidly, with some 2 billion people (ASEAN and China) moving from modest to middle income and making use of a broader range of energy services in the process.  Immediate growth in the region will draw heavily on existing energy sources and services, given their availability and scalability. Only in the fastest of transitions is this trend overcome with new energy sources scaling quickly enough to match new demand.

Where Singapore stands as an energy hub in 2050 and beyond has yet to be established. But now is the time for the bold decisions necessary to create the best possible future. Scenario analysis is a useful tool for understanding new trends and directions. We hope this publication helps inform readers about an otherwise uncertain future and positions them for the journey ahead.

Also check out the scenario infographic here.

Shell’s scenarios, including this Singapore Sketch, are not intended to be projections or forecasts of the future and they are not Shell’s strategy or business plan. When developing Shell’s strategy, our scenarios are one of many variables that we consider. Ultimately, whether society meets its goals to decarbonise is not within Shell’s control. This Singapore Sketch is based entirely on the data and findings of the Shell Energy Transformation Scenarios, released in February 2021. Please read the full cautionary note at: http://www.shell.com/investor and http://www.sec.gov

The simple climate maths the IPCC didn’t fully explain

August 19, 2021

When I first started delving into the issue of climate change about 20 years ago, the clarion call of the day was to reduce emissions by 50% by 2050. Today, as we all know, the call is for net-zero emissions by 2050. Last week we also heard again from the Intergovernmental Panel on Climate Change (IPCC) with the release of the first part of the 6th Assessment Report (AR6), which the United Nations Secretary General called a ‘code-red for humanity’. But both the call in 2001 and again in 2021 are entirely consistent. It’s not the climate science that has changed, just the carbon maths associated with it.

As the IPCC clearly state in Part D of the Summary for Policymakers of AR6-WG I;

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

While the biggest difference between now and 2001 is the shift in the goal from below 2°C to 1.5°C which in turn has contributed to the change in required emissions trajectory, this is not enough to explain the shift in the required outcome by 2050. That change is more a function of the cumulative carbon math associated with any level of warming.

To limit the temperature rise to 1.5°C, the notional carbon budget based on the above best estimate of TCRE is 1.5/0.45*1000 =  3330 Gt CO2 and for 2°C it is 4440 Gt. This is effectively targeting the central estimate in a range and is a calculation you might do before emissions start. However, we already know from IPCC AR6 that cumulative emissions of 2390 Gt correspond to a 1.07°C temperature rise in 2010-2019 vs. 1850-1900. They also indicate that the remaining carbon budget from 1.1.2020 for 1.5°C is 400 Gt and 2°C is 700 Gt for a 67% likelihood, which implies an overall carbon budget of 2790 Gt for 1.5°C and 3090 for 2°C with a good degree of certainty.

In the following calculations and accompanying charts I will work on the basis of a simple linear reduction in emissions to net-zero from a particular point in time to calculate the overall cumulative emissions. Returning to 2001, the annual CO2 emissions (from energy, cement and land use) were approximately 30 Gt, the cumulative emissions from 1850 at that time were about 1700 Gt and a linear reduction pathway from 2001 for 2790 Gt final cumulative emissions (1.5°C) means net-zero emissions in about 2073. This is illustrated in the chart below.

As noted for 2001, cumulative carbon dioxide emissions since 1850 were at 1715 Gt (Source: Our World in Data), which means net-zero emissions in 2073 for 1.5°C and 2123 for 2°C. Back in 2001 the focus was more on 2°C, so targeting well below 2°C, to completely avoid the 2°C threshold, would mean net-zero emissions around 2100 and therefore a 50% reduction in emissions by 2050 assuming a linear decline.

But twenty years later the story is very different. At the time of the IPCC Special report on 1.5°C cumulative carbon dioxide emissions had reached 2300 Gt, so a linear reduction to net-zero had a target date of 2040. For 2°C it was 2077. In fact the IPCC opted for scenarios with a steeper early reduction pathway, and therefore targeted 2050 for net-zero emissions, but that means a very steep early reduction of over 50% by 2030 to balance the longer tail to 2050. With twenty further years of rising emissions, a considerable portion of the 2001 carbon budget had been consumed and therefore the date for net-zero emissions had moved forward in time dramatically.

In fact, for each year that emissions don’t reduce, the requirement for net-zero emissions comes towards us by a year, effectively narrowing the gap for action by two years. The IPCC Special Report on 1.5°C was baselined from 1.1.2018, so another four years has passed (or will soon pass). Even the recent IPCC AR6 is two years out of date now in terms of its carbon budget baseline. This rapidly shifting picture is shown below. In 2015 the target year for 1.5°C is shown to be 2042, a gap of 27 years, but by 2019 the target year is 2038, a gap of only 19 years.

Should carbon dioxide emissions remain at 40 Gt (below the pre-COVID high) for the coming few years, the available carbon budget for 1.5°C is rapidly consumed, as illustrated in the chart below. By 2025 net-zero emissions would be required by about 2033 and by 2029 net-zero emissions would be required before 2030, in other words the available carbon budget will have been consumed.

All the above presupposes that emissions cannot go below zero in the future, thereby drawing carbon dioxide out of the atmosphere and eventually correcting any overshoot of the carbon budget and its associated temperature goal. But negative emissions are a possibility, through the implementation of large scale air capture systems with geological storage (BECCS or DACCS) and enhancement of natural carbon uptake in the biosphere via programmes such as those that increase global forest cover and improve soil carbon management in agriculture.

Today, the carbon budget is still a rather arcane subject, well understood by a few but not widely appreciated in terms of relevance to managing surface temperature. That understanding will need to improve rapidly so policymakers can develop better mechanisms to manage it, also ensuring large scale deployment of atmospheric drawdown practices and technologies.

Are we now range bound on temperature?

July 6, 2021

In my last post I discussed the recent IEA 1.5°C Scenario that sets out what is required to reach net-zero emissions by 2050 and manage the transition within a carbon budget of 500 Gt CO2. The IEA have shown that while this is a relatively straightforward calculation to do (and last year I presented a similar one), the resulting energy transition pathway is extraordinarily difficult to imagine, let alone achieve. While such a pathway might be technically possible, is it actually plausible? Is society socially ready to embark on such a journey and inflict such large scale change upon itself?

A new report coordinated through the University of Hamburg’s Center for Earth System Research and Sustainability (CEN) in close collaboration with multiple partner institutions and funded by the Deutsche Forschungsgemeinschaft (DFG) attempts to answer the question of plausibility. In the annual Hamburg Climate Futures Outlook, researchers make the first systematic attempt to assess which climate futures are plausible, by combining multidisciplinary assessments of plausibility. The inaugural 2021 Hamburg Climate Futures Outlook addresses the question: Is it plausible that the world will reach deep decarbonization by 2050? The authors discuss the outcome in their own blog post, found here.

The methodology employed isn’t a direct technical analysis of the pathway steps, but rather an assessment of a number of social drivers that would be required to underpin such a transition. The authors conclude that deep decarbonisation by 2050 isn’t currently plausible, meaning that warming will exceed 1.5°C. None of the drivers show enough momentum to bring about deep decarbonisation by 2050 and they find that some drivers are currently inhibiting progress.

The authors combined their assessment of social plausibility with the latest set of socioeconomic future emissions scenarios (SSPs) and the latest physical science research on climate sensitivity to show that warming lower than 1.7°C and higher than 4.9°C by the end of the century as currently not plausible. The lower figure of 1.7°C relative to pre-industrial levels corresponds to the lower bound of the 90% uncertainty range in a low emissions IPCC scenario (SSP1-2.6) and  the higher figure of 4.9°C corresponds to the upper bound of the 90% uncertainty range of a higher emissions IPCC scenario (SSP3).

Source: Hamburg Climate Futures Outlook 2021

Reframing this around central estimates for the scenarios gives a plausible range of 1.8°C to 3.8°C for warming by the end of the century. The original Shell Sky 2018 scenario also had a central estimate of about 1.8°C.

While the lower end of the range was analysed by the Hamburg team in terms of social plausibility, the upper end was not (see chart below); presumably that is a task still to be done.

Source: Hamburg Climate Futures Outlook 2021

However, the upper end of the range has been the subject of social plausibility analysis in a recent paper released by the MIT Joint Program on the Science and Policy of Global Change and discussed in this blog. That analysis was led by MIT, with me and my colleague Martin Haigh as contributing authors. A scenario called Growing Pressures was developed to illustrate how and why there is now an inevitable trend towards near zero emissions, catalysed by the physical reality of a rising average surface temperature. Near (net) zero emissions means that warming will stop and the temperature will plateau, but only a rapid shift to near (net) zero emissions will deliver the 1.5°C. The question the analysis sought to answer was what the highest plausible warming outcome might be given that an energy transition is clearly underway and there is real concern growing across society around the issue of climate change.

While political trends, such as populism or leaning to the left or right, tend to come and go over time and social norms shift around as the decades pass, the temperature trend is essentially a monotonic increasing function. As such, the influence it has on our consciousness will only grow over time.  The cascade can be simplified as follows;

  • Climate changes;
    • Global surface temperature continues to rise, and impacts become more apparent.
    • Sea level keeps rising with visible consequences.
  • Concern rises;
    • Voter pressure on cities, states and countries to develop ‘green’ policies.
    • Shareholders pushing companies to take on net-zero emission goals and targets.
  • Local and national governments pursue (piecemeal) interventions;
    • Ongoing actions under the UNFCC under the banner of the Paris Agreement and the emergence of net-zero emissions (NZE) as a framing concept.
    • Incentives and mandates drive down the cost of new energy technologies and lead to further uptake.
    • Large established NZE policy frameworks continue to operate (e.g. EU, California) and some new NZE policy frameworks emerge (e.g. China by 2060).
  • Technology marches on;
    • Renewable energy access becomes cheaper.
    • Developments in physics, chemistry and materials sciences (e.g. PV, storage).
    • Rapid and broadening digitalization of society.
  • Markets rule;
    • Financial markets distance themselves from fossil fuel investments, but particularly coal, and climate-related financial disclosures bring increasing transparency.
    • Demands by businesses and consumers for lower carbon footprint products and some preparedness to pay for this.
    • Development of markets to support low-carbon investment (e.g. nature-based solutions).
    • Alternatives to coal, oil and gas becoming increasingly competitive.

While each of these will undoubtedly vary over time, their ongoing combined effect gives rise to a scenario of continuous change and transition. The central estimate temperature outcome for Growing Pressures is 2.7°C in 2100 leading to a 2.8°C plateau in 2150, well below the 3.8°C central estimate upper threshold discussed above.

Source: MIT Joint Program

Combining the findings of the these two separate analyses indicates that at the current stage of the energy transition, the warming outcome is now range bound between 1.8°C and 2.7°C in 2100, based on central estimates. That range is partly dictated by the development and availability of energy technologies, but is perhaps overwhelmingly driven by social plausibility, as discussed by the Hamburg team and in the MIT report.

The range may well narrow as time goes by. In the short term, if emissions don’t fall quickly, society will rapidly consume the available carbon budget for 1.5°C and then upwards. As was shown in the IPCC 2018 Special Report on 1.5°C (SR15) report and again by the IEA in their own NZE2050 scenario, that budget is less than 500 Gt CO2 for 1.5°C of warming and is currently being consumed at the rate of over a gigaton every ten days (41 Gt per year). However, as the temperature rises and it becomes apparent to society critical thresholds are being passed, that in turn increases the drivers in the Growing Pressures scenario, as well as opening the social plausibility for nearer term reductions. Under such circumstances, repeating the two analyses in 2030 could well see a much narrower range, perhaps 2.0°C to 2.5°C.

None of the above is meant to argue that such a range is a good thing; the IPCC made it plain in their SR15 that we need to stay as close to 1.5°C as possible. However, the analyses are nevertheless important as they act as a signpost to help guide us forwards and they demonstrate that the energy transition is having an impact.

You can read the MIT report here.

Featured image courtesy of the UK Met Office.

Note: Scenarios don’t describe what will happen, or what should happen, rather they explore what could happen. Scenarios are not predictions, strategies or business plans. Please read the full Disclaimer here.

Pathways to 1.5°C

June 11, 2021

In 2018 when the IPCC released their Special Report on 1.5°C, they presented four archetype scenarios to help readers understand that there were fundamentally different approaches to limit long term warming to 1.5°C or below. The scenario pathways are shown below and vary significantly in their approach, time horizon and use of sinks.

Source: IPCC SR15

All four scenarios (P1, P2, P3, P4) are based around the same carbon budget, or total cumulative emissions of 420 Gt from 1.1.2018 consistent with providing a 66% chance of limiting warming to 1.5°C. Whether the carbon budget is aligned with 420 Gt (67th percentile) or 580 Gt (50th percentile), it represents a very limited amount given that annual CO2 emissions are in excess of 40 Gt, so these represent 10-15 years of emissions at current levels. Since this IPCC publication, a further 160 Gt will have been emitted by society by the end of 2021, meaning that the budget is reduced to 260 – 420 Gt.

Source: IPCC SR15

In attempting to align with a very limited carbon budget, the P1 scenario imagines a world of falling overall energy use and a very rapid shift away from fossil fuels. There is no use of geological storage of CO2 and a modest reliance on natural sinks, although in doing so the world must shift away from net-deforestation by the 2040s. By contrast, the P4 scenario sees increasing demand for energy and as a consequence, a much more difficult decarbonisation journey that involves considerable use of sinks in the second half of the century. Notably, the P4 scenario exceeds the carbon budget by quite some amount with peak emissions to the atmosphere of 900 Gt, before reining in the amount to 200 Gt by 2100. This results in P4 being a so-called overshoot scenario, in that the world exceeds 1.5°C during the century before returning to 1.5°C and below by the end of the century.

Source: IPCC SR15

All the above might seem a bit academic, but it became very real recently when the IEA released their 1.5°C scenario and some commentators began comparing it to one of the very few other 1.5°C scenarios, notably Sky 1.5 from Shell.

In fact, the two scenarios are at near opposite ends of the P1 to P4 spectrum.

The IEA 1.5°C scenario looks at the period from 2020 to 2050 and presents a proposal for the problem of containing emissions to a 500 Gt carbon budget (the 580 Gt IPCC number less 80 Gt for the years 2018 and 2019). Apart from recognising that the land based system is likely to reduce this budget by a further 40 Gt over the period (i.e. reducing it to 460 Gt), the analysis limits itself to the energy system and the changes that would be required to meet a 460 Gt cumulative emissions constraint within a 30 year time frame. As is the case in similar scenarios, including Sky 1.5, their analysis assumes rapid electrification of final energy (e.g. electric cars instead of gasoline) and makes use of renewables  and nuclear power generation to produce the electricity. They introduce hydrogen as an energy carrier, make use of bioenergy and include carbon capture and storage (CCS) where fossil fuel remains in use. For the latter, the IEA deploy CCS directly on facilities that use fossil fuels and indirectly through direct air capture for fossil fuel use in applications such as aviation.

All the above steps are well understood, but even given rapid and stretching deployment rates of all technologies, these steps are unlikely to contain emissions to less than 500 Gt in under thirty years. This is because of the expected increase in overall energy use, a consequence of economic growth, the general rise in population and the shift of billions of people from very low energy use lifestyles to at least modest energy use, a simple outcome of development and the provision of basic services like lighting, clean water, food refrigeration and some mobility.

As such, energy modelers looking at a very constrained time frame of 30 years must make the assumption that energy growth can be contained or even fall, as in the IPCC P1 scenario. This is exactly what the IEA have done to meet the carbon constraint. In the 1.5°C Scenario primary energy demand falls from 612 EJ in 2019 to 543 EJ in 2050, a drop of over 10%. Efficiency will certainly help deliver such an outcome and the use of renewable electricity gives the story a big boost as the thermal losses in power stations vanish, although new losses emerge through the use of transmission and storage. But the big story is the widespread assumption of behavioural change across society to reduce energy demand. The chosen measures include steps such as;

  • Ride-sharing in all urban car trips
  • Reducing motorway / freeway speeds to below 100 kph / 60 mph.
  • Increasing temperatures in air conditioned vehicles and buildings.
  • Lowering temperatures in heated buildings.
  • Replacing short flights with high speed rail.
  • Limiting long haul air travel to 2019 levels.

With low energy demand and high deployment rates of new energy technologies it then becomes possible to resolve the carbon budget within a 30 year time frame.

At the other end of the spectrum is the Sky 1.5 scenario, which tackles the problem of a limited carbon budget in a very different way. Sky 1.5 looks at the period from 2020 to 2100, an 80 year time frame, and starts with an expectation of rising global energy demand, even assuming significant energy efficiency improvements across society. The growth in population and the demand for energy services, including significant new demand from developing countries for basic services, cannot be contained and energy demand rises. This immediately poses a challenge in that rising demand more quickly consumes the available carbon budget at the front end, when alternative energy technologies and sinks have not been deployed.

Sky 1.5 also recognises that for many energy technologies, the 2020s still remain a period of development and limited deployment and even for more mature technologies such as solar and wind, a period of early growth where change on a global scale will remain limited.

The solution to this approach is to accept that, at least in the short term, the carbon budget may be consumed and the temperature it is linked to (1.5°C in this case) potentially surpassed for a period of time. The subsequent rapid deployment of sink capacity, both manmade in the form of air capture with geological storage and natural as reforestation, then offers the possibility of a period of net-negative emissions later in the century, to redress the imbalance and reduce cumulative carbon dioxide emissions and therefore temperature. This is the approach that Sky 1.5 takes, as do the IPCC P3 and P4 scenarios. Sky 1.5 takes this approach out of necessity, in that the scenario reaches a limit on energy technology deployment and does not foresee a fall in energy demand.

The end carbon budget for both the IEA 1.5°C scenario and Sky 1.5 are similar, but the IEA restricts itself to a thirty year time-frame, whereas Sky 1.5 operates over an eighty year time-frame. Sky 1.5 is also remodeled by MIT within their integrated assessment model to give a temperature outcome, rather than simply using the IPCC central estimate for a carbon budget. The two scenarios are attempting to answer the same question, but take very different approaches to doing so. There is no right or wrong here, just different ways of solving a tough problem.

Note: Scenarios don’t describe what will happen, or what should happen, rather they explore what could happen. Scenarios are not predictions, strategies or business plans. Please read the full Disclaimer here.

Growing pressures

March 18, 2021

The task of getting to net-zero emissions by 2050 has become the rallying cry behind COP 26 and considerable diplomatic effort is now being applied to the push to get countries to sign up to such an outcome. But plans and outcomes aren’t always aligned, however plans often set the scene for outcomes that at least align with the intention.

Thinking back even a decade, the concept of net-zero emissions barely registered in the political consciousness. In the Copenhagen Accord of 2009, there is only mention of ‘deep cuts in global emissions are required according to science, and as documented by the IPCC Fourth Assessment Report with a view to reduce global emissions so as . . . . ‘ and in the IPCC 4AR, while some of the scenarios show emissions falling to zero late in the second half of the century, this wasn’t a key message for policymakers. Rather, the key message in 2007 in relation to mitigation in the long term, i.e. after 2030, was;

  • In order to stabilize the concentration of GHGs in the atmosphere, emissions would need to peak and decline thereafter. The lower the stabilization level, the more quickly this peak and decline would need to occur. Mitigation efforts over the next two to three decades will have a large impact on opportunities to achieve lower stabilization levels.

By the time the IPCC Special Report on 1.5°C (SR15) appeared in 2018, the key mitigation message was very different.

  • Reaching and sustaining net zero global anthropogenic CO2 emissions and declining net non-CO2 radiative forcing would halt anthropogenic global warming on multi-decadal time scales. The maximum temperature reached is then determined by cumulative net global anthropogenic CO2 emissions up to the time of net zero CO2 emissions and the level of non-CO2 radiative forcing in the decades prior to the time that maximum temperatures are reached.

Moreover, a timeline to 2050 was proposed in SR15 for reaching net-zero emissions.

The history for this change is a separate discussion, but it perhaps started with the simple recognition that climate change is a stock problem and that the stock will only stop growing (and therefore stop the problem getting worse) when the flow into the atmosphere is the same as the flow out, i.e. net-zero. The science community has always known this, but the concept has taken some time to register more widely. I first discussed this in a blog post and made mention of net-zero emissions in 2009.

Today, with society having done little to arrest the flow of carbon dioxide into the atmosphere, the timing for net zero has been brought forward from late in the century to around 2050, based simply on the relationship between temperature and cumulative emissions, or stock. Both companies and policymakers are now focused on the actions required for net zero as 2050 is, in many cases, within their long term planning horizon window for major capital investment.There is growing pressure on all parties to do something, which leads to the declarations of net-zero emissions goals from many countries, with presumably many more to come.

The effort required to achieve an outcome of net-zero emissions by 2050 will be extraordinary, which might raise the question of why countries are being so ambitious (apart from the fact that it is necessary). One answer is perhaps because now, versus just a few years ago, we are heading there anyway; it is just a question of when the goal is reached.

One of the key observations that emerges from the recently released Shell Energy Transformation Scenarios is that within the course of about a century all three scenarios (namely Waves, Islands and Sky 1.5) reach net-zero emissions. In Sky 1.5 is it in in the late 2050s, in Waves around 2100 and Islands perhaps the 2120s (by extrapolation as the Shell World Energy Model doesn’t extend past 2100). The recognition of net-zero emissions as a possible inevitable outcome has been on my mind for some time now and I felt that it needed further analysis. To that end, Shell supported a project by the MIT Joint Program on the Science and Policy of Global Change to look at the implications of where the energy transition is taking society.

The analysis MIT did recognises that there is now a cascade of growing pressures operating in society, starting with the physical reality of a rising average surface temperature. While political trends, such as populism or leaning to the left or right, tend to come and go over time and social norms shift around as the decades pass, the temperature trend is essentially a monotonic increasing function. As such, the influence it has on our consciousness will only grow over time.  The cascade can be simplified as follows;

  • Climate changes;
    • Global surface temperature continues to rise, and impacts become more apparent.
    • Sea level keeps rising with visible consequences.
  • Concern rises;
    • Voter pressure on cities, states and countries to develop ‘green’ policies.
    • Shareholders pushing companies to take on net-zero emission goals and targets.
  • Local and national governments pursue (piecemeal) interventions;
    • Ongoing actions under the UNFCC under the banner of the Paris Agreement and the emergence of net-zero emissions (NZE) as a framing concept.
    • Incentives and mandates drive down the cost of new energy technologies and lead to further uptake.
    • Large established NZE policy frameworks continue to operate (e.g. EU, California) and some new NZE policy frameworks emerge (e.g. China by 2060).
  • Technology marches on;
    • Renewable energy access becomes cheaper.
    • Developments in physics, chemistry and materials sciences (e.g. PV, storage).
    • Rapid and broadening digitalization of society.
  • Markets rule;
    • Financial markets distance themselves from fossil fuel investments, but particularly coal, and climate-related financial disclosures bring increasing transparency.
    • Demands by businesses and consumers for lower carbon footprint products and some preparedness to pay for this.
    • Development of markets to support low-carbon investment (e.g. nature-based solutions).
    • Alternatives to coal, oil and gas becoming increasingly competitive.

While each of these will undoubtedly vary over time, their ongoing combined effect gives rise to a scenario of continuous change and transition. The resultant MIT ‘Growing Pressures’ scenario is built on a series of simple premises; for example, if by 2050 the push-back by financial markets in combination with the falling cost of renewables means that new coal fired power station development ceases globally, then by about 2100 at the latest coal fired generation of electricity will have ceased (because the power stations built up to 2050 would have been largely decommissioned by then). An overview of the premises is shown below, set against the Growing Pressures emissions trajectory.

Progression towards net-zero emissions in the Growing Pressures scenario (Source: MIT Joint Program)

The premises are not meant to be the fast pace changes needed to limit warming to 1.5°C, but an assessment of events that are now seemingly locked into our collective energy system future as a result of the growing pressures. This then establishes a new baseline from which to think about mitigation actions and to assess the progress that is being  made towards a better outcome.

With net-zero emissions looking more like an inevitable outcome than an aspiration, the framing of the climate issue may also change. Looking at the IPCC 5th Assessment Report, readers were presented with a series of impact risk tables that gave the impression of a binary outcome, i.e. society could take action and limit warming to 2°C or accept the consequences of 4°C of warming.

Risk assessment example in IPCC 5th Assessment Report (Source: IPCC)

But the Growing Pressures scenario limits warming to around 2.8°C (central estimate), effectively eliminating the IPCC central outcome of 4°C. In less than a decade the framing of the climate issue has moved from being somewhat unbounded in terms of temperature rise, to one that is bounded between central estimates of 1.5°C and 2.8°C. Both the Shell Waves and Islands scenarios fall within this range and of course Sky 1.5 is at the low end of the range (i.e. 1.5°C).

MIT assessed scenario outcomes (Source: MIT Joint Program)

This finding is not an argument for just letting events play out; 2.8°C would have serious consequences in terms of adaptation. Rather, the finding illustrates that change is underway and highlights the steps needed to accelerate that change. It also strengthens the hand of policymakers as they encourage adoption of a net-zero emissions goal by as many countries as possible.

Returning to this analysis in a decade hence might see the boundaries contract further. Scenarios that continue historical trends of unfettered fossil fuel use no longer seem relevant when a shift toward a low-carbon society is already under way. The task in front of society is now about the pace of change, not whether change can happen.

You can read the MIT report here.

Note: Scenarios don’t describe what will happen, or what should happen, rather they explore what could happen. Scenarios are not predictions, strategies or business plans. Please read the full Disclaimer here.

Featured image courtesy of the UK Met Office.

The importance of sinks

March 2, 2021

A review of the 2018 IPCC Special Report on 1.5°C shows that all four archetype scenarios (P1, P2, P3 and P4) make use of sinks – or the ability to remove carbon dioxide from the atmosphere and store it geologically or retain it within the land. The reasons for needing to do this fall into two categories;

  1. The point at which net-zero emissions is required (i.e. 2050) comes before all anthropogenic emissions can be stopped, so remaining emissions have to be balanced with sinks to remove the same amount of carbon dioxide from the atmosphere as added by remaining sources.
  2. By the time net-zero emissions is reached, the carbon dioxide load in the atmosphere has exceeded that associated with 1.5°C of warming, so sinks are required to lower atmospheric levels at a faster rate than natural decline, ensuring a 1.5°C or lower outcome by the end of the century.

The four scenarios are shown below.

Diagram Description automatically generated
Source: IPCC SR15

In the P1 scenario sink use is minimal, highlighted by an end to land based anthropogenic emissions and the subsequent development of the land as an enhanced sink from mid-century on, at about 5 Gt per annum drawdown of carbon dioxide. P1 makes no use of geological storage. By contrast, the P4 scenario makes very extensive use of geological sinks with BECCS playing a substantial role even as land based emissions are eventually reigned in. But why is there such a difference in sink use between these scenarios?

A deeper dive into the four stories reveals an interesting trend – an almost linear relationship linking cumulative sink capacity to 2100 with the growth in final energy demand (measured as the increase in 2050 demand over 2010 demand).

This trend points to two aspects of the energy transition which are in turn related to the two reasons for needing sinks outlined above;

  1. As energy demand increases and emissions rise from sectors of the economy where no large scale mitigation solutions currently exist, perhaps a sector like aviation, greater and greater sink capacity will be required.
  2. With energy demand rising quickly and a starting dependency on fossil fuels to meet that demand, the carbon budget that equates to 1.5°C is exceeded well before the point of net-zero emissions, which then means extensive sink capacity is required to remove this carbon from the atmosphere and meet 1.5°C later in the century.

That then brings into focus the question of energy demand. In the Energy Transformation Scenarios released recently by Shell, all three scenarios show rising energy demand through the century, although in the Sky 1.5 story this is curtailed from the 2070s onwards due mainly to efficiency practices and rapid electrification (which can also lead to greater efficiency). 

Energy demand growth across all three Shell scenarios contrasts with the IPCC range, where the P1 archetype imagines a fall in energy demand. But a fall in energy demand over the next thirty years is in sharp contrast with history, where energy demand has only ever risen, even as very significant efficiency gains have spread throughout society.

For comparison, over the last 30 years (to 2019), world total primary energy grew by 68%. This derives from GDP growth of 180%, and a Shell assessment of total energy service growth of 130%. In a discussion on energy growth, it is important to focus on non-OECD countries, because that is where the relationship of GDP growth to energy service growth is strongest. OECD countries are not far from the point where energy service growth is matched by energy service efficiency improvement and hence energy demand stays flat. In the last 30 years, non-OECD primary energy growth was over 80% of the global total and in the next 30 years we may see non-OECD growth making up almost all of the global energy demand increase. But this is the portion of the word where population increase continues in many countries and where access to energy is growing at a rapid rate. This in turn creates new demand for energy services. In short, we are more likely to underestimate energy demand than overestimate it.

There are also other reasons for continued energy demand growth.

  • Efficiency rebound on a macro scale is widespread and often not recognised. For example, when I was growing up in Australia in the 1960s, air conditioned cars hardly existed. I still remember when we lived outside the country in an American community (in SE Asia) in 1967 and I got in my first air conditioned car; I really couldn’t believe such a thing was possible. Today, you can’t buy a car without air conditioning. So in the 1960s we had maybe 50 million upscale cars globally with expensive inefficient air conditioners, but now we have over one billion cars with cheap efficient air conditioners. That’s lots more energy than the 1960s.
  • Society continues to find and adopt new and interesting ways to consume energy. When energy is available, it gets used. Think how much more energy intensive our life is compared to our parents or grandparents. One example – millions of people around the world are starting to adopt and make use of Bitcoin, but the media recently reported that Bitcoin ‘mining’ at various sites around the world collectively consumes more electricity than the Netherlands.
  • Adoption of new technologies can lead to explosive growth in energy services. The internet and all the servers and devices connected to it is one such example. It didn’t really exist thirty years ago, at least not as a consumer service.

Even with significant energy efficiency improvement over time, the Sky 1.5 scenario which is comparable with IPCC P1 to P4 in terms of temperature rise (i.e. 1.5°C), sees final energy demand increasing by 49% in 2050 relative to 2010. The scenario also employs significant sink capacity globally to achieve an outcome of 1.5°C in 2100. The cumulative total across nature based and manmade carbon dioxide removal to 2100 is around 1,000 Gt for Sky 1.5. Plotting this on the chart above, we see that although Sky 1.5 has a similar, but slightly higher final energy demand than P4, it makes less use of sink capacity by about 20%.

Both Sky 1.5 and IPCC P4 demonstrate the considerable sink capacity required for a 1.5°C outcome, unless energy demand can be significantly curtailed in the near term and rapid solutions found and deployed for current hard-to-abate sectors.

Note: Scenarios don’t describe what will happen, or what should happen, rather they explore what could happen. Scenarios are not predictions, strategies or business plans. Please read the full Disclaimer here.