Land use change – Shell Climate Change

One of the differentiating features of the Shell scenarios work is the timeline through to 2100 that is offered. Many other energy scenarios more typically model through to 2050, such as in the World Energy Outlook from the IEA. But for a thorough analysis of the long term emissions of CO₂ and temperature, a view to 2050 isn’t sufficient.

The Shell scenarios have always recognised that while fossil fuels lose market share and eventually make their way out of the energy system, in the medium term there will continue to be abundant use. This is the result of a world that still depends on fossil fuels for nearly 80% of global energy needs and for many other uses too. Even in the long term, under the most rapid transition pathway we could devise, a modest tail of fossil fuel use extends into the 22^nd century before finally declining to almost zero use. Without managing carbon emissions, the CO₂ from this tail will add up, which in turn would drive up temperature until fossil fuel use stops, given increases in temperature come from the accumulation of CO₂ in the atmosphere over time, not the level of CO₂ emissions in any given year.

The 2025 Energy Security Scenarios extend through to 2100 and therefore offer insight into this long tail of fossil fuel use and how the associated CO₂ emissions might be managed. The scenarios comprise three storylines; two exploratory scenarios called Surge and Archipelagos, and Horizon, our third scenario, normative and illustrative of a rapid acceleration of the energy transition. In Surge, an era of robust economic growth is ushered in by artificial intelligence technologies, with the transition accelerating as a result, whereas the Archipelagos scenario sees a world where trade friction and geopolitics impinge on the speed of the transition.

In Horizon, the CO₂ still to come, assuming no management of CO₂, amounts to 1 trillion tonnes, enough to take the world to almost 2°C from where we are today. In Surge and Archipelagos the numbers are 1.7 trillion tonnes and over 2 trillion tonnes respectively, which implies temperatures well over 2°C. The long tail is important because climate action to date has largely assumed that fossil fuels could be quickly phased out by a rapid transition. Rather, a dual focus is required, comprised of building a new energy system but also recognising the need to mange the CO₂ from the legacy system as well.

While the Horizon scenario serves as a useful reference for the pathway to net-zero emissions in 2050, Surge and Archipelagos offer a flavour of the world that we are actually dealing with. Surge embodies a rapid transition, with technologies like solar PV and grid batteries scaling at rates considerably faster than now. But it is also a world of higher economic growth, which brings with it more demand for goods and services (which includes those solar PV panels) and therefore more energy demand. In the short term that means even more fossil fuel use. But by the end of the century fossil fuels have shifted from the current level of 78% of the energy system to just under 10% – a startling transition in 75 years. With a focus on carbon management, net-zero emissions comes earlier, in 2080, too late for limiting warming to 1.5°C, but sufficient for 2°C in 2100 after a short period of overshoot of 2°C.

Nevertheless, Surge still requires a commercial breakthrough for the deployment of carbon capture and storage (CCS) technology. In the scenario this happens via direct air capture (DAC) with geological storage (DACCS), which is deployed at very large scale after 2040. The big technology companies, seeking ways to manage their growing indirect carbon footprints, step in and invest. DAC also lends itself to modular assembly line production, which is how the technology scales rapidly. The scenario recognises that a complete end to fossil fuel use is a 100-year journey, during which time carbon management must play an increasing role.

A DACCS unit operating late in the century in **Surge** (AI generated).

The three scenarios don’t just focus on technology to capture carbon but also highlight the importance of land carbon management. This includes ending deforestation, encouraging the agriculture sector to engage in carbon farming (soil carbon management), embarking on large scale reforestation and protecting critical ecosystems with high carbon stocks, such as mangroves, wetlands, and grasslands. The size of the land management prize, as demonstrated in the Horizon scenario, is 600 billion tonnes of CO₂ over the course of the century, or 15 years of current CO₂ emissions.

The current global CO₂ story can be illustrated as shown below, with most CO₂ emissions coming from fossil fuel use, but there are contributions from current land use activities and industries such as cement manufacture. The bioenergy industry is shown as carbon neutral, as the CO₂ that is emitted when the fuel is used is reabsorbed when the originating biomass grows.

By 2060 in the Surge scenario, the global CO₂ story has changed considerably. Fossil fuel use has dropped by about half but remains a big part of the energy system. However, emissions are down by nearly 75% due to extensive carbon management activities. By 2080, when Surge reaches net-zero emissions, fossil fuel use has fallen by two-thirds, but is still important in industry and aviation.

The importance of carbon management throughout this century cannot be understated, and this was the message from a recent Tony Blair Institute report as well. Their report states (amongst other key points);

Prioritise global investment in carbon capture –
- investing in solutions that capture emissions at source before they reach the atmosphere, together with breakthrough technologies like direct air capture that permanently remove carbon. Both are technologically feasible but need policy and capital to scale.

Scale up nature-based solutions
- from planting forests to developing carbon-smart crops, we must harness the power of nature and science together. Nature is one of our best allies in this fight, and we need to back it with smart science and innovation.

Coming back to the evidence from the scenario stories, managing carbon in this century means the difference between limiting warming to a level society can adapt to or allowing the surface temperature rise to exceed 2°C, and possibly by several tenths of a degree.

Note: Shell Scenarios are not predictions or expectations of what will happen, or what will probably happen. They are not expressions of Shell’s strategy, and they are not Shell’s business plan; they are one of the many inputs used by Shell to stretch thinking whilst making decisions. Read more in the Definitions and Cautionary note. Scenarios are informed by data, constructed using models and contain insights from leading experts in the relevant fields. Ultimately, for all readers, scenarios are intended as an aid to making better decisions. They stretch minds, broaden horizons and explore assumptions.

I recently had the honour to represent Shell as an industry observer and panellist at the 80^th anniversary of the International Civil Aviation Organisation (ICAO). This important United Nations agency emerged during the final months of the Second World War, after several years of negotiation. Agreement was reached in early December 1944 at the famous Stevens Hotel in Chicago. 80 years later delegates met again at the same location, now the Hilton Chicago, to celebrate the achievement and to recognise all that ICAO has done over the years to steer civil aviation to be such a successful, safe and highly valued global enterprise.

Today civil aviation constitutes some 28,000 planes carrying nearly 5 billion passengers per year and over 60 million tonnes of cargo, but this operation runs almost exclusively on jet fuel derived from crude oil. In 2024 about 7 million barrels per day of jet fuel is consumed by civil aviation activities, with a resultant global CO₂ footprint of about 1.1 billion tonnes annually, or just over 3% of global energy related CO₂ emissions.

In Chicago, one of the key themes of the 80^th anniversary event was sustainability, with CO₂ emissions from the sector prominent within the panel discussions. While there were some fascinating discussions about short haul electric aviation and longer haul hydrogen powered planes, these upcoming technologies are not going to make any real dent in the aviation carbon footprint for some decades, so the focus for now is on the fuel used by existing planes and those being built with similar engine types over the coming twenty or more years. Given the very long lead times in aviation to develop, test and certify as safe even minor variations of the current technology set, we shouldn’t expect new technologies to displace the existing set anytime soon.

Sustainable aviation fuel (SAF) has become a key focus for the aviation industry. These are fuels that have their origin outside the fossil fuel supply chain, such as from biogenic sources, various waste streams and eventually via direct synthesis from carbon and hydrogen molecules derived from the air and water. As such, their carbon footprint can be much lower than conventional fuel. Carbon emissions can still result from land use change, when biogenic feedstocks are grown and harvested, and when energy is used in the production and transport of SAF. For example, using SAF today (the predominant current feedstock being used cooking oil) can result in a reduction of up to 80% in carbon emissions compared to conventional jet fuel, depending on the feedstock used, production methods, and supply chain logistics (IATA).

In the Sky 2050 scenario, developed as part of The Energy Security Scenarios published by Shell in 2023, SAF make major progress in replacing fossil derived fuels. Nevertheless, even with the rapid progress illustrated in Sky 2050 to limit warming to less than 1.5°C by 2100, the SAF journey for aviation is one that takes over 50 years.

Within this storyline, another discussion emerges and this featured in the panel sessions at the ICAO 80^th event in Chicago. It’s the issue of land use to make the significant amount of biogenic SAF. By 2065 in the chart above, biogenic SAF production has passed 6 million barrels per day, eclipsing the current 2.7 million barrel per day production of biofuels, which are primarily for cars and trucks. Such a level of production has raised concerns about the sustainability of these fuels, given the amount of land that might be needed to grow the crops and whether or not that competes with the need to grow crops for food or leads to further deforestation for agriculture in some parts of the world.

This is a valid set of questions and to help answer them there is a new analysis conducted by MIT and co-authored by three of my colleagues; Land-use competition in 1.5°C climate stabilization: is there enough land for all potential needs?; Gurgel A, Morris J, Haigh M, Robertson AD, van der Ploeg R and Paltsev S (2024), Front. Environ. Sci. 12:1393327. doi: 10.3389/fenvs.2024.139332. The MIT earth-system integrated modelling capability is ideal for such complex questions.

In this analysis the data in the Sky 2050 scenario is used to create a deeper understanding of the land pressures that confront the world. There is a need to grow food and potentially supply much more bio-energy from the land, and consideration must also be given to continued human development, land for wind turbines and solar PV and for land management and restoration to preserve biodiversity and grow the land carbon stock. These current and future needs all intersect.

The authors found that with proper regulatory policies and radical changes in current practices, global land is sufficient to provide increased consumption of food per capita (without large diet changes and accounting for a larger population) over the century while also utilizing 2.5–3.5 billion hectares (Gha) of land for nature based practices that provide a carbon sink of 3–6 gigatonnes (Gt) of CO2 per year as well as 0.4–0.6 Gha of land for energy production—0.2–0.3 Gha for 50–65 exajoules (EJ) per year of bioenergy and 0.2–0.35 Gha for 300–600 EJ/year of wind and solar power generation.

The authors set out the case starting with the split of current global land use, shown below.

They note that global land use was quite stable before the Industrial Revolution, but in the middle of the nineteenth century, changes in land use from natural vegetation to pasture and cropland accelerated—1.08 Gha of natural forests and natural grassland that existed in 1800 became agricultural areas by 1900, and had risen to 3.41 Gha converted by 2000. The most recent 50 years have experienced declining rates of land use conversion worldwide (refer to 4.1 Global land use: 1700–2100, in the paper).

Looking forward, land use becomes a critical consideration in any scenario. There will be more demand for food, there will be more renewable energy production, urban areas will expand and we are likely to see greater demand for bioenergy. At the same time, growing societal pressure to address biodiversity loss may become overwhelming for policymakers and planners, as well as the need to manage global carbon stocks much more proactively. As such, well financed nature-based solutions (NBS) become important, as can be achieved through carbon markets. The paper finds that the two largest adopted options are related to agricultural areas, such as in cropland (including both biochar and a broad suite of regenerative agricultural practices) and optimal grazing in pasture area. Natural forest protection also increases. Other relevant NBS practices accumulate to sizeable amounts by the end of the century, which is the case for reforestation of natural forest areas. Total land managed for NBS by the end of the century is projected to be about 3.5 Gha, of which 0.77 Gha is related to forest, 1.17 Gha to cropland, 1.17 Gha to pasture, 0.26 Gha to grassland and 0.15 Gha to other land types. Globally, the analysis finds there is enough land in each category to accommodate the NBS projections from Sky 2050, while also ensuring growing demand for food and other land-based products is met.

The paper authors project that global land area dedicated to bioenergy more than doubles by mid-century. It grows from about 100 Mha in 2020 to 242 Mha in 2050 and 286 Mha by 2100. Dedicated biomass growing areas enable growing bioenergy consumption. The total commercial bioenergy use grows from about 20 EJ in 2020 to about 50 EJ in 2050, and about 70 EJ in 2100. Land use at the global level can accommodate these demands expected under a 1.5°C climate stabilization scenario. At the regional level, however, challenges to integrate all land uses may arise and the paper explores this aspect in further detail.

The novelty of the study is in providing a clear message that it is possible to meet the land needs for major human requirements such as food and energy, while protecting and restoring land more broadly. The study shows the feasibility of achieving the land-use optimization needed for a climate stabilization scenario. With all inherent uncertainty about the potential cost reductions for existing technologies and deployment of new regulatory and technological options, one message is clear: there is an urgent need for advancing sustainable land management for food, energy and nature.

Note: Shell Scenarios are not predictions or expectations of what will happen, or what will probably happen. They are not expressions of Shell’s strategy, and they are not Shell’s business plan; they are one of the many inputs used by Shell to stretch thinking whilst making decisions. Read more in the Definitions and Cautionary note. Scenarios are informed by data, constructed using models and contain insights from leading experts in the relevant fields. Ultimately, for all readers, scenarios are intended as an aid to making better decisions. They stretch minds, broaden horizons and explore assumptions.

Category: Land use change

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Future fuels, food and land use implications