SIMULATING THE FUTURE: En-ROADS AND THE DRIVE TO LIMIT GLOBAL WARMING

by

Sharizal Ahmad Sobri, Farnaz Sanei, Melika Shabaninasiri, Linu Ann Thomas, Sunanda Plaha, & Sahaana Theivaseelan

Department of Engineering

Nottingham Trent University (NTU)

1.0 INTRODUCTION

Recent reports from the Intergovernmental Panel on Climate Change (IPCC) underscore the narrowing window of opportunity to limit global warming. Current trajectories place the world on a path toward a 3°C temperature rise by 2100, far exceeding the 2°C threshold. This increase would exacerbate extreme weather events, sea-level rise, and biodiversity loss, disproportionately affecting vulnerable populations. The time to act is now, leveraging tools like En-ROADS to enable evidence-based climate action.

The global challenge of climate change demands urgent action to limit global warming to below 2°C above pre-industrial levels, a threshold critical for avoiding catastrophic environmental, economic, and social impacts. Achieving this ambitious goal requires a comprehensive understanding of interconnected factors, including energy systems, land use, industrial processes, and societal behaviours.  The En-ROADS Climate Solutions Simulator (https://www.climateinteractive.org/en-roads/), developed by Climate Interactive and MIT Sloan Sustainability Initiative, offers a powerful, user-friendly platform to explore these dynamics.

En-ROADS enables stakeholders, from policymakers to educators, to model pathways and strategies for mitigating climate change. By simulating the outcomes of various interventions—such as shifts to renewable energy, energy efficiency improvements, carbon pricing, and reforestation—this tool provides evidence-based insights into the complex trade-offs and synergies required to achieve a sustainable future. This introduction delves into how En-ROADS can guide decision-makers in crafting effective policies and strategies to keep global warming below the critical 2°C threshold, ensuring a resilient and equitable future for all.

1.1 Introduction to EN-ROADS Simulation

EN-ROADS (Energy-Rapid Overview and Decision Support) is a dynamic climate solutions simulator developed by Climate Interactive and the MIT Sloan Sustainability Initiative. It is an interactive, user-friendly tool designed to explore the impacts of various policy and technological interventions on global climate outcomes. By simulating real-world dynamics of energy, land use, industry, and societal behaviour, EN-ROADS provides evidence-based insights into the pathways required to address climate change.

At its core, EN-ROADS enables users to test "what-if" scenarios in real time, helping decision-makers, educators, and stakeholders understand the trade-offs and synergies of different strategies. For instance, users can explore the effects of transitioning to renewable energy, implementing carbon pricing, enhancing energy efficiency, or promoting reforestation on global temperature outcomes. What makes EN-ROADS particularly powerful is its ability to bridge the gap between science and policymaking. The simulator integrates complex data on emissions, energy systems, and economics, presenting results in a clear and accessible format. This makes it an invaluable tool for fostering collaborative discussions, building climate literacy, and crafting effective policies to limit global warming to below 2°C—a target critical to preventing severe climate impacts. Figure 1 shows the key interventions on global temperature reduction.

Figure 1: Impact of Key Interventions on Global Temperature Reduction

1.2 The Role of Stakeholders

Addressing the climate crisis is a shared responsibility that requires active participation from all stakeholders:

• Governments: Establishing robust climate policies, investing in green infrastructure, and leading by example in international negotiations.
• Businesses: Driving innovation through sustainable practices, reducing emissions in operations, and adopting circular economy models.
• Communities: Advocating for policy changes, adopting sustainable lifestyles, and participating in local climate initiatives.

These efforts must be coordinated to maximize impact, ensuring that actions in one sector complement those in another. Collective action amplifies the effectiveness of interventions and accelerates progress toward climate goals.

2.0 OVERVIEW OF KEY INTERVENTIONS

The success of interventions varies significantly across regions due to differing levels of development, economic priorities, and resource availability. For instance, while renewable energy adoption has surged in developed nations, many developing countries face barriers such as inadequate infrastructure and financing. Bridging these gaps requires international cooperation and tailored strategies to ensure no region is left behind in the fight against climate change.

2.1 Renewable Energy

Transitioning energy production from fossil fuels (coal, oil, and gas) to renewable energy sources (such as solar, wind, and hydropower) is crucial. Increasing investments in renewable energy infrastructure reduces greenhouse gas (GHG) emissions significantly. Phasing out fossil fuel-based power plants while ensuring grid stability and energy access is essential.

2.2 Energy Efficiency

Implementing technologies and practices that reduce energy consumption in buildings, transportation, and industries can dramatically lower emissions. For example, include upgrading to energy-efficient appliances, retrofitting old buildings, and adopting efficient manufacturing processes. Improved efficiency reduces demand for energy, which complements renewable energy adoption.

2.3 Carbon Pricing

Introducing a price on carbon emissions through carbon taxes or cap-and-trade systems encourages polluters to reduce emissions. Carbon taxes set a fixed price on emissions, while cap-and-trade limits total emissions and allows trading of emission permits. Revenue generated can be reinvested in renewable energy projects or used to support affected communities.

2.4 Land Use

Expanding forests through reforestation and afforestation acts as a natural carbon sink, capturing CO2 from the atmosphere. Promoting sustainable agricultural practices minimizes methane and nitrous oxide emissions. Avoiding deforestation ensures the preservation of existing carbon storage and biodiversity.

2.5 Technology Innovation

Advancing carbon capture, utilization, and storage (CCUS) technologies helps remove CO2 from industrial processes and power plants. Innovations such as green hydrogen, advanced nuclear energy, and energy storage systems can transform energy and industry. These breakthroughs are critical for sectors that are hard to decarbonize, like aviation and heavy industry.

2.6 Behavioural Change

Encouraging individuals to adopt sustainable habits, such as using public transport, conserving energy, and reducing meat consumption, can reduce carbon footprints. Raising awareness about the impacts of consumption patterns fosters societal shifts toward sustainability. Behaviour changes complement policy interventions by reducing demand for high-emission products and services.

3.0 IMPACT OF KEY INTERVENTIONS IN LIMITING GLOBAL WARMING BELOW 2°C

To limit global warming to below 2°C, a combination of targeted interventions across energy, industry, land use, technology, and societal behaviour is critical. As can be seen in Figure 1, each intervention contributes uniquely to reducing greenhouse gas (GHG) emissions and achieving climate goals. Here is an analysis of their impacts:

3.1 Energy Supply

Transitioning from fossil fuels to renewable energy significantly reduces carbon dioxide emissions, as the energy sector is the largest contributor to global GHG emissions. Increasing renewable energy deployment can lower emissions from electricity generation by up to 70-80% by mid-century. Phasing out coal, the most carbon-intensive fuel, provides the quickest reductions in energy-related emissions.

Phasing out fossil fuels and ramping up renewables like solar and wind can reduce energy-related emissions by up to 80% by 2050. Challenges include high upfront costs, grid stability concerns, and resistance from fossil fuel-dependent economies. Solutions such as advanced energy storage systems and subsidies for renewable energy in developing regions can address these issues.

3.2 Energy Efficiency

Enhancing energy efficiency reduces overall energy demand, making it easier to meet needs with low-carbon or renewable sources. In sectors like transportation, buildings, and manufacturing, efficiency improvements can cut emissions by 20-30%. Energy savings also reduce costs, enabling investments in further mitigation measures.

3.3 Carbon Pricing

Carbon pricing internalizes the social cost of carbon, incentivizing industries and consumers to adopt low-carbon technologies. It discourages fossil fuel use while generating revenue that can fund renewable energy, energy efficiency, and adaptation projects. Regions with strong carbon pricing frameworks have demonstrated faster decarbonization compared to those without.

3.4 Land Use

Reforestation and afforestation act as carbon sinks, sequestering millions of tons of CO2 annually. Preserving and expanding forests can offset emissions from sectors like agriculture and transportation. Sustainable agricultural practices, such as reducing fertilizer use and methane emissions from livestock, further mitigate emissions.

3.5 Technology Innovation

Carbon capture, utilization, and storage (CCUS) enables the removal of CO2 from industrial processes and power plants, making it a key solution for hard-to-decarbonize sectors. Technologies like green hydrogen and advanced nuclear power open pathways to decarbonize transportation, heavy industry, and energy storage. Innovation accelerates the deployment of scalable solutions, driving down costs and enhancing global adoption.

3.6 Behavioural Change

Shifts in consumption patterns, such as adopting plant-based diets or reducing energy use can significantly lower individual carbon footprints. Widespread adoption of sustainable behaviours can reduce demand for high-emission goods and services, complementing technological and policy interventions. Behavioural changes often have co-benefits, such as improved public health and reduced air pollution.

 

4.0 THE OUTCOME OF En-ROADS SIMULATION

Figure 2 showcases the output of the En-ROADS Climate Simulator, which is designed to explore how various policies and actions impact global energy use, greenhouse gas (GHG) emissions, and temperature change by the year 2100.

The first graph which is the Global Sources of Primary Energy, illustrates the changes in energy sources (coal, oil, gas, renewables, bioenergy, nuclear, etc.) over time under the selected policy scenario. Notable reductions are visible in fossil fuel usage (coal, oil, and natural gas), with significant growth in renewable energy sources like wind, solar, and others. The transition reflects policies like high taxation on coal and oil, subsidies for renewables, and breakthroughs in new zero-carbon technologies.

The second graph which is the Greenhouse Gas Net Emissions, demonstrates the trajectory of global GHG emissions. The blue line (current scenario) shows a sharp decline, dropping to net-negative emissions by the latter half of the century due to aggressive mitigation strategies. Actions include carbon pricing, improved energy efficiency, and expanded carbon dioxide removal technologies.

The simulator projects a +1.7°C temperature increase by 2100 compared to pre-industrial levels under the current scenario. This improvement is significant compared to the baseline (+3.1°C), indicating that the chosen measures are effective in mitigating climate change.

 

Figure 2: The Outcome of En-ROADS Simulation

 

5.0 TRADE-OFFS AND CHALLENGES ACROSS KEY INTERVENTIONS

Implementing the key interventions to limit global warming below 2°C involves complex trade-offs and challenges. These arise from technical limitations, economic constraints, social resistance and the need for global cooperation. Geopolitical factors complicate climate interventions. International tensions and competition for resources, such as rare earth metals required for renewable energy technologies, can hinder progress. Socio-economic disparities mean that the burden of climate action often falls disproportionately on developing nations, which have contributed the least to global emissions. Equitable mechanisms, like the Green Climate Fund, are essential to ensure that vulnerable countries can actively participate in global mitigation efforts. Addressing these challenges requires transparent governance, equitable resource allocation, and a commitment to inclusive policies. Below is a detailed exploration of the trade-offs and challenges associated with each intervention.

5.1 Energy Supply

Trade-offs:

Shifting to renewable energy requires significant upfront investment in infrastructure such as solar farms, wind turbines, and energy storage systems. Intermittency of renewables (e.g., solar and wind) can strain grid reliability without adequate storage solutions.

Challenges:

Fossil fuel-dependent regions may resist the transition due to potential job losses in coal, oil, and gas industries. High material demand for renewable technologies (e.g., rare earth metals) can lead to supply chain and environmental issues.

5.2 Energy Efficiency

Trade-offs:

Improving efficiency often requires retrofitting existing infrastructure which can be costly and disruptive. Efficiency gains in one area may lead to a rebound effect where savings are offset by increased consumption elsewhere.

Challenges:

Scaling efficiency measures in developing countries can be difficult due to limited financial and technical resources. Lack of awareness and regulatory support can slow adoption rates in households and businesses.

5.3 Carbon Pricing

Trade-offs:

Carbon taxes can disproportionately affect low-income households, increasing energy costs for basic needs. Industries may relocate to regions with less stringent carbon pricing, causing “carbon leakage.”

Challenges:

Achieving political and public acceptance of carbon pricing schemes can be difficult, particularly in regions reliant on fossil fuels. Ensuring effective use of revenue generated from carbon pricing requires transparent governance.

5.4 Land Use

Trade-offs:

Large-scale reforestation may compete with agricultural land, potentially raising food prices. Managing reforested areas sustainably is resource-intensive and can lead to conflicts over land rights.

Challenges:

Protecting forests from illegal logging, fires, and encroachment requires strong enforcement mechanisms. Implementing sustainable agricultural practices can be costly for farmers, particularly in developing countries.

5.5 Technology Innovation

 Trade-offs:

Carbon capture and storage (CCS) technologies are expensive and energy-intensive, reducing their efficiency. Investment in CCS may divert resources from renewable energy development.

Challenges:

Scaling up advanced technologies like green hydrogen and nuclear power requires significant research, development, and infrastructure. Public opposition to certain technologies (e.g., nuclear energy) can slow their deployment.

5.6 Behavioural Change

Trade-offs:

Encouraging lifestyle changes such as reducing meat consumption or car use, can face resistance due to cultural habits and personal preferences. Over-reliance on voluntary behavioural changes may not yield sufficient emission reductions without supporting policies.

Challenges:

Influencing mass behaviour requires sustained education, awareness campaigns, and incentives. Equity concerns arise when lifestyle shifts are easier for affluent populations but harder for those with limited resources.

6.0 SOLUTIONS FOR CHALLENGES ACROSS KEY INTERVENTIONS

Overcoming the challenges and trade-offs of key climate interventions requires a multi-faceted approach that integrates technological innovation, policy reforms, financial mechanisms, and public engagement. Here are detailed solutions for each intervention's challenges:

6.1 Energy Supply

Build advanced grids with energy storage solutions (e.g., batteries, pumped hydro) to manage renewable intermittency and ensure grid stability. Provide training and job transition programs for workers in fossil fuel industries to help them adapt to new roles in the renewable energy sector. Subsidize renewable energy deployment in developing countries to accelerate global adoption and ensure equitable access.

6.2 Energy Efficiency

Introduce tax breaks, subsidies, or low-interest loans to encourage retrofitting of buildings and industrial facilities. Mandate energy efficiency standards for appliances, vehicles, and industrial equipment. Launch public campaigns to educate households and businesses about cost savings and environmental benefits from energy efficiency measures.

6.3 Carbon Pricing

Use carbon tax revenues to fund renewable energy projects, subsidize energy bills for low-income households or support vulnerable industries during the transition. Work towards international agreements to prevent carbon leakage by establishing consistent carbon pricing mechanisms across countries. Ensure that carbon pricing schemes are transparent and revenues are used effectively to build public trust.

6.4 Land Use

Combine reforestation initiatives with sustainable agriculture and urban planning to avoid competition for land. Use technology (e.g., satellite monitoring) to prevent illegal logging and deforestation. Provide subsidies or incentives for adopting sustainable farming practices, such as organic farming and methane-reducing feed for livestock. Involve local communities in reforestation projects to ensure equitable land rights and long-term sustainability.

6.5 Technology Innovation

Governments and private sectors should invest heavily in research and development for carbon capture, advanced nuclear power, and green hydrogen. Collaborate between industries, governments, and academia to accelerate innovation and commercialization of clean technologies. Deploy small-scale demonstrations of advanced technologies to test feasibility before large-scale rollouts. Address public concerns about technologies like nuclear energy through transparent communication and stakeholder engagement.

6.6 Behavioural Change

Use subsidies, tax breaks, or credits to encourage sustainable behaviours, such as purchasing electric vehicles or using public transportation. Conduct campaigns highlighting the climate benefits of plant-based diets, reduced energy consumption, and waste reduction. Design behavioural interventions tailored to regional cultural and economic contexts to maximize acceptance. Combine behavioural nudges with policy measures (e.g., mandatory recycling laws or energy-saving regulations) to amplify impact. By combining these solutions, we can address the challenges of climate interventions while fostering a collaborative, inclusive, and sustainable path to limiting global warming below 2°C.

7.0 RECOMMENDATIONS

To achieve the goal of limiting global warming to below 2°C, a strategic and integrated approach across sectors is essential. Below are actionable recommendations based on key interventions:

7.1 Energy Sector Transformation

Governments should prioritize investments in solar, wind, geothermal, and other renewable energy sources through subsidies and tax incentives. Implement policies to reduce coal, oil, and natural gas consumption, such as banning new fossil fuel infrastructure and eliminating fossil fuel subsidies. Develop large-scale energy storage systems to address the intermittency of renewable sources and ensure grid stability.

7.2 Boost Energy Efficiency

Introduce mandatory efficiency standards for appliances, vehicles, and industrial processes. Launch large-scale initiatives to retrofit existing buildings with energy-saving technologies like insulation and efficient lighting. Promote the adoption of smart grids, energy management systems, and IoT devices to optimize energy use.

7.3 Implement Carbon Pricing Mechanisms

Adopt carbon taxes or cap-and-trade systems that cover all major emitting sectors, ensuring a level playing field. Use revenues from carbon pricing to fund renewable energy projects, support vulnerable communities, and drive innovation. Coordinate international efforts to minimize carbon leakage by harmonizing carbon pricing policies across borders.

7.4 Promote Sustainable Land Use

Commit to large-scale reforestation and afforestation programs to enhance natural carbon sinks. Support farmers in adopting climate-smart practices, such as agroforestry, reduced fertilizer use, and methane-reducing livestock feed. Strengthen protections for existing forests and ecosystems to prevent deforestation and habitat loss.

7.5 Drive Technological Innovation

Governments and private sectors must invest heavily in research for carbon capture and storage (CCS), green hydrogen, and advanced nuclear energy. Support pilot projects to test and refine emerging technologies before full-scale implementation. Foster partnerships to accelerate the commercialization of clean technologies and lower costs.

7.6 Encourage Behavioural Change

Educate the public on reducing meat consumption, conserving energy, and adopting circular economy practices. Invest in public transit systems and infrastructure for walking and cycling to reduce reliance on private vehicles. Use behavioural science techniques, like default green energy options or small financial incentives, to encourage sustainable choices.

7.7 Strengthen Global Cooperation and Finance

Mobilize funding for mitigation and adaptation in developing countries through mechanisms like the Green Climate Fund. Strengthen commitments under the Paris Agreement and ensure accountability through transparent reporting systems. Provide resources to communities dependent on fossil fuel industries to transition to green jobs and livelihoods.

7.8 Foster Education and Innovation

Incorporate climate change education into school curriculums and public awareness campaigns. Create centres for climate technology and policy research to share solutions globally. Support community-led initiatives that promote local resilience and sustainable practices.

8.0 CONCLUSIONS

Limiting global warming to below 2°C is both a challenge and an opportunity to secure a sustainable future for our planet. Achieving this goal requires bold and coordinated action across sectors, including energy, land use, industry, and societal behaviour. Through interventions such as transitioning to renewable energy, improving energy efficiency, implementing carbon pricing, reforesting degraded lands, fostering innovation, and promoting sustainable lifestyle choices, it is possible to significantly reduce greenhouse gas emissions and curb global warming. While each intervention presents unique trade-offs and challenges, integrated solutions—backed by technology, policy, and finance—can maximize their impact and address barriers effectively. Tools like the EN-ROADS simulator underscore the importance of multi-faceted approaches and highlight the synergies needed to meet climate targets.

To succeed, collaboration is essential. Governments, businesses, and individuals must work together to enact policies, adopt innovations, and drive cultural shifts. Additionally, ensuring equity and justice in climate solutions will be critical to ensure that the benefits of mitigation efforts are shared by all, especially vulnerable communities. The path to staying below 2°C is ambitious but achievable. By prioritizing immediate action and long-term planning, humanity can transform the climate crisis into an opportunity to create a more resilient, inclusive, and sustainable world for future generations.

The road to achieving the 2°C target is fraught with challenges but is not insurmountable. Each sector and stakeholder has a role to play in this global effort. Innovation, inclusive policies, and community-driven initiatives are critical pillars of success. The question is no longer whether we can limit global warming, but whether we will rise to the occasion with the urgency and unity this crisis demands.