Suresh Kumar Govindarajan

These are insightful and highly relevant questions on the current global debate surrounding climate change, energy transition, and the path toward achieving net-zero emissions. Below are responses to each of these key points:

1. Scientific Evidence on CO2 Emissions and Climate Change

Yes, there is scientific evidence that supports and challenges the view that CO2 emissions from fossil fuel combustion are the primary cause of global climate change. Over geological time scales, Earth has experienced significant climate shifts due to natural factors such as volcanic activity, solar radiation variations, and Earth's orbital changes. However, since the late 20th century, there is overwhelming evidence (such as temperature records, ice core data, and climate models) indicating that human activities, particularly the burning of fossil fuels, are the dominant drivers of recent climate change. Some argue that natural variability could still play a role, but the consensus in climate science is that anthropogenic (human-caused) CO2 emissions are the main contributors to the rapid warming observed since the industrial revolution.

2. The Era of Energy Transition

While many countries have committed to transitioning to cleaner energy sources, this transition is uneven, with some nations moving faster than others. The starting points, resources, and challenges differ widely:

• Developed countries tend to have better access to capital, advanced technology, and established infrastructure for renewables. They have also been historically responsible for a large share of emissions and thus face pressures to decarbonize faster.
• Emerging economies often face challenges such as poverty, a heavy reliance on fossil fuels, limited access to renewable technologies, and the need for affordable energy to fuel development. Each country’s energy transition speed and pathway depend on factors like national resources, energy security concerns, and economic priorities.

3. Feasibility of Decarbonizing Electricity in Emerging Economies

Decarbonizing electricity in emerging economies within the next few decades is feasible but challenging. Many of these countries rely on coal, oil, and natural gas for electricity generation, which makes decarbonization difficult. However, emerging economies also have significant renewable energy potential (such as solar, wind, and hydro) that could help in their energy transition. The challenges include financing renewable energy infrastructure, developing energy storage solutions, and ensuring grid reliability. Furthermore, international support, including technology transfer, financing mechanisms (like green bonds), and capacity-building, will be crucial.

4. Advancement of Technology Towards Net Zero

Technology in areas like renewable energy, energy storage, and carbon capture is advancing rapidly but not uniformly across the globe. Developed countries have made substantial progress in deploying and improving these technologies. However, for many developing nations, the cost and technical barriers can slow down adoption. Global cooperation, increased research funding, and innovative financing models (like green technologies and climate finance) can help accelerate technology deployment worldwide.

5. Non-linear Pathways to Net Zero

A non-linear pathway to net-zero emissions is a concern, as the transition may face abrupt shifts, disruptions, and unpredictable challenges. Non-linear factors such as economic crises, technological breakthroughs, geopolitical issues, or sudden climate impacts could affect the pace and direction of decarbonization. For instance, energy system changes might occur faster than anticipated in some regions but slower in others due to structural constraints. Policymakers need to plan for flexibility and resilience in the transition.

6. Reducing Uncertainty in GHG Emissions Reduction Pathways

Yes, reducing the range of uncertainty in greenhouse gas (GHG) emissions reduction pathways is a significant challenge. There are many variables involved, such as technological advancements, policy implementations, global economic trends, and societal behaviors. More accurate and frequent emissions data, as well as advancements in climate modeling, can help reduce uncertainty. Greater international collaboration on emissions reporting, shared climate goals, and transparent data would also improve the predictability of emissions reduction trajectories.

7. Carbon-Neutral Electricity from Fossil Fuels vs. Renewables/Nuclear

Carbon-neutral electricity from fossil fuels with Carbon Capture and Storage (CCS) can technically help in reducing emissions, but it faces challenges such as high costs, efficiency limitations, and the need for large-scale infrastructure for capturing and storing CO2. On the other hand, renewable energy sources (solar, wind, hydro) and nuclear power are considered more sustainable in the long term, as they do not produce direct CO2 emissions during operation. However, both come with their own set of challenges: renewables need solutions for intermittency (e.g., energy storage), and nuclear faces public concerns, waste management issues, and high initial capital costs. Whether CCS outperforms renewables and nuclear depends on the context, particularly the availability of resources and cost considerations.

8. Energy-Intensive Sectors Switching to Low-Carbon Electricity

The energy-intensive sectors (e.g., steel, cement, chemicals, and heavy transport) face significant challenges in switching from fossil fuels to low-carbon electricity. These sectors often require high heat and energy, which is difficult to provide with renewable electricity alone. While electrification is a viable path for some industries (e.g., through electrifying processes), others may require breakthroughs in alternative fuels, such as hydrogen, or new methods like carbon capture. Innovations in industrial processes, alongside renewable electricity, could help these sectors transition, but they are likely to require additional support in terms of technology, infrastructure, and investment to drastically reduce GHG emissions.

In summary, while the path to net-zero emissions is challenging and complex, it is not only necessary but also feasible, depending on how technology, policy, and global cooperation unfold. The transition will vary widely across countries, with many hurdles to overcome, but it is essential for combating climate change and achieving sustainability.

Six roadblocks to net zero — and how to get around them

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https://www.nature.com/articles/d41586-025-00935-1