Subject of Discussion

Climate change mitigation is a broad-ranging effort that is developing daily as an industry and institution, with abundant detailed information that seems to leave little room for misunderstanding. Moreover, since each country's systems and initiatives differ significantly, conveying these details in this article would deviate from its purpose. However, among the things that are somewhat believed or widely accepted, there are many aspects that are problematic when considered calmly. Therefore, through collectively pointing out such issues, this article organizes fundamental knowledge for understanding essential problems.

Confirmation of Fundamental Facts

CO₂ Emissions by Major Countries

First, let's confirm the facts about emissions by country. Particularly when considering specific countermeasures, cooperation among nations is unavoidable. According to The Global Carbon Budget 2022, the following data compares carbon emissions by country in 2021. China ranks first with 32% of the total, the United States second with 14%, Russia third with 8%, India fourth with 8%, Japan fifth with 3%, and other countries and regions account for the remaining 39%.

Looking at these facts, it is clear that the trends in China and the United States play an extremely important role. For this reason, arguments that shift responsibility to China and the United States are often seen. However, it can be understood that the 39% portion of other countries and regions also has a sufficiently large impact. In other words, this is a structural problem that cannot be solved through consensus among only the major emitting countries. Therefore, long-term efforts by transnational and scientifically-oriented institutions like the IPCC that promote consensus among nations become important.

Since the IPCC is not a scientific research institution but an organization for establishing consensus, for example, regarding the subject of "human influence on the climate system," in the Fifth Assessment Report, an agreement was reached declaring that "warming of the climate system is unequivocal, and human influence on the climate system is clear." However, in the Sixth Assessment Report, a more concrete expression was adopted: "It is unequivocal that human influence has warmed the atmosphere, ocean and land. Widespread and rapid changes in the atmosphere, ocean, cryosphere and biosphere have occurred." Since the items to be declared are extensive, please refer to the IPCC reports for details.

Power Generation Mix of Major Countries

Next, let's also confirm the power generation mix of major countries. According to IEA (World Energy Balance 2022) data, it is as follows. China and India's coal consumption stands out prominently. The U.S. and Russia, being rich in natural gas resources, appear to be supported by LNG. Canada and Brazil's hydropower is also particularly striking. France's nuclear power is also notable, and the progress of solar and wind power generation efforts by European countries can be observed.

Indeed, Europe is a developed region in renewable energy and is known for strict CO₂ regulations. Meanwhile, the image has become established that Japan is still relying on thermal power generation and is lagging behind. Certainly, renewable energy accounts for a large proportion in Europe as a whole, but France prominently uses nuclear power generation.

In Europe's case, like Japan, natural fossil fuel resources are scarce, and they have depended on Russian LNG (natural gas), but there were concerns about stable supply from a political perspective. (In fact, an explosion occurred on September 26, 2022, at Nord Stream, which exports Russian natural gas to Europe.) LNG has been Germany's Achilles' heel and a major challenge for Europe, so escaping from LNG dependency has long been a significant issue. However, using coal is difficult in Europe, where environmental protection groups have strong influence. Yet Germany faces a deadlock due to its promotion of zero nuclear power. Therefore, if they import nuclear-derived electricity from France, there would be no domestic legal problems since there are no nuclear power plants in their own country. Given this background, when looking at Europe as a whole, nearly 30% relies on nuclear power.

Incidentally, as a side note, given the above, readers who have understood the above can correctly point out that the following type of argument occasionally seen in Japan is fundamentally misguided:
"Germany is wonderful. Japan should also aim for zero nuclear power like Germany by introducing renewable energy and avoiding fossil fuels."

Also, in Europe, efforts have been made to focus on biomass power generation among renewable energies. However, as pointed out in the biomass power generation section above, it should be noted that the evaluation of biomass power generation within the EU may change.

Power Generation Efficiency and CO₂ Emissions by Generation Method

At the end of the fact-checking chapter, let's confirm what major power generation methods exist in the world and what their generation efficiency and CO₂ emissions are.

Generation Method	Generation Efficiency	CO₂ Emissions per kWh
Solar	20%	NA
Wind	20-40%	NA
Hydro	80%	NA
Geothermal	10-20%	NA
Biomass	20%	1257g
Nuclear	33%	NA
LNG (Single)	38%	476g
LNG (GTCC)	57%	310g
LNG (GTFC)	63%	280g
Coal (Conventional)	34-40%	958g (global standard)
Coal (USC)	40-48%	806g
Coal (IGCC)	46-50%	650g (1700℃ class)
Coal (IGFC)	55%	590g

There are various other approaches such as diesel power generation, but these are omitted. In any case, power generation methods that do not emit CO₂ can be said to be clean, except for nuclear power. Also, it should be noted that biomass power generation, which is commonly considered clean, does emit CO₂. Additionally, the next-generation LNG GTFC has a high generation efficiency of 63%, second only to hydropower, and the next-generation coal-fired IGFC is likely to achieve a high efficiency of 55%.

However, even with the highly efficient LNG (GTFC) method, it emits 280g of CO₂ per kWh, so if this accumulates worldwide, it is inevitable that it will have a significant impact.

Thinking this way, the following question arises.

Is Nuclear Power Generation Clean?

The following claims are often made regarding nuclear power generation:

• Nuclear power generation is "clean energy"
• Nuclear power generation is energy efficient and provides "low-cost electricity"
• Nuclear power plants must never be allowed because the damage from accidents would be catastrophic

Let's examine these.

Nuclear Power Generation Cannot Possibly Be "Clean"

I would like to point out that the argument that nuclear power generation is "clean because it does not emit CO₂" is fundamentally logically flawed. People who say such things have made not emitting CO₂ their goal and their thinking has stopped there. Why should we not emit CO₂ in the first place? It is because global warming is anticipated, and as a result, human living conditions are expected to deteriorate significantly, and catastrophic damage to biodiversity, including wild animals and plants, is anticipated. In other words, according to the original intent, something that does not have the possibility of significantly deteriorating people's living conditions or causing catastrophic damage to biodiversity can be called "clean." In contrast, the damage when an accident occurs at a nuclear power plant is needless to say. Therefore, nuclear power generation cannot possibly be truly "clean."

Is Nuclear Power Generation Energy Efficient and Provides "Low-Cost Electricity"?

The energy efficiency of nuclear power generation is about 33% as shown in the table above. While it is good compared to the poor efficiency of other alternative energies, it is nowhere near as good as fossil fuel-based thermal power generation. This efficiency cannot be touted as good.

So what about price? The following is the breakdown of nuclear power generation costs disclosed by Japan's Agency for Natural Resources and Energy. This is the result of significantly revising the cost calculation method based on lessons learned from the nuclear accident caused by the Great East Japan Earthquake.

Nuclear power costs can be divided into "generation cost" and "social cost" as follows. Through such cumulative calculations, the generation cost is 10.1 yen per kWh.

• Generation Cost: Costs related to the construction and operation of power generation facilities. Specifically, this includes facility construction costs, fuel costs, operation and maintenance costs, nuclear fuel cycle costs for processing used nuclear fuel for reuse as fuel, costs for decommissioning measures (back-end costs), and additional safety measure costs based on new regulatory standards established in 2013.
• Social Cost: Costs indirectly related to nuclear power plant operation, such as accident risk response costs including compensation costs, and subsidies to nuclear plant construction sites (taxes). Accident risk response costs assume about 9.1 trillion yen, based on the accident response costs at Fukushima Daiichi Nuclear Power Plant, assuming an accident at a 1.2 million kW nuclear plant.

Let's compare the generation unit price calculated with this approach across different power sources.

Indeed, when comparing horizontally like this, nuclear power generation costs certainly seem competitive. It appears that "low-cost electricity" itself can be claimed.

Must Nuclear Power Plants Never Be Allowed Because the Damage from Accidents Would Be Catastrophic?

This problem is also a difficult theme involving political issues. There are two points of discussion here:

• Compared to what is the damage "catastrophic"?
• Is not allowing new nuclear power plants an appropriate solution to the assumed problem?

Japan's Agency for Natural Resources and Energy assumes accident risk response costs of about 9.1 trillion yen, based on the Fukushima Daiichi Nuclear Power Plant accident response costs, assuming an accident at a 1.2 million kW nuclear plant. Even so, when viewed as a unit price per kWh, it only has an impact of 0.3 yen. Is this unacceptably high?

Furthermore, our original problem should have been more serious. If we leave the increase in CO₂ concentration unchecked, humanity as a whole will suffer damage, nature as a whole will suffer damage, and the global environment will become one from which recovery cannot be expected over the ultra-long term. Rare nuclear accidents that occur in small parts of the earth do not, for better or worse, become catastrophic threats that threaten the entire earth's environment. In other words, while the damage to local residents in case of an accident is naturally catastrophic, it cannot be said to be catastrophic compared to the seriousness and catastrophic nature of the entire earth's environmental problems.

Next, not allowing new nuclear power plants means, for example in Japan, relying on thermal power generation, which is nothing less than strangling our children and grandchildren slowly from the perspective of CO₂ emissions. The attitude of "I won't allow nuclear power plants as long as I'm alive, so we can use thermal power, but even if future generations cannot live in that environment, I won't suffer so it doesn't matter" is unlikely to gather much respect.

In other words, the claim that "new nuclear power plants should not be allowed to eliminate the possibility of causing catastrophic damage to local residents" does not seem strong enough to overcome the claim that "nuclear power plants need to be introduced (even temporarily) to prevent the possibility of causing catastrophic damage to future inhabitants of the earth".

Questions Remaining About High-Level Radioactive Waste

In nuclear power generation, plutonium-239 is produced based on uranium-238. Plutonium-239 is generated when uranium isotopes contained in reactor fuel rods undergo nuclear transformation. Plutonium-239, along with uranium-235, has high fissionability. In particular, high-purity plutonium-239 can be mass-produced much more cheaply than weapons-grade highly enriched uranium-235, so it is used in nuclear weapons and nuclear power plants. The half-life of this plutonium-239 is 24,000 years.

It takes 24,000 years for radioactivity to halve! 50,000 years to become one-quarter! By that time, the next ice age will have arrived, and it's questionable whether humanity will have survived. When we talk about this timescale, it exceeds the range where conventional assumptions make sense. High-level radioactive waste is supposed to be buried deep underground, but what happens if the nation managing it becomes a terrorist state? Even SF-like assumptions become normal scenarios that could naturally occur on this timescale. Rather, isn't the conventional assumption of "management by a proper nation" something that cannot be trusted at all, like a myth?

Meanwhile, regarding the final disposal facilities for high-level radioactive waste, working groups have been set up gathering government bureaucrats and scholars from developed countries to discuss and decide on management frameworks and laws. However, it is questionable how decisions are being made, as it is impossible to discuss unconventional assumptions spanning tens of thousands of years in places of wise, conventional, and official meetings.

Who submits a 50,000-year management plan to whom, and who approves that budget?
Is this perhaps expecting that future technological innovations will somehow solve this problem? If so, isn't that too optimistic?

Is Biomass Power Generation Clean?

What is Biomass Power Generation?

Biomass refers to biological resources derived from animals and plants, and biomass power generation generates electricity by "directly burning" or "gasifying" these biological resources. Looking at the classification of biomass fuel raw materials, you can see that a wide variety of fuels are used.

Thinned wood, livestock excrement, food waste, wheat straw, rice husks, rice straw, waste paper, and more - efforts and research are actively being conducted to burn anything and somehow create new energy sources. This itself is a wonderful initiative, and there is potential for technological innovation to emerge from such efforts.

Do Not Be Deceived by "Biomass Power Generation is Carbon Neutral"

Now, this biomass power generation has a generation efficiency of about 20% and emits as much as 1257g of CO₂ per kWh. This power generation performance is clearly significantly inferior to fossil fuel thermal power generation. Why is such a thing justified and included among "clean energy"? It is because of the concept of "carbon neutrality."

Biomass power generation is often explained as "carbon neutral" because the CO₂ emissions at the combustion stage of the fuel plants and the CO₂ absorption through photosynthesis during the plant growth process offset each other. However, this is premised on the assumption that plants will regenerate to the same extent or more, absorbing the same amount or more of CO₂ in the process of regeneration compared to the increase in CO₂ from "combustion."

Therefore, if forests are harvested faster than they can regenerate, they will not regenerate to their original state, and carbon neutrality does not hold. Without evaluating this, thinking stops at chanting the mantra that biomass power generation is carbon neutral and therefore clean energy. So let's look at the transition of global forest area according to the Global Forest Resources Assessment 2020 in the following table.

Year	Forest Area (1000 ha)
1990	4,236,433
2000	4,158,050
2010	4,106,317
2020	4,058,931

The world's forests have decreased by 4.2% over 30 years. At this point, it can be confirmed that "carbon neutrality" does not logically hold because the premise that "plants regenerate to their original state," which is the basis for justifying biomass power generation at the macro level, has collapsed. In fact, the European Commission's Joint Research Centre states in Carbon accounting of forest bioenergy that the assumption that biomass power generation is carbon neutral is "incorrect."

Supplementary Explanation for Minor Counterarguments

I am of course aware that there are detailed counterarguments to this. For example, the claim that forests also emit CO₂ through the decomposition of trees by microorganisms, so using that portion as fuel is the same thing, and if it's going to be emitted anyway, it's okay to use it as fuel.
This is a type of self-serving sophistry, but since it's confusing and people might be deceived, let me explain it correctly.

Let me reorganize the fundamental philosophy.
The original concept of carbon neutrality was that CO₂ exchange through the atmosphere between the "plant world" and the "human world" should balance out to plus-minus zero.

The above sophistry expands the interpretation of "carbon neutrality" to include the "soil world," saying, "The soil is not a carbon-fixing entity but actually a CO₂-emitting entity. This CO₂ emission has been able to maintain neutrality even though it has been emitted, so if humans emit instead of natural decomposition, the amount emitted is the same, so it's okay."

However, if we revise the concept of carbon neutrality to include the "soil world," it must be defined as CO₂ exchange through the atmosphere among the "plant world," "soil world," and "human world" balancing out to plus-minus zero. Here, the only CO₂ absorption source is the "plant world." The CO₂ release rate from the "soil world" has been extremely gradual up to now, and the "neutral equilibrium level" has been maintained by the equally gradual absorption by the "plant world." However, if only the release rate of the "soil world" is artificially accelerated, naturally, neutrality cannot be maintained. If the emission rate of the "soil world" is artificially accelerated, unless the absorption rate of the "plant world" is artificially accelerated by the same amount, the disrupted equilibrium cannot be maintained.

Adverse Effects of Biomass Power Generation: Promotion of Unjust Deforestation

The European Academies' Science Advisory Council (EASAC) points out that the EU has given distorted incentives to harvest forests. There is EASAC's correspondence with the President of the European Commission on the role of biomass energy.

In this, EASAC states that "the legal requirement to count forest biomass combustion energy as contributing to EU renewable energy targets has created demand for harvesting trees in Europe and elsewhere to burn for energy, resulting in the counterproductive effect of releasing carbon that would otherwise be locked in forests into the atmosphere while significantly reducing the carbon absorption capacity of forest ecosystems."

In fact, looking at Wood Resource Balances of European Union, wood resources used as biomass fuel are far more than wood collected from forests through harvesting, etc., as legitimate biomass fuel. While there are statistical inadequacies in this difference, concerns have been indicated that forest resources are being improperly harvested.

The EU is a leading region in biomass power generation, with achievements in covering household heating, and this trend is expected to continue. However, if biomass power generation does not contribute to carbon neutrality, a major change in direction will eventually be forced.

Carbon Neutrality and Achievement Goals

The Goal of Achieving Carbon Neutrality by 2050

Here, carbon neutrality means reducing "emissions" of greenhouse gases such as CO₂ by the "absorption" through afforestation, forest management, etc., to achieve a net total of effectively zero. As of November 2021, when COP26 ended, 154 countries and 1 region had announced the realization of carbon neutrality with deadlines such as 2050. The proportion of CO₂ emissions and GDP in the world from these countries reached 79% and 90%, respectively.

The following figure shows countries and regions that have announced carbon neutrality with deadlines.

We hope these goals will be achieved through hard work, but even if major countries achieve carbon neutrality by 2050, the accumulated amount in nature from the past will not disappear. If global warming has progressed considerably by 2050 and it becomes irreversible, there would be no point. I would like to organize some thinking about this problem.

Carbon Neutrality as a Stock

The current concept of carbon neutrality only considers the balance of annual income and expenditure. However, originally, humanity should fill the gap by planting trees, etc., so that it can absorb the CO₂ emitted in the past from biomass or fossil fuels. And considering the fact that the problem is that human activities have continued to disrupt the natural balance, shouldn't we be able to say "neutral as a stock" only when we can return to pre-industrial revolution levels? (Incidentally, it would be best to go back to before the agricultural revolution, but if we did that, according to Milankovitch cycles, the current Earth's environment appears to be quite cold.)

Here, based on the common understanding that the fundamental problem is the rapid increase in CO₂ since the Industrial Revolution, let's define the zero point of stock as the pre-industrial revolution state. And suppose that the total emissions can be calculated for each country. Then, each country's cumulative CO₂ emissions from the past become each country's "CO₂ debt to the Earth" that should be reduced thereafter. Naturally, developed countries and countries with large carbon dioxide emissions will incur huge debts. It is required to reduce this debt through afforestation and achieving zero emissions through technological innovation.

However, the concept of "CO₂ debt to the Earth" is an inconvenient truth that countries that have already emitted large amounts of CO₂ find difficult to accept. For this reason, rather than deciding whose fault this is, the current IPCC approach is to use the concept of remaining carbon budget, which is how much more can be emitted while still being barely safe, for international coordination. This is a concept like "we can only emit another 900Gt CO₂ to keep the temperature increase within 2℃ compared to pre-industrial revolution levels."

Challenges of Emissions Trading

By the way, the current world emissions trading system is structured to trade the difference against the annual emission quota (cap). If a country is allowed to emit only 100 units this year but emits 120 units, it needs to buy 20 units of emission rights from the market. Conversely, a country that emitted only 80 units can profit by selling 20 units on the market. This is a useful approach from the perspective of suppressing global annual emission quotas.

However, the challenge is that annual emission quotas depend on each country's emission reduction target setting. If emission quotas are reset every year, there is no need to visualize the impact on "CO₂ debt to the Earth." There is no awareness that the "CO₂ debt to the Earth" of that country accumulates as countermeasures are delayed. It is clear that a system where it is visible that addressing it later will become more difficult later provides stronger incentives to work seriously than a system where addressing it later or now makes no difference in difficulty.

Thinking this way, how about making it a law that power companies conducting thermal power generation have an obligation to plant trees, etc., equivalent to the amount of CO₂ they emit, and that cost is added to the electricity unit price? That way, wouldn't it help promote rapid conversion of LNG thermal power to GTFC and coal thermal power to IGFC?

For example, Japan is a country with many forests, but maintenance is so poor that forests are left abandoned because they have no value. However, what if local electric power companies purchase mountain forests abandoned due to aging of forest owners, and as their responsibility, own and protect healthy and vast mountain forests rooted in the region?

Do Electric Vehicles (EVs) Contribute?

Electric vehicles (EVs) are discussed here because they are closely related to a country's power generation mix. Certainly, EVs do not emit carbon dioxide, but they use electricity generated at power plants. When fossil fuels are burned for generation at these power plants, considerable CO₂ is emitted. And at this power generation point, considerable energy is lost, and the generated electricity reaches homes, etc., via the power grid, but further loss occurs during this transmission process, leaving quite little in hand. The power plant route is inefficient, yet EVs rely on these power plants—don't they actually not contribute much to CO₂ emission reduction?

There is research by Fujimori et al. at Kyoto University that provides an answer to this question. According to that, the following conclusions have been obtained:

• The introduction of electric vehicles significantly reduces energy consumption from the transportation sector and suppresses direct CO₂ emissions from automobiles, but when the power generation system depends on thermal power generation as in current Japan, emissions from human society as a whole actually increase
• By converting all cars to electric vehicles and replacing the power generation system with renewable energy, CO₂ emissions can be reduced by about 20%
• The electrification of cars alone is far from the Paris Agreement's 2℃ target, and to achieve the goal, it is necessary for energy demand in households, industry, and transportation, as well as energy supply including power generation, to be totally mobilized for de-fossilization

In other words, as far as EVs are concerned, they are meaningless without the spread of nuclear power and renewable energy or the reduction of thermal power generation. Elon Musk probably realizes this too, but driving EVs in America or Japan is not particularly ecological. In other words, the trend of promoting EVs as part of SDGs marketing is not rational behavior unless thermal power generation can be reduced. Companies and consumers should reconsider what value they seek from EVs.

Access to the Series

• The Truth About Global Warming: ① Do You Really Understand "Global Warming"?
• The Truth About Global Warming: ② History of Research
• The Truth About Global Warming: ③ History of Earth's Atmosphere
• The Truth About Global Warming: ④ Global Warming and Solar Energy Balance
• The Truth About Global Warming: ⑤ Verification Through Mathematical Models of Global Warming
• The Truth About Global Warming: ⑥ Population Growth and Its Impact on Global Warming
• The Truth About Global Warming: ⑦ Future Damage Projections
• The Truth About Global Warming: ⑧ Basic Understanding of Global Warming Countermeasures
• The Truth About Global Warming: ⑨ To You in 1000 Years
• The Truth About Global Warming: Appendix