So You Think This Is About Climate Change?

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Nerd Cheat Sheet: A Tail of Six Cities │End Notes: So You Think This Is About Climate Change?

Environmental Dynamics

(See End Notes 2 & 8).

Our lives are defined by motion. As soon as movement stops completely, life ends. The senses and interpretation of the world explored in Abstract Senses within Relativity and Reaction are fundamentally about judging how the world around us is changing. A photograph may capture a moment in time, but the source material itself is always in motion. The image only hints at that reality and beauty.

Humans naturally perceive the dynamics that are relevant to immediate experience. Waiting ten seconds may seem short, five minutes may feel long, and an hour can become unbearable without meaningful distraction. Our perception of time is relative to context, attention, and consequence.

Ancient societies understood that measuring time and environmental cycles did not come naturally. The Druids, among others, constructed systems and structures to reduce uncertainty and improve prediction. Observing seasons, celestial movement, and repeating natural patterns allowed communities to better understand and adapt to the changing world around them

The Earth’s environment has been changing since the planet’s formation. Life itself has influenced that development. As carbon-based organisms evolved, they interacted continuously with the atmosphere, oceans, and land. Humanity has taken this interaction further by learning to utilise environmental resources not only to improve survivability, but also to increase comfort, productivity, and quality of life.

This development has brought enormous benefits, but it has also produced waste and environmental consequences on a scale previously unknown. Human activity now releases many forms of effluent into the environment, some of which are harmful to wildlife, ecosystems, and ultimately humanity itself.

Comprehending how the world is changing often lies outside direct personal experience. Confirmation of our suspicions is difficult. Measurements, documentation, and photographs exist, but living memory is limited. Human beings are not naturally equipped to perceive environmental change occurring across centuries or millennia.

The issue of climate change is closely linked to the use of fossil fuels, which accelerated during the Industrial Revolution in the mid-1800s. This creates a period of approximately 225 years during which human industrial activity has increasingly influenced the environment. At first glance, this appears insignificant when compared to the Earth’s roughly 4.5-billion-year environmental history. However, the perspective changes when compared to the approximately 300,000 years that Homo sapiens have existed, and especially the roughly 10,000 years since the establishment of organised farming cultures and permanent settlements.

This does not mean that catastrophic environmental change affecting human civilisation is impossible within such a comparatively short period. Rather, it highlights the challenge of understanding environmental dynamics across timescales far beyond ordinary human experience.

Framing the Climate

(End See Notes 1)

The climate system can be defined as the interacting components of the Earth that determine long-term environmental conditions at the surface. This includes the land surface, the oceans from surface to seabed, and the atmosphere extending upward through the troposphere and into the stratosphere. These components interact through energy exchange, fluid movement, and chemical processes, forming a coupled system that influences the conditions experienced by living organisms.

The purpose of defining this system is to establish a clear frame of reference, so that we are precise about what we are observing when we refer to the climate system. Within this frame, we can examine:

what occurs within the system
what transforms and what accumulates
what enters the system
what leaves the system

In this chapter, climate change and the associated political landscape since 2016 will be examined as a starting point for broader analysis. This discussion must also consider climate-related issues within the larger context of Earth’s environmental history. To establish that context clearly, however, it is first necessary to take a brief and simplified look at the history of the Earth’s climate as it is currently understood.

A Carbon Balance

(See End Notes 3)

For practical climate timescales, the total amount of carbon available within the Earth system is effectively finite. The Earth does not significantly create new carbon; instead, carbon is continuously redistributed between reservoirs and chemical forms. The same is true for oxygen. These finite quantities place theoretical limits on how much carbon dioxide could exist within the atmosphere at any one time.

Carbon exists throughout the Earth in many forms. In the atmosphere it is present primarily as carbon dioxide (CO₂), currently at approximately 420 ppm by volume (2026), and in smaller quantities as methane (CH₄) and other carbon-containing compounds. However, atmospheric carbon represents only a very small fraction of the Earth’s total carbon inventory.

Most carbon within the Earth’s crust is locked into carbonate rocks such as limestone and chalk, primarily in the form of calcium carbonate. Carbon is also stored in fossil fuels such as coal, oil, and natural gas. Coal is generally understood to have formed from ancient plant matter accumulated before extensive vertebrate animal life existed on land, while oil and gas are believed to have formed through long-term heat and pressure acting on microscopic marine organisms and organic material buried within sediments.

Carbon dioxide is also naturally released through volcanic activity, where carbon contained within the Earth’s interior is emitted through magma and geothermal processes. Although volcanic emissions can be locally large and historically important over geological timescales, they are not considered the dominant cause of the rapid increase in atmospheric CO₂ observed over the last approximately 225 years.

Follow the Carbon

(See End Notes 2 & 3)

At any point in time, carbon is distributed throughout the Earth in several major reservoirs. These reservoirs exchange carbon continuously and, together, influence the long-term evolution of climate.

The approximate distribution of carbon relevant to climate evolution is:

Limestone and carbonate rock in the Earth’s crust
Approximately 65,000,000 Gt of carbon are stored as calcium carbonate (CaCO₃). This value refers only to the carbon component and excludes the calcium and oxygen mass.
Fossil fuels within the Earth’s crust
Up to 5,000 Gt of carbon are stored as coal, oil, and natural gas.
Again, this represents only the carbon content and excludes hydrogen, sulphur, and other elements present in fossil fuels.
Carbon dissolved in the oceans
Approximately 38,000 Gt of carbon exist in seawater in the form of dissolved carbon dioxide, bicarbonates, and carbonates.
Carbon dioxide (CO₂) in the atmosphere
The atmosphere currently contains roughly 890 Gt of carbon as CO₂, excluding the oxygen component.
Methane (CH₄) in the atmosphere
Atmospheric methane contains approximately 5 Gt of carbon, excluding the hydrogen component.

Together, these reservoirs form the active inventory of carbon that can influence climate and environmental conditions. Carbon constantly moves between these reservoirs through biological activity, ocean exchange, weathering, sediment formation, volcanic activity, and human actions.

Although these systems are never in perfect equilibrium, the atmosphere and oceans continuously exchange carbon dioxide in an attempt to balance concentrations between air and water. Changes in one reservoir therefore influence the others.

The limestone and fossil fuel reservoirs formed over geological timescales spanning hundreds of millions of years. Much of this carbon originally passed through the oceans and atmosphere before becoming trapped in sediments or buried organic matter.

When carbon is removed from the oceans through limestone formation or biological burial, the ocean-atmosphere balance draws additional carbon dioxide from the air. Conversely, when carbon is rapidly released from geological storage — such as through fossil fuel combustion — carbon dioxide accumulates in the atmosphere far faster than natural geological processes can remove it.

Current estimates indicate that human activity releases approximately 10 Gt of carbon per year from fossil fuels into the atmosphere (End Notes 3).

At current emission rates, the carbon released annually from fossil fuels is approximately equivalent to just over 1% of the carbon currently present in the atmosphere as CO₂, before accounting for uptake by oceans, vegetation, and other sinks.

If approximately 5,000 Gt of carbon are available as fossil fuel, then at current consumption rates this inventory would theoretically last about 500 years. These estimates are not precise, but they do illustrate constraints and limits.

The Greenhouse Effect

(See End Notes 2)

The Earth receives energy from the Sun primarily as visible light. Much of this radiation passes through the atmosphere and warms the Earth’s surface.

The warmed surface then attempts to lose this energy back to space as infrared radiation.

Carbon dioxide (CO₂), water vapour, methane, and several other gases absorb specific frequencies within this infrared spectrum. After absorbing this energy, the molecules re-radiate it in all directions. Some radiation continues outward toward space, while some is directed back toward the Earth’s surface and lower atmosphere.

This process does not create additional energy. Instead, it partially slows the transfer of heat from the Earth’s surface to space.

As a result, the surface and lower atmosphere must rise to a higher temperature before the rate of outgoing energy once again balances the incoming energy from the Sun.

In simple terms, the greenhouse effect acts less like a heater and more like insulation. The Earth is still cooling to space, but the cooling process becomes less efficient.

The critical factor is not that carbon dioxide “stores” large amounts of heat, but that it changes the rate at which heat can escape from the planet.

Complex Behaviour

(See End Notes 3, 4)

Over historical timescales, the total energy received from the Sun and the geometry of the Earth have remained relatively stable. This means that the average energy entering the Earth’s climate system is approximately constant, and therefore — over time — the Earth must also radiate approximately the same amount of energy back into space.

Greenhouse gases absorb specific frequencies within the infrared spectrum emitted by the Earth’s surface. As carbon dioxide concentrations increase, additional absorption still occurs, but the effect is not perfectly linear. However, absorption broadening and secondary atmospheric interactions mean additional warming still occurs as concentrations rise, meaning progressively larger increases in concentration are required to produce the same additional greenhouse effect.

In this sense, the process is somewhat analogous to adding layers of clothing in cold weather. The first layers provide the greatest increase in insulation, while additional layers continue to increase insulation but with diminishing effect.

This does not mean additional carbon dioxide has no effect. Rather, it means the relationship between concentration and warming becomes progressively less direct.

Mean Surface Temperature

(See End Notes 4)

The parameter most commonly quoted in discussions of climate change is the mean global surface temperature. This provides a useful overall indicator of changes occurring within the climate system, but it remains an abstraction that is difficult to intuitively visualise.

During geography lessons in secondary school, climate was described as the aggregate weather prevailing in different regions of the planet. There were tropical climates, continental climates, desert climates, polar climates, and many others — each shaped by geography, solar energy, oceans, atmosphere, and altitude.

One example that stood out was the tropical rainforest climate. Near the equator, where sunlight passes through the shortest atmospheric path, energy input is consistently high. The result is persistent heat, humidity, strong evaporation, cloud formation, and frequent thunderstorms as rising water vapour condenses.

These tropical regions are major energy-processing areas within the climate system. Although land masses, ocean currents, mountains, and seasons create substantial regional variation, the tropics remain dominant drivers of atmospheric circulation and energy transfer.

Not all parts of the Earth therefore influence the climate system equally.

Approximately 70% of the Earth’s surface is covered by oceans, while land exists across widely varying altitudes and environments. Oceans store and transport enormous quantities of heat, while atmospheric conditions vary dramatically between locations.

As a result, a change in mean global surface temperature of even one or two degrees does not mean every location becomes uniformly warmer by that amount. The number instead represents a shift in the overall energy balance of an extremely large and complex system.

This makes climate change difficult to communicate intuitively. Humans experience weather locally and immediately, while climate is a long-term statistical behaviour of the entire planetary system.

Evidence

(See End Notes 4 & 5)

The current release rate of approximately 10 Gt of carbon per year has not existed continuously throughout the industrial period. Fossil fuel consumption increased progressively over the last two centuries, with several major transitions in industrial scale and energy use occurring along the way.

Because the greenhouse effect of carbon dioxide is approximately logarithmic, increases at lower atmospheric concentrations would be expected to produce proportionally larger incremental radiative effects than equivalent increases at higher concentrations.

The First and Second World Wars represented periods of rapid industrial expansion and technological acceleration. In particular, the Second World War involved global-scale manufacturing, transportation, resource extraction, and fuel consumption. The post-war period then transitioned rapidly into the industrial and consumer expansion of the 1950s and 1960s.

Approximate atmospheric carbon dioxide concentrations were:

1930: ~305 ppm
1945: ~310 ppm

This indicates that atmospheric carbon dioxide concentration continued to increase during the period surrounding the Second World War despite the comparatively smaller industrial scale relative to the modern world. These values do not represent total emissions, since substantial quantities of emitted carbon dioxide would have been absorbed by oceans, vegetation, and other carbon sinks.

One expected symptom of increased global surface temperature would be rising sea level through:

thermal expansion of seawater,
glacier melt,
and ice-sheet mass loss.

Historical tide-gauge reconstructions suggest that global mean sea level was already rising during the late nineteenth and early twentieth centuries, with twentieth-century average rates commonly estimated at approximately 1–2 mm per year prior to the satellite era. However, confidence in precise historical rates decreases significantly further back in time due to sparse observations, changing methodologies, and the fact that measurements were not originally collected for modern climate analysis purposes.

The following approximate ranges have been extrapolated from multiple historical reconstructions (End Notes 5):

Period	Approximate Global Mean Sea-Level Rise Rate
1800–1914	~0.2 to 1.0 mm/year
1914–1939	~1 to 2 mm/year
1939–1945	difficult to isolate clearly
1945–1965	~1.5 to 2 mm/year

Approximation drawn from (Endnote 2)

This evidence does not directly confirm that the industrial acceleration surrounding the Second World War and post-war expansion caused an immediate acceleration in sea-level rise through increased surface temperature.

However, if historical estimates indicate that sea level was already rising between 1914 and 1965, then additional water must already have been entering the oceans through ice melt, thermal expansion, or both.

This implies that climatic and cryospheric change was already occurring prior to the major post-war industrial expansion. Historical evidence does indicate that many glaciers had already been retreating since the late nineteenth century following the end of the Little Ice Age.

***
An additional complication in interpreting environmental trends is that measurement systems themselves evolve over time.

Prior to the 1990s, sea-level observations relied primarily upon coastal tide gauges, which were geographically uneven and influenced by local land movement and regional conditions. From the early 1990s onward, satellite altimetry enabled near-global measurement of ocean surface height with substantially improved coverage and consistency.

This transition improved observational capability but also introduced an important interpretive challenge. Whenever measurement systems change, care must be taken to distinguish between genuine environmental trends and artefacts introduced by differing methodologies, calibration techniques, or resolution.

The further back historical analysis extends, the more interpretation depends upon reconstruction, statistical inference, and extraction of information from observations that were not originally intended for the questions now being asked.
***

Nerd Cheat Sheet: A Tale of Six Cities

(See End Notes 5, 6 & 7)

The increase in atmospheric carbon dioxide concentration from approximately 305 ppm to 310 ppm during the period surrounding the Second World War indicates that additional carbon dioxide was entering and accumulating within the atmosphere.

Independent historical evidence also suggests that global mean sea level was already rising during the same broad period, implying ongoing thermal expansion, ice melt, or both.

To examine whether these large-scale changes produced directly observable local environmental signatures, a number of geographically and climatically diverse cities were selected where comparatively consistent historical records of precipitation and tide or sea level exist.

The selected locations:

Los Angeles,
New York,
Manchester/Liverpool,
York,
and London,

represent different meteorological and geographical contexts including Atlantic maritime climates, Pacific coastal climates, rain-shadow effects, major river systems, and long-duration urban observational environments.

Within the limits of the available historical records, the increase in industrial activity and carbon dioxide release from the beginning of the Second World War through the post-war industrial expansion to 1965 does not appear to produce a simple, directly distinguishable, and geographically consistent local signature across these selected rainfall and tide-level observables.

This does not necessarily imply an absence of climatic influence. Rather, it highlights the complexity of extracting systemic climatic signals from local observables subject to large natural variability, differing response times, evolving measurement systems, and substantial environmental noise.

Cause and Effect

(See End Notes 8)

Since 1945 the atmospheric concentration of carbon dioxide has risen from approximately 310 ppm to more than 420 ppm. This indicates that a measurable anthropogenic greenhouse contribution already existed by the end of the Second World War, although the incremental radiative forcing at that time was substantially smaller than that associated with present-day concentrations.

With the available historical evidence, global mean sea level appears to have been rising since before the nineteenth century through a combination of thermal expansion, glacier melt, ice-sheet mass loss, or other long-term climatic recovery processes. However, within the data analysed in Nerd Cheat Sheet: A Tale of Six Cities, no clearly distinguishable acceleration specifically associated with the period surrounding the Second World War and extending to approximately 1965 was identified within the selected local rainfall and tide-level observables.

One possible explanation is that the selected observables possess substantial natural variability and environmental noise. Local precipitation is strongly influenced by regional circulation dynamics, while sea level represents a slowly integrating response of the climate system. Consequently, relatively small long-term climatic trends may be difficult to isolate clearly within geographically localised historical datasets.

Currently, climate discussion is frequently communicated to the wider population through a single aggregate parameter: mean global surface temperature (MGST). While useful as a broad indicator of planetary thermal state, MGST represents a statistical abstraction rather than a complete physical description of the climate system.

This raises several important interpretive questions:

Do all regions of the planet contribute equally to climatic behaviour?
Does a rise of 2°C necessarily represent double the climatic, ecological, or economic consequence of a rise of 1°C?
Does the climatic interpretation of MGST depend upon the underlying atmospheric state, including whether atmospheric carbon dioxide concentration is approximately 310 ppm or 420 ppm?
How do climate models process these changing baseline conditions and nonlinear system responses?

Consequence

(See End Notes 9)

Discussion surrounding a rise of approximately +1.5°C in mean global surface temperature frequently includes projections of substantial environmental, economic, and societal consequence.

If such projections are to be treated seriously, confidence must exist not only in the underlying observations, but also in:

the interpretation of aggregate indicators,
the validity of modelling assumptions,
the physical meaning of the chosen parameters,
and the extrapolation of present relationships into future conditions.

The existence of atmospheric carbon dioxide concentrations of approximately 310 ppm around the end of the Second World War places modern climate discussion within a longer historical context. Atmospheric carbon dioxide concentrations have clearly increased substantially since industrialisation, and the greenhouse mechanism itself is physically credible. However, interpretation of the magnitude, timing, and consequences of resulting climatic change remains dependent upon:

complex system modelling,
historical reconstruction,
statistical aggregation,
and interpretation of incomplete observational evidence.

The question therefore is not simply whether climate change exists, but rather:

how confidently complex climatic behaviour can be interpreted through aggregate indicators such as mean global surface temperature,
what those indicators physically represent,
and how directly they map onto projected real-world consequences.

Another Perspective

(See End Notes 9)

Interacting factors were introduced in the sections above, although the broader implications of this increasing interpretive complexity have not yet been fully explored.

In the section Evidence between the *** marked passages, and in Nerd Cheat Sheet: A Tale of Six Cities, additional clarifications are provided to explain why historically collected data from the 1800s to 1965 do not display simple or geographically consistent relationships with current interpretations of how atmospheric CO₂ influences localised climatic behaviour.

Examined critically, if the historical observations had provided strong and directly distinguishable confirmation of current climatic interpretations, the explanatory framework would be substantially simpler. However, the absence of such direct confirmation does not in itself invalidate the underlying greenhouse hypothesis. Rather, the observations help define the limits, interpretive confidence, and scope of validity associated with the conclusions that may reasonably be drawn from them.

The following context factor however, may help focus attention.

The estimate of 5,000 Gt of carbon available as fossil fuel is likely optimistic when considered from a practical planning perspective.

Not all identified fossil carbon is recoverable. Some portion may be technically inaccessible, economically uneconomic, environmentally unacceptable, or geopolitically unavailable. Even where resources exist, extraction efficiency limits how much can realistically be obtained.

If, for example, significant fractions are:

physically or technically unrecoverable,
left behind due to extraction inefficiency,
restricted by cost, regulation, or geopolitics,

then the usable fossil fuel inventory is much smaller than the theoretical geological inventory.

This leads to an important conclusion independent of climate-change arguments: over the next century, industrial society must systematically reduce dependence on fossil fuels.

The transition should not be treated as a short-term emergency panic, but as a long-duration engineering, economic, and social project.

Some uses are easier to replace than others. Electricity generation, domestic heating, and some forms of road transport have emerging alternatives. Aviation is more difficult. Kerosene has exceptionally useful properties: high energy density, liquid storage, established infrastructure, and suitability for long-distance flight.

For this reason, the value of remaining liquid hydrocarbon fuels may be underestimated. Aviation, shipping, defence, emergency services, agriculture, and chemical feedstocks may require prioritisation if fossil fuel availability declines or must be constrained.

A rational response would therefore be consistent, systematic, and long-term: reduce avoidable fossil fuel use where alternatives exist, preserve high-value uses where substitutes are weak, and develop replacement technologies before scarcity or political pressure forces reactive decisions.

The planning horizon should be measured in decades, not election cycles.

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