Warming Climate and Entropy

I like to devote this piece to a very important issue of our time – and perhaps it will continue to be so in the future. We all know it – there is hardly a single day passes that does not have some sort of news on the warming climate of our planet Earth – and all the consequences associated with it. Not to speak of colossal amount of scientific literature – sponsored by different international and national organizations, universities and research institutes, private entities, etc. One can literally get drowned by them – with very little clues on how to make sense – of the many details they present in totality. It is not only the literature, but also the complex nature of the issue – many interactive systems and processes are embroiled in it. Unless one has made himself or herself a profession of climate scientist – it is very unlikely that one can ever be able to spend time or effort – to be fully cognitive of many details. Yet the conclusions they present are corroborative and compelling founded on consensus. This piece is only an attempt to throw a little ray of light on the issue – but I will try to capture some of its essential elements – including examining them through a different angle.
Writing this piece relied on: Several WMO and UNEP researches under the umbrella of IPCC (Intergovernmental Panel on Climate Change): 2019 – The Ocean and Cryosphere in a Changing Climate; 2013 – IPCC 5th Assessment Report (AR5) of different Working Groups; 2021 - IPCC AR6 of different Working Groups; Government of Canada: 2019 – Canada’s Changing Climate Report (CCCR); Harvard Business School: 2018 – Climate Change in 2018: Implications for Business; US Global Change Research Program (USGRP): 2017 – Climate Science Special Report; National Academies Press: 2013 – A Review of the Draft 2013 National Climate Assessment; US Climate Change Science Program (CCSP): 2008 – Weather and Climate Extremes in a Changing Climate; R Bradley 2015 – Paleoclimatology: Reconstructing Climates of the Quaternary, Elsevier; and a WIDECANVAS piece posted earlier: 2019 – Entropy and Everything Else.
The importance of this issue deserves it to be looked into – from longterm sustainability perspectives. Therefore, it only makes sense that this piece must start by describing our deep understanding of the climate first – including the paleoclimate, because to understand the present – one needs to know how the climate of the Earth was in the very distant past. Next, laying down the synoptic facts of contemporaneous climate science observations, I will briefly outline the future projections and uncertainties. This will be followed by energy balance and Entropy associated with the 2nd Law of Thermodynamics. One outcome of the warming climate is the rising of sea level – the science and the consequences of it were discussed earlier in: Sea Level Rise – the Science, and Sea Level Rise – the Consequences and Adaptation. I will prevent myself from citing numbers – because they are rather fluid – constantly changing as new observations continue to pour in – or as prediction models and routines are getting more robust and sophisticated. Unlike many of our colleagues in the broad environmental science category, I will mainly focus on the physics of climate dynamics and warming.
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1. The Earth System
Our solar system as a member of the Milky Way galaxy system is subject to the effects of causes that happen beyond its boundary – like the Asteriod impacts that rattled the Earth in the past. Such episodes, especially the catastrophic impacts – by their very nature impose new conditions on the existing processes that take many years to adjust or balance out. Additionally, Earth's dynamic position in the solar system - the changes in its axial tilt and orbital trajectory - affect energy gain and climate. The system of the Earth – comprising of 5 interactive subsystems works in some balancing processes to conditioning the climate of - the past and the present, and will lead to the evolution of the same in the future. Human interventions since the Industrial Revolution have changed the balancing processes of Natural causes and conditions. The nature of future evolution will depend on us - on humans - how smart and careful we are in recognizing the effects and footprints we are creating to jeopardize the Natural balance. 
The subsystems can be grouped into three: the Fluid System of atmosphere, hydrosphere and cryosphere; and the Solid System of lithosphere; these two systems sustain the Life System – plants and animals known as the biosphere. The cryosphere, comprising of the frozen water lies at the boundary between the solid and fluid systems with glacial and interglacial periods that occurred all along the history of the Earth. Most of the information about these three systems is common knowledge now – but for the sake of completeness, let us have a brief look into the characteristics and the delicate dynamic balance of these interactive systems. The balance is delicate, because the thresholds are often very narrow – when it comes down to sustenance and survival of the entities using them.
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1.1 The Fluid System
The Fluid System is the most dynamic of all the climate systems – it’s time-scales vary from short time scales of weather to the long climatic variation and trend. It is the most important measuring stick of climate – in its characterization and variation of temperature, pressure and composition (e.g. increasing proportion of greenhouse gases, GHG; methane; acidification of the warming ocean water; pollution of all sorts; etc.) – and in the quality and quantity of these parameters in supporting the Life System. Also important is the Ozone layer in the stratosphere – because it filters the Sun’s radiation to protect the Life System from harmful UV rays.
The atmosphere, and the hydrosphere (covering some 71% of the Earth’s surface) continuously interact with each other at their interface – creating the hour-to-hour weather dynamics, the cloud formations, the precipitations, the storms, the ocean waves, etc. The precipitation dissolves atmospheric CO2 to bring it down to cause hydrosphere acidification. The huge density difference between the two – some 1000 kg/m3 of the hydrosphere compared to the 1.23 kg/m3 of the atmosphere – makes it imperative that the atmosphere reacts faster than the hydrosphere in continuously evolving micro and macro circulations - in response to the changes in temperature and pressure variations. To such stimulus of variations, weather instabilities do occur as an attempt to restore the dynamic balance.
Of this trio of the Fluid System, the response time of cryosphere – as a frozen water mass in the forms of sea ice, glaciers and continental ice masses (cover some 10% of the Earth’s land surface) – is understandably slow but very important. The relation of the cryosphere with others in the Fluid System – can be best be discerned from the past glacial and interglacial periods. During these cycles, the corresponding regression and transgression of the shoreline occurred with lowering and rising of the sea level, respectively. Additionally, the snow mass Albedo affects the Sun-Earth energy balance system. The cryosphere is also a storehouse of information of the past climate change – and scientists have taken full advantage of this gift.
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1. 2 The Solid System
The Solid System, the Earth’s crust or lithosphere – consists of the oceanic plates and the continental plates (cover some 29% of Earth’s surface). Although it is a single solid phase – the majority covered by the ocean – it represents a multiplicity of plate configurations and movements, topography, textural and mineralogical compositions. Apart from that, the continental plates accommodate the vegetative covers, land-water drainages to the ocean, and carry the burden of frozen ice of glaciers and ice masses. It is hard to imagine life without the interactive foundations created by solid and fluid systems – in germinating growths and in sustenance of everything life depends on. The influence of the continental plates on the climate, can better be appreciated from the following example: imagine the Himalayas is gone from the Earth’s surface – the weather and climate of Asia (and to some extent of the Earth) will be totally transformed – with the monsoon and the mighty Himalayan river systems gone – also gone will be the diverse flora and fauna that call this part of Asia home. Or, in the continuous and vigorous interactions between breaking waves and sand – between the Fluid and Solid systems as in The Surf Zone – defining a very dynamic habitat for the Life System in that zone. Therefore plate tectonics, and the past and present earthquakes play a very important role in climatic change – by reorientation and relocation, deformation, upheaval and subduction of the Earth’s crust - in the relative and evolving positions of continents vis-a-vis the change in the volume of oceans basins. And the role of Solid System in defining the micro-climates of dynamic interactions with the Fluid and Life systems.
The second most important connection of this system to the climate is the surface and under-water volcanic activities. They are the reasons - why the Hot Plate Analogy - as a mechanism of warming up the surface of the Earth - is not tenable. The hot plate being the molten hot core of the Earth - on which Earth's crust sits. Volcanic activities not only lead to climate change in terms of spewing out gases and ashes – but also add to energy of the Earth. In particular, volcanic contributions to CO2 have been responsible for many paleo-climate changes. Scientists also say that the past volcanic activities were partly responsible for initiating geochemical processes giving birth to the Fluid and Life Systems that we have today.
Also very important is the fossilized remnants of the past – among these some are convertible to energy. We all know these – the extensive extraction and utilization of fossil fuels of coal, oil and gas – have transformed human life on the planet in rapid industrialization. These energy sources – while led to the human prosperity, have added an adverse twist to the Earth’s Natural energy balance.
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1.3 The Life System
The evolution of the Fluid and Soild systems over millions of years created the environment on which life originated and flourished in multiplicity of plants and animals. Most of the diverse flora and fauna that we see now have evolved to their present states since the Holocene transgression that started in about 10,000 years ago. Over time, all of these species have adapted to living in a certain range of temperature, pressure and composition of the Fluid System – and together they define the biosphere. Some adapted to living in the hot and humid climate, some in cold climate, etc. The implications of adapting to and surviving within the climate range thresholds – mean that any imbalance in the parameters would affect the livelihood of many.
The Life System depends on the average composition of the Earth’s atmosphere – 78.09% nitrogen, 20.95% oxygen, 0.04% carbon dioxide, 0.40% water vapor, and others. Among these, all air-breathing animals live on oxyzen, the plants on the other hand, lives on carbon dioxide. Air-breathing Animals: user of oxygen by inhaling air, and the producer of carbon dioxide by exhaling. Plants: use sunlight and carbon dioxide to produce food through photosynthesis – generating oxygen in the process. Thus there is reciprocity between these two species – complementing each other. Most notable among the plant processes – is the enormous contribution by a tiny ocean life – the phytoplankton – a real life giver that contributed more than 50% of oxygen. The importance of the plant contributions can further be appreciated if one imagines the disappearance of the Amazon Rain Forest.
But the most important adverse twist to the balance of the climate processes has been and is being made by one species of the animal class – the humans. Climate scientists could not find causes other than the extensive fossil fuel use (that started in the 1860s with rapid industrialization) – to the rise in atmospheric, land and oceanic temperatures, and GHG.
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2. The Paleoclimate
Let us attempt to understand some key important paleoclimatic characteristics briefly.
The first remarkable thing to notice in the paleoclimatic temperature data (the image credit, Bradley 2015; reconstructed Earth’s temperature for the past 500 million years, referring to the 1900-1990 average; 500 million years represent only 11% of the 4.5 billion years of the Earth’s history) is that – there have been a continuous downward trend since the beginning of the Cenozoic Era. The trend is marked by many ups and downs of different time-scales – indicating how Nature worked in its recovery processes of dynamic balance – after the catastrophic Asteriod impact that occurred about 66 million years ago at the beginning of the present Cenozoic Era.
The downward trend of recovery continued to the last Ice Age or the Pleistocene Epoch (from 2.6 million years to about 12,000 years). The minimum cold peak occurred about 18,000 years ago when the Earth’s average temperature reached a whopping - 6oC, lowering the sea level to about 100 m below the present – this is the time of maximum regression of the shoreline (shoreline was at the seaward limit of the present continental shelf).
From that period forward – temperature continued to rise. From about 10,000 years ago, the temperature seems to have stabilized to the present state until about the beginning of the present rapid industrialization. True to the nature of dynamic balance – the stabilized temperature was a showcase of ups and down about a mean trend.
One intriguing fact about the concentration of atmospheric CO2 is that – at some time during the Cenozoic Era, the CO2 level was same, if not higher than what we have now. The global atmospheric CO2 has now reached a level of 400 ppm (parts per million) – a level that also occurred about 3 million years BP when both the global average temperature and sea level were comparable to the present time. How could that occur without anthropogenic contributions? Scientists point fingers to one particular cause, the volcanic eruptions that spew out CO2 - for greenhouse trapping of Earth's radiation - for the abundance of early species of Life System during those times.
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3. The Climate of the Present Time
Let us attempt to see this aspect of climate change very briefly – because news media, climate science research and other outlets are full of stories nearly everyday.
Global mean surface temperature of the land, ocean and air has been on the rise since the mid 19th century. The trend is alarmingly higher during the past 3 decades than the earlier decades. The current peak (refer to the image at the right hand) rise in temperature is startlingly unusual – but real.
This temperature increase is highly correlated with increased level of GHG, together with the rise in atmospheric vapor content or specific humidity.
In line with the above, also well documented are the melting of glaciers, diminishing of snow cover extents, shrinking of sea ice, change in ocean circulation, ocean acidification and rising of sea level. With the rising sea, increased frequencies of tidal flooding of coastal low lands are being observed worldwide.
Also in line with the warming climate – are the behaviors of different extreme events – tropical storms/hurricanes/cyclones, heavy rainfalls and flooding, heat waves and forest fires – all are showing increasing trends in frequency and intensity.
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4. The Climate of the Future
This is the most difficult and somewhat intriguing aspect of climate science. A high confidence in projecting the present to the future is not something easy to achieve. Let us attempt to see why so – by delving briefly into different aspects of this part of climate science.
The piece on The World of Numbers and Chances tells about the difficulty associated with handling huge amounts of stochastic data and making probabilistic sense of them – despite continual progress in sophistication. Their analyses and statistical generalization invariably contain certain uncertainties. Projecting such numbers into the future – either in ways of simple extrapolation, or by fitting suitable probability distributions to them – is subject to further uncertainties.
With such uncertainties associated with data and future projection, it becomes difficult fordecision makers to undertake risks. We have seen different aspects of it in the Uncertainty and Risk piece.
Perhaps the most effective way is to model the climate change – but it also comes with certain uncertainties. This is because as we have seen earlier, several interactive processes of different scales and intensity are interlinked. The result is that many assumptions are needed to develop a numerical model. In the Water Modeling piece posted earlier we have seen some 8 limitations and constraints associated with it. The level of modeling uncertainty or confidence depends on: (1) representitiveness of the applied model to the actual field conditions, (2) empiricism embedded in modeling code, (3) discretization processes of the continuum, (4) iterations associated with the convergence to solutions, (5) rounding-off of numbers to certain digits, (6) level of input data accuracy, (7) level of scientific capability or competence of the modeler, and (8) possible errors in modeling code. With so many constraints, even the simulations of different existing global-scale phenomena become error-prone. If the simulations of existing conditions are so uncertain, it is only likely that simulations of future scenarios are no better – perhaps even worse. An example of it can be seen in the differences of the predicted future sea level rise (see the image posted in the Sea Level Rise – the Science).
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5. Extreme Events
There are many reports and papers on climate change induced causes – that are conditioning the enhanced occurrences of extreme events – both in frequency and intensity. Here are some relevant excerpts from NAP and IPCC assessments.
NAP Assessments
In Chapter 9: Coastal Effects, the 2023 NAP # 26757 presented a rather detailed findings of traceable accounts of climate change effects – and expert comments on them. Some statements read like this:
. . . Coastal Hazards Are Increasing Rapidly. The severity and risks of coastal hazards across the Nation are increasing rapidly (very likely, high confidence), driven by accelerating sea-level rise and changing storm patterns, resulting in increased flooding, erosion, and rising groundwater tables. Over the next years, sea-level rise along the majority of US coasts is expected to be as much or greater than the observed rise in sea-level over the last 100 years (likely, high confidence) and will cause significant disruption to coastal residents, including damage to livelihoods, economies, infrastructure (e.g., roads, utilities, wastewater facilities), and ecosystems (likely, high confidence). Accounting for mounting coastal and compound hazards could inform meaningful actions to address the cascading impacts of climate change . . .
. . . Coastal Impacts on People and Ecosystems Are Increasing. Climate change is already affecting the resilience of coastal ecosystems and communities (very likely, high confidence). Climate change and human modifications to coastal landscapes, such as seawalls, levees, and urban development, are limiting the capacity of coastal ecosystems to adapt naturally and are compounding the loss of coastal ecosystem services (very likely, high confidence). Without proactive strategies, the combination of reduced ecosystem services and damage to the built environment from exacerbated coastal hazards will increasingly burden communities, industries, and cultures, degrading the quality of life in the coastal zone (very likely, high confidence) . . .
. . . Transformative Adaptation for Coastal Communities. Marginalized coastal communities are disproportionately vulnerable to the impacts of climate change and have limited resources for adaptation (high confidence). Maintaining cultural and economic connections within coastal communities will require transformative adaptation that addresses the interconnection between ecosystems, communities, and governance (high confidence). Transformative adaptation, including incremental adaptations, community co-development of adaptation strategies, nature-based solutions, and managed retreat, can equitably respond to coastal climate change impacts (high confidence) . . .
IPCC Assessments
Here is something written in the 2nd Chapter of the 2021 IPCC WGII Sixth Assessment Technical Summary Report. . . Cumulative stressors and extreme events are projected to increase in magnitude and frequency (very high confidence) and will accelerate projected climate-driven shifts in ecosystems and loss of the services they provide to people (high confidence). These processes will exacerbate both stress on systems already at risk from climate impacts and non-climate impacts like habitat fragmentation and pollution (high confidence). Increasing frequency and severity of extreme events will decrease recovery time available for ecosystems (high confidence). Irreversible changes will occur from the interaction of stressors and the occurrence of extreme events (very high confidence), such as the expansion of arid systems or total loss of stony coral and sea ice communities . . .
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6. The Sun-Earth System – Entropy and Energy Balance
An application of the 2nd Law of Thermodynamics would indicate that the Entropy of the Earth has been increasing since the birth of our solar system, and will continue to increase in time. This subtle but inevitable Natural process is destined to warm up the Earth and cause it to become unlivable at a certain time, but perhaps far – far in the distant future. Let us attempt to see how the warming of Earth’s climate is tied to the net gain of Entropy in simple terms – relying primarily on a piece posted earlier, Entropy – and Everything Else.
As a one-way process and in analogous with a hot rod becoming colder by warming up the surrounding – the Earth as a colder planet is becoming warmer by receiving part of the solar radiation. In the Sun-Earth system, the colder Earth cannot give the heat it receives back to the Sun (although it does radiate back some to the surrounding) with the result that the Entropy of our Earth is continuously increasing in the arrow of time. With the decreasing Albedo, and the trapping of atmospheric radiation by high loading of GHG - the gain in Entropy is only likely to increase further. Some of the gained Entropies get stored in different forms – one such familiar major process is the fossilized energy – like oil, gas and coal deposits.
In another example of irreversible processes, an ice cream melts by gaining heat from the surrounding – which means, a system of higher order becomes disordered (a mess of melted nuisance) by gaining heat. Therefore disorderliness is an indication of randomness and high Entropy. In context of the Sun-Earth system, the Earth as a cold system (like the ice cream) is not only getting hot by gaining Entropy from the Sun, but the 2nd law says it is also getting continuously disordered. In terms of climate, disorderliness means that – increased Entropy is bound to usher in instabilities in the dynamics of warming process. Perhaps increasing occurrences of extreme events indicate a good example.
The first intervention on the Sun-Earth thermodynamic process – started during the dawn of fossil fuel use in the 1860s in Europe and North America. This intervention in adding to the enhancement of Entropy – began showing noticeable consequences about 100 years later – exacerbated further by the rapid and extensive industrialization that started in the 1950s. The consequences in the form of warming of the global climate, rising sea and weather instabilities – continue to be measured by all organizations and entities around the world. Therefore, it is the new reality and an undeniable fact.
Apart from the reversibility in the dynamic balance of ups and downs throughout the history of the Earth, we have seen three basic one-way contributions to the Earth’s energy balance. Two of them are Natural – and have been occurring since the birth of our solar system. The first is the net gain of Entropy that will continue to affect the Earth in subtlety for all time to come (including the new reality of the decreasing effects of Albedo). The second is the energy released by volcanoes in raising temperature as well as in changing the composition of the Fluid System. These two – made the Earth livable in broader contexts, and are beyond human control.
The third one-way contribution is human made – with the net addition of energy and in changing the composition of the Fluid System - that enhanced the trapping of atmospheric radiation by high concentration of GHG. It is derived from fossil fuel use, that primarily started with the rapid industrialization. While this human innovative use was responsible for our prosperity and civilization – its adverse effects were either ignored or not considered significant, but the damaging consequences started to become clear during about the past ½ century. The adverse consequences are multiple in terms of intensity, frequency and instability – and it seems some of them are already beyond control. When people cry out by witnessing the changes that affect them – one cannot but realize the wisdom – of the necessity for finding ways to limit the human-made one-way contribution – together with suitable adaptation strategies to face the consequences.
Despite these facts, one cannot afford not to notice the paleoclimatic cycles and trends in climate change. Is our present planetary warming has anything to do with the past trends and cycles of the Holocene? If the answer is yes, then it is reasonable to conclude that human-induced causes are an exacerbating factor – not the sole cause. This answer should not deter us to act, however. One important reason is that over thousands of year of evolution – and our way of livelihood, especially during the past few centuries – have made us very vulnerable to the exceedence of the narrow thresholds we got used to.
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7. Some Thoughts on Mitigation, and Warming Climate in a Lighter Vein
As we see suggestions in nearly every discussion, the action should be in terms of positive climate interventions – such as gradually but slowly phasing out massive dependence on fossil fuels, as well as limiting the industrial emissions. These are important concerted necessities, not trade-off choices. Three energy sources in harnessing of the Natural existence - that we know and are already in various phases of implementation all around the world are: (1) the solar power using photovoltaic panels, (2) the wind power, and (3) the hydropower (rivers and streams, tide and waves). They seem to be the only ones that do not add to the net one-way contribution to the Sun-Earth energy balance. They are also the ones - that just extract energy without really consuming any source materials. However attractive they are – the feasibility of such measures must examine local adverse impacts, if any. Deflecting Sun’s radiation away from the Earth – may appear as an interesting research topic – but it hardly qualifies as a practical and full-proof option that can encompass all.
Finally, warming climate as a global problem – simply on the premise that interacting players – the Fluid, Solid and Life Systems do not know or care about the confines defined by the national boundaries and jurisdictions. But as with everything else that humans have eyes on – politics has its hand on twisting and convoluting the challenges of – global responsibilities, consequences and mitigation. Let us attempt to see some scenarios of interests and conflicts through a lighter vein: Melting Arctic Ice - Global warming is such a beautiful gift of Nature! It’s time to sharpen our skill to open the Northern Route, and exploit the treasure trove of minerals in the polar areas. Flooding Coastal lowlands – let’s get away from those filthy overcrowded areas – our mountains and midlands are sparsely populated and are ready for sale. Technology to Deflect the gift of Sun’s energy – The peoples of cold polar and sub-polar Scandinavia, Russia, Canada and northern USA: hold on, we are freezing down here and it’s very depressing; we need more sunshine. The Equatorial peoples: good idea, it’s very hot down here. The peoples of middle countries: hold on, what will happen to our beautiful seasons?
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Let me finish this piece by quoting Einstein (1879 – 1955): the measure of intelligence is the ability to change. Indeed the modern human history is an evolving canvas of change and adaptation – but there is a price to pay when the past changes leading to the adverse consequences are not fully appreciated or ignored. And the cost of the price may be painful, even lethal – more for the vulnerables than others. That does not mean that all should not act collectively. Awareness must lead all changes to sorting out smart choices to cope with the global challenge – at the same time realizing that any mob mentality on such an important popular issue, first of its kind of humans’ own making – has the potential to mislead responses. The reality of interwoven dependence and complementarities of the Fluid, Solid and Life systems – must be the foundation on which longterm sustainable options should be built upon.

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- by Dr. Dilip K. Barua, 15 December 2019

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