Climate Change – Part I – The Basics

Introduction

Climate change is a global issue that has wedded science to politics while simultaneously transcending the social responsibilities held by both institutions. A polarizing subject in many ways, climate change is considered as one of the most daunting challenges humanity currently faces; at its crux is an initiative towards global communication, and environmental responsibility.

To this day, there remains a schism between the public, and the scientific community when it comes to understanding climate change, and what it essentially means for our world. In a manner that follows the development of various other issues over the course of history, climate change highlights a certain measure of conflict in science, and ignorance.

Investing the time to learn the basics can prove the difference in being knowledgeable and informed or confused and manipulated. This is particularly crucial as climate change is a phenomenon that has wide implications to civilization, and overtly emphasizes the need for humanity to collaborate with each other in tackling the problem.

In this three-part series, we will address various facets of this issue ranging from the basics of the science behind the phenomenon as well as the consequential symptoms  or effects of climate change for the present, and the future. We will conclude by discussing the options that we must consider in our transition to achieve progress.

Let’s begin!

Dissecting Weather and Climate

Le’ts review the difference between weather, and climate. Simply, weather is local, and short-term while climate is long-term, and doesn’t relate to one single location. More precisely, the climate of an area defines the average weather conditions in the given region over a long period of time. The time period being considered generally involves changes taking place over tens of thousands of years. So, whenever we pass by a few winters that aren’t as cold as usual, it does not necessitate a change in climate. Such events are rather anomalies that don’t represent any long-term change.

Moving forward in our discussion, it is also imperative that we don’t underestimate the effects of small changes in climate. To put in perspective, the “Ice Age,” often talked about by scientists involved a world where the Earth’s average temperature was only 5 degrees Celsius cooler than modern day temperature averages. Small changes in climate can equate to major effects around the world. 

Climate Change or Global Warming

We often hear the phrases climate change, and global warming used interchangeably in describing climate transitions but there is a subtle difference. In the early 20th century, scientists used the term climate change when writing about events such as ice ages. But once scientists recognized the specific risks posed by human-produced greenhouse gases on the Earth’s climate, they needed a term to describe it.

Wallace Broecker’s paper in the journal Science, in 1975, entitled “Climate change: Are we on the brink of a pronounced global warming?” introduced the word global warming into the public lexicon.

Soon enough, the phrase global warming gained currency, and the term global change emerged as a way to describe all modes of large-scale impact on the planet, including issues such as the Antarctic ozone hole.

The planet as a whole is warming, but scientists prefer the term global change or global climate change. The reasoning behind this is that global warming can be interpreted as a uniform effect (warming everywhere on Earth), while a few regions may in fact cool slightly even if the planet were to warm up. In fact, it is a popular opinion that climate change sounds less frightening to the ear than global warming; the latter though catches more attention in the public eye. A few scientists, and activists also prefer to use global warming to imply human involvement in the process of describing climate transitions.

So, is the planet really warming up?

The short answer: YES! After laboriously working through a century’s worth of temperature records, various independent teams of scientists have converged on a rise of 0.8 degrees Celsius in the average surface air temperature of Earth when comparing the periods from 2003 – 2012 to 1850 – 1900. While this degree of warming may not sound like a big deal, it does make a big difference when it is in place everyday. Small changes can become amplified into bigger ones. Any warming can serve as a base from which heat waves can become worse. The effects are particularly pronounced in certain locations like the Arctic which has experienced an overall warming. Apart from the numbers, there’s a wealth of environmental evidence to bolster the case in favor of the Earth’s warming up. Without going too much into detail,

(1) Ice on land, and at sea has melted dramatically in many areas outside of interior Antarctica and Greenland.

(2) A lengthening of the growing season around much of the Northern Hemisphere.

(3) The migration of various forms of life, including mosquitoes, birds, and other creatures to higher altitudes, and latitudes due to the increasing warmth. Likewise, the migration of many forms of marine life moving poleward (the shift in ranges is 10 times the average for land-based species).

Other observations from the Intergovernmental Panel on Climate Change (IPCC) highlight the warming trend of the last 50 years being nearly the double of the last 100 years; a vast increase in ocean temperature to greater depths (the oceans absorb 80% of the heat of Earth’s climate system); increasing droughts; increased precipitation in eastern regions of the Americas, and northern regions of Europe, and Asia; drying trends in Africa, and the Mediterranean etc.

How Global Warming Works? 

Global warming is caused by an increase in the greenhouse effect. The greenhouse effect is not bad on its own, and is in fact a natural circumstance of the Earth’s atmosphere. It is also the reason why the Earth is warm enough for life to survive.

The greenhouse effect, in essence, involves a play of energy balance on the Earth’s. When sunlight reaches our planet, 30% of its gets reflected or scattered back to space by clouds, dust, or the Earth’s surface. More than 20% of the sunlight is absorbed in the atmosphere, mainly by clouds, and water vapor. Lastly, almost 50% is absorbed by the Earth’s surface including land, forests, pavement, oceans etc.

Now, all this energy doesn’t stay permanently on the Earth. If it did, the Earth would literally be on fire. In fact, the Earth’s oceans, and land masses re-radiate the heat, some of which makes it into space. Most of it though is absorbed by clouds, and greenhouse gases which in turn radiate the heat back to the surface, and some out to space. Since the heat doesn’t make it out through the Earth’s atmosphere, the planet becomes warmer. It is basically an energy imbalance scenario where there is more energy coming through the atmosphere, than that leaving the Earth.

The two main components of air include nitrogen (78%), and oxygen (20%) gas, both of which aren’t efficient in absorbing radiation from the Earth due to their two-atom structure. On the other hand, other gases with three or more atoms can capture energy far out of their scant presence. These are the greenhouse gases, the ones that keep Earth inhabitable. That’s all well, and good, but the same gases also warm the Earth. The more greenhouse gases we add to the atmosphere, the more our planet warms. The major players involved include: Carbon dioxide, Nitrous oxide,  Methane, and to a lesser extent, Water vapor.

 Greenhouse Gases: What’s Happening? 

The greenhouse effect is driven by naturally occurring substances in the atmosphere. This is predicated by a necessity for balance referring to the radiation cycles of the Earth mentioned earlier. Unfortunately, since the Industrial Revolution, humans have been pouring huge amounts of greenhouse gases into the atmosphere thus tipping the balance toward an amplified warming of the planet.

Carbon dioxide makes up less than 0.04% of the Earth’s atmosphere, most of which is due to early volcanic activity in the planet. Today, we are pumping huge amounts of the gas into the atmosphere as the gas is produced when fossil fuels are burned, as well as when people, and animals breathe, and when plants decompose. Extra carbon dioxide results in more energy absorption, and an overall increase in the Earth’s atmosphere. In fact, the average surface temperature of the Earth has gone from 14.5 degrees Celsius in 1860 to 15.3 degrees Celsius in 1980.

Nitrous oxide is another important green house gas, and while we don’t release great amounts of this gas through human activity, nitrous oxide absorbs much more energy than carbon dioxide. For example, the use of nitrogen fertilizer on crops releases nitrous oxide in great quantities.

Methane is a combustible gas, and the main component of natural gas. It also occurs naturally through organic material decomposition. Other man-made processes that produce methane include: extraction from coal, digestive gases in large livestock, bacteria in rice paddies, and garbage decomposition etc. Like its fellow compatriot greenhouse gases, methane also absorbs infrared energy, and keeps up the heat on Earth.

Apart from their devastating effects, it takes a long time for the planet to naturally recycle these various gases. For example, a typical molecule of carbon dioxide can stay airborne for more than a century. Thus, greenhouse gases have both a potent, and a long-standing impact on the Earth’s ecosystems. A few other gases that make up for the rest of the greenhouse players include the Chlorofluorocarbons (CFCs), water vapor, ozone etc. Water vapor is particularly interesting, as it isn’t a very strong greenhouse gas, but makes up for this in sheer abundance. As global temperatures rise, oceans, and lakes release more water vapor, up to 7% more for every degree Celsius of warming, which adds to the warming cycle.

What’s next? 

In conclusion, the mechanisms involved in climate change, or global warming, are largely positive feedbacks that amplify the warming of the planet: the evaporation of water from the oceans doubles the impact of carbon dioxide increase, and melting sea ice reduces the amount of sunlight reflected to space etc. While not all feedbacks are certain, it is a grounded truth that the planet has to constantly readjust to the changes we make in our environment, in the case of global warming, the consistent addition of greenhouse gases into the atmosphere. So far, I have laid the  basic groundwork for the symptoms we can expect to see, as a consequence of global warming, in our environment. Moving on in Part II, we will consider those changes in greater detail, and what they entail for the future of our planet.

Cages

A few months ago, I had visited my family at Bangalore, India. Returning to my homeland was a nostalgic experience. During this period, my family, and I took a trip to a biological park.

While I enjoyed my time at the park, the excursion accompanied a fair share of contemplation on my part particularly with regards to the treatment of the world’s wildlife, and environment.

As much as I enjoyed observing the various species of animals that the park hosted, I felt a certain measure of guilt, remorse, and even anger at the state of said animals within their caged amenities.

I felt distraught that the freedom of said beasts, so majestic, was dampened within these structures, structures that were all too human; built around our ego, and will for dominance that have left us blind to the truth that we all depend on the measured balance of the ecosystem for survival.

While we pride upon our intellect to differentiate, and set us apart from the beasts, it grieved me to think, that in this modern day, and age humankind continues to  digress to a base notion of primacy in its interaction with other species on this planet, and the environment.

Ruminating on these thoughts, I passed by a message upon our departure from the park. Carved along the head of a rock, the message read, (as I recall, it was a quote by the founder of the institution)

 The survival of man is dependent on the survival of animal, and plant life.

Providing poetic irony to my reflections, the message inspired me to write the poem below, a brief meditation on the Cages that imprison human nature.


Cages

Decrepit,
Those shadows stare,
The blackened soot of their vacant eyes,
Clamoring against the leering smiles,
Forcing open the void from whence,
Comes that onerous resonance,
Tarnished ivories gaping amid the sputum,
Coagulating in the filth of their stature,
Wrinkled by the posture of their pride,
Dictating their steps,
Upon the earth they tread,
Mutely claiming what they desire,
Declaring their supremacy,
In these rusted chains,
So to rest,
Behind these bars,
Where this existence caged,
In limbo dwells,
Awaiting the spell,
That falls to the ground,
Submitting to the prejudice of vanity,
In ignorance of an action,
That remains,
Human, all too human…

crime-search-and-seizure-dna-bars
“They’re animals, all right. But why are you so goddamn sure that makes us human beings?” – The Long Walk, Stephen King

 

Hypernovas: Explosions in Space

Big Numbers in Time

The average lifespan of a human being is approximately 80 years. This number pales in comparison to the lifespans of celestial bodies such as the stars, luminous spheres of plasma that illuminate the night sky (Figure 1).

Figure 1. Stars burning brightly in the expansive void of a night sky.

The lifespan of a star depends on its mass. Interestingly, it is found that the more massive the star, the faster it fades away. The Sun, for example, is about 4.6 billion years old, and will last another 9 billion years. Stars that are 10 times the mass of the Sun burn only for 100 million years. On the other hand, stars one-tenth the mass of the Sun burn 100 billion years or longer. Those are some large numbers being thrown about, but in astronomy, these orders of magnitude are quite common. To put this in perspective, our ancestors have been around for about six million years, but the modern form of humans, or homo sapiens evolved only about 200,000 years ago. Human civilization is a recent enterprise of 6000 years, with industrialization beginning only in the 1800. Our existence is a fleeting instance compared to the lives of stars, a rich history woven through several evolutionary stages of enormous extravagance, which begs the question, what happens when a star dies?

Colors of an Explosion

Stellar evolution is the process by which a star changes over the course of time. As mentioned earlier, the more massive a star, the faster it burns out. All stars are born from nebulae, clouds of gas and dust, and over the course of millions of years, these proto- or infant stars settle down, and transform into what is known as a main-sequence star. The Sun is a typical main-sequence star (Figure 2).

Figure 2. An artist’s depiction of the evolution of a sun like star from its main sequence phase (far left) to a planetary nebula (far right).

The death of a star is intrinsically related to the energy source that powers a star for most of its life: nuclear fusion. If one were to peel open a star, they would find a ring structure like that inside an onion. Initially, the energy generated by a main-sequence star is through the fusion of hydrogen atoms at its core. Hydrogen atoms fuse to produce Helium resulting in an abundance of the latter, and the depletion of the former fuel. Eventually, the star begins to fuse the Hydrogen fuel along a spherical shell surrounding a mostly Helium core. This process causes the star to grow in size, and evolve into what is known as a Red Giant. Stars with half the mass of the Sun can also generate Helium fusion at their core, while more massive stars fuse heavier elements in a series of concentric shells. In general, the more onion rings, the more massive the star (Figure 3).

Figure 3. Onions have layers, stars have layers.

Once this nuclear fuel has been exhausted, a star like the Sun collapses into a dense, small body known as a white dwarf, with much of the outer layers of the Sun being expelled into a planetary nebula (Figure 4).

We learn about the stars by receiving and interpreting the messages which their light brings to us. The message of the Companion of Sirius when it was decoded ran: “I am composed of material 3,000 times denser than anything you have ever come across; a ton of my material would be a little nugget that you could put in a matchbox.” What reply can one make to such a message? The reply which most of us made in 1914 was—”Shut up. Don’t talk nonsense.” – Sir Arthur Eddington

The word “planetary nebula” is a misnomer. It does not mean clouds of gas and dust consisting of planets. The word originated in the 1780s when astronomer William Herschel viewed these objects through his telescope, naming them so because they resembled the rounded shapes of planets.

Figure 4. The Ring nebula (M57), a diffuse shell of gas and dust ejected from the parent star at the center.

Stars more massive than the Sun can explode in a supernova releasing much of the material that they were composed of in a shock-wave into the vacuum that is space. By releasing the bulk of the chemical elements that they had originally sustained in their core (the list includes: Hydrogen, Helium, Carbon, Neon, Oxygen, Silicon, and Iron), stars enrich the interstellar medium. The resulting shock-wave produced from a supernova also helps trigger the formation of new stars. The cores of such massive stars collapse into an extremely dense neutron star, and in certain cases, a black hole (Figure 5).

A normal-sized matchbox containing neutron-star material would have a mass of approximately 13 million tonnes, or a 2.5 million m3 chunk of the Earth (a cube with edges of about 135 metres).

The decisive factor is always the mass of the star, which in simple terms, is proportional to the strength of its gravity.

Figure 5. Interstellar’s Gargantua, a black hole, the literal heart of darkness.

Gravity is a one-dimensional force, in that it is always attractive, and tries to pull things together. We are held to the surface of the Earth by the planet’s gravitational force. A black hole is born when an object is unable to withstand the compressing force of its own gravity. Stars use their nuclear fusion to maintain a tremulous balance, for several million years, in an exhaustive fight against gravity. The Sun will never become a black hole, as its gravity isn’t sufficient to overpower the force produced by its nuclear furnace. But in more massive stars, gravity ultimately wins.

Then what are hypernovas?

Even Bigger Explosions

Simply put, hypernovas are pretty much the same thing as supernovas, just on a much grander scale. Hypernovas are extremely energetic supernovas, and though their formation is similar, they are both distinct phenomena (Figure 6).

Figure 6. Finally a Hypernova!

In a supernova, a star sheds its outer matter leaving behind a dense core in a neutron star. In a hypernova, the force of the explosion tears the inner star apart as well. Hypernovas only occur in stars with greater than 30 times the mass of the Sun. Like in a supernova, the star runs out of fuel, unable to support itself under the weight of its own gravity. As it collapses, the star subsequently explodes, spewing matter in all directions. The energy released within mere seconds of this explosion is greater than the energy that the Sun will release in its entire lifetime.

Time for an analogy. The sun radiates ~ 3.83 x 1026 W of energy. The standard light bulb for a table lamp has a wattage of 60 W. Thus, the sun radiates energy equivalent of 7 x 1024 light bulbs. Supernovas shine with the brightness of 10 billion suns (1 sun = 7 x 1024 light bulbs, then 10 billion suns = 10 x 109 x 7 x 1024 light bulbs = 7 x 1034 light bulbs), their total energy output being ~ 1044 J, which is the total energy output of the sun in its 10 billion year lifetime. Hypernovas release energy in excess of this amount. That’s a lot of light-bulbs!

Two plausible reasons currently conceived on the formation of a hypernova include:

  • A massive star (rotating at a very high speed or encased in a powerful magnetic field ) exploding, resulting in the inner core being ripped apart.
  • Two stars in a binary system colliding, forming one gigantic mass, and exploding.

The result is ultimately clear: a black hole is produced, and a huge amount of energy is released in the form of a gamma-ray burst, one of the brightest known events in the universe. The light released in a hypernova is several million times greater than all the light of the stars in the Milky Way galaxy put together.

Introducing the Universe

The world is very old, and human beings are very young. Significant events precede our appearance on Earth in what is an awesome vista of time. But in our vanity, we find the stubborn pride which motivates our claims, and actions as a higher organism on this planet. Thus, we are blind to the overwhelming reality that our existence on Earth, and the very existence of the planet itself, is nothing more than a single thread woven into the rich tapestry that is the universe. There, beyond the confines of our world and among the stars, lies unfathomable mysteries of great wonder. Hypernovas are a small shade of that enormous spectrum of amazing phenomena in our universe.

References

Wikipedia Articles:

Other Articles:

The Dragons of Eden – Chapter 1 – The Cosmic Calendar

“What seest thou else in the dark backward and abysm of time?” – William Shakespeare

Time is a component quantity of our daily lives. It is symbolic of the indefinite progress of existence, and events that are generally considered to occur in an apparently irreversible sequence from the past, to the present, and onto the future.

The concept of time has been central to the growth, and evolution of human civilizations. It has also served as an important facet of knowledge that has been studied to a great effect in religion, philosophy, and science. But, to this day, an absolute definition of time still evades scholars.

In The Dragons of Eden, Sagan does not extend his arguments toward an extensive discussion on the concept of time, but rather focuses on its use as a metaphor to describe humanity’s place in the cosmos. To infer the future, it is necessary for us to understand our origins. This is the basis of Sagan’s approach.

Now, it is argued that the predecessors of modern-day human beings, the Homo sapiens¸ evolved somewhere between 250,000, and 400,000 years ago. This number pales in comparison to the appearance of the first primitive humans, such as the Australopithecines, which happened somewhere between 8-9 million years ago. But, even these events, are preceded by an even greater “vista of time” reaching far back into the history of our planet, the solar system, and the universe. Very little is known about these periods of time, and even with the numbers mentioned earlier, we still struggle to grasp the immensity of these time intervals (Figure 1).

Figure 1. Humanity is yet to define its existence amidst the vast cosmos.

Nevertheless, science has found success in the establishment of specific methods that have allowed us to date events from the remote past, such as geological stratification (Figure 2), and radioactive dating (Figure 3).

Figure 2. Geological stratification, bluntly said, involves the study of rock layers, and layering.
Figure 3. Radioactive dating is a technique involving the tracing of radioactive materials in select objects, carbon dating is one such method that is limited to the dating of organic (carbon-based) organisms.

These two methods have provided information on archaeological, paleontological, and geological events. Astrophysical theory has provided for the same on a grander scale involving the dating of stars, planetary surfaces, galaxies, and the even the age of the universe (Sagan states this to be 15 billion years old, though recent results from the Wilkinson Microwave Anisotropy Probe (WMAP) puts the number somewhere at 14 billion years old). The earliest event known in record is called the Big Bang, an intense explosion from the universe is said to have formed, but rather than a beginning, the Big Bang is generally considered to be a discontinuity in time where the earlier history of the universe was destroyed.

To put this further into perspective, Sagan introduces the Cosmic Calendar, where he compresses the 14-billion-year-old chronology of the universe, into the span of a single earth year. In this manner, one billion years of Earth history is the equivalent of twenty-four days of our cosmic year, and one second of the cosmic year is the same as 475 real revolutions of the Earth about the sun. The Cosmic Calendar is a humbling account of humanity’s place in the universe, with all our recorded history occupying the last few seconds of December 31.

Though a short chapter, Sagan’s use of the Cosmic Calendar is quite analogous to a common argument used in astronomy to provide a picture of our place in the universe (Figure 4).

 

Figure 4. Our place in the universe. The planet Earth is smaller than a speck among the greater part of the observable universe.

While the major premise of Sagan’s book focuses on discussions on the evolution of human intelligence, this introductory chapter is a necessary prelude that helps to symbolize the significance of the subject matter. While it may be true that humanity occupies an insignificant instance in the face of cosmic time, we are now embarking on a new cosmic year, one which is highly dependent on our ability as a species to come together, use our wisdom, and unique sensitivity to the world for our survival, and a greater future.

References