Climate Change – Part III – What can be done?

With the veritable amount of evidence that has been laid out before us, why is it that people aren’t concerned about global warming? Despite scientific consensus on the subject, some people think global warming isn’t happening at all. There are several reasons for this, and they cover various overlying and conflicting themes on global communication, and an incentive towards environmental action.

Beginning with the common lay-person, a popular speculation is formulated in the form of this question: If simple forecasts can’t get next week’s weather right, how is it that we can trust the predictions that have been made on the basis for decades or centuries from now?

The answer to this is quite simple, and once again highlights the necessity towards scientific communication, and public education. Weather and climate are not the same. Weather relates to individual, and day-to-day changes in the atmosphere; climate is the statistical average of such changes. Weather is short-term, and of a chaotic nature, thus making it inherently unpredictable beyond a few days. Meanwhile, climate is long-term average weather, controlled by the composition of the atmosphere, and is thus more predictable on the time-scales considered.  A simple analogy is provided at the Climate Communication website,

While it is impossible to predict the age at which any particular man will die, we can say with high confidence that the average age of death for men in industrialized countries is about 75. The individual is analogous to weather, whereas the statistical average is analogous to climate.

Stepping beyond the individual, we encroach upon a global dialogue between, and within political and scientific institutions. While most scientists recognize the phenomenon that is global warming, there still remain a few who believe that there is nothing to be worried about. The latter argue that the Earth is more resistant to climate change than proposed. Many of the consequential changes are, in their opinion, not disastrous, and that cutting down the emission of greenhouse gases may result in economic damage far more potent than any of the effects of global warming.

The uncertainty that exists within the scientific community has been carried over to the political realm. Skeptics use it to argue for postponing action, while contenders point out that there are various other facets of life that require action in the face of uncertainty, such as buying health insurance. The IPCC has also pointed out that confronting a large-scale task such as climate change will not occur in an economic dissolution. As quoted from the 2014 report by the IPCC’s Working Group III,

Climate policy intersects with other societal goals, creating the possibility of co-benefits or adverse side effects. These intersections, if well-managed, can strengthen the basis for undertaking climate action.

Ultimately, what can we do about it? It isn’t possible to simply “stop” climate change. Even if we turned off every fuel-burning machine on Earth, the planet would warm at least another 0.5 degrees Celsius as the climate adjusts to the greenhouse gases that already have been emitted. Nevertheless, progressing toward the future, we can still make efforts in decreasing activities that may help propagate and positively reinforce global warming.

On a local level, we can do this basically by not using as much of the stuff that creates greenhouse gases as well as using less energy. Electricity governs much of the modern world, and much of the electricity that operates many of the devices in our homes comes from a power plant, which most likely burns fossil fuels to generate that power. The simple action of turning off lights when they are not in use, and using a fan or an air-conditions only when necessary can help. Similar initiatives can be taken in the view of using public transportation, efficient recycling and waste management, reforestation etc. Beyond all of this, we need to develop non-fossil fuel energy sources. Hydro-electric power, solar power, hydrogen engines, and fuel cells could help in this initiative towards a global change in energy sources.

In conclusion, much of this is easier said than done but that doesn’t mean we should give up. Given the global nature of the climate problem, we all have a hand in contributing to the solution, and in confronting the necessary alternatives and options we must also be willing to face agreements and disagreements in faith of positive communication. The real power to enact significant change rests in the hands of those who devise national and global policies. International and scientific collaboration on technology sharing, effective communication and education of the public supplemented by an efficient transition toward alternative, and green-energy initiatives would help make a difference in the long run.

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The environment’s role in our survival, and the importance of its preservation is common sense. There is nothing wrong in creating a better world. We have a moral responsibility in protecting and handing the planet over to the next generation. 
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Climate Change – Part II – Consequential Symptoms

The Symptoms

So far, we have had a taste of the basic science behind climate change or global warming. Now, it’s time to look at the consequences. Let’s dive right in.

There is a lot that is happening now which may serve as prelude to what may happen in the future. Briefly, the major consequences of global warming would involve: extreme heat (a warmer Earth), extensive floods and droughts (but not everywhere), a big melt (say goodbye to glaciers), rising oceans and stormy weather (friendly neighborhood hurricanes and other storms), as well as ravaged ecosystems and agriculture (a price for life inclusive of all species on Earth).

Rising Temperatures 

Much of the effects of global warming comes down to discussing the effects of an average rise in the planet’s temperature. Remember, small changes in climate can equate to major effects around the world.  The “Ice Age” was caused by an average drop of just 5 degrees Celsius over a time period of thousands of years. So, what can we say about the opposite scenario? What will happen in the Earth’s average temperatures increases a few degrees in just a few hundred years?

Graph of global mean temperature from 1880 to 2009 (NASA).

Note the shorter time span. Why? Well, as humans, we have had quite the impact on the planet. Picking up around the era of industrialization, we have come far, and in our development, we have meted out a measurable influence in the biosphere. Global warming is a significant increase in the Earth’s climatic temperature over a short period of time due to human activity. We are living in the Anthropocene epoch (the term itself is yet to be deemed official).  The largest human influence has been the emission of greenhouse gases such as carbon dioxide, methane, and nitrous oxide, thanks to the heavy utilization of fossil fuels.

This is a big deal. To put things in perspective, natural changes in climate would follow rises, and falls in temperature amounting to 1 degree Celsius over thousands of years. The Earth’s climate can change due to volcanic activity, plant life, solar radiation, and atmospheric chemistry. Significant evidence from the IPCC now shows our role in accelerating these changes over shorter time periods.

Glaciers and Ice Shelves 

One of the most publicized effects of global warming is the melting of glaciers and ice shelves. This is quite a problem as ice plays a prominent role in reflecting solar radiation away from Earth. Thus, the loss of large surfaces areas of ice could accelerate global warming. The chain of effects, mentioned earlier, pretty much follow in response.

An immediate result of melting glaciers would be the rise in sea levels. As glaciers  melt, they are adding to the water already in the Earth’s oceans. While the rise in sea level may be modest, amounting to an inch or two, this can still cause various problems, namely the flooding of low-lying coastal areas. The scenario is particularly dire if the West Antarctic Ice sheet were to melt. This would push sea levels up to 10 meters, and many coastal areas would completely disappear.

Research predictions indicate rising sea levels up to 22 inches by the year 2100. As of now, the main big melt is occurring in the North Pole where the ice is not as nearly thick as at the South Pole. Nevertheless, we cannot ignore the possibility of a summation of gradual increases in temperature to slowly, but surely, affect all corners of the planet.

A poster child for the consequences of climate change, the nation of Maldives is facing a rise in sea levels and the bleaching of its coral reefs. 

The Age of Storms

With a rise in the overall temperature of the ocean, tropical storms and hurricanes will increase in force. This is most evident in the North Atlantic where ocean temperatures have risen through long-term warming, and the cyclical nature of Atlantic currents. Think of it as a cyclic storm generator. In fact, the tropics as a whole are experiencing a general trend towards ocean warming that follows global warming.

Now, despite these projected trends, one cannot tie any single devastating hurricane or other weather event directly to global warming. This was a popular opinion when Hurricane Katrina ravaged New Orleans in 2005. While the devastation, and damage caused to the city were horrible, it is well understood that Katrina’s impact also takes into consideration the storm’s track, the weaknesses of levees, and many other factors. Nonetheless, the verdict is that for the storms to come in the future, there will be an overall strengthening of winds and rainfall.

A Changing of the Seasons 

While global warming will cause a certain lengthening of the seasons, its most devastating effects, the ones that are most difficult to predict, involve its impact on the world’s biosphere. Changing seasons may benefit certain parts of the world, while other temperate parts of the world would face long droughts, and a general decrease in precipitation.

This will be particularly influential to the ecosystems that currently thrive on the planet. Ecosystems are delicate, and even the slightest change can kill off several species. Furthermore, ecosystems are interconnected, and so what may begin as a simple symptom may develop into a chain reaction that will ravage the biosphere.

Mapping vulnerability and conservation adaptation strategies under climate change   James E. M. Watson, Sept 2013 Nature 

Life, in essence, will once again become a competition revolved around a species’ ability to adapt to the shifts in climate, though it is highly likely that many will become extinct. The most drastic example of change, in light of global warming, is actually displayed on the documentary Planet Earth where we are shown how the tundra in Northern Canada has turned mostly to forest.

Last, but not least, much of this will have a human cost. It is hard to quantify the exact amount but we can expect a greater number of medical occurrences involving heat-strokes, and other heat related trauma. Poor, and underdeveloped nations will suffer the worst effects as they do not have the financial resources to deal with the problems that follow. Prolonged droughts may lead to desertification of areas, and widespread starvation. Decreasing precipitation would limit crop growth, and coastal flooding would result in a spread of water-borne illnesses. All in all, the world’s economy will take a wallop, and so will the condition of life on Earth.

It Does Not Compute!

So, after all is said and done, why is it that some people still aren’t concerned about global warming? Despite a scientific consensus on the subject, many believe global warming to be a farce. In Part III, we shall bring this discussion series on climate change to a conclusion by addressing quite possibly the two most crucial elements of the crisis: communication, and the incentive towards action.

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.

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:

Next Up on Let’s Get Thinking: Hypernovas!

This was a request from one of my readers! It should be a colorful post, so look forward to it, as we take a trip to outer space to peer into a rare, and beautiful phenomenon at the far reaches of our universe!

Why Is Snow So Bright?!

If one wishes to experience the full spectrum of the annual cycle of the four seasons, Edmonton is certainly the place to visit. Though it varies every year, you can expect an early start to spring around March, with summer setting the pace in June, autumn settling in with September, followed closely by winter arriving around October at the earliest. Winter, in fact, is the chief minstrel of Edmonton’s seasonal ballad (Figure 1), with Boreas providing for the brittle winds, and dense snowfall that sweep across the city during this season.

Figure 1. Edmonton’s winter skyline

Who doesn’t like snow? I myself have never denied an opportunity to jump into or wade my way through a dense pools of snow (just make sure you are wearing the appropriate gear for the occasion), or on some occasions push others into them (my partner, Leina, in particular, could relate to a few “sweet” memories). In fact, it was only after arriving in Edmonton, 19 years old to boot, that I first saw snow in my life. This was back in 2009, and now that 2016 has come to an end, I have rounded off seven years to my predominantly snow-filled life in Edmonton, Alberta, Canada. Despite all of this, if there is one thing that I could never get used to in all these years, it would have to be waking up in the early hours of the day to the bright, and mildly annoying  pure, ambient white light emanating from the snow outside my apartment, leading now to the subject of our post, “Why Is Snow So Bright?”

The answer is quite simple. Snow has the highest albedo of any naturally occurring substance on Earth. Albedo is the percentage of reflectance (of light) off the surface of an object. Snow is ~ 90% reflective, which is why it is so damn bright. This begs the question of how a reflective surface may appear brighter than its diffuse illuminant (the sky, in this case). Having done a little bit of back-reading, it is reported,

“Three factors are largely responsible for this visually striking effect: the law of darkening for the cloud cover, the reflectivity of the snow and the average landscape albedo, and the observer’s contrast sensitivity function.”

 J.J. Koenderink, and W.A. Richards, Why is snow so bright?, J. Opt. Soc. Am. A, Vol. 9, No. 5, May 1992. 

We find that the explanation for the brightness of snow is a mixed physical, and psychophysical phenomenon. While the paper provided by J.J. Koenderink, and W.A. Richards go into great detail on the scientific methods that support these observations, I will provide a summary covering some of the interesting facts found in the paper. The three factors, aforementioned, are examined in a sequential manner, and the necessary conclusions derived accordingly.

The Scattering of Light

We begin with the law of darkening for the cloud cover. This involves intuitive observations we often make about the radiance or illuminance of the sky. The sky is not uniformly illuminated. This is quite noticeable depending on the elevation of our line of sight with respect to the horizon. Two factors are largely responsibly for the darkening that is usually observed from the maximum brightness we find at the zenith (point in the sky directly above us) to the grayish haze that we identify as the horizon:

“The angular distribution of the forward scattering (average differential scattering cross section) and the backreflectance to the clouds off the surface of the Earth.”

Light, or electromagnetic radiation, from the sun is scattered by particles in the atmosphere. This is commonly known as Rayleigh Scattering named after the British physicist Lord Rayleigh (Figure 2), a principle that describes the scattering of light by particles much smaller than the wavelength of the radiation.

John William Strutt.jpg
Figure 2. Lord Rayleigh

These particles can be individual atoms or molecules. The light from the sun is a mixture of all colors of the rainbow. Using a prism one can separate the “white” light from the sun to its different colors forming a spectrum (Figure 3). These colors are distinguished by their different wavelengths. Our vision is limited to what is known as the visible part of the spectrum ranging between red light at wavelengths of 720 nm to violet with a wavelength of 380 nm.

Figure 3. The visible spectrum (ROYGBIV)

In between, we have orange, yellow, green, blue, and indigo. The retina of the human eye has three different types of color receptors that are most sensitive to red, green, and blue wavelengths providing us the colored vision of our environment. On a clear cloudless day, we observe that the sky is blue. This is because molecules in the air scatter blue light from the sun more than they scatter red light. Meanwhile, at sunset we see the familiar red, and orange haze because the blue light from earlier has been scattered out, and away from our line of sight (Figure 4).

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Figure 4. Why is the sky blue?

Similarly, forward scattering is a subset of radiation scattering which involves changes in direction of less than 90 degrees. In contrast, the effect of the backreflectance of the surface of the Earth is found to be largely independent of the visual angle of observation as the clouds of an overcast sky are roughly Lambertian. No matter from what angle the observer views a Lambertian surface, the brightness of the surface apparently is the same. Unfinished wood is known to roughly exhibit Lambertian reflectance, while a glossy/coated wooden surface does not. These two factors, forward scattering and backreflectance, contribute to the radiance of the sky, and the observed darkening of the sky from the bright zenith to the grayish horizon.

What about our eyes?

From here onwards, it is smooth sailing. The paper discusses the last two major factors including the reflectivity of snow and the average landscape albedo, and the observer’s contrast sensitivity function. It is found that the albedo of snow typically ranges from 80% to 95% across the spectrum with lower values for higher snow densities. Though snow is not a true Lambertian surface, the approximation is satisfactory. The landscape albedo figures into much of the calculations involved, and we find that it is only in extreme situations that the radiance of the snow is equal to the radiance of the horizon sky. In general, a whiteout (Figure 5),  is only possible if the reflectance of the landscape is above 50% which rules out most effective natural landscapes with the exception of snow itself.

Figure 5. Whiteout, a weather condition where visibility and contrast is severely reduced by snow (or sand). As can be observed, the horizon disappears completely.

Much of what is demonstrated in the paper shows that the contrast effect of snow can cause the sky at the horizon to appear darker than the zenith sky. But, the zenith sky is still found to be brighter than the snow, so why is it that we are not able to recognize this difference, and identify that the sky is indeed brighter than the snow? The answer is once again quite simple. The sky at the horizon is darker than at the zenith owing to the law of darkening described earlier. This results in a gradient over the circular dome above us, but one that is so shallow that the gradient is generally not noticeable to the comparative resolution of our eyes, thus leading us to believe that the snow is in fact brighter than the sky that illuminates it.

References

  •  J.J. Koenderink, and W.A. Richards, Why is snow so bright?, J. Opt. Soc. Am. A, Vol. 9, No. 5, May 1992.

 

On the Nature of Knowledge

Introduction

So, after a week of thoughtful contemplation amid myriad deadlines, I’m excited to finally post my discussion “On the Nature of Knowledge.” I contested two methods of approach in presenting this topic: one that is grounded in philosophy, and the other that is inspired from my personal experience as a student. Ultimately, I’ve decided to stick with the latter as it would be consistent with how I’ve addressed most of the topics posted on this blog. For anyone wishing to tackle the same topic from a philosophical perspective, check out epistemology (the Stanford Encyclopedia of Philosophy provides an awesome introduction on the subject).

Our discussion will be divided into three separate parts dealing with the following questions:

(1) What is knowledge?
(2) What is knowledge from a student’s perspective?
(3) What is the purpose of knowledge?

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Seems simple enough!

My objective today will be to share my personal experience and growth over the last seven years of my undergraduate and graduate studies, during which I actively and repeatedly engaged these questions. I’m well aware of the various generalizations that can be made in answering these questions, but my opinions will converge and revolve around the viewpoints I’ve accepted in my personal journey to discover those same answers as a student. Let’s begin!

What is knowledge?

I believe knowledge can be defined via three categories: personal, factual, and action-based knowledge.

Personal knowledge revolves about the knowledge gained by acquaintance with the objects, the events, and the people in one’s environment. Having just arrived in Canada for my undergraduate studies, the foundation of my life was built around the expectations and experiences I had with my family living in India, Egypt, and Sudan. Commencing my studies at the University of Alberta while living in student residence, working part-time and volunteering in various activities, my personal growth as an individual continued as I mingled and became familiar with an alien environment. My new-found freedom allowed me to fully experience and question my individuality, a process that would culminate in my identity crisis several years down the road (one that I have thankfully resolved). Knowledge, in this sense, is acquainted with my familiarity toward objects in my environment as well as the delegation of my recognition to said objects, and was highly influential in defining my identity and my decisions. Altogether, personal knowledge is very much a book in progress in our individual lives. Its measures and ends are dictated by our environments, personal motivations, and growth while actively influencing all three of those aspects.

Action-based knowledge is the knowledge of how to do something. This would involve one’s abilities to do something, like driving a car or starting a campfire.

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On the other hand, factual knowledge, as is obvious, is the knowledge of facts. Action-based knowledge is different from factual knowledge. One may know the theory behind driving a car, while not actually knowing how to drive a car. Factual knowledge is evident in both action-based, and personal knowledge. With personal knowledge, in order to speak with others, one must  know how to communicate. One doesn’t necessarily know a person just by meeting them, one must also know a few things about them. Similarly, with action-based knowledge, one must know certain facts about driving, like the motion of the car with respect to actions on the steering wheel, to assist and help them actually drive the car.

Despite this, factual knowledge is alone not enough. Personal knowledge involves the need for action-based knowledge that helps an individual acquire the necessary skills to interact with his/her environment, and action-based knowledge may require some factual knowledge, but that same factual knowledge cannot amount towards action-based knowledge. In fact, one could say that there is no definitive standard of connection between these three categories of knowledge, seeing how much they intermesh. For the philosophy lovers, epistemology deals largely with the views of factual knowledge.

What is knowledge from a student’s perspective? 

How does this all come together for a student? Well, one of the main reasons we go to school is to cultivate our knowledge and understanding of the world. At university, this may largely be oriented by our aspirations on a field that would preferably model our future careers. I say “may” as I believe the purpose of higher studies does not have to primarily revolve about one’s career or prospective choice of employment (this in itself, leads to the crucial discussion on the structures of education or educational systems).

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Have…To…Keep…Going….

As a student, much of our time at university involves absorbing the factual knowledge before actually implementing them in the real world. Our action-based knowledge is attested to our success with such implementations. It is pretty similar to the notion of the scientific method, where theory precedes experiment in a repetitive cycle. This is where we also learn the difference between the static process of remembering knowledge versus the dynamic process of applying said knowledge. This is at the core of our ability to learn and interact with our environment, and is a social behavior whose roots are sown in our evolution as a species.

Factoring on to this is the personal knowledge that every individual inhibits. Being a student, you’re part of a community, one that we may or may not socialize with (each with its own share of circumstances). Putting aside the knowledge we gain from our courses, the personal knowledge we exhibit provides for the competitive play of our social lives from networking, to the establishment of our status, while satiating our thirst and drive for recognition.

All of which now leads us to ask, what is the purpose of knowledge in general?

What is the purpose of knowledge? 

Personally, to this day, I believe an individual’s knowledge is characterized not only by their ideas, but also how they act upon them. The question on the purpose of knowledge derives greatly from the means of education an individual may seek, which by itself, is an even bigger discussion.

I’ve come to recognize how influential the methods utilized to propagate knowledge at an academic institution can be on its community (teachers and students alike). After my four years of undergraduate studies, I was spent, and in many ways had to rediscover my personal creativity and motivation. Following a gap year, I pursued graduate studies, which I just recently completed. Looking back at my experience, I must say that a large part of my journey also had its run of the mill circumstances surrounding my identity crisis, but I cannot deny that it came with its share of new and enlightening perspectives involving my personal opinions on the educational systems of modern-day academic institutions.

What is the purpose of knowledge? I believe it is what it is, for every one of us, however we wish to see it.

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 If there is one attribute to my personality that I have always been proud of, it would be my undying curiosity, and endless thirst for knowledge. In my life, this has changed from a wish to understand the world, to sharing said knowledge, and to contributing my own by enhancing the source of said knowledge. The Pensive Reverie is in fact a personification of my desire to share my knowledge, as an individual, to the world. Ultimately, as Francis Bacon put it, “Knowledge is power” but I also believe what we do with said power defines the object for each and every individual.