By: Arjun Mirani
On February 14th, 1990, the spacecraft Voyager 1 took an iconic photograph of the Earth from over 4 billion miles away, as it zoomed towards the edge of our Solar System. From this humbling vantage point, our planet appears to be no more than a speck – 0.12 pixels in size – in an enormous arena of darkness. Here is Carl Sagan’s oft-quoted response (1) :
“Look again at that dot. That’s here. That’s home. That’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization… every ‘superstar’, every ‘supreme leader’, every saint and sinner in the history of our species lived there – on a mote of dust suspended in a sunbeam.”
The Earth has always seemed powerful, solid, and reliable to us humans. We are awed by the tempestuous rise and fall of our oceans. Fresh air seems infinite in supply. The sun seems a tranquil yellow circle in the sky, bathing our homes and fields in warmth. As nature wends its cyclical way, we have constructed the grand edifice of human culture – literature, art, music, architecture, philosophies of politics and society, economic systems and governmental regimes. We take it for granted that these things will exist, in all their splendor, for generations to come.
The unfortunate truth is that our human viewpoint is severely limited by our size. Let us take a step back and view humanity for what it is – an incredibly young species, adrift in an unimaginably vast universe. The piece of rock on which we stand is the only thing tethering us to life. Our atmosphere is barely a membrane separating us from the vacuum of space (where we would instantly suffocate and explode), and preventing us from being killed by deadly ultraviolet radiation. Our existence is far more precarious than the solid ground beneath our feet makes it seem.
Despite the billions of galaxies out there, we have not seen any trace of other intelligent civilizations, or even basic life forms. The fact that life exists on our little blue bubble – something we tend to take for granted – is truly remarkable. The universe is an incredibly hostile place. An asteroid impact of sufficient strength could render Earth completely devoid of life. If our planet were twice as close to the center of our galaxy as it happens to be, gamma ray bursts would have prevented the formation or long-term development of life. Notwithstanding external threats, a supervolcanic eruption on Earth could cause mass extinction (which happened 250 million years ago). These are very real possibilities that routinely occur elsewhere in the universe.
Tragically, we humans are currently pushing the boundaries of our luck towards breaking point. We are eroding the conditions of our home planet that have nurtured the beautiful miracle of life, unaware of how tenuous and precious they are.
Since the Industrial Revolution, human activity has been significantly altering a climate that has just the right calibration to support life. Remarkably, Earthly life consists of not just a few strains of microbes, but millions of stunningly diverse species that give this planet color and flair. Climate change has the capacity to be an existential threat. At the very least, it can consign humanity to a terribly frugal existence, while other more helpless forms of life are destroyed.
To climate change skeptics: Species are already going extinct at an alarming rate. The concentration of carbon dioxide and other heat-trapping gases has risen dramatically, at a completely unnatural rate, in the past 50 years, directly attributable to human activity. Several independent studies show that the evidence is overwhelming and scary. Natural causes, like changes in solar energy output, simply cannot account for what we see today. Climate change is real – according to the vast majority of the world’s highly capable scientific community.
To those who acknowledge the existence of climate change, but do not consider it a priority: Climate change demands urgent attention. This is not to say that other issues like poverty and violence do not – they certainly do. But climate change ranks as high as any of them. It has far-reaching implications that go beyond one or two generations. It impacts the future of humanity as a whole, and all other forms of life that are equally entitled to the food, water and air we share.
First, let us consider the human repercussions. Stable civilizations began to form only about 11,500 years ago, when naturally induced climatic fluctuations settled down into predictable patterns. Civilizations cannot take root in protean natural conditions. Even during the course of human history, the rise and fall of civilizations has often been linked to climatic changes. According to Harvard anthropologist Dr. Jason Ur, “When we excavate the remains of past civilizations, we very rarely find any evidence that they as a whole society made any attempts to change in the face of a drying climate, a warming atmosphere or other changes. I view this inflexibility as the real reason for collapse” (4).
It is no surprise that under a Department of Defense Directive, the United States’ military has made responding to climate change a national security priority (5). History has shown, all too often, that humans can be helpless in the face of nature’s wrath. For instance, Hurricane Katrina (2005) destroyed numerous innocent lives, and cost $108 billion in damages (6). Droughts in countries such as India have not only parched crop fields, but also spurred large numbers of farmers to suicide – leaving their children without sustenance or hope. With the climate in human-induced flux, hurricanes like Katrina, droughts, and floods will become much more frequent and intense (7). The human toll is undeniable. For countries with agriculture-based economies, changes in the timeframe and quality of crop growth can be debilitating.
Furthermore, consider the fate of something as fundamental as food. Much of the developed world currently takes consumable food and water for granted; we are headed towards a shortage of both these essential resources, due to human profligacy. Our descendants will neither care about, nor be able to contribute to, the development of human culture if they must struggle to eat, drink and breathe everyday. Furthermore, we are ravaging our atmospheric shield, directly exposing ourselves to ultraviolet radiation that causes cancer. Imagine how much suffering this would cause to people of all ages, especially those who cannot afford healthcare. We are literally destroying the very things that keep us alive.
At present, the Earth is all we have. Some people believe that if we ruin the climate beyond repair, we will be able to move to Mars and live on. This is simply not feasible in the near future. It is indeed likely that we will establish a self-sustaining Martian colony at some point, but that is decades away at the very least. While companies like SpaceX are actively working towards this goal, current technology is simply not advanced enough to take even five people to Mars at an affordable rate. Even SpaceX’s audaciously ambitious CEO, Elon Musk, dreams not of moving the entire human population to Mars, but setting up a self-sustaining colony of 1 million people – this could ensure the survival of the human race even if all links to Earth were severed (8).
There are two points to note here – first, this is a very small group in comparison to Earth’s total human population. It in no way ensures the survival of most people (who cannot afford the trip/cannot be accommodated in the nascent colony) and their descendants. Climatic trouble on Earth would still bode ill for the vast majority of mankind. Second, establishing a human colony on another planet involves overhauling its environment and atmosphere to make it suitable for life. This ‘terraforming’ process is highly challenging and could well have adverse consequences. The difficulties of re-engineering a planet aside, the human body has not evolved to permanently live in low-gravity conditions (Mars’ gravity is three times weaker than Earth’s), and the health impacts of long-term space habitation are still an area of research (9). Moving all humanity to Mars is a highly distant dream. Given the current pace of climate change, it will become lethal well before the ultimate Mars dream becomes viable.
The eventual fate of our planet is sealed – 7 billion years from now, the Sun will engulf the Earth. Our oceans will evaporate much sooner, in about a billion years (2). By then, if humanity is to survive, we will have left our planet and journeyed into the stars. However, we have a moral obligation to preserve the Earth for as long as possible, rather than prematurely sabotaging it.
Here’s why: humanity is not alone on this planet. We are extremely young – if the Earth’s lifetime were compressed into 24 hours, humans have existed for just the last second of the day (10). In this short timespan we have managed to forcefully impose our dominance, continually encroaching upon Earth’s other inhabitants and causing their extinction. Extinction, when dwelled on, is deeply tragic – a life form that may have been utterly unique in the entire cosmos fades forever into dust.
The sheer biodiversity on Earth is mind-boggling. There are around 8.7 million species of life, of which we are just one (11). Land-based life alone has dazzled humanity with its beauty for centuries. The intricate patterns of butterfly wings; the luminescence of fireflies punctuating the night; the lilting call of a songbird yearning for courtship – these bring such richness to a silent and impersonal universe. Even more fantastic is the world within the oceans – coral reefs of myriad hues transforming the seafloor into a work of art; enigmatic creatures hidden in depths we can never reach.
We deprive ourselves when we fail to notice these things, lost in a world of cellphones, stock markets and traffic. We deprive the universe when we snuff out their existence in our blindness. And that is exactly what we are doing with climate change, more rapidly than ever before. Without immediate action, a third of all land plant and animal species on Earth will be extinct by 2050 – a mere 34 years from now (12). The artistry of life is one of the most ineffable features of the cosmos, and it is surely our duty to preserve it for as long as we possibly can.
The natural environment is not just central to other life forms – human happiness hinges deeply on it too. We take for granted the fact that we can go for a walk, perhaps by a river, enjoying a cool summer breeze. We can wake up to a shining sun that subconsciously lifts our spirits. We can step outside and smell the enchanting aroma that follows a new rainfall. Gravity doesn’t bother us; breathing is free and satisfying. But there are worlds where none of this is possible. One of them is a dying Earth, where we must venture outdoors wearing oxygen masks, faced with tumultuous weather, surrounded by parched plants and barren ground. Another is Mars, where we must venture outdoors in bulky spacesuits, beneath a black sky, a new gravitational field making each step feel strange.
This is not a prediction of an imminent doomsday. Both these worlds are unavoidable in the long run, but with sufficient effort, permanently living in either can be postponed for thousands, if not millions, of years. Even if humans survive climatic catastrophe, as we probably will, it will be a half-existence devoid of the things that make life worth living – things no human can artificially replicate. The laws of nature have manifested themselves in singular ways on planet Earth. As Carl Sagan so eloquently noted, this “underscores our responsibility to preserve and cherish the pale blue dot, the only home we’ve ever known” (1).
Arjun Mirani ‘20 is a freshman in Thayer.
 http://www.planetary.org/explo re/space-topics/earth/pale-blue-dot. html (The Planetary Society). Picture is a NASA/JPL public domain image.
 Barras, Colin. ‘How Long Will Life Survive On Planet Earth?’, BBC Earth, 23 March 2015. Web. http://www. bbc.com/earth/story/20150323-howlong-will-life-on-earth-last
 ‘Climate Change – How Do We Know?’, NASA – Global Climate Change: Vital Signs of the Planet. Web. http://climate.nasa.gov/evidence/
 Sohn, Emily. ‘Climate Change and the Rise and Fall of Civilizations’, NASA – Global Climate Change: Vital Signs of the Planet. Web. http://climate. nasa.gov/news/1010/climate-changeand-the-rise-and-fall-of-civilizations/
 Dept. of Defense Directive 4715.21. http://www.dtic.mil/whs/directives/corres/pdf/471521p.pdf
 National Hurricane Center. http://www.nhc.noaa.gov/pdf/nwsnhc-6.pdf
 Climate Change Effects, NASA – Global Climate Change: Vital Signs of the Planet. Web.
 Urban, Tim. ‘SpaceX’s Big Rocket – The Full Story’ – based on interview with Elon Musk, Wait But Why, 28 Sept. 2016. Web. http://waitbutwhy. com/2016/09/spacexs-big-fking-rocketthe-full-story.html
 Scharf, Caleb A. ‘So You Want To Terraform Mars?’, Scientific American blog ‘Life, Unbounded’, 29 Sept. 2016. Web. http://blogs.scientificamerican. com/life-unbounded/so-you-want-toterraform-mars/?WT.mc_id=SA_FB_ SPC_BLOG
 Urban, Tim. ‘Putting Time Into Perspective’, Wait But Why. Web. http://waitbutwhy.com/2013/08/putting-time-in-perspective.html
 Mora, C., Tittensor, D., Adl, S., Simpson, A., Worm, B. ‘How Many Species Are There on Earth and in the Ocean?’, Public Library of Science: Biology Journal, 23 Aug. 2011. Web. http:// journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.1001127
 UN TEEB, US Geological Survey, BP, London Market Exchange (2012) and Worm et all (2006)