No, this is not a joke, although I’m not referring to the sprites of fairy tales…
A “sprite” is a whimsical name given to a particularly ephemeral upper atmosphere phenomenon that’s generated by lightning discharges in powerful thunderstorm clouds. Sprites are witnessed as whispy colourful flickering shapes above the thunderstorm clouds and in this video, we watch a team of storm-chasers in hot pursuit of these large-scale electrical discharges.
The things people do for science…
Video Source: “Storm Chasing in a Jet – Capturing Upper-atmospheric Lightning” Uploaded by CuriousVideos to YouTube channel www.youtube.com/watch?v=vSCwiQWzMa0.
Original Source: From NOVA – At the Edge of Space by PBS
It took two long haul flights, six plastic wrapped airline meals, three movies, two cantankerous airhostesses and a dangerous brush with halitosis for me to learn about the latest crisis throwing a spanner in the works of the mankind’s (mostly shoddy) attempts to run things smoothly on planet Earth.
I’m talking, of course, about El Niño.
I had to come to Los Angeles to learn that we’re actually teetering on the edge of what the western media is referring to as a “monster El Niño event” and by the time I publish this, we may very well have taken the dive. Where I come from – South Africa – the media and moreover the government pay scant attention to weather and climate issues. This is extremely ironic considering our economy is based on primary industry and that El Niño years are linked with drought in Southern African’s interior. So, in keeping with this relationship, we’re currently facing critical drought conditions for which the government has done nothing to prepare.
Alas! Here in South Africa, the government is far too distracted by President Zuma’s antics in and out of parliament and the country’s courtrooms to worry about the fact that our crops are about to shrivel up faster than Zuma’s manhood when it was explained to him that showering after intercourse does not in fact prevent the transmission of HIV. And unfortunately, they would also rather spend taxpayers’ money on private jets, fancy cars and extravagant lifestyles for its unprecedented number of officials than on research into, and mitigation for climate change and global climate phenomena like El Niño. If you were a selfish, uneducated pack of pricks, wouldn’t you too?
Anyway, that is where my political rant ends. The point is this: I only recently learned that the planet is facing the meanest El Niño event since 1997 and is set to become one of the three strongest on record, like, ever. It’s already causing all kinds of interesting weather anomalies across the world, especially in the United States. So, it’s time for a new blog in which we’ll meet “the boy” wreaking an incredible amount of wanton mischief on our biology, biomes and backyards.
Who Is This “Boy” And Why Does He Mischief Thusly?
El Niño refers to the periodic, unusual warming of the ocean waters of the central and eastern equatorial Pacific and it’s named “the boy” in Spanish after the baby Jesus, since it typically occurs around Christmas time. Understanding why El Niño has such extensive impacts upon weather requires us to take a closer look at a very important variable (sea surface temperature) as it usually is versus what it becomes when El Niño buggers around with ocean and atmospheric circulations. And so, the instigator of it all – the key player I need to introduce you to first is…
The Easterly Trade Winds!
Image Source: mrspruillscience.weebly.com
Over the tropical Pacific Ocean, in other words around the equator, the trade winds blow roughly from east to west (see diagram above). Now, wind may seem like nothing more than moving air until your house gets relocated by a tornado; only then do you realize it’s a force to be reckoned with! So, the effects the northeast and southeast trade winds have on the ocean surface in the equatorial Pacific are quite significant.
The easterlies exert a force on the warm surface water, pushing it and causing it to pile up in the west, so much so that there is actually a 500-milimetre difference in sea surface height between Indonesia (west) and Ecuador (east)! This does a few things:
With the warm surface waters being piled up in the west, an 8°C temperature difference is created between the eastern and western equatorial Pacific, with the west being beautifully toasty. A warm ocean surface makes for a sexy, moist atmosphere and the result is a lot of rainfall. This is why Indonesia is beautifully lush.
On the other side of the Pacific, the wind pushing the surface waters away from the South American coast causes cold water from depth to rise to the surface (upwell), thereby leaving the ocean here chilly enough to embarrass you if you were dude wearing a speedo swimsuit. And, of course, the air overlying a cold ocean is typically dry and promotes little rainfall.
Ocean upwelling is a really important process, so it deserves a little conversation before we continue. When ocean creatures and critters die, their bodies sink, making the waters at depth wonderfully fertile. The upwelling of this water to the surface brings all this organic matter into the glorious sunshine and this leads to a surge in primary productivity. Of course, with great volumes of delicious algae, plankton and other tiny sea squishies available, every critter in the food chain is given the energy influx it needs to prosper, which essentially means lots of rodgering, lots of babies and lots of biological success. It also means lots of sushi for us.
So, we have a warm western equatorial Pacific with a rainy atmosphere and a cool eastern equatorial Pacific and a dry atmosphere. That’s the way it USUALLY is with the northeast and southeast trade winds happily blowing.
However: every two to seven years – and there doesn’t appear to be any strict rhyme or reason as to the frequency of this – the normally healthy trade winds stagger and weaken and you would scarcely BELIEVE the cluster f**k of consequences that follow.
A Specific Account of the Cluster of F**ks That Follow
With the easterly trade winds fizzling out, all the beautifully warm water that is usually swept to the west is allowed to slough back into the east. This causes a tongue of warm water to spread out from the western coastline of North America (see diagrams below).
A key point you must remember is that the ocean and atmosphere seldom, if ever, act independently of each other. One minor change in sea surface temperature can cause the atmosphere to overreact like your girlfriend approximately one week before Aunt Flo arrives for her monthly visit. A warm sea surface leads to greater evaporation, a more humid atmosphere and therefore more rainfall.
So, with ocean heat draining from the usually wet western Pacific, the region is typically left in drought while the east, which is usually dry, becomes unusually wet. On the ground, Indonesia and Australia can experiencing drought and, in Australia’s case, a much greater risk of catastrophic bush fire. On the eastern side of the Pacific, where the ocean has become anomalously warm, unusually heavy rainfall can lead to flooding with the risk being greatest to the southern states of America and Peru.
The weakening of the trade winds also negatively affects the upwelling that usually occurs off the western coast of South America and by throttling the source of nutrients these marine ecosystems rely on, organisms of all echelons in the food chain take a major blow. Less importantly (in the grand scheme of things – don’t tell any local fisherman I’m saying this) our fishing industries also suffer. That’s right: less sushi.
If you thought that’s where it ends, think again. El Niño’s impacts spread further than a desperate housewife’s legs. The accumulation of vast reservoirs of heat energy at the eastern periphery of the equatorial Pacific drive significant changes in global atmospheric circulation, which essentially means that no matter where in the world you live, you can possibly expect the next few months’ of weather to be, uh… interesting.
Crappy Weather Coming To a Neighborhood Near You
Air in the atmosphere is constantly on the move and it’s thanks to our major global atmospheric circulations that all the crap going down in the Pacific is felt in varying degrees across the globe. Here are some cherry-picked samples of other global consequences:
El Niño events are linked with wilder hurricane seasons in the Pacific. This is terrible news for the Philippines, which is already one of the most disaster-struck countries in the world. According to Colorado State University, there have been 21 Category 4 and above (read: holy crap that’s big!) hurricanes in the north Pacific this year alone. This total has obliterated the previous record of 17, which was set during the monster El Niño of 1997. The good news for Florida and southern Texas is that hurricanes in the Atlantic tend to stay home and pursue their hobbies during El Niño months.
Africa may be half the planet away, but the continent has a decent sized serving of interesting weather to expect. Southern Africa is currently in the throes of severe drought, while several East and North African nations are being pelted by heavy rainfall. I mean, can’t we ever just get the RIGHT amount of rain?? Why must it be one extreme or the other?
And, of course, we can’t leave out the main character in this story of wanton weather: MURICA! The following prediction maps for temperature and rainfall have been issued by the National Ocean and Atmospheric Administration (NOAA) on their amazing website, which you can view at www.climate.gov.
What we can tell from this map (aside from the fact that NOAA doesn’t give a hoot about Canada) is that there is a good chance of temperatures being hotter than usual in much of Alaska, Washington and the northern U.S. with dark red indicating a 70%+ probability of hotter than usual conditions. Texas and much of the southern states, on the other hand, may actually have to invest in a sweater or two.
Class Dismissed: Your Take-Home Message Is it the end of the world? Should you start looting your neighborhood grocery store and stocking up on bottled water and canned beans? No. Well, no to the first one: no harm ever came from having an extra can of baked beans, but you may want to prepare your home if you’re in an area that’s at risk of flood or drought. The question on the media’s lips is: is this particularly strong El Niño event proof of climate change and the severe weather we can come to expect from a globally warmer atmospheric environment?
Until we can say what causes the easterly trade winds to die down every two to seven years, we won’t be able to define the relationship between El Niño events and global warming. What is pretty evident – and has been talked about by climate scientists for years – is that a warmer atmosphere contains more moisture (due to greater evaporation) and more energy and is therefore more prone to the development of severe storms.
Your take-home message is this: The atmosphere is like the movie Cloud Atlas: It’s complicated and no matter how closely you study it, you still wonder what the f**k happened in the end. Just remember that the next time you hurl insults at the weatherman for getting the forecast wrong!
And now for a sampling of nature’s finest hurricane videos. Batten down the hatches, because it’s only in the bedroom that it’s fun getting banged like a screen door in a hurricane!
#1: “Hurricane Wilma Hits Southern Florida”
In this awesome science video, watch palm trees head-banging in the wind like a gathering of gangly punk rock kids as hurricane Wilma flattens South Florida in 2005.
#2: “Hurricane Sandy: Timelapse of the Storm from the New York Times Building”
Appreciate a far better vantage point than most New Yorkers had of the storm that caused the Big Apple a serious headache in 2012! Watch Hurricane Sandy roll in and over NYC from the safety of the Times Building. It’s terrifyingly beautiful from this ivory tower.
#3: “Hurricane Katrina Satellite Timelapse”
Katrina’s fender bender with the southern states (2005): This is a must-see for a lesson in hurricane formation, from hazy blip over the Bahamas to a monstrous storm system that swarms and spins like your head after a night of tequila swilling!
This clip from Discovery Channel’s “Raging Planet” shows lightning in super slow motion leave the cloud and connect with the ground. Capturing and watching this footage is helping atmospheric scientists develop a much better understanding of how lightning works. For the rest of us lay folk, it makes for some super interesting visual entertainment!
Video Source: Discovery Channel “Raging Planet” – Lightning. Uploaded by ONE Interpreting on YouTube channel www.youtube.com/watch?v=64WMsNRJvDo
What’s more than ten kilometres (6 miles) long, five times hotter than the surface of an average star and packs in more strokes per second than an over-zealous teenage boy who’s just discovered the joy of internet porn?
Yeah, I know. The picture kind of gives it away doesn’t it?
I have had a complete love affair with thunderstorms for as long as I can remember. I think they are the most awe-inspiring and yet paradoxical demonstration of nature’s prodigious temper and seductive grace. In the space of an hour, the sky can go from an azure blue to the colour of dark slate as giant cumulonimbus clouds broil and swell with latent energy.
Thunderstorms generate all kinds of severe weather: torrential downpours, vicious winds, hail, microbursts and even tornadoes. But they indirectly owe their very name to the one weather feature that claims the lives of, on average, 55 people every year in the United States: lightning!
Source: Global distribution of lightning April 1995 – February 2003 from the combined observations of the NASA OTD (4/95-3/00) and LIS (1/98-2/03) instruments.
Approximately 8 million bolts of lightning strike the Earth every single day, starting 10,000 forest fires annually. In the United States, over 300,000 insurance claims are made against lightning damage every year and the bill for this damage is a staggering $400,000,000.
Yes. Thunderstorms are seriously dangerous systems. I shouldn’t have to tell you that and yet countless golfers are killed by lightning every year. Could there be anything less intelligent than standing in the middle of a wide open space during a thunderstorm with a metal rod in your hand pointed at the sky? With five billion joules of energy surging through a single lightning bolt – enough energy to illuminate a 100 watt bulb for three months – you are picking a fight you simply cannot win.
Against all logic, according to the U.S. National Weather Service, lightning STILL kills more people than tornadoes AND hurricanes combined. What is this madness?
Thunderstorms are extremely busy weather systems. Within a storm cell, legions of water vapour particles are whipped, flung and tumbled around by complex air circulations. Storms themselves are powered by strong updrafts of hot, moist air. This air cools and condenses as it rises through the heights of the lower atmosphere, becoming dense. It consequently loses its upward momentum and sinks and spills out of the rear of the thunderstorm (check out the diagram below).
Photo Credit: “Thunderstorm formation” by NOAA T-storm-mature-stage.jpg. Licensed under Public Domain via Wikimedia Commons
Together, these motions form a continuous cycle of updrafts and downdrafts, which provides the storm system the energy it needs to electrocute golfers, whip cows into the air and blow Dorothy and her dog, Toto, into a parallel reality.
How does this explain what lightning is? Well, it brings us a lot closer to understanding cloud polarization. OMG. What does that mean?
Clouds Can be Bi-Polar Too
Just like batteries, molecules and certain members of your family, clouds too can become bi-polar. Within a thunderstorm, legions of water vapour particles get swirled around violently by the turbulent air circulations. But there are two predominant movements of air in a single cell storm system: hot moist air going up and colder drier air going down.
The water vapour particles being swept up into the cloud smash into those going down and these collisions, while totally invisible to us, are violent enough to cause the descending water particles to literally tear electrons off of the ascending water particles. Electrons are negative. So you see there is a gradual separation of charge within a thundercloud as the descending water particles become negatively charged and the rising water particles (having had an electron or two pilfered from their orbitals) become positively charged.
As a result of particle motions within a thunderstorm, the lower cloud regions become negatively charged and the upper cloud regions positively charged. A positive charge is induced in the ground immediately below the thunderstorm in response to storm’s electric field.
The story doesn’t end here: the polarization of the thundercloud has an effect on its environment, namely, the surface of the Earth and the various objects on it. An electrical field swells outwards from the cloud, caressing the electrons belonging to Earth’s atoms, seducing them into moving. Those who studied physics will remember, electron movement = charge.
The presence of such a massive reservoir of negative charge immediately above the Earth’s surface repels its negatively charged electrons (like repels like), causing an opposing positive charge to build up. In other words, trees, poles, buildings and your head actually develop a static positive charge in the seconds prior to lightning strike. This is probably why people who have been struck by lightning and have lived to tell the tale say that they felt their hair stand on end just before they become a living conductor for 1,000,000,000 volts of electricity.
At some critical juncture, nature notices the thunderstorm’s complete disregard for her love of equilibrium and so a raging streak of electricity discharges between the negative and positively-charged cloud regions. Or the negatively charged lower cloud regions and the positively charged ground immediately below it. And ZAP! You get lightning!
I can feel the cogs of your mind over-heating. So, if you aren’t quite happy with this explanation, then watch the movie Thor. While it doesn’t provide any scientific explanation on lightning genesis whatsoever, Chris Hemsworth is so beautiful you will forget your intellectual torment immediately *swoon*
Guys… you can enjoy watching Natalie Portman at her career low. In a lab coat.
I know I did.
Thunder, Contrary to Kindergarten Mythology, is Not God’s Fart
In spite of my illuminating explanations above – coupled with your homework to watch Thor – the exact physics of lightning generation are not entirely understood. Thunder, on the other hand, is and its explanation makes for a very interesting story. You may want to remember this so you can impress a future date with it…
When lightning tears out of a cloud, the air in the discharge channel heats up from ambient air temperature to a toasty 28,000°C or 50,000°F. That’s approximately five times hotter than the surface of our Sun. And all of this happens in as little as 90 microseconds. I know, right? A yawning chasm of a time denomination.
The problem is, you can’t heat anything up from 10°C to 28,000°C in this short amount of time without some kind of catastrophic consequence. So when lightning shows the ill social etiquette of doing so, the air expands violently, generating a shockwave that explodes outwards from the discharge channel. This shockwave travels faster than the speed of sound – it’s supersonic – so we can’t actually hear it. Dogs probably could, but you’ll have to ask one to be certain.
With distance from the discharge channel, this shockwave slows down and as it does it falls within our audio range. That’s when we hear thunder. I have heard that if you stand close enough to lightning you won’t actually hear it, because the shockwave is supersonic. While this makes sense in theory, human trials are pending. It also explains why, when a storm is very close, the lightning makes a sharp cracking explosive sound while, when further away, you hear the thunder as a low sexy rumble.
Class Dismissed: Your Take-Home Message
More people die of lightning injuries in Florida than anywhere else in America and perhaps even the world. While I’m aware that they have an amazing water world playground at their feet, they also have the highest lightning strike density in the entirety of the United States. Perhaps y’all should bear that in mind the next time you go wind surfing in an electrical storm.
Regardless of where you live, however, if you value your life then don’t swim, don’t bath, don’t chat on a land line, don’t play golf, don’t stand under a tree and don’t go running around like Julie Andrews in a thunderstorm. Otherwise, it won’t just be music the hills are alive with.
Image Source: “Rainbow Ignites” over Grand Canyon, uploaded by Cathy Smart to travel.nationalgeographic.com
Rainbows have enchanted humankind since our very beginnings, leading to the spinning of countless myths and legends about why and what they are. Just about every ancient civilization, culture and religion has its unique explanation of rainbows; all of them creative, but absolutely NONE of them correct. There is no pot of gold.
Aside from the fact that they look like a hippy has barfed across the sky, rainbows have quite a fascinating backstory involving the physics of light, which really isn’t all that complicated! In this blog, we’ll be taking a look at the physical laws and facts that give rise to some spectacular atmospheric masterpieces and a sky that would put a tie-dye T-shirt convention to shame.
The first ingredient on our palette is solar radiation…
You Need Sunshine, On a Cloudy Day!
Sunshine. It’s a simple concept: light from the sun. But one does not simply have interminable nuclear reactions without generating a spectrum of electromagnetic radiation. Our sun is a star and in keeping with the personality of stars, things are positively nuclear beneath its photosphere. These nuclear fusion reactions release a broad range of radiation types (see diagram below), from low energy, long wavelength infrared radiation (left) to the high energy, short wavelength Gamma radiation (right).
Image Source: The Electromagnetic Spectrum – faculty.olympic.edu
Slap bang in the middle of the electromagnetic spectrum is visible light, which only accounts for a narrow portion of the total energy generated by our sun day-after-day. This visible light pours out into space faster than Kris Jenner can say to Bruce “You’re becoming a what!?” covering the vast distance between the Sun and Earth in just 8 minutes and 20 seconds. It then smacks into our atmosphere and all its constituent gas and water vapor molecules. The photons (particles of light) that manage to escape atmospheric collision end their journey at the Earth’s surface, which is what brings warmth to our lives and color to our environment.
Snow White Light and the Seven Composite Colors
As I explained in the blog The Sky Is Only Sometimes Blue, visible (white) light is composed of seven different colors. Each of these colors has a different wavelength and ranges from the lower frequency, longer wavelength color red to the higher frequency, shorter wavelength color violet.
When visible light from the sun strikes a white surface, all of its seven dwarfs, I mean constituent colors get scattered in every direction, which is why we view the object as Snow White, I mean white. If that object is black, however, all of those seven colors become absorbed by the object, which is why you can cook an egg on the dashboard of your black Merc after leaving it in the sun for an hour.
Violet surfaces, like your gay best friend’s curtains, selectively scatter light with a wavelength of around 400 nanometers and absorb the rest. As such, you perceive the color violet (and bad taste) when you look at them.
Blue surfaces, like your lover’s eyes, selectively scatter light with a wavelength of around 450 nanometers. As such, you perceive the color blue and experience inappropriate clenchings in the nethers.
MIRRORS, interestingly enough, reflect all the seven colors of incoming visible light, but instead of scattering them in random directions, they reflect them at precisely the same angle as they arrived at and so the integrity of the image is preserved.
WHAT does this have to do with rainbows?
This discussion is intended to help you understand and appreciate the nature of visible light and the fact that it’s composed of different colors, which are capable of acting independently of each other due to their different wavelengths.
Now it’s when visible light strikes water droplets in our atmosphere that the real magic can begin to happen, potentially making it look like a unicorn wiped its butt on the horizon…
So far, we’ve spoken about light as though it travels in a straight line, which is typically what it does between bouncing off of and being scattered by objects. However, this isn’t the case when it travels through water. When visible light travels from one medium to another – from air into the water – its pathway becomes slightly bent in a process termed “refraction.” This explains why objects under water look so strange: the light that enables us to perceive them is being refracted or bent and this makes your toes (or whatever body part you happen to be scrutinizing) look bigger and closer to you than they really are.
When sunlight passes through a water droplet, it deviates slightly from its incoming direction, because it’s refracted (see diagram below). A portion of this light is then reflected off the far surface of the raindrop. If this angle is at 40° – 42° to the original direction of incoming sunlight, we get a rainbow!
Image Source: What Causes a Rainbow? NASA/NOAA – scijinks.jpl.nasa.gov
So you see, rain droplets not only refract the sunlight that passes through them, they also act as prisms. The reason this process results in a rainbow is because the seven constituent colors of visible sunlight become refracted to different degrees: the shortest wavelength light (violet) becomes refracted the most and so it’s bent the most. The largest wavelength light (red) becomes refracted the least and so it’s bent the least. As such, when white light passes through a water droplet, it becomes split into its seven different personalities, from violet, blue and green to yellow, orange and red!
This is beautifully captured in the following 40-second video:
We can now understand how white visible light, upon passing through water droplets suspended in the atmosphere, is split into its seven constituent colors. The final piece of the puzzle is looking at this process on the large scale. There are billions of water droplets in clouds or mist and each one disperses and refracts the sunlight that hits it. The overall result is a vast display of color in a circular or semicircular arc. Obviously, to us here on Earth, most rainbows would appear to be semi-circular, because the ground gets in the way of us seeing the other half. However, viewed from the air or from the following rare perspective at the top of Zambia’s Victoria Falls, we can see the full glorious monty:
What I haven’t mentioned yet is that perspective plays a major role in our ability to visually enjoy rainbows. The sun has to be behind you and the angle of dispersion – the angle between the incoming sunlight and the direction the refracted light is exiting the raindrop – has to be between 40° and 42°.
Rainbows have this wonderful effect on people: they make us look. They compel us to forget for just a few seconds everything it is we are thinking/worrying/stressing about and look up to the sky and admire. Really, all a rainbow is is water droplets playing with the paths and emotions of sunlight… but they are beautiful and a reminder that God – or whatever deity is or isn’t up there – is in fact a fan of gay people.
Hail is formed by severe thunderstorms and can range in size from super tiny pellets, which sound as though a mouse is tap-dancing on your roof, to massive grapefruits that plough straight THROUGH your roof. In this collection of three videos, we see just how large hailstones give tornadoes a run for their money in terms of the damage they can do.
This incredible video clip was filmed – mercifully – from the safety of a residential home. It records the deafening sound of massive hailstones slamming into the roof, as well as into the garden and pool. Note the huge splashes generated by the falling hailstones hitting the water and the size of the stones themselves as they accumulate on the grass.
Insurance companies in Oklahoma must have a very long and convoluted “Terms and Conditions” clause under the “Act of God” claim.
Just when you think it can’t get any worse than having large chunks of ice smashing into your roof, porch, pool and garden vegetation, the intensity of the hailstorm swells. Suddenly, it LITERALLY starts raining branches, leaves and torn-up vegetation as this colossal hailstorm shows off its mettle. According to the person who filmed this video, the hailstones ranged in size from peas to baseballs and actually halted traffic on the interstate highways.
Thankfully, the kind of large hail produced by these large thunderstorms tends to fall in narrow swaths and as such, they rarely last longer than a minute in any one area. Still, though, that’s all it takes to leave you with enough yard cleaning to do for weeks!
From beginning to end, this amazing hailstorm video shows the incredible damage done by hailstones the size of tennis balls as they smash into Woodson Texas soil, cars and even electrical cables. The guy filming it manages to pick up a couple of the hailstones to show us the size of these monsters in comparison to a quarter (US currency). Towards the end, an ambulance loads a patient who unfortunately got caught in the hailstorm and hopefully only sustained minor injuries. It just goes to show that, in storms the size and strength they are in the American Midwest, not even your car offers you sufficient refuge.
Welcome to the second installment of this two-part series on climate change, Climate Change™, global warming and the many degrees of human idiocy that have generally resulted in a cluster you-know-what of misunderstanding on both sides of the debate. It’s the aim of this blog to discuss just why it is climatologists believe human activity (particularly our industrial activity) has and is causing global weather patterns and characteristics to change. In Part 1, we set the scene and provided the context for our debate by defining some key concepts in atmospheric science. If you haven’t read Part 1, SHAME ON YOU! All the same, here’s what you need to know all wrapped up like a delicious lightly toasted and seasoned McDonald’s McMuffin McMeal.
Important Terminology from Part 1
Weather: The day-to-day expression of the atmosphere as it is experienced on the ground. Look outside your window: is it raining today? It is sunny? Are you and your dog Toto en route to Oz on a twister? That’s what weather is.
Climate: The average weather characteristics of a region over a minimum period of 30 years. If it’s summer where you are, what weather do you expect to see outside your window? Do you expect it to be rainy because you live in the tropics and during summer it pisses down every afternoon? Do you expect it to be sunny because you live in southern California and southern Californian summers are like totally freakin’ awesome, hashtag #beach, like, yesterday, like oh my gaad! OR do you expect to be hitching a lift to Oz on a twister because you live in Oklahoma, which is a veritable super highway for summertime tornadoes?
THAT, my friend, is climate.
Climate change: A significant and lasting shift in average global weather and global weather patterns, which can take place over a time period of decades to thousands of years. It can be caused by all sorts of things, from variations in solar energy and plate tectonic activity to volcanic eruptions and meteorite strikes.
Climate Change™: Significant and global scale changes in climate, weather patterns and characteristics caused by anthropogenic (human-originated) emissions of greenhouse gases. In other words, the stuff the movie “An Inconvenient Truth” was about.
Greenhouse gases: The atmospheric gases that absorb the thermal energy emitted by the sun and in doing so, contribute enormously to the warming of the lower atmosphere. Greenhouse gases include carbon dioxide, water vapor, methane, sulphur dioxide, ozone and nitrous oxide.
Great, now that you’re up to speed, let’s try to answer the following question…
Why Have We Buggered Things Up So Enormously?
The logic is simple. Greenhouse gases cause the warming of the lower atmosphere and because of this, they are very important to life on Earth. But, as it was mentioned in Part 1, too much of a good thing can be a bad thing. The persistent melting of Earth’s major ice sheets is direct evidence of the continued warming of Earth’s atmosphere.
Since the industrial revolution, when we discovered how to harness the energy released by burning coal, oil and other fossil fuels, the concentrations of carbon dioxide, methane, sulphur dioxide and other key greenhouse gases contained by our atmosphere have increased significantly. As each new discovery and development lead to the conception of newer and more sophisticated technologies, our output of greenhouse gases increased. Cars were once considered a luxury. Now, even beggars own Audis (true story; happened to me in Bahrain) and it’s not uncommon for the rich and famous to own more motor vehicles than they do teeth made from natural dental enamel and not gold.
The result of all the cars, industries, factories, refineries and other man-made technologies that require oil, coal, gas or petroleum is that we are relentlessly pumping out gases that are the by-products of burning fossil fuels. What I don’t understand is how anyone might expect this to NOT have an impact on our atmosphere and on its temperature characteristics.
Don’t The Forests And The Oceans Absorb CO2?
Yes! Plants, trees and other green things absorb CO2 at night, which definitely relieves the atmosphere of its burden of greenhouse gases. But look what we’ve done to them! What used to be verdant rainforest are now leveled, muddied and trampled pasturelands for cows. What used to be thriving woodland is now choked up with concrete, tar, brick and glass. There is only so much CO2 our dwindling green spaces can soak up.
What about the oceans? While they remain a massive sink (sponge, in layman’s terms) for CO2, the absorption of this greenhouse gas isn’t going without consequence. When you mix water and carbon dioxide, you get a weak acid called carbonic acid (H2CO3). And so, slowly, the oceans are becoming increasingly acidic. This is having a devastating effect upon the myriad of creatures whose shells are made out of calciferous compounds, from the beautiful coral reefs and their crusty citizens to Ariel the Little Mermaid, who will soon be swimming around topless without her bivalve bra.
The more greenhouse gases you pump into the atmosphere, the more enhanced their effect will be. What is their effect? Warming, in theory.
Natural Variability Versus Anthropogenic Climate Change
The most infuriating argument put forward by people who don’t believe that mankind is having any kind of affect on our climate is that any evident changes can be attributed to the natural variability of our climate system. While it is true that Earth’s climate has undergone some dramatic shifts in the past – the premise for the movie Ice Age wasn’t thumb-sucked – these changes occurred over a time period of many thousands, if not tens of thousands of years. Natural variability typically takes a very long time to happen and the effects brought about by events, such as volcanic activity and meteorite impacts tend to be localized.
What we know is that global temperatures have changed at an unprecedented rate and that this change began around the time of the Industrial Revolution, which was only a few hundred years ago. Not a few thousand. In other words, the rate of change of global temperatures is unprecedented and there is a clear connection with the increased anthropogenic emissions of greenhouse gases, like CO2.
In even plainer, perhaps somewhat vulgar English:
Denying climate change is like pooping in the toilet and denying the presence of a turd.
How Do We Know All of This?
Studying present and recent past climate has been made easier through the use of satellites, our vast array of ground weather stations and weather buoys. We have also developed the sophisticated computer software and modeling programs necessary to collate all of this data and provide us with a visual picture of climate, both past and present. But our historical records only date back a few decades, after which they become a little iffy to say the least. An appreciation of scientific rigor is something that was only cultivated towards the latter half of the 20th Century. So how do we know enough about historic climate to say anything about what’s normal versus what isn’t?
The answer lies in super deep deposits of ice, as one finds at the northern and southern poles, as well as borehole temperature profiles, deep layers of sedimentation and middens, which are accumulations of animal crap, urine, bones and shells in natural catchment areas. All of these and more reveal secrets about Earth’s history and in particular, the environment and the composition of the atmosphere at the time. By examining deep ice cores extracted from super-thick ice sheets at the poles, we are provided with a perfectly preserved timeline of the atmosphere’s carbon dioxide content (and other gases).
What we can tell from these sources is that natural variability is normal, but it happens slowly and that recent changes in atmospheric composition are happening at an unprecedented rate and are likely attributed to mankind.
If You Don’t Believe Me, Ask the IPCC
The Intergovernmental Panel on Climate Change (IPCC) is a global effort by climate scientists to present to the world and to world governments a robust and thoroughly researched report on global climate change driven by humankind. It’s essentially a document that is aimed at helping governments around the world understand and prepare their countries for the changes in weather patterns and characteristics that are anticipated as a consequence of climate change.
The opening paragraph reads:
“Climate Change 2013: The Physical Science Basis” presents clear and robust conclusions in the global assessment of climate change science – not the least of which is that the science now shows with 95% certainty that human activity is the dominant cause of observed warming since the mid-20th Century. The report confirms that warming in the climate system is unequivocal, with many of the observed changes unprecedented over decades to millennia: warming of the atmosphere and the ocean, diminishing snow and ice, rising sea levels and increasing concentrations of greenhouse gases. Each of the last three decades has been successfully warmer at the Earth’s surface than any preceding decade since 1850.”
You can read this and the rest of the report by clicking on This Link.
If You Don’t Believe the IPCC, Use Your Noodle
Anyone who has lived in a big to moderately sized city will know from personal experience that the climate in the city is typically different to the climate in the countryside. It’s hotter in the city during the day and it’s colder in the countryside at night. Generally speaking.
This is no accident… the type of land cover (vegetation versus concrete) influences how thermal energy from the sun is absorbed or reflected and this, in turn, has a great influence on average temperatures and temperature variation. The greater levels of pollution above a city also influence the temperature characteristics of the air. In fact, the greater number of small particles of dust, smoke and other pollutants in the air above cities can even cause clouds to form more readily, because these tiny particles offer water vapor a tantalizing surface around which they can condense.
None of this is a statistical projection spat out by some computer model and it isn’t the musings of some climate scientist pushing for government funding. It’s sound, solid fact and the kind of stuff you get taught in High School geography. THIS IS ANTHROPOGENIC CLIMATE CHANGE! Change brought about by human kind. It may be localized around major cities, but it is still noticeable to our skin and it is still change. The altering of the atmosphere’s temperature characteristics around our cities paints an irrefutable picture of how humans have changed climate.
Climate change on a global scale may be driven by different and/or more complex mechanisms, but to say that it is a natural, normal process that has nothing to do with our activity on this planet I find to be ridiculously ignorant. Tell me, do you enjoy sand in your ears? I think it’s dangerously erroneous to assert that we have not had an effect upon our environment, which includes the ground beneath our feet as much as it does the air above our heads… and in some people’s cases, in their heads.
Class Dismissed: Your Take-Home Message
Over the many decades since the Industrial Revolution, we have pumped billions of tons of carbon dioxide, methane, sulphur dioxide and other greenhouse gases into the atmosphere. We’ve changed tens of thousands of square kilometers of our planet’s essential land surface characteristics by leveling forests for agriculture and allowing livestock to raze grasslands to the ground. We’ve polluted water sources, wiped out thousands of different animal and plant species and pretty much made a total mess of our natural environment. We have had a definitive impact upon planet Earth and no one in his or her right mind can debate that point.
It has been the aim of this two-part series is to unravel the knotted, warped information we are fed by the media and help us regular folk better understand it: to see through the sensationalist claims to the logical, underlying science. Climate change has become a media buzzword and a vastly popular issue that has been the driving point of many political campaigns in first world nations (*cough*America*cough*). It has become a passionate, political issue and as a result, sides have been created: those who believe we’ve caused our climate to change and those who don’t.
What I want you to do is to look through all the bullshit of BOTH sides of the argument and ask yourself the following question: am I surprised that our ruthless industrial activity and atmospheric pollution has caused global climate to change?
Whether you trust what the scientists say or not, you simply can’t say no. And if you do, I challenge you to tell me why.
If asked what colour Earth’s sky is, you wouldn’t be unforgivably wrong to answer that it’s blue. A more correct answer, however, would be “it’s blue, sometimes”.
Earth’s sky is black at night and grey in overcast weather. It’s brilliant crimson, orange and yellow at sunset, and a sultry blend of indigo, violet and pink at dawn. Around noontime on clear days, it’s white at the horizons and on brooding, stormy days, when there is a promise of severe thunderstorms and hail, it can be slate grey with a slight tinge of green.
The sky is many colours. It’s only sometimes blue. Ever wonder why? Doesn’t matter, I’m going to tell you anyway and what better place to start than by shedding some light on… light!
What Is Light?
What we know as light really only represents a fraction of the full spectrum of energy radiated by the sun and the other stars in our Universe (and other possible Universes). Visible light is the narrow range of electromagnetic energy that can be seen by humans and is responsible for illuminating our world in a cacophony of beautiful colour. It’s made up of teensy particles called photons (think photography, meaning “light”), which, unlike gas molecules, don’t float about arbitrarily bumping into the sides of objects like pong balls. Rather, photons travel in waves, just like nausea after some bad Chinese.
Waves are awesome for more than just surfing. They have all sorts of physical properties that, once understood, give us the key to understanding the behaviour of sound and light and our perceptions thereof… such as the colour of the sky!
Like, Wave Properties, Man
Any (serious) surfer will tell you that waves have many properties, including height, amplitude, energy, frequency and wavelength. These are all measurable quantities that can be applied to ALL kinds of waves, including energy and sound waves. For this particular topic, however, we shall be focusing on a property called frequency.
The frequencyrefers to the number of waves that occur in a given time period. So, imagine you’re sitting on a cliff that faces out to sea. In a period of one minute, you count every wave crest that passes your direct line of sight. The number of crests you count per minute is the frequency. Sounds pretty simple doesn’t it? Now try counting the light waves that are bouncing off your dad’s horrible Hawaiian shirt. Obviously you can’t. We can’t see light waves, or sound waves for that matter, but we CAN perceive the differences that arise as a result of differences in their frequency.
Sound waves with a high frequency (refer to the above diagram with the squiggly lines) are perceived by our ears to be high-pitched. Like the sound your wife makes when she gets mad at you for leaving your cheesy socks next to the bathroom sink. Sound waves with a low frequency are perceived by our ears to be low-pitched, like Barry White’s crooning. Similarly, light that travels at a high frequency is perceived by our eyes to be blue or violet and light with a low frequency, as red or orange. In between, you’ll find green and yellow. Together, they all make up the gay flag!
As it was initially explained, visible light represents a mere fraction of the full range of energy produced by our star. The “electromagnetic spectrum” may sound like a horribly complex term, but you’ve actually met most of the members of the family! Let’s take a look… Take a deep breath. It’s not complicated. I believe in you!
The Electromagnetic Spectrum
The squiggly line in the middle represents the size of the wavelengths of the various “kinds” of electromagnetic energy, from the low energy radio and microwaves (that you use to heat up your TV dinners) to the high energy X-ray and Gamma rays (that you definitely don’t use to heat up your TV dinners).
Slap bang in the middle of this diagram, you will see the blue box titled “visible”. This is visible light and it refers to a range of energy frequencies that account for all the colours we see and, in general, the light that illuminates our world.
Now, as we move to the right of the spectrum, the waves become more energetic and the frequency increases. Electromagnetic radiation becomes ultraviolet and then X-ray, as is used in medical diagnostic technology to reveal your bony insides. Finally, at the high-frequency end of the electromagnetic spectrum, we get gamma radiation, which is so ridiculously energetic that a minute’s exposure would either incinerate you, or cause such terrible mutation of your cells that you’d turn into Joan Rivers.
Thankfully, the gamma radiation produced by the unending nuclear fusion reactions in the heart of the Sun doesn’t quite make it to the Sun’s surface and so, our little planet is safe. Earth’s ozone layer also manages to deflect much of any high-energy radiation that heads our way from other locations in the universe, except for small amounts of UV light, which can cause sunburn and melanoma, amongst other kinds of skin cancers.
But, how on EARTH does this all link back to the colour of the sky?
By understanding how the frequency of visible light determines its position on the colour spectrum, we are given the key to understanding the colour of the sky!
Why Is The Sky (Sometimes) Blue?
When visible light reaches our planet, it encounters all the trillions of molecules of gas, water and other particulates that are so abundant in the atmosphere. While the majority of the spectrum can travel through this veritable obstacle course unscathed, blue light is unlucky enough to be of the perfect wavelength or “size” and so can’t help but collide with all these molecules and particles.
It’s like trying to roll a marble (blue light) tennis ball (green light), skateboard (yellow light), bicycle (orange light) and car (red light) through a car park FULL of marbles. Which one do you think it going to have the greatest difficulty getting from A to B without being deflected off its path? Blue light obviously and as a result, it gets scattered off its original course, which is what we see when we look up at a blue sky. This effect is known as Rayleigh scattering and is named after the obnoxiously titled English physicist, John William Strutt, 3rd Baron Rayleigh Peacock Eminent La-di-da.
In reality, more than just blue light is scattered. A little bit of violet and green and even red light is scattered, too. But it’s predominantly blue that has fender benders across the daytime sky. If you throw a teaspoon of violent, green and red into a bucket of blue paint, the resultant colour will still be blue. This all changes, however, as the sun carves its path across the sky, drawing inexorably closer to the horizon…
Red, Orange and Yellow Sunsets
From our perspective, the atmosphere at the horizons is thicker owing to the oblique angle at which we are looking at it. The following two diagrams illustrate this point beautifully, saving me a fair amount of wind…
In the first image, the length of the path the sunlight travels to reach the little sunbathing dude, as denoted by the black arrow, is much shorter than in the second image, when the sun sits on the horizon. This longer distance means that by the time the light finally does arrive at the dude’s eyeballs, all the blue light has been scattered out, leaving only the low-energy frequency light: reds, oranges and yellows. This is why sunsets look like sex-on-the-beach cocktails.
It’s also why they inspire cocktails… and sex on the beach.
Interestingly, at midday, the light travelling to us from the horizon still needs to claw its way through a thicker layer of atmosphere. While this light IS scattered red light, its mixture with all the blue scattered light from the rest of the sky causes the one extreme end of the colour spectrum to meet the other, effectively cancelling each other out. The resulting colour is white. In other words, at the horizons, all members of the visible colour spectrum are reunited, leaving you with *drumroll* white light.
Why Are Some Sunsets More Spectacular Than Others?
Discounting the sunsets you watched while totally baked on that good shit your cousin somehow smuggled in from Canada, the more spectacularly hued sunsets can be attributed to the composition of the atmosphere.
The more particles there are in the sky, be it dust, pollution, smoke, water vapour or the workings of a local volcano with indigestion, the more aggressive the scattering and the more enhanced these effects will be. This explains why there is nothing more beautiful – implications aside – than a sunset over a horribly polluted sky.
Cloudy With A Chance Of Green
There is a strange greenish tinge to the sky that can sometimes develop just before a severe thunderstorm drops its load. It’s especially noted with powerful storms that are able to form large hail and tornadoes. I’ve heard two theories explaining why this happens, but it would seem that the jury is still out on which one is more correct:
Severe thunderstorms typically occur during the latter half of the day and especially towards sunset. These kinds of thunderstorms also form very high cumulonimbus towers and the abundant water vapour within these clouds sends blue light scattering like skittles on a waxed floor. With the sunset throwing red scattered light on the blue underside of the clouds, the resultant visual effect can be a greenish tinge, as you can see in the picture above.
The other explanation is that the presence of large hailstones within a thundercloud can actually scatter light whose frequency is slightly lower than the standard blue. What colour comes next after blue? Green of course, hence the greenish otherworldly tinge. I prefer this explanation since it’s more awesome.
Having said all this, a greenish sky is not a sure-fire indicator that a tornado is on the way, as is a popular myth amongst the residents of Tornado Alley. But it does indicate the presence of a very tall convective storm, which you can pretty much bank on ruffling a few leaves. Maybe even relocating a cow.
Class Dismissed: Your Take-Home Message
The sky appears to us in a myriad of colours throughout the day and it all comes down to the fact that visible light has multiple personality disorder. Whichever colour you do see is a result of that particular frequency of light being scattered more effectively than the others. But our foray into the physics of light has explained more to us than just the hue of the sky… it has also revealed just how many fascinating things wave properties account for, from the pitch of your irate wife’s voice to Indian Ocean tsunamis.
I intend to explore both of these in good time, but in the meanwhile…
Some things on our planet are so ridiculous that when you really think about them, it’s enough to make you go biblical. Frogs falling from the sky, crop circles, giant swirling hurricanes, belching volcanoes, sulphur-based life forms and Paris Hilton’s immense wealth (and equally as immense lack of IQ). And then there’s hail. The fact that the updrafts within a thunderstorm can be strong enough to hold grapefruit-sized hail in suspension is nothing but ridiculous and wholly impressive.
Great balls of ice!
How Hail is Made
Hail consists of balls of ice shockingly called “hailstones”. You may even say that hail is frozen rain, but it deserves a slightly more complex explanation than that…
Hail is made within powerful thunderstorms or cold fronts. Cold fronts tend to produce smaller hail that might inconvenience your dog’s plans to go do his business outside (thereby inconveniencing your plans to keep your house hygienic). The large hail responsible for denting cars, destroying crops and severely upsetting your heard of cows is typically associated with large thunderstorm systems that are well-endowed in the vertical and are sustained by powerful updrafts. These traits are especially exhibited by the “Big Daddy” of all small-scale tempests: supercell thunderstorms. These you will find all over the world, but most notoriously skipping across “Tornado Alley” during the northern hemisphere’s summer months.
What cold fronts and thunderstorms have in common is that they are both low pressure systems that suck in air and expell it out their rear. Thunderstorms pull in great volumes of warm and moist air, which rise, cool and condense to form towering cloudy behemoths. Yes, cumulonimbus clouds. The air, once cooled, loses its momentum and proceeds to sink towards the ground. Together, these two channels of air comprise the updraft and downdraft zones that sustain a thunderstorm: its lungs if you’ll indulge a bit of poetic licence.
Now, as you know, temperature decreases with height in the atmosphere. That’s why the tops of high mountains are frozen and it’s why you should always, ALWAYS go for a pee before sky diving. At a certain altitude within a thunderstorm, which can soar to as high as the interface between the troposphere and stratosphere at approximately 10 km above sea level, the temperature reaches zero degrees Celsuis – the temperature at which water freezes. Above this 0°Cisotherm (an obnoxious way of saying “line of equal temperature”) all the water droplets in suspension are frozen.
The strong updrafts within a thunderstorm sweep water droplets above the 0°Cisotherm where they freeze (consult the pretty diagram below). These pellets of ice then fall back down towards Earth in the downdraft zone, plummeting below the 0°Cisotherm and defrosting into big globs of water. This is why thunderstorm rain gets you soaking wet in 10 seconds flat. Just like Channing Tatum in “Magic Mike”.
However, some of these falling frozen pellets of rain get caught up in the updraft zone again and are swept back up above the 0°Cisotherm. Only, they’ve gained a layer of water, which they collected as condensation while chilling out below the 0°Cisotherm. This additional layer of moisture freezes, forming a new layer of ice over the original ice pellet.
This process can repeat itself several times and each time, the hailstone will grow larger and larger and larger as it collects more and more layers of ice. The next time you’re in the middle of a raging supercell storm, run outside, collect a couple of decent-sized hailstones, run back to the tornado shelter, bolt the trapdoor, watch your dad arm wrestle said trapdoor with an F5 tornado, watch your dad lose, resolve to become a hardcore white vest-wearing, tornado chasing sexpot with a serious deathwish. Oh! And remember those hailstones you collected? Cut them open to see those concentric circles of icy awesomeness.
When a hailstone finally gets too heavy for the thunderstorm’s updrafts to hold in suspension depends entirely on the strength of those updrafts. The stronger they are, the heavier the hailstones. This is why larger hailstones are associated with powerful thunderstorms, such as the Midwest supercells that are sustained by incredibly strong updraft zones.
And when hailstones get heavy, it’s time to run for cover.
Sorry Boys… Size Really Does Matter
Farmers are more obsessed with size than that clutch of vacuous floozies and jockstraps in Jersey Shore. Considering their livelihood depends on it (and not their egos), this is easy to understand and empathize with. But, in no other aspect are they more obsessed with size than with hail. The happiness and health of their livestock and crops depend on it.
Some thunderstorms can create hailstones that are big enough to cave your head in. Even if you do have brains. The next time you’re at a party, scoop an ice cube out your rum and coke and toss it at your mate (preferably the one who’s hitting on your girlfriend). Listen to the dulcet sounds of squealing as it clobbers him in the noggin. Now imagine something easily ten times the size of that ice cube falling thousands of metres (or feet) from the heavens. Yup! Ouch.
On 23rd June 2010, the largest hailstone in recorded American meteorological history fell in Vivian, South Dakota (image above). This great ball of ice weighed in at 0.88 kg (1.93 lbs) and was a staggering (if it had hit you in the head) 20 cm (8 inches) in diameter.
That’s two inches longer than your average you-know-what, tee hee!
Class Dismissed: Your Take-Home Message
Hailstones are physical evidence of the incredible air circulations going on inside a thunderstorm. Can you imagine how strong air must be to prevent something that weighs almost a kilogram from succumbing to gravity? I don’t know about you, but that blows my mind in the most delicious way. And so we see that thunderstorms are about so much more than just thunder and lightning and the occasional airborne cow. These bad tempered weather systems can also be that jerk at a party who throws ice at you.