The Earth Story

Apparent Polar Wander

This image shows one of the fundamental techniques geologists use to reconstruct the motion of plates on Earth. These plots are called “apparent polar wander” plots.

Certain rocks contain magnetic minerals, like the mineral magnetite. When these minerals either grow or move around freely (like in flowing water) they align themselves relative to the Earth’s magnetic field. A rock formed in the presence of a magnetic field will wind up with its own magnetic field that points towards the north/south pole at the time it forms.

If 2 continents are joined together, 2 rocks formed on those continents at the same time will point to the same North Pole. But the trick for geologists is…what happens if the continents move after the rocks form?

Once a rock is formed, the magnetic field is (mostly) locked in. If a scientist measures the magnetic field in rocks across time, that paleomagneticist (also sometimes nicknamed paleomagicians) will be able to see how the magnetic pole moves relative to the continent. Of course, the North Pole isn’t really what is moving, the continent itself is moving – hence the name “apparent polar wander”. The North Pole recorded by the rocks seems to change because the rocks themselves move relative to the North Pole.

Finally, go back to our case of 2 rocks forming on 2 continents that are together at one time and rift apart later. Once the continents separate, their rocks will record different magnetic poles as a result of the continental motion, but the tracks of the rocks can be treated like a jigsaw puzzle. In the 2nd image here the apparent polar wander paths from North America and Europe have been altered by assuming that the continents used to be joined together; if you make the assumption that the Atlantic Ocean once closed, suddenly the two curves plot on top of each other for the time when the continents were joined!

These kinds of paths are one of the key ways plate motions over time have been reconstructed.

-JBB

Image credit: Marshak Essentials of Geology textbook, licensed to me for teaching purposes

True Polar Wander

As a spinning top slows down, it will start to wobble to the side and eventually tip over all the way. The top is, well, “top-heavy”. If it’s spinning rapidly enough, it stays balanced with the weight at its farthest edge, but as it slows down the weight wants to shift position. Planets can do something kind of like this; the Earth can actually tip over like a slowing top. This process is called True Polar Wander.

The Earth’s outer core is made of liquid iron. Outside of it is a solid mantle; the mantle is literally a solid floating on top of a liquid. The planet is actually broken into these layers and so the mantle can actually change its position and rotate relative to the core.

The Earth also spins, like a top, around its north-south axis, which we call the poles. The stable position for the Earth is one where any extra mass is also at the equator. For a metaphor, imagine that you’re swinging a weight around your body on a string. The weight will pull your arms out as you swing it around. If you try to hold your arms straight up, as the weight moves around it will tug your arms to the side.

This weight is like any weight on the Earth’s surface; as long as it’s at the equator, the weight is happy. But, if there’s extra weight at the poles, the planet becomes unbalanced. Just like the swinging weight would pull your arms farther out, weight near the poles will pull itself towards the equator.

Extra weight near the poles will therefore be able to actually cause the Earth to roll, taking mass near the poles and moving it to the equator. This process is called “True polar wander”, because the spot that was once the North/South pole actually shifts to a different point, and another spot rolls into its place. This name is in contrast with “apparent polar wander”, a seeming motion of the poles relative to the continents that is caused by plate tectonics. Apparent polar wander happens even if the poles don’t move; true polar wander is the poles actually shifting (https://tmblr.co/Zyv2Js1LJUEUa).

Geologic evidence suggests that true polar wander has happened several times in Earth’s history, most recently a pair of shifts of roughly 9°, starting in the Cretaceous when the planet rolled to the side and then shifting back the other way during the Paleocene-Eocene when the modern day pole rolled back. There are arguments for far larger shifts in the Earth’s pole position going farther back in time.

What types of mass shifts might cause one of these rollover events? Mostly it is thought to be big things in the mantle. A plume of hot material rising through the mantle will be low density because hot things expand and rise. That low-density material might want to be closer to the poles. However, if the hot mantle reaches the surface and triggers massive volcanic eruptions, that pile of igneous rock on the Earth’s surface could be a high-density feature that would want to roll towards the equator.

This image shows a pair of mantle plumes rising up through the planet, depositing large amounts of lava and mass on the surface, and triggering true polar wander. There was a mantle plume near the equator about 70 million years ago when the planet started rolling – the end result is the Deccan traps, a large lava field in India that erupted 65 million years ago. That plume is right around the time where it could have triggered the rolling in the geologic record.

A recent study simulated what would happen on an Earth-sized planet closer to a star, as has been seen in many Exoplanets. The simulations showed that the greater the gravitational force is at the equator, the more easily planets would roll over. True polar wander, therefore, could be a regular feature of planets orbiting stars other than our own.

-JBB

Image credit and Exoplanet Paper: https://www.nature.com/articles/s41561-018-0071-2 References: https://www.nature.com/articles/s41561-018-0079-7 http://onlinelibrary.wiley.com/doi/10.1029/2011JB009072/full https://www.nature.com/articles/nature10174

Poles warmed more than models expected

56 million years ago marks the boundary between the Paleocene and the Eocene Epochs. At that time, there was a rapid climate change on Earth, with extremely high temperatures at the planet’s poles, comparable to the tropics today (https://tmblr.co/Zyv2Js1vvz8m2). It is thought that at the Paleocene-Eocene boundary there was a rapid release of carbon trapped in the oceans and this triggered rapid climate change by increasing greenhouse gas abundances.

This picture shows a shell of one foraminifera, a single-celled organism that precipitates the mineral calcite from the ocean. Scientists have developed several ways to use the chemistry of this mineral as records of the temperature in the water that they formed from, specifically by measuring the abundances of the isotopes of each isotope of oxygen in the carbonate mineral.

This foram formed in the surface ocean at the North Pole during the Eocene. After it died, its shell found its way into sedimentary rocks and eventually it was measured by scientists from Yale University. They used the abundances of all 3 oxygen isotopes and the ratio of magnesium to calcium in forams like this to reconstruct the chemistry and temperature of the Eocene ocean.

They found that this foram, found at the North Pole, formed in waters that were at temperatures from 30–36°C. Not only is that vastly warmer than the nearly 0°C waters found at the North Pole today, but it is several degrees warmer than even the highest temperatures predicted by climate models for the poles at this time. Scientists base those models on the physics of the atmosphere, but they have to calibrate them based on the measurements geologists can give of what the Earth did millions of years ago.

These results imply that temperatures at the poles go up even more than predicted when there are huge spikes in atmospheric carbon dioxide, the poles are even more sensitive than scientists had previously predicted. This result, therefore, implies that the potential costs of increasing carbon dioxide in the atmosphere are even higher than scientists were predicting even last year.

-JBB

Image credit: Laura Cotton http://bit.ly/2E1etWg

Original paper: http://www.pnas.org/content/early/2018/01/12/1714744115

A Tale of Two Poles

The first rule of navigation is that a compass needle points towards the North. But where exactly is ‘North’? The Earth has two North poles, a geographic North pole and a magnetic North pole. The geographic North pole is what we most commonly think of as the North pole. This is the fixed point where the surface of the Earth intersects its axis of rotation and where the meridians (lines of longitude) converge in the northern hemisphere.

Our planet also has a magnetic North pole. This is the location where the Earth’s magnetic field lines converge at the surface. Put simply, the Earth can be though of as a giant bar magnet with ends at the magnetic North and South poles. The Earth’s magnetic field is the result of the motion of molten metals in the outer core; a self-sustaining process known as the geodynamo.

A compass needle will align with the Earths Magnetic North pole. While the geographic pole is a fixed point on the surface, the magnetic pole migrates across the Earth’s surface over time. This ‘polar wander’ is due to changes of the motions in the inner core. Currently, the magnetic pole is located to the East of the geographic pole, and is moving up to 10’s of kilometres per year towards Siberia. Scientists have been tracking the movement of the magnetic North pole for almost 200 years, as shown in the image below.

The angular difference between the geographic and magnetic North poles is called magnetic declination. Declination varies depending on where you are located on the globe, generally increasing closer to the poles and changing at you move from East to West. Take two cities at similar longitudes but different latitudes, Toronto (~ 43 degrees N) and Miami (~ 25 degrees N). Toronto has a magnetic declination of ~ 14 degrees to the West while Miami has a declination of ~6 degrees to the West. If you are interested in finding out what the magnetic inclination is where you live, check out http://bit.ly/1ZWPful.

Setting magnetic declination on your compass is a critical first step toward successful navigation, or you might just end up somewhere you don’t expect.

Sources The Solid Earth: An Introduction to Global Geophysics 2nd ed. Fowler, C.M.R. 2010. Cambridge University Press. http://bit.ly/2r6TZIG http://bit.ly/2EG7vF1 https://go.nasa.gov/2wquiAa http://bit.ly/2arsQbc

Image Source http://bit.ly/2r0ufgU

Solstice

About 12 hours ago we passed the solstice, the start of Winter for the Northern Hemisphere and Summer in the Southern Hemisphere. I’d have had this post done but my computer was misbehaving.

Anyway, one of my favorite things to check out on the solstice is the view from the Japanese Himawari-8 weather satellite. That satellite, launched a few years ago, sends back HD pictures and video from a geostationary orbit over the Pacific. That means it can watch as the earth rotates into shadow each night. Here’s its lovely solstice view from today – a thin band of light is always present at the south pole, and the north pole never appears.

-JBB

Video credit: https://twitter.com/himawari8bot/status/943853755753263104

Well, this wasn’t particularly normal.

Light and Dark

 This video shows one of my new favorite things about the solstice. The Japanese Meteorological Agency’s Himawari-8 weather satellite is in a geostationary position over the Pacific Ocean and eastern parts of Asia, sending down pictures to monitor weather over that part of the planet. In the process, it gets a full frame view of the orb of the Earth, and it automatically shares clips from its cameras online. Here’s the view taken as the sun set yesterday just before the official solstice time – take a look at the poles. The North pole never exits a shadow and the South Pole is a tiny sliver of light that never goes away – the best shot you’ll get of this arrangement for a year. This one also gives some nice sunglint on the sea just before the sun goes down – reflection of the sunlight off the smooth surface of the ocean.

 -JBB

Video Credit: Himawari-8 satellite

https://twitter.com/himawari8bot/status/811255063255650304

Climate change moves the world.

The rotation pattern of our globe seems to be changing, as mass is redistributed around the world due to the effects of global warming. The change is small, but clear, and is one of global warming's most interesting but least threatening consequences. The entire planet has always wobbled as it turns due to its uneven shape, since the centrifugal force acting on all the spinning rock causes a big uneven bulge at the equator.

Earth's geographical poles therefore oscillate naturally like the ends of a top or gyroscope in a variable but predictable cycle (about 25000 years long), but since 2005 an small anomaly has crept into this movement. This cycle is the cause of the phenomenon known as the precession of the equinoxes, whose best known effect is the shifting of the pole star over time- 5000 years ago it was Alpha Draconis, the head of the dragon, rather than the familiar Polaris in the great bear. This precessionary cycle is also one of three astronomical sub-cycles forming the Milankovich cycles that affect Earth's climate cycles and ice age patterns.

The movement of masses on the surface affects our planet's gravity and rotation. Water is the biggest mobile mass moving around our planetary surface. The yearly season cycle redistributes water as snow and rain patterns move around the world. Plants also absorb moisture in spring and release it in winter in a biannual transfer of water between the hemispheres. There is also a small yearly motion thought to be caused by continental drift, and it was the change in this pattern that alerted the researchers that something unusual was afoot. Water is the largest shifting mass in the world's gravity map, and climate change has altered its movement patterns in many ways.

This polar movement is determined using GPS with millimetric precision, but in 2005 the North Pole started moving anomalously. The North Pole had been wandering six centimetres a year towards Labrador, but shifted unexpectedly eastwards in the direction of Greenland, accelerating to a speedy annual 27 Cm . The cause turns out to be a redistribution of mass on the Earth's surface, linked to the accelerated melting of the Greenland ice cap and the consequent sea level rise. An American-Chinese research team used data from NASA's GRACE gravity observation satellites to measure this redistribution across the globe, publishing their results in Geophysical Research Letters. The last decade was the hottest on record, and the ice cap has melted at faster than expected rates, alarming climate scientists.

The laws of physics provide a simple explanation for the change in direction towards Greenland. If one removes mass from a rotating sphere, the axis of rotation will tend to shift towards the place where the loss happened. Current estimates put the annual ice loss between 1992 and 2011 at a weighty 142 billion tonnes. If the researchers are correct, then the continued acceleration of the polar wobble towards Greenland should correlate with future rates of ice melt. Scientists hope to use this effect to constrain results from other means of measuring ice loss. They also hope to use records of polar drift to estimate ice growth and loss over the last century, since polar wandering was monitored long before detailed ice melt data became available.

Loz

Image credit: Nick Hughes.

http://www.scientificamerican.com/article.cfm?id=climate-change-has-shifted-location-north-south-poles

The last sunrise of the year 2015 over the Pacific Ocean, video from the Japanese Himawari-8 Weather Satellite.

I’ve really been enjoying how, in these videos taken close to the winter solstice, you can clearly make out how Antarctica never sees a sunset and the north pole never sees sunrise. 

Are you colder than the North Pole?

The record-strength El Niño event this year and the unusual atmosphere conditions around the world are, right now, creating an almost unbelievable weather pattern in one of the most extreme climates on the planet.

It’s the end of December, just after the solstice. It will be several months before the sun is seen across the fields of sea ice. However, an intense weather system, the same low-pressure cell that caused flooding and tornadoes in Texas last weekend, is currently over the North Atlantic Ocean and dragging air with it.

This weather system is forecast to become one of the most powerful ever observed over the North Atlantic at this time of year, potentially reaching hurricane force winds.

This storm is going to drag enough warm air from more southerly latitudes along with it that the North Pole, locked in darkness, will actually be above the freezing temperature of water both today and potentially tomorrow.

Depending on the exact air currents of the storm, the North Pole could reach temperatures as high as 5°C (~41°F). If the actual pole does get above the freezing temperature of water, it will be only the 4th time that the North Pole has recorded a December temperature above 0°C in the historic temperature record, going back to 1948.

Much of the Northern Hemisphere is in winter and therefore much of that area is at or below 0°C despite the extreme effects of the El Niño, many areas are still seeing the occasional burst of cold temperatures. For the next day or so, it is likely to be warmer at the North Pole (90° latitude) than in Oklahoma City (35.5°N latitude).

This curiosity unfortunately will not be the only effect of this storm. This intense low pressure system is drawing warm air and moisture north and when it crosses the British Isles it will produce more heavy rains, wind, heavy waves, and flooding, in areas just starting to recover from flooding last weekend (http://on.fb.me/1PuX6OQ).

All of this weather is being driven by the strongest El Niño event on record in the Pacific Ocean. The pool of warm water in the Eastern Pacific causes shifts in high/low pressure patterns and the jet stream around the world, producing storm patterns that are extreme for local environments across the globe. This El Niño event has already broken records for strength set during the 1998 El Niño event that caused tens of billions of dollars worth of damage worldwide. Although it’s impossible to link a specific storm to the increased greenhouse gases in the atmosphere, the trend of ever-stronger El Niño events is directly linked to increasing amounts of heat-trapping gases in the atmosphere.

-JBB Image credit: Climate Reanalyzer, Climate Change Institute, University of Maine http://wapo.st/1NLZwpP http://climatereanalyzer.com

More: http://bit.ly/1YPS9Rc https://twitter.com/bhensonweather/status/681685436264132608

Wonderland: Northern Lights over Svalbard

Looking like a backdrop just waiting for the Polar Express to come whistling through, this scene is found on Svalbard, where the northern lights shine over the snowy Longyear Breen glacier. Found about halfway from Norway to the North Pole, the Svalbard archipelago is about as close to Santa's home base as you could get if you want to leave there year-round; it's the northernmost settlement that has a permanent civilian population. (Alert, Nunavut is farther north and is occupied all year, but only by rotating shifts of researchers and military personnel.) The archipelago sits at the tail end of the Gulf Stream, which here is called the West Spitsbergen Current, so it is similar to the British Isles in that it is warmer than other lands found at the same latitudes. The (comparatively) warm waters of the current fuel plankton blooms, which in turn feed greater numbers of fish and seals, attracting large numbers of polar bears to the islands in turn. Reindeer roam the interior of the islands, fattening themselves up for the dark winters by eating and eating throughout the whole of the Arctic summer days. The midnight sun in the summer lets them disregard the usual diurnal rhythms, and only rest when they need a break from chowing down. By the time winter and the polar night comes, they have a four inch layer of fat to protect them. It might make taking off with a full sleigh harder, but it provides the reindeer with energy and warmth to survive in this beautiful northern outpost.

-CEL

Image: Dmitry Kuznetsov (distributed via imaggeo.egu.eu) Source: http://bit.ly/1QY3duM http://bit.ly/1mgTCnb

Rodinia Reconstructed

We received this interesting question submitted through our blog at http://the-earth-story.com/ (Seriously, visit & follow us, I just paid the fee to reregister the domain name).

“I have a question I was hoping you guys might be able to explain, please. I'm fascinated by plate tectonics, and reconstructing ancient continents, but how do they do it? I get the principle of 'rewinding' current continental movement to get to Pangaea, but how can they produce a map of, say, the Ordovician or the Precambrian, and say with any certainty that's how the continents were arranged so far back in time?”

To use that term, “rewinding” the Atlantic Ocean is pretty easy, you just have to move the continents back together like puzzle pieces. However, the Pacific and Indian Oceans are much tougher; you can’t easily tell exactly how places like Antarctica and Australia fit together, and parts of Asia were only assembled out of volcanic arcs over the last 250 million years.

To fit these plates back together, we use magnetic anomalies on the seafloor. Every few hundred thousand years on average, the Earth’s magnetic field flips, switching the North and South Poles. If we tow an instrument called a magnetometer behind a boat and measure areas where the magnetic field in the ocean is strong and weak, we get a measurement that tells us the orientation of mid-ocean ridges and how they were moving.

Igneous rocks contain minerals like magnetite that record the direction of the magnetic field when they formed. When a magnetic mineral cools through its Curie Temperature, it picks up whatever magnetic field is present and locks that magnetic field in. The rocks of the ocean floor therefore record the flips between north and south; if they are measured across the ocean floor they provide a record of the motion of any oceanic plate.

The oldest oceanic crust on Earth is Jurassic in age, about 200 million years old. By measuring oceanic magnetic anomalies we can therefore project the motion of the continents going as far back as 200 million years, about the time Pangaea began breaking apart.

This image, however, is a reconstruction of Rodinia, a proposed supercontinent 700 million years ago. How on Earth do we get information going back that far?

Part of the answer is continents. Igneous rocks that form on continents also record the ambient magnetic field and point to the North Pole as well. Sedimentary rocks on a continent also record the magnetic field since magnetic minerals in sediments adjust to the magnetic field while they flow in water. But, not only will those rocks tell you about magnetic flips, other properties of magnetism can be measured as well.

The magnetic field in a rock points towards the pole whenever it forms. If you measure the preserved magnetic field in rocks of different ages on a single continent, all of them point to the same North Pole. If the observed North Pole changes over time and a continent is actually solid, then any change in the North Pole direction is actually reflecting movement or rotation of the continent. Measuring the changes in North Pole direction within a continent produces a curve called an “apparent polar wander” curve – a measurement of how the continent has moved assuming the pole is actually fixed.

This gives us several new tools. For example, if 2 continents show a similar apparent polar wander curve over several hundred million years, you can project that they were likely joined together at that time (see more here: http://tmblr.co/Zyv2Js1LJUEUa).

Magnetics also gives another piece of information: inclination. We’re used to magnetic declination; that’s what a standard handheld compass measures, the angle to the North Pole. Although a normal compass can’t measure it, the Earth’s magnetic field also dips up and down. The dip of the magnetic field can tell the latitude of a continent. Steep magnetic inclinations means a rock formed at high latitudes near the pole, and shallow magnetic inclinations means a rock formed near the equator.

Therefore, using magnetic measurements on continents, we can tell where continents sat even without oceanic crust. However, none of these measurements are as good as oceanic north/south anomalies, so there are larger errors. Furthermore, sometimes you just don’t have the right rocks; if rocks are metamorphosed or eroded it will destroy previous magnetic information.

To build upon that measurement, you can use plate tectonic information. If you can match mountain ranges from one continent to another, you can come up with better estimates of which continents were in contact. If you find limestones, which commonly form in warm waters near the tropics, you can estimate that a continent must have been near the equator even if the rocks don’t have a strong magnetic signal. If you find glacial sediments, a continent must have been near the poles.

None of those are perfect. In fact, there is variation even in reconstructions of continental movement over the last 200 million years. Even when we have oceanic magnetic anomalies it isn’t always clear how continents moved; 2 different groups trying to reconstruct continental motion over the past 200 million years will often find important differences.

Even farther back in time the differences increase. There are some scientists who have argued that the supercontinent Rodinia didn’t even exist. However, enough scientists have argued for it that its name is well known and has its own Wikipedia entry.

That’s the way ancient continental movements have been reconstructed. Continent collisions leave a record in rocks. Continental motions leave a paleomagnetic record. However, there are gaps. There are proposals for multiple supercontinents before Rodinia, but those are even more poorly constrained and less accepted. One proposal even argues based on ancient paleomagnetic measurements that all the continental cores originally formed as one supercontinent and rifted apart, but ideas like that will remain controversial until we figure out ways to produce much better evidence than what we currently have.

-JBB

Image credit: https://en.wikipedia.org/wiki/Rodinia#/media/File:Rodinia_reconstruction.jpg

References: http://www.sciencedirect.com/science/article/pii/S0040195113000267 http://www.utm.utoronto.ca/~w3gibo/How%20to%20do%20field%20studies/properties_of_magnetic_field_at_.htm http://austhrutime.com/rodinia.htm http://www.earth.ox.ac.uk/~conallm/Rodinia.pdf

Paradise by the Northern Lights

The warming of the world is settled fact. That we humans and our activities are largely the primary driving force behind that ongoing warming is not seriously disputed by scientists. But what’s a few degrees between friends?

The reality is, not all of the world will experience the same level of warming. In fact, parts of the world are already warming a great deal more than the rest. One of those rapidly warming parts is that part of the Northern Hemisphere known as the Arctic.

As the area of the world closest to the North Pole, the Arctic has historically been extremely cold in winter and considered by most humans to be barely livable at the height of its brief summers. But that is changing.

A study just released shows that over the past 3 decades, the Arctic has experienced greater warming than the rest of the planet, and that the portion of the year spent above freezing has grown longer and hotter. As a result, the growing season has become longer and more hospitable to plant growth.

Interestingly, temperatures and vegetation growth now resemble those found 4-6 degrees of latitude or 400-700 kilometers to the south (250-430 miles).

"It's like Winnipeg, Manitoba, moving to Minneapolis-Saint Paul in only 30 years," said study co-author Compton Tucker of NASA's Goddard Space Flight Center in Greenbelt, Md.

So why is this not the ideal problem some might think it to be? As the vegetation cover increases, the albedo of the Earth (the “whiteness” of the Earth) darkens, which means that the Earth will retain even more energy from the Sun than it has in the past. This in turn will further warm the Earth.

"This sets in motion a cycle of positive reinforcement between warming and loss of sea ice and snow cover, which we call the amplified greenhouse effect," said the study co-author Ranga Myneni said. "The greenhouse effect could be further amplified in the future as soils in the north thaw, releasing potentially significant amounts of carbon dioxide and methane."

As the Earth warms, the Arctic will warm further still. As the Arctic warms, much of the permanently-frozen ground (known as permafrost or yedoma) will thaw, releasing vast quantities of stored carbon in the form of greenhouse gases such as methane and carbon dioxide. And the summer sea ice covering the Arctic Ocean will continue to dwindle, eventually disappearing altogether (the subject of my next post).

By the end of this century, the increases in temperatures and vegetation growth now resemble those found 20 degrees of latitude or 2,000-3,500 kilometers to the south (1,250-2,150 miles).

The last time that the Earth experienced the level of atmospheric carbon dioxide we now see was 3.5 million years ago, when temperatures in the Arctic were some 11-16°C (19-28°F) and global sea levels were some 23 meters (70 feet) above those of today. Given the ongoing increase in atmospheric CO2 from our human activities, that is the world we are returning our climate to.

-DB

Image Credit: NASA's Goddard Space Flight Center Scientific Visualization Studio

Story Source: Amplified Greenhouse Effect Shaping North Into South http://www.nasa.gov/topics/earth/features/growth-shift.html http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate1836.html

Resources: Ancient Fossils Hold Clues for Predicting Future Climate Change http://xa.yimg.com/kq/groups/18383638/756302608/name/sdarticle.pdf http://www.sciencedirect.com/science/article/pii/S0012821X11001099

Thawing Permafrost Likely Will Accelerate Global Warming http://www.tellusb.net/index.php/tellusb/article/view/16197

Caves Point to Thawing of Siberia: Thaw in Siberia's Permafrost May Accelerate Global Warming http://www.sciencemag.org/content/early/2013/02/20/science.1228729.abstract

Not-So-Permanent Permafrost: 850 Billion Tons of Carbon Stored in Frozen Arctic Ground Could Be Released http://onlinelibrary.wiley.com/doi/10.1029/2012GL051958/abstract;jsessionid=CE309CAE91402E485689AAA6F160A093.d02t03

Abrupt Permafrost Thaw Increases Climate Threat http://www.nature.com/nature/journal/v480/n7375/full/480032a.html

Sunlight Stimulates Release of Climate-Warming Gas from Melting Arctic Permafrost http://www.pnas.org/content/110/9/3429

Carbon Release from Collapsing Coastal Permafrost in Arctic Siberia http://www.nature.com/nature/journal/v489/n7414/full/nature11392.html

Why do we study the Poles?

Polar Regions are of upmost importance to our planet and are formidable ecosystems with harsh conditions. A large number of scientists globally devote their careers to studying them, but why? Why should we study areas with little human population, or potential for human settlement?

Firstly, Polar Regions act the same way a thermometer acts in a first aid kit, giving us early warning of when climate change is occurring. In our case this early warning is telling us the Poles are warming up. This can be evidenced as in the Arctic sea ice is retreating and glaciers moving faster than before. Meanwhile in the Antarctic ice shelves are breaking up and melting.

Secondly, the Artic and Antarctica act as regulators for climate globally; for example European weather is often affected by cold Arctic winds. Warming will continue to accelerate in the Poles, potentially affecting climate globally, as stated by the Intergovernmental Panel on Climate Change (IPCC) in 2007. This panel has projected the Arctic could be free of ice anywhere between 2050 and 2100 depending on our continued responses as a species.

Finally, the Poles tell us about processes affecting the globe. The Arctic and Antarctica are linked in to natural processes occurring worldwide. One such process is the ocean conveyer belt. The ocean conveyer belt is controlled by currents and circulation and transports vital nutrients for ocean flora and fauna worldwide. Changes in climate at the poles is projected to increase freshwater in the ocean due to melting ice and increases of precipitation. As more freshwater is produced by the melting process they inhibit mixing with lower layers of water, which prevents formation of deep water, thus disrupting the circulation of nutrients. ~SA

Picture: http://bit.ly/1EjElqm By Andrew Mandemaker. Showing Mount Herschel, Antarctica in 2006. Further Reading: http://bit.ly/1GCcp1K and http://bit.ly/1DI0Z9n. Both by the British Antarctic