Hardly a day goes by without new media reports on climate change and melting glaciers. We have all seen footage of enormous drifting icebergs, images of rapidly shrinking glaciers and headlines trying to draw public attention to potentially catastrophic consequences of vanishing ice. The times we live in are marked not only by the Great Melt, but also by what is known as the Sixth Mass Extinction, which is a widespread and rapid disappearance of a large number of species due to human activity.
While browsing through photos of increasingly smaller glaciers, many biologists kick themselves for not being quick enough to discover and describe their inhabitants, especially now that global biodiversity is on a steep decline. After all, the world’s glaciers are not only cold, ominous and melting, but also inhabited. By whom? A whole range of creatures, from minute, single-cell organisms, such as bacteria or microscopic plants, to animals consisting of numerous cells and tissues, but still too small to see with a naked eye.
Glacier surfaces crawling with life
In order to be properly understood, glacial ecosystems need to be considered on a microscale. This is why a microscope is an indispensable piece of equipment for every scientist studying biodiversity on glaciers. During the summer, the snow accumulated on glacier surface melts, providing creatures which live on the ice with liquid water and basic nutrients necessary for them to grow. The most common among the creatures are cyanobacteria, which most of us know as blue-green algae. They are one of the most ancient organisms on the planet and one of the pioneers of early oxygen production.
Over the course of Earth’s history, cyanobacteria have skilfully handled a range of adversities and adjusted to highly unpleasant conditions. Some of them have developed a liking for cold places, like ice. Blue-green algae, however, are not the only inhabitants of glacier surfaces. They share their territory with distant cousins of trees, or – to be more specific – microscopic ice algae, which belong to a group of plants known as Zygnematophyceae. Both types of organisms serve a very important role and are often referred to as the engineers of glacial ecosystems. In other words, it is them that produce the organic matter which makes life possible for other creatures, such as bacteria, protozoa, and microscopic animals.
Blue-green algae and ice algae are made up of cells which contain a pigment protecting them from high doses of UV radiation, typical of mountainous and polar regions. Mass algal blooms may lead to ice darkening, which causes increased heat absorption and thus makes glacier surface melt more rapidly. Scientists from different countries observe the phenomenon very closely and try to figure out the impact of these organisms on the rate of glacier melting on a global scale. Paradoxically, by protecting themselves from solar radiation, the tiny plant organisms inhabiting glacier surfaces contribute to the destruction of their icy homes.
Cryoconite and its inhabitants
Contrary to what many of us tend to think, glaciers are not white and immaculate. Looking at their surface, we may notice a dark residue made up of mineral dust, which comes from nearby mountains and the tundra, but also – by means of long-range wind transport – from much more distant places, such as far-away deserts. Beside mineral particles, the residue contains microorganisms (like the above-mentioned types of algae) which live on glacier surface. At first glance, the ice may seem to be polluted, but in most cases it is just how it naturally is. The first person to take notice of the residue was the Finnish traveller and geologist Adolf Erik Nordenskiöld, who called it cryoconite (which is Greek for cold dust).
The interaction between mineral dust and the organisms which use it as an additional source of nutrients reduces the albedo (or the amount of solar radiation reflected off the surface of ice) and causes the ice underneath to melt. Cylindrical melt holes that form as a result are known as cryoconite holes and, despite being only several centimetres in diameter and depth, they constitute one of the most extreme freshwater ecosystems on Earth. The temperature inside them is seldom above 0.1°C, nutrients are scarce, and – if this wasn’t bad enough – they are under constant threat of destruction by heavy rains and warm winds.
So who would ever want to live there? The above-mentioned organisms and, believe it or not, a good few more. At the bottom of cryoconite holes lies a layer of residue (cryoconite), which is home for tardigrades and rotifers. Despite being invisible to the naked eye, they are the most dominant and numerous of all the animals inhabiting the little ecosystems. Tardigrades are colloquially referred to as water bears and they do indeed resemble clumsy bears (or little sausages with four pairs of limbs, if you will). Rotifers, on the other hand, are more like tiny swimming bags. Their name comes from a Latin word meaning wheel-bearer, and was inspired by the circular structure found on top of their body. It is called the corona (crown) and is used for feeding and movement. Rotifers and tardigrades measure typically about 0.3 mm but, despite their diminutive size, it is them that are the greatest glacial predators, feeding on bacteria and algae.
Both tardigrades and rotifers can be found in the soil, mosses and lichens, as well as lakes and seas. Those that live on glaciers, however, endure serious thermal hardships and – from the point of view of any biologist studying glacial ecosystems – they are absolutely extraordinary. They survive in temperatures oscillating around 0°C and may be repeatedly frozen, defrosted, and – in some cases – even dried. They freeze for many months, without even knowing if the place they froze in would still be covered in ice the following summer. They do struggle in high temperatures, however, which means they are probably well impressed by their savannah-dwelling cousins.
The little creatures inhabiting glacier surfaces have another distinctive feature – they are exceptionally cute. The most interesting of them have unique morphological characteristics which distinguish them from their relatives in lakes or in the soil. For instance, some tardigrades found on glaciers are black. It is likely that the dark pigment helps them survive and protects them against high doses of UV radiation they are exposed to once they have been washed out from the relative safety of their cryoconite hole and deposited directly on glacier surface. Tough life, right?
Mysterious organisms in the ice
Apart from tardigrades and rotifers, the inhabitants of glacier surfaces include little arthropods known as springtails (Collembola), which feed on organic matter. Their name is far from accidental. Springtails are equipped with a furcula, or a forked, tail-like appendage, which enables them to jump. On a glacier, they look like tiny, dark fleas. But the greatest surprise awaits those who study glacial ecosystems along the western coast of the USA and Canada, where in the ice (yep, right inside it) live the so-called ice worms. Measuring up to 3 mm in length, they are classified as the annelids (Oligochatea) and are thus related to earthworms. Due to a long series of events, however, they have come to inhabit the inside of glaciers rather than the good old soil.
Ice worms live inside glaciers found along the coast. This is because these glaciers contain microchannels with liquid water, which do not freeze even during the winter. It is these channels that ice worms squeeze through. At night, they crawl to the surface and feed on algae until dawn, when they withdraw back into the ice to hide from the sun. They serve as an inspiration for astrobiologists who dream of discovering macroscopic life on ice-covered planets and moons. After all, if earthly ice can be inhabited, it does not take much to imagine life thriving inside glaciers enveloping other celestial bodies. For the time being, however, such concepts are still pure science fiction.
Z BIEGUNÓW DO GWIAZD
Po co w ogóle eksplorować kosmos? Po co przekraczać kosmiczne granice dzięki kosmicznie drogim projektom? Nie brakuje opinii, że lepiej wszystkie nasze wysiłki skoncentrować jak najbardziej – dosłownie – przyziemnie, zamiast „trwonić” je na realizację ambicji wizjonerów/narcystycznych hochsztaplerów (niepotrzebne skreślić) takich jak Elon Musk. Opinie takie często wygłasza się korzystając nieświadomie z technologii, które nasze społeczeństwo zyskało dzięki programom kosmicznym. Z pewnością nie tylko po to, by podziwiać niebieskie zachody Słońca na Marsie, które czerwona planeta zawdzięcza cienkiej i pełnej pyłu atmosferze, w której światło inaczej się rozprasza niż na Ziemi.
Neons up in the atmosphere
Auroras, or the polar lights, are magnificent light shows held in the Earth’s atmosphere. The curtains of shimmering light stir the imagination and feature prominently on people’s bucket lists. What causes this remarkable phenomenon and why is it so much more common in the polar regions than in the tropics? Can we ever hope to see it in Poland? What are the colours of the polar lights and why do they die down only to light up again a moment later?
When did people turn their backs on science? What has led to widespread scepticism and a growing tendency to challenge the methods of scientific inquiry? Who is to blame for the situation? The public, who find conspiracy theories more satisfying than scientific facts? Or the scientists, who – focused on ever more complex data, models and charts – have failed to convince the society that we’re all part of the growing civilisation of knowledge? Or is it, perhaps, that scepticism towards science actually stimulates progress? After all, the Greek word “skeptikos” meant someone “inquiring” and “reflective”, who might have well been dissatisfied, but spared no effort to find the truth.
Even though deep scepticism has long been a typical response to new scientific theories (those of Copernicus, Descartes or Kepler were all initially dismissed as heresies), its intensity has become much greater in the 21st century. Despite the increasing reliability of data, widespread consensus among scientists and overwhelming evidence, scientific discoveries are met with a growing pseudo-scientific distrust. Everything is seen as questionable, with the topic of climate change and the intense emotion it provokes being perhaps the most glaring example.
“But wait a second”, you may say. “Isn’t challenging popular beliefs, thinking outside the box and asking difficult questions a vital prerequisite for progress? After all, that’s the approach adopted by Copernicus, Darwin and many others, whose discoveries shaped our perception of the world”. Of course! But the majority of climate-change sceptics follow a very different approach, undermining the fundamental principles of science, disregarding the laws of nature, and ignoring valid scientific evidence that contradicts their ideas. It is true that, at first glance, some arguments put forward by climate-change sceptics seem logical, convincing and grounded in hard science, but appearances are deceptive. While their arguments are not downright lies, they are invariably based on incomplete information and are therefore seriously misleading.
Here are six of the most common myths and scientifically-sound responses that debunk them:
MYTH 1: “Global warming? But it was terribly cold yesterday!”
This misconception is both the most common and the easiest to understand, as it doesn’t take much to lose sight of the difference between current weather phenomena and long-term climate trends. An unpleasantly cold summer day in your hometown has nothing to do with a long-term increase in global temperature. In order to notice climate trends it is necessary to observe changes in the weather over a longer period of time. What appeals to our imagination, however, are record temperatures, and high temperature records occur twice as often as low temperature ones. What makes the myth even more confusing is that one of the reasons behind extremely cold winters in the northern hemisphere is the loss of sea ice in the Arctic, which is to say, global warming. In a nutshell, the melting of sea ice in the far north affects the temperature and salinity of ocean water, which – in turn – upsets the functioning of the global system of sea currents, which have so far been responsible for the mild climate in coastal areas. Another important factor is the so-called polar vortex and the fact that the reduction in the amount of sea ice causes changes in atmospheric pressure. It is these changes that were responsible for the winter Armageddon that hit New York, leaving the locals to deal with empty shelves in supermarkets and frozen hydrants.
MYTH 2: “The climate has changed before, so there’s nothing to worry about.”
The climate has indeed changed during Earth’s history and has included both colder and warmer periods. The fact remains, however, that sudden increases in temperature on a global scale have generally been catastrophic for life on the planet, causing mass extinctions, like the so-called Great Dying at the end of the Permian. Climate changes associated with these events include a considerable and rapid increase in global temperatures, a rise in sea level and growing acidity of ocean water, which are the exact same phenomena we’re dealing with today. What is more, the global warmings of the past were always related to a relatively high content of carbon dioxide and methane in the atmosphere. And although it is true that life flourished in the Eocene, the Cretaceous and other periods when the CO2 content in the atmosphere was rather high, this was possible because greenhouse gasses were in a state of balance with carbon contained in ocean water and the process of weathering occurring on land. Atmospheric gases, chemistry of the oceans and living creatures had millions of years to adjust to these levels. Sudden changes, on the other hand, have invariably had a devastating impact on life.
MYTH 3: „Alright, so things are changing, but it’s not our fault. It’s the Sun that determines what our climate is like.”
In this case, a reply is rather short. Fine, the Sun is our main source of energy and its activity does fluctuate periodically (with a period of about 11 years). The thing is, though, that for the last 40 years the Sun has been considerably less active and the temperatures keep going up nonetheless. If the amount of solar energy is reduced and the Earth continues to get warmer, the Sun can’t be the main factor behind the Earth’s temperature. Simple as that.
MYTH 4: “It’s not carbon dioxide that the problem. We should worry about water vapour instead.”
Contrary to what many people think, the gas that’s chiefly responsible for the greenhouse effect is indeed water vapour. Climate-change sceptics, however, use the fact to suggest that the increasing concentration of carbon dioxide in the atmosphere is no cause for concern, which – once again – exposes their selective approach to facts. An issue they choose to ignore this time is that the climate is a system. The amount of water vapour in the atmosphere depends on the temperature, as the higher the temperature the more water evaporates, turning into water vapour. If, therefore, a different gas causes the temperature to rise (as is the case, for example, with extra CO2 produced when burning fossil fuels), the rate of evaporation rises too. Additional water vapour causes a further increase in temperature, creating a vicious circle or the so-called positive feedback loop. In other words, climate-change sceptics are right to suggest that, in terms of its amount in the atmosphere, water vapour is a dominant greenhouse gas. What they fail to mention is that the positive feedback loop associated with water vapour makes temperature changes caused by CO2 twice as great as they would normally be.
MYTH 5: “Greenhouse gas emissions from human activities are very small compared to the amount of CO2 emitted naturally.”
They truly are tiny, but don’t let this mislead you. A lethal dose of potassium cyanide is tiny too. Moreover, natural CO2 is not static. It is generated as a result of natural processes and absorbed by the ecosystem. Although our output of 29 gigatons of CO2 may seem negligible compared to the 750 gigatons moving through the carbon cycle each year, nature can only absorb about 40% of the surplus. The rest of it gradually accumulates in the atmosphere.
As for the popular claim that volcanos emit more carbon dioxide than humans, it is simply not true. Anthropogenic CO2 emissions are a hundred times higher than volcanic emissions.
MYTH 6: “Climate changes aren’t all that bad.”
Wouldn’t it be great to have orange groves outside Warsaw or the sunny paradise of the Maldives in Kołobrzeg? A list of potential advantages of global warming is as long as it is exciting and includes, among others, intensive plant growth (also in the far north), agricultural expansion, and new opportunities for development, exploitation of natural resources and transport in a world free of sea ice. Unfortunately, the risks far outweigh any potential benefits. Among them are catastrophic weather phenomena, massive waves of migration, devastated cities, limited access to drinking water, floods, droughts, and rampant diseases. If you think such prospects are as far-removed from your daily life as sinking islands in the Pacific, think again. Whether we like it or not, Europe will not become a beneficiary of climate changes and Poland will not turn into a tropical paradise. Global warming will have a range of unpleasant consequences, from a destabilized economy, erratic energy supply or even total blackouts, through severe droughts causing catastrophic crop failures and food shortages, to forest fires and lethal heat waves. Apart from dying coral reefs that we so often hear about, global warming is a serious risk for infrastructure and invaluable architectural heritage, with tremendous amounts of money necessary to adapt to climate changes and alleviate their consequences. It’s the tragedy of Venetians standing helpless in the face of destructive floods and of those who fell victim to tornadoes that swept through Polish forests. The Earth will surely survive, but it will no longer be the place that made our civilisation possible to develop.
And now, just for a brief moment, let’s assume that climate-change sceptics are right. Climate changes aren’t certain, they may be unrelated to human activity, and their consequences may be nothing to lose sleep over. Let’s ignore measurements, models and the shared opinion of 99% of all world’s scientists, who are sure the opposite is the case. Climate is an immensely complex system. Our observations are incomplete and our models may not be 100% accurate. We do not understand all mechanisms behind climate change. Can we, however, afford to ignore what we do understand?
The Arctic is generally associated with a cold, extreme climate. We all know that temperatures up there differ tremendously from those typical of Europe. While in Poland it is not uncommon for summer temperatures to reach 30°C, in Northern Canada they usually hover around 8–10°C. In winter, the Polish norm is about -5°C, while in Greenland even -40°C raises no eyebrows. In recent years, however, the contrast is gradually becoming less striking. Although climate changes affect the entire globe, nowhere are they as dramatic as on its northern outskirts. The Arctic is warming up faster than the rest of the world, which has long caused serious concern among scientists. Let us therefore have a closer look at the underlying mechanism of this phenomenon and its possible consequences.
One way to measure the intensity of climate changes is to compare the mean temperature from a given multi-year period (say, thirty years) with the mean temperature from a preceding multi-year period. The method is very straightforward. All we need is to get temperature records for a selected time period from all over the world, calculate the mean value, repeat the procedure for an earlier period, and subtract one value from the other. What we end up with is a single number, which is easy to grasp even for non-scientists.
In a nutshell, this is how „climate targets”, which we hear about so often, come into being. By stating that “we must not allow for global warming to exceed 2°C” we mean that “we must not allow for global mean temperature in the future to be higher by more than 2°C than the global mean temperature in the past”.
As is usually the case, however, the price to pay for making the message easy to comprehend is gross oversimplification. When calculating the global mean change in air temperature, we bring the world’s immense biodiversity and all the many ways in which it can and does react to climate changes down to a single number. So let us now try to bring the diversity back by calculating the mean temperature change separately for different places in the world. What we get as a result is the following map:
The difference between the mean temperature in 2019 and the mean from the years 1970–2000. The map was generated on https://data.giss.nasa.gov/gistemp/maps/index_v4.html. Visit the website and play with various parameters to see how the process of global warming affects the world and your country.
The darker the colour the greater the increase in mean air temperature in the area. So what is it that strikes us the second we look at the map? The Arctic, which in terms of the cold is second only to the Antarctic, warms up the fastest.
The phenomenon of intensive warming in polar regions is known as polar amplification. These days, the amplification occurs mostly in the vicinity of the Earth’s North Pole, which is why the term “Arctic amplification” is often preferred. Its intensity is considerable. While the global mean temperature increase in the years 1970–2000 was approximately 0.7°C, in the Arctic the mean temperature rose by over 2°C. What is the reason behind this disproportion? The most convincing explanation links polar amplification to the rapid reduction in the extent of sea ice. To put it simply, the mechanism works as follows:
When the climate becomes a little warmer (due to, for example, the emission of anthropogenic greenhouse gases), it is followed by an increase in the amount of sea ice that melts in the Arctic Ocean during the polar day. During the polar night, which is to say – in winter, the ice cover builds up at a slightly slower rate and does not therefore reach the same extent as it did the year before. This means that parts of the ocean which used to be covered in ice remain ice-free throughout the year, a fact has a profound impact on the temperatures in the Arctic. Sea ice is white, which means that it reflects a vast majority of solar radiation. Sea water, on the other hand, is dark and, instead of reflecting the radiation, it absorbs much of it and thus becomes warmer. Warmer waters freeze less readily, so in the following year the extent of white sea ice is even smaller and the surface area of dark sea water – bigger. Consequently, more radiation is absorbed, which makes the water even warmer. And so it goes on year after year
The diagram shows the positive feedback loop, or the „vicious circle” effect, which speeds up the warming of the Arctic. An increase in temperature makes sea ice melt. This leads to the uncovering of dark ocean surface, which absorbs more radiation and thus leads to a further increase in temperature.
This self-perpetuating cycle is referred to as a positive feedback loop. The vicious circle of ice loss and ocean warming is generally considered to be the main cause of Arctic amplification. It is not, however, the only one. Higher temperature of ocean water boosts evaporation. As a result, the atmosphere in the Arctic becomes richer and richer in water vapour, which is the most common of all greenhouse gases found in Earth’s atmosphere. The heat from the atmosphere is transferred to the ocean, which further accelerates the rate of ice loss. At the same time – contrary to what happens, for instance, around the Equator – air circulation in polar regions “traps” the air. In the tropics, storms lift the heat and water vapour to higher layers of the atmosphere, from where it is carried off by the winds and dispersed around the globe. An increase in evaporation at the Equator leads to a corresponding increase in the frequency and intensity of storms that sweep through the area. A mechanism of the sort, which helps to disperse excess heat, is missing in the Arctic. Storms are a rarity in the far north, and – to make things even worse – growing amounts of water and heat are transported to the area from the tropics.
If the intensity of climate changes depends on the location, does it also depend on the season? An attempt to answer this question was made by Polish scientists – Prof. Marzena Osuch and Dr Tomasz Wawrzyniak from the Institute of Geophysics, Polish Academy of Sciences. Their academic article from 2017  deals with climate variability along the western coast of Spitsbergen. The scientists checked if the change in mean temperature measured at the Polish Polar Station Hornsund is the same or different on particular days of the year. One of their results can be seen in the chart below:
Changes in the mean daily air temperature at the Polish Polar Station Hornsund. Chart based on . The data were averaged in two dimensions over a shifting time horizon. The final value for each day of the year was calculated on the basis of the mean value from a multi-year period (which is to say, the mean value recorded on a given day over ten consecutive years) and from a 30-day period (the mean value recorded on a given day as well as on 15 days before it and 15 days afterwards). For example, the value for 16 Jan 2014 was calculated on the basis of the mean temperature recorded on 16 Jan in the years 2005–2014 and the mean temperature from 1–31 Jan 2014.
Each line in the chart illustrates an averaged temperature recorded over a decade, with each decade starting in a different year (e.g. 1988–1997, 1989–1998, etc.). The cooler the colour of a line, the more distant the past it represents. Looking at the chart, it is easy to see that the temperatures increased in all months of the year, but the biggest increases were recorded between November and February. From March till mid-October, differences in air temperature between particular periods are very slight. In autumn, the lines start to diverge to reach maximum divergence in December and January. But what does it mean in practice? Climate warming is a lot stronger in winter than it is in summer. As a result, the coldest month in Spitsbergen is no longer January or December, but March. This situation is a direct consequence of the positive feedback loop described above. Ice loss plays a particularly important role during the cold season, when the ocean, instead of freezing over, returns to the atmosphere the heat it absorbed during summer.
Should we view polar amplification as a mere geographic curiosity or a factor that has the power to affect our lives?
There is no agreement among scientists regarding the potential impact of the violent warming of the Arctic on regions located further south. Some models indicate that changes in the far north disturb atmospheric circulation, causing severe droughts and devastating floods . Other research suggests that such extreme weather phenomena are a consequence of very different processes (such as changes in the temperature of tropical oceans), and polar amplification plays second fiddle, if that, in the shaping of climate in Europe, USA and Siberia . There is no doubt, however, that the rapid warming of the Arctic exerts a profound impact on the Arctic itself, destabilizing not only natural local ecosystems, but also the daily lives of its human inhabitants. As a result, Arctic amplification should be kept in mind whenever the conversation turns to global warming.
The author would like to thank Prof. Marzena Osuch and Dr Tomasz Wawrzyniak for scientific consultation and constructive advice.