The Importance of Polar Science
In an era where politicians and the 24-hour news media often talk about climate change, polar science gets hardly any mention. Even during the fourth International Polar Year (IPY) 2007-08, when polar scientists from around the world mobilized in an international effort to study the Polar Regions – something that happens only every 50 years or so – acknowledgement from politicians and the media was minimal.
However the amount of attention polar science receives isn’t proportionate to its importance, given that the Polar Regions play such an important role in regulating the Earth’s climate. Even though they are the most remote regions of the planet with some of the harshest climates, what happens there can influence people living anywhere on the planet.
Due to the differences in solar energy input between the Tropics and the Poles, both the Arctic and the Antarctic introduce large masses of cold air and water into the global wind and ocean circulation, affecting climate not just in the high latitudes, but across the entire planet. And the fact that climate change seems to be having a significant effect on the Polar Regions – especially the Arctic – more than any other part of the planet is certainly a good reason to pay closer attention to them.
Regulating the planet’s energy budget
One of the most important aspects of the Polar Regions is that they play a crucial role in controlling the planet’s energy budget. They possess an inherent inertia that – at least until recently – has protected the rest of the planet from rapid global warming. The fact that water exists as ice at the planet’s poles is a key part of making this possible.
Water in its liquid state absorbs most of the solar radiation it receives from the sun, and in its gaseous state can even act as a powerful greenhouse gas. However in solid form, both snow and ice have a high albedo or reflectivity, meaning they have the ability to reflect a significant part of the solar radiation they receive. The fact that the snow and ice in the Polar Regions reflect a lot of solar radiation the Earth receives from the sun helps keep the planet cool.
However as temperatures rise, sea ice, glaciers and ice sheets in the Polar Regions are becoming vulnerable to melting, especially in the Arctic and along the Antarctic Peninsula. As the surface area of highly reflective snow and ice diminishes and darker-coloured ocean and land emerges from underneath, it absorbs more solar radiation, which contributes to a rise in temperatures. This in turn causes more snow and ice to melt, creating a positive feedback cycle. If this trend continues unimpeded, it will eventually greatly affect the ability of the Polar Regions to regulate the planet’s climate.
Regulating ocean currents
What happens in the Polar Regions also plays a major role in regulating the planet’s ocean currents which in turn play a major role in regulating the planet’s climate. Deepwater formation, which takes place primarily in the Labrador and Greenland Seas in the sub-Arctic, and also in the Weddell Sea in Antarctica, is one of the principal drivers of global Thermohaline Circulation, the network of ocean currents that circulate throughout the world’s oceans. The rate at which deepwater formation occurs determines the strength of currents such as the Gulf Stream, for example, which transports warm water from the Caribbean to northern Europe and therefore helps keep European winters mild.
The temperature (thermo-) and salinity (-haline) of the water in the Labrador and Greenland Seas determines how quickly deepwater formation occurs. If the water in the Labrador and Greenland Seas were to become suddenly less saline from a massive freshwater influx from a large mass of melting land ice such as the nearby Greenland Ice Sheet, it could slow down Atlantic deepwater formation, which would in turn weaken the Gulf Stream and lead to Western Europe experiencing colder, harsher winters than it currently does.
Archives of the past
Meteorological observations have been taken in the Polar Regions for over a century, including regular satellite observations since 1979. These observations have provided data that experts have used to develop models to describe past climates and project future trends regarding things such as climate and sea ice cover.
However, there is also a lot to be learned from past climates for which scientists do not have observational data. By looking at how the Earth’s climate has changed over thousands of years we can gain useful insight into how it might change in the future, and the Polar Regions provide a wealth of knowledge in helping scientists do this.
This branch of scientific research – paleoclimatology – relies heavily on scientific research conducted at the poles. Why? Because the Polar Regions are important archives of the Earth’s climate history. This is due not only to the fact that they have been relatively isolated from most of human activity since the dawn of human civilization, but that they also are home to unique features such as ice sheets containing ice dating back several hundred thousands of years, which provide key information about the planet’s climate from long ago.
Ice cores are long cylinders of ice extracted primarily from the planet’s two ice sheets - the Greenland Ice Sheet and the Antarctic Ice Sheet – although it’s possible to extract ice cores from smaller ice caps as well. Ice sheets in Antarctica and in Greenland were formed over millions of years by the accumulation of snow compressed into ice as additional layers of snow built up over time, trapping air bubbles in the ice as it formed. By looking at the tiny bubbles of air trapped in annual layers of ice in ice cores, one can determine the composition of the atmosphere hundreds of thousands of years ago, and by looking at the ratio of heavier oxygen 18 isotopes to lighter oxygen 16 isotopes in the ice, it’s even possible to reconstruct the average temperature from past eras. Ice cores taken from the Greenland Ice Sheet can go back as far as 110,000 years, while those taken from the Antarctic Ice Sheet can date back to 800,000 years ago.
It’s also possible to look at climate history by looking at sediments in bodies of water in the Polar Regions which experience regular ice cover such as lakes. The remains of tiny creatures such as diatoms and the pigments left by cyannobacteria can give indications of temperature and ice extent in the lake, and can date back up to 14,000 years ago during the last Ice Age, and in some cases even further. While they may not go as far back as ice cores, the information obtained from them is more detailed for the region where they are located, and some even can indicate what was going on from year to year.
Sediments taken at the bottom of the ocean in the Polar Regions can also be useful in studying past climates. While they are not as detailed as an ice core or a lake sediment core, they can give a broad idea of how climate has changed over the past several million years, helping to determine how fast, how large and how frequent glacial and interglacial changes have been in Antarctica, which has given scientists an idea of what was happening elsewhere on the planet during past eras in the planet’s history.
Changing ecosystems
Climate change is having a marked effect on the ecosystems of the Polar Regions. They are some of the most sensitive areas to climate change of the planet, Whether it be disappearing sea ice affecting the natural habitats of polar bears across the Arctic and Adélie penguins along the Antarctic Peninsula, or warmer-weather invasive species encroaching into areas where they were never seen before, the flora and fauna of the Polar Regions are the first to show the signs of a changing climate.
Through the study of polar ecosystems, scientists can learn more about how climate change is affecting these ecosystems and their biodiversity as well as gain insight into how ecosystems and biodiversity in other parts of the planet might be affected by changes in climate, effectively acting as an alarming signal for other parts of the world.
Indigenous Knowledge
Overlooked by the natural science community as an important source of information until recently, traditional knowledge of indigenous Arctic inhabitants can be of great benefit in better understanding the Polar Regions and how they are being affected by climate change. Having lived off the land in the Arctic for several millennia hunting, fishing, herding reindeer and gathering, indigenous Arctic people from the Inuit to the Sámi to the Nenets have gained intimate knowledge about their polar environment.
This knowledge, which is just starting to be used by researchers in the natural sciences, can be particularly useful in the study of climate change, as it can provide a wealth of knowledge about when certain ice conditions should normally occur (some Inuit can tell what ice conditions will be by the phase of the moon) or the traditional migration routes and distribution areas of certain animals.
An ongoing quest
Although polar research activities increased greatly during the most recent IPY and will provide a wealth of additional knowledge about the Polar Regions and how they influence our planet’s climate when their results are presented at the IPY Oslo conference in June 2010, we are only beginning to understand the vastly important role of these beautiful and mysterious regions of the planet. Scientists from all over the globe from disciplines ranging from glaciology to oceanography , geology, biology and even the social sciences will help in the continuing quest to know how our planet and its climate system functions. The Polar Regions have a lot more to tell us if we continue to listen to what they have to say.
