Climate change is at its most fierce at our planets Polar Regions. Average temperatures in the Arctic are rising twice as fast as they are elsewhere on earth. This warming effect is causing the world’s ice sheets to melt fast. We have all seen the photos of broken sea ice and malnourished polar bears, but not many people realise that the loss of our ice sheets will not only kill our polar species but also have chaotic effects on our planets weather systems. Essentially the Polar Regions act as the worlds air conditioning unit, and we are about to pull the plug out.
Everywhere on Earth ice is changing. Glaciers in the Garhwal Himalaya in India are retreating so fast that scientists believe that most central and eastern Himalayan glaciers could disappear by 2035. The majestic snows of Kilimanjaro have melted more than 80% since 1912. The northern ice cap has been rapidly shrinking since the 1970’s losing about ¾ of its volume so far. But recent heat in the Arctic has been shocking scientists, temperatures 33c above average in parts of the Russian Arctic and 20c higher in some other regions. From the Arctic to Peru, from the Alps to the equatorial glaciers of Man Jaya in Indonesia, tremendous ice fields, monstrous glaciers and sea ice are all disappearing at alarming rates.
The reason why the Arctic and our northern ice fields are heating more than the rest of the world is due to a phenomenally destructive feedback loop. Unlike on the Antarctic continent, melting ice in the north exposes dark ocean beneath, which absorbs more sunlight than ice and warms further, melting more ice. The snows ability to reflect sun rays from its white surface is called the albedo effect. An ice covered surface has an albedo effect of around 70% compared to an open-water surface with an albedo effect less than 10%. This causes more radiation to be absorbed by the earth, causing an acceleration of warming.
Unfortunetly the already weakening albedo effect of our ice fields is also been reduced by an occurrence known as “dark snow”. Almost invisible particles of black carbon resulting from incomplete combustion of fossil fuels from diesel engines are being swept thousands of miles from industrial centres in the US, Europe and South- East Asia. Dust is being blown from Africa and the Middle East, where dust storms are becoming bigger as the land dries out with increasingly long and deep droughts. The result is a significant dimming of the brightness of the world’s snow and icefields, leading to a longer melt season, which in turn creates feedback where more solar heat is absorbed and the melting accelerates.
It is clear that our planets Polar Regions are changing quickly, it is also clear that these changes are going to cause drastic alterations to the earth’s geography. Mass extinction of our polar species is inevitable as these species are already at their thermal limits and will not have the time to adapt to a rapidly changing environment. Although devastating, this is not what the governments of the world are worried about. The issues of sea level rise and potential effects on our earth’s circularity systems are the issues that could cause not only economic turmoil but also destroy civilisations.
When temperatures rise and ice melts, more water flows to the seas from glaciers and ice caps, and ocean water warms and expands in volume as it does so. This combination of effects has played the major role in raising average global sea level between 10 and 20 cm in the past hundred years. Sea levels have risen and fallen vastly over earths 4.6 billion year history. But the recent rate of global sea level rise has drastically surpassed the average rate of the past two to three thousand years and is rising more rapidly. Scientists project rising sea levels to continue through the 21st century, with levels increasing between 7 and 22 inches by 2100. The rising sea level is going to cause a lot of destruction along every coastline on our planet, but most at risk are low lying coastal cities such as New York, Venice, Bangkok etc and not to mention low lying islands which are home to already impoverished communities.
Following on, sea level rise is something that is going to devastate coastal environments but the melting of the Polar Regions will have much further reaching consequences. The polar ice caps have an extremely key role in our planets weather systems. Oceans circulatory systems, in effect, mimic the human’s circulatory system. Just as arteries carry oxygenated blood from the heart to the extremities, and veins return blood to be replenished with oxygen, oceans provide life-sustaining circulation to the planet. Propelled by differences in water density, which changes with the temperature and salinity of the seawater, ocean currents are critical in cooling, warming and watering the planets terrestrial surfaces whilst transferring heat from the equator to the poles.
The mechanics behind this conveyor belt is the density-driven thermohaline circulation system (“thermos” for heat and “haline” for salt). Warm, salty water flows from the tropical Atlantic, north towards the Pole in surface currents. This saline water loses heat to the air as it is carried to the far reaches of the North Atlantic. The coldness and high salinity together make the water denser, and it sinks deep into the ocean. Surface water moves in to replace it. The deep, cold water flows into the South Atlantic, Indian, and Pacific Oceans, eventually mixing again with warm water and rising.
Scientists believe that oceans hold the key to potential dramatic shifts in the Earth’s climate. The threat is that too much change in ocean temperature and salinity caused by melting ice sheets could disrupt the circulation system. This could cause drastic climate change in time spans as short as a decade.Freshwater is pouring into our northern seas at drastic rates from melting ice. This freshwater is less dense than salty sea water. As a result the water mass sinks less and the current that drags warm water up the Atlantic is weakened. Some climate models predict a 20% weakening of the current by the century’s end. Europe therefore would find itself cooling on its Western edges, as the circulations bringing warm water/air will be reduced.
Intertwined with the ocean currents are the air circularity systems. Arctic warming is also altering the heat between the North Pole and the equator, which is what drives the strong current of upper level winds in the northern hemisphere commonly known as the jet stream. The jet stream streaks around the pole at up to 250mph and about 8km above the surface. The current forms a boundary between the cold north and the warmer south, but the lower temperature difference means the winds are now weaker. This means the jet stream meanders more, with big loops bringing warm air to the frozen north giving record high temperatures and cold air into warmer southern climes leading to some disastrous weather events.
These blocking patterns caused by slow-moving meanders of the jet stream have been firmly linked to some devastating events, including the 2010 summer floods in Pakistan, which killed 2,000 people and affected 20 million, and also the searing heatwave in Russia in the same year, which killed 50,000 people and wiped out £12bn worth of crops. The fact that these weather systems are already feeling the effects of warming Polar Regions is extremely worrying, as these are the systems that control the climate for almost all of our planet.
The melting of the polar ice caps could be the most devastating effect of global climate change. The negative feedback loop associated with the system is leading to unthinkably rapid change. As the ice is melting it causes the area to heat even more, melting more ice. Considering that the Polar Regions are such important regulatory factors in our planets weather systems, it’s difficult to understand why the melting of our ice caps is not considered one of the greatest threats to humanity. We must do what we can individually to halt climate change by reducing our reliance on the livestock industry (the greatest contributor to climate change) and converting our lives to a more sustainable existence. But most importantly we need to lobby our governments to do more to help save our polar ice caps. Little of us have ever been to the regions concerned but yet their destruction could lead to the most devastating changes to our planets weather systems.