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The melting Arctic

The melting Arctic


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In September 2012 the extent of sea ice in the Arctic reached a new record low. Climate change is melting sea ice in the region at a much faster rate than previously estimated. Snow cover also shows a downward trend. The melting Arctic could impact not only the population living in the region, but also in other parts of Europe and beyond.

Over the past 20 years, the extent of summer sea ice in the Arctic has been declining. But at the end of the fusion season in the summer of 2012 (late September), it hit a new record low, which was well below previous projections. Compared to the annual average of 6.5 million square kilometers (1) between 1979 and 2010 for September, Arctic sea ice shrank below 4 million square kilometers in September 2012, which is the lowest value observed in recent three decades.

In the panel discussion on the melting of the Arctic at the EEA (European Environment Agency), Professor Peter Wadhams from the University of Cambridge explained what could have contributed to this unprecedented annual drop: 'Year by year since the end of the 20th century , the sea ice has been slowly descending as the climate has been warming. The last IPCC report of 2007 (2) indicated that sea ice would last for another 70 years. However, its contraction has recently accelerated as the ice is getting thinner. Global warming affecting the oceans and the atmosphere causes the ice to grow less in winter. '

The thickness and age of the ice play an important role in this collapse. Thinner ice melts faster. Wadhams added: ‘A few decades ago, the Arctic Ocean was covered almost entirely by multi-year ice, where we had ice created more than a year ago. Now, multi-year ice can only be found in a limited area of ​​the north coast of Greenland and Baffin Island in Canada. '

It's not just that sea ice is melting in the Arctic. The Greenland ice sheet is also losing ice mass at an alarming rate especially at the margins, according to Professor Dorthe Dahl-Jensen of the Niel Bohr Institute of the University of Copenhagen: 'Compared to the rest of the world, the Arctic has become been heated almost twice. The most active glacier in Greenland - the Jakobshawn - was pouring into the ocean at a rate of 7 kilometers per year in 2002, now, this has increased to 15 kilometers per year, which is twice the amount of ice that is released into the ocean like icebergs that contribute to rising sea levels. '

During the same meeting, Dahl-Jenses added, ‘The extracted sea ice cores show us that we are experiencing exceptionally warm years. We could consider 2012 as an extreme event in climatic terms, but already in 2010 and 2011 the Greenland ice sheet was losing more than 350 gigatons of ice mass per year compared to the average of 240 gigatons per year that we registered for the period 2003 -2010. '

Sea level rise

The Greenland ice sheet contains enough water to raise global sea levels by up to 7 meters. In any case, to fully melt, it would take many centuries. The recent melting of the Greenland ice sheet is estimated to have contributed as much as 0.7 millimeters a year to sea level rise (about a quarter of the total global average of about 3.1 mm / year). The projections for the rise in the average global sea level estimate that by 2100 it will vary between 0.2 and 2.0, depending on the model and scenario used.

"There is great uncertainty about how much sea level might actually rise," said Professor David Vaughan of the British Antarctic Survey (of the Ice2sea project) (3) during his presentation. 'Once the sea level rises, it is very difficult to make it go down again. Right now, sea level is increasing by about 3mm per year, but with climate change, this rate is likely to increase. '

Vaughan continued, 'There are different factors behind the rise in sea level. About a third of the rise that we can expect could be linked to the thermal expansion of the oceans. The melting of glaciers in the mountains is also predictable and its contribution can be roughly estimated. The great uncertainty is in the Greenland and Antarctic ice sheets. We have studies of how they are losing ice, but the projections indicate a high degree of uncertainty. '


According to Vaughan, estimates of the lowest and highest levels of sea level rise are extremely unlikely. He estimates that the mid-range (0.4 - 1.0 meters) by the end of this century is the most likely. Vaughan also pointed out that sea level rise is not a uniform event; Some areas of the world will experience a higher than average rise in sea level, while other places will see a drop due to gravitational forces acting differently on the planet. On the other hand, sea level rise is not expected to stop at the end of the century. Consequently, politicians and residents of areas near the coast will need to prepare for more increases in the next century.

Vicious circle

Higher temperatures in the Arctic accelerate the melting of ice, which produces darker surfaces on land and sea. These darker surfaces retain more of the solar energy rather than reflect it. Warmer air and water temperatures in the region also affect nearby lands, including permafrost, which has begun to melt on land and underwater.

Arctic permafrost contains carbon dioxide (CO2) and a large amount of methane, which is emitted into the atmosphere when the permafrost melts. 'Methane is a greenhouse gas 20 times more powerful than carbon dioxide. So now we are facing increased global warming and even faster melting in the Arctic, 'adds Wadhams.

Livelihoods in the Arctic

In addition to potentially causing sea level rise and contributing to global warming, the melting of the Arctic could also alter the salinity levels of the oceans and affect ocean currents. On the other hand, increased CO2 uptake can lead to acidification in the ocean and this in turn can alter the composition and distribution of key Arctic species such as crustaceans, krill or plankton.

According to Morten Olsen, director of the recent Arctic Council report on changes in Arctic snow and ice conditions, 'changes in the climate and cryosphere fundamentally put Arctic ecosystems at risk. Warmer water temperatures could result in an invasion of species moving north, affecting local species and ultimately local economies. '

Almost four million people live in the Arctic region and have developed their communities and economies to adapt to their environment. Climate change and higher temperatures will force them to adapt to the new conditions.

Tove Søvndahl Pedersen, President of Greenlandic Representation in Denmark, highlighted during his speech the day-to-day challenges that the Greenlandic population has to face due to climate change: "As an example, we are currently fighting a mold epidemic in our heritage. A large number of homes and public buildings are infected with fungi, hitherto never seen in Greenland, and this has huge implications for human health and our economy.

On the other hand, higher temperatures also offer new opportunities for the people of Greenland, such as increasing the scope of agricultural production in southern Greenland or the exploration and extraction of mineral veins, some of which are strategic for environmentally friendly technologies. climate and have the potential to provide much-needed alternative income because traditional sustenance cannot sustain the well-being of the population. As oil, gas and mineral exploitation and transportation increase could contribute to further warming and the likely melting of permafrost will emit methane, Greenland is keenly aware of the need for a balanced approach.

Beyond the arctic

The Arctic and Antarctica act as the planet's cooling system. This cooling effect, known as the ‘albedo effect’, decreases when the Arctic ice extent falls and the net heat balance shifts. Arctic warming could produce more extreme summers and winters in the Northern Hemisphere as it might affect the North Atlantic Oscillation by pushing the jet stream further south and causing more precipitation.

Since changes in the planet's cooling system have the potential to shift many global systems from weather patterns and ocean currents to species distribution, the melting of the Arctic will affect not only the population in the Arctic but also the rest of the world. world population.

Many European cities are built on the coast and, depending on how much the sea level rises, we will need to adapt and prepare. Barriers to prevent damage from current storms need to be improved, and erosion will have to be better managed to maintain coastlines, protected beaches, infrastructure and residential areas. In Europe alone, 70 million people live less than 500 meters from the sea and economic assets have an estimated value of between 500 and 1000 million euros. Other parts of the world such as Bangladesh or low-lying island states are also at risk from rising sea levels.

"The challenge is to understand how all these different factors are connected and continue to adapt in a coordinated way while reducing greenhouse gases," said Professor Jacqueline McGlade, Executive Director of the EEA. ‘It is clear that our understanding and knowledge of the Arctic and how climate change in the Arctic could impact the rest of the world is improving every year. Science continues to advance. The speed of change in the Arctic that we have seen in recent years urges us to update policies much more regularly and to ensure that interconnections are adequately addressed.

Impacts of climate change in Europe

The EEA has just published a report (4) on the impacts and vulnerability of climate in Europe. The document includes many indicators on changes in the climate system and the cryosphere, indicators of impacts on the environment and society, and indicators on changes in the Arctic cryosphere (Arctic sea ice and Greenland ice sheet).

According to this report, climate change is affecting all regions in Europe, causing a wide range of impacts. More impacts are expected in the future, which could cause great cost damage. The report highlights the need for adaptation in all regions and sectors across Europe. The EEA document supports the European Commission's Adaptation Strategy, which will be published shortly.

Article published in the European Environment Agency
European Environmental Agency, 03/23/2013, www.eea.europa.eu

References:

Translated by Mario Cuéllar

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