Question: By how many days per decade has the melt season lengthened in the shallowest of the world's major oceans?

full_context: Document 1: Ilulissat Declaration: The Ilulissat Declaration was announced on May 28, 2008 by the five coastal states of the Arctic Ocean (United States, Russia, Canada, Norway and Denmark), meeting at the political level during the Arctic Ocean Conference in Ilulissat, Greenland to discuss the Arctic ocean, climate change, the protection of the marine environment, maritime safety, and division of emergency responsibilities if new shipping routes are opened.
Document 2: Arctic Ocean: The Arctic Ocean is the smallest and shallowest of the world's five major oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, although some oceanographers call it the Arctic Mediterranean Sea or simply the Arctic Sea, classifying it a mediterranean sea or an estuary of the Atlantic Ocean. Alternatively, the Arctic Ocean can be seen as the northernmost part of the all-encompassing World Ocean.
Document 3: Europe: Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. Europe is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, and the Mediterranean Sea to the south. It comprises the westernmost part of Eurasia. Europe is generally considered as separated from Asia by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways of the Turkish Straits. Yet the non-oceanic borders of Europe—a concept dating back to classical antiquity—are arbitrary and amount to a historical and social construct. The primarily physiographic term "continent" as applied to Europe also incorporates cultural and political elements whose discontinuities are not always reflected by the continent's current overland boundary with Asia.
Document 4: Territorial claims in the Arctic: The Arctic consists of land, internal waters, territorial seas, exclusive economic zones (EEZs) and high seas. All land, internal waters, territorial seas and EEZs in the Arctic are under the jurisdiction of one of the five Arctic coastal states: Canada, Norway, Russia, Denmark (via Greenland), and the United States. International law regulates this area as with other portions of the Earth.
Document 5: Arctic realm: The Arctic realm is one of the planet's twelve marine realms, as designated by the WWF and Nature Conservancy. It includes the coastal regions and continental shelves of the Arctic Ocean and adjacent seas, including the Arctic Archipelago, Hudson Bay, and the Labrador Sea of northern Canada, the seas surrounding Greenland, the northern and eastern coasts of Iceland, and the eastern Bering Sea.
Document 6: North American Arctic: The North American Arctic comprises the northern portions of Alaska (USA), Northern Canada and Greenland. Major bodies of water include the Arctic Ocean, Hudson Bay, the Gulf of Alaska and North Atlantic Ocean. The western limit is the Seward Peninsula and the Bering Strait. The southern limit is the Arctic Circle latitude of 66° 33’N, which is the approximate limit of the midnight sun and the polar night.
Document 7: Arctic cooperation and politics: Arctic cooperation and politics are partially coordinated via the Arctic Council, composed of the eight Arctic nations: the United States of America, Canada, Iceland, Norway, Sweden, Finland, Russia, and Denmark with Greenland and the Faroe Islands. The dominant governmental power in Arctic policy resides within the executive offices, legislative bodies, and implementing agencies of the eight Arctic nations, and to a lesser extent other nations, such as United Kingdom, Germany, European Union and China. NGOs and Academia play a large part in Arctic policy. Also important are intergovernmental bodies such as the United Nations (especially as relates to the Law of the Sea Treaty) and NATO.
Document 8: Arctic ecology: Arctic ecology is the scientific study of the relationships between biotic and abiotic factors in the arctic, the region north of the Arctic Circle (66 33’). This is a region characterized by stressful conditions as a result of extreme cold, low precipitation, a limited growing season (50–90 days) and virtually no sunlight throughout the winter. The Arctic consists of taiga (or boreal forest) and tundra biomes, which also dominate very high elevations, even in the tropics. Sensitive ecosystems exist throughout the Arctic region, which are being impacted dramatically by global warming. The earliest inhabitants of the Arctic were the Neanderthals. Since then, many indigenous populations have inhabited the region, which continues to this day. Since the early 1900s, when Vilhjalmur Stefansson led the first major Canadian Arctic Expedition, the Arctic has been a valued area for ecological research. In 1946, The Arctic Research Laboratory was established in Point Barrow, Alaska under the contract of the Office of Naval Research. This launched an interest in exploring the Arctic examining animal cycles, permafrost and the interactions between indigenous peoples and the Arctic ecology. During the Cold War, the Arctic became a place where the United States, Canada, and the Soviet Union performed significant research that has been essential to the study of climate change in recent years. A major reason why research in the Arctic is essential for the study of climate change is because the effects of climate change will be felt more quickly and more drastically in higher latitudes of the world as above average temperatures are predicted for Northwest Canada and Alaska. From an anthropological point of view, researchers study the native Inuit peoples of Alaska as they have become extremely accustomed to adapting to ecological and climate variability.
Document 9: Greenland Sea: The Greenland Sea is a body of water that borders Greenland to the west, the Svalbard archipelago to the east, Fram Strait and the Arctic Ocean to the north, and the Norwegian Sea and Iceland to the south. The Greenland Sea is often defined as part of the Arctic Ocean, sometimes as part of the Atlantic Ocean. However, definitions of the Arctic Ocean and its seas tend to be imprecise or arbitrary. In general usage the term "Arctic Ocean" would exclude the Greenland Sea. In oceanographic studies the Greenland Sea is considered part of the Nordic Seas, along with the Norwegian Sea. The Nordic Seas are the main connection between the Arctic and Atlantic oceans and, as such, could be of great significance in a possible shutdown of thermohaline circulation. In oceanography the Arctic Ocean and Nordic Seas are often referred to collectively as the "Arctic Mediterranean Sea", a marginal sea of the Atlantic.
Document 10: Arctic sea ice decline: Arctic sea ice decline is the sea ice loss observed in recent decades in the Arctic Ocean. The Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report states that greenhouse gas forcing is largely, but not wholly, responsible for the decline in Arctic sea ice extent. A study from 2011 suggested that internal variability enhanced the greenhouse gas forced sea ice decline over the last decades. A study from 2007 found the decline to be "faster than forecasted" by model simulations. The IPCC Fifth Assessment Report concluded with high confidence that sea ice continues to decrease in extent, and that there is robust evidence for the downward trend in Arctic summer sea ice extent since 1979. It has been established that the region is at its warmest for at least 40,000 years and the Arctic-wide melt season has lengthened at a rate of 5 days per decade (from 1979 to 2013), dominated by a later autumn freezeup. Sea ice changes have been identified as a mechanism for polar amplification.
Document 11: Baltic Sea: The Baltic Sea is a sea of the Atlantic Ocean, enclosed by Scandinavia, Finland, the Baltic countries, and the North and Central European Plain. It includes the Gulf of Bothnia, the Bay of Bothnia, the Gulf of Finland, the Gulf of Riga, and the Bay of Gdańsk. The sea stretches from 53°N to 66°N latitude and from 10°E to 30°E longitude. A mediterranean sea of the Atlantic, with limited water exchange between the two bodies, the Baltic Sea drains through the Danish islands into the Kattegat by way of the straits of Øresund, the Great Belt, and the Little Belt.
Document 12: Arctic policy of Russia: The Arctic policy of Russia is the domestic and foreign policy of the Russian Federation with respect to the Russian region of the Arctic. The Russian region of the Arctic is defined in the "Russian Arctic Policy" as all Russian possessions located north of the Arctic Circle. (About one-fifth of Russia's landmass is north of the Arctic Circle.) Russia is one of five countries bordering the Arctic Ocean. In 2011, out of 4 million inhabitants of the Arctic, roughly 2 million lived in arctic Russia, making it the largest arctic country by population. However, in recent years Russia's Arctic population has been declining.
Document 13: Poverty in the Arctic: The Arctic is a vast polar region comprising the northern most parts of Canada, Norway, Greenland (Denmark), Sweden, Finland, the United States (Alaska), Iceland and Russia. In recent years, the Arctic has been at the forefront of political and social issues. Several matters have risen surrounding the issues of poverty and global warming and their effects on indigenous people in this region. Indigenous people in the Arctic statistically fall below their nation’s poverty line.
Document 14: Arctic: The Arctic ( or ) is a polar region located at the northernmost part of Earth. The Arctic consists of the Arctic Ocean, adjacent seas, and parts of Alaska (United States), Northern Canada, Finland, Greenland (Denmark), Iceland, Norway, Russia and Sweden. Land within the Arctic region has seasonally varying snow and ice cover, with predominantly treeless permafrost-containing tundra. Arctic seas contain seasonal sea ice in many places.
Document 15: North America: North America is a continent entirely within the Northern Hemisphere and almost all within the Western Hemisphere; it is also considered by some to be a northern subcontinent of the Americas. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the west and south by the Pacific Ocean, and to the southeast by South America and the Caribbean Sea.
ground_truth: 5 days per decade