Alaska\u2019s thawing permafrost is releasing acid and metals that turn rivers orange, changing water chemistry for dozens of miles. <\/span><\/p>\n
About Permafrost<\/b><\/h2>\n
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Permafrost is any <\/span>ground that remains completely frozen<\/b>\u201432\u00b0F (0\u00b0C) or colder\u2014for <\/span>at least two years straight.\u00a0<\/b><\/li>\n
While two years is the minimum for permafrost consideration, <\/span>some regions <\/b>have had <\/span>frozen ground for hundreds of thousands of years.\u00a0<\/b><\/li>\n
Scientists discovered the <\/span>oldest known permafrost in Siberia<\/b>, which has been frozen for the past 650,000 years.<\/span><\/li>\n
Where are they found?<\/b>\n
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These permanently frozen grounds are most common in <\/span>regions with high mountains<\/b> and in <\/span>Earth\u2019s higher latitudes<\/b>\u2014near the <\/span>North and South Poles<\/b>.<\/span><\/li>\n
It can be <\/span>found on land<\/b> and<\/span> below the ocean floor.\u00a0<\/b><\/li>\n
Its <\/span>thickness can range<\/b> from <\/span>one meter to more than 1,000 meters,<\/b> covering <\/span>entire regions, such as the Arctic tundra, or a single, isolated spot<\/b>, such as a mountaintop of alpine permafrost.<\/span><\/li>\n
Permafrost covers <\/span>large regions of the Earth. <\/b>Almost a <\/span>quarter of the land<\/b> area in the <\/span>Northern Hemisphere<\/b> has permafrost underneath.\u00a0<\/span><\/li>\n
It occurs in <\/span>85 percent of Alaska <\/b>and<\/span> 55 percent of Russia and Canada,<\/b> and covers probably all of Antarctica.\u00a0\u00a0<\/span><\/li>\n<\/ul>\n<\/li>\n
What Is Permafrost Made Of?<\/b>\n
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Permafrost is made of a <\/span>combination of soil, rocks, and sand<\/b> that are<\/span> held together by ice.\u00a0<\/b><\/li>\n
The <\/span>soil and ice <\/b>in permafrost <\/span>stay frozen all year long.<\/b><\/li>\n
Although the ground is frozen, permafrost regions<\/span> can be snow-free in summer.\u00a0<\/b><\/li>\n
Near the surface<\/b>, permafrost soils also contain <\/span>large quantities of organic carbon<\/b>\u2014a material leftover from dead plants that couldn\u2019t decompose, or rot away due to the cold.<\/span><\/li>\n
Lower permafrost layers<\/b> contain <\/span>soils made mostly of minerals.<\/b><\/li>\n<\/ul>\n<\/li>\n
Permafrost loss<\/b>, also known as <\/span>permafrost thaw, <\/b>is the <\/span>progressive loss of ground ice in permafrost<\/b>, usually due to <\/span>input of heat.\u00a0<\/b><\/li>\n
A layer of soil on top<\/b> of permafrost <\/span>does not stay frozen all year<\/b>. This layer, called the <\/span>active layer<\/b>, t<\/span>haws during the warm summer months<\/b> and <\/span>freezes again in the fall.\u00a0<\/b><\/li>\n
In colder regions<\/b>, the<\/span> ground rarely thaws<\/b>\u2014<\/span>even in the summer.<\/b> There, the<\/span> active layer <\/b>is <\/span>very thin<\/b>\u2014only 4 to 6 inches (10 to 15 centimeters).<\/span><\/li>\n
A <\/span>thawing permafrost layer<\/b> can lead to <\/span>severe impacts<\/b> on people and the environment.<\/span>\n
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When permafrost melts, it<\/span> raises water levels in Earth’s oceans.\u00a0\u00a0<\/b><\/li>\n
Melting permafrost<\/b> and <\/span>warming global temperatures<\/b> have a <\/span>positive feedback loop.\u00a0<\/b><\/li>\n
Organic matter <\/b>currently frozen in the permafrost will <\/span>start to decompose<\/b> when the ground thaws, resulting in the <\/span>emission of methane and carbon dioxide<\/b> into the atmosphere.\u00a0<\/span><\/li>\n
As ice-filled permafrost thaws, it can <\/span>turn into a muddy slurry <\/b>that<\/span> cannot support<\/b> the <\/span>weight <\/b>of the soil and vegetation above it.\u00a0<\/span><\/li>\n
Infrastructure <\/b>such as roads, buildings, and pipes <\/span>could be damaged <\/b>as permafrost thaws.<\/span><\/li>\n
Melting permafrost also<\/span> releases heavy metals<\/b>, such as mercury, and other toxins.\u00a0<\/span><\/li>\n
As it melts, the contaminated permafrost can<\/span> pollute water sources<\/b> for local people.\u00a0<\/span><\/li>\n
It is even possible that thawing permafrost <\/span>may release dormant, disease-causing microbes<\/b> that are harmful to animals and humans.<\/span><\/li>\n<\/ul>\n<\/li>\n<\/ul>\n