Their roots don't grow very deep, so the permafrost doesn't interfere with their growth.

它们的根长得不深，所以永久冻土不会影响它们的生长。

Beneath this active layer is a second layer called "permafrost", which is frozen all year around, and is impermeable to water.

在这一活跃层下面，是被称为“多年冻土”的第二层，终年冻结，不透水。

There're two reasons for this: first, they live in the active layer, which, remember, contains water that doesn't penetrate the permafrost.

造成这种情况的原因有两个：首先，它们生活在活动层中，请记住，活动层中包含的水不会渗透永久冻土。

Geologists think that this fluidized ejecta crater indicates that a layer of permafrost, or water ice, lies just a few meters under the surface.

地质学家认为，这个具有流体化喷出物的陨石坑表明，在地表下几米深处有一层永久冻土层或水冰。

The answer may be that virtually all the water on Mars is now locked in the permafrost layer under the surface, with more contained in the planet's polar caps.

答案可能是，现在火星上几乎所有的水都被锁在地表下的永久冻土层中，更多的水被包含在这个星球的极地冰帽中。

It is practically all ice -permafrost - and it is thawing.

几乎到处是冰——永冻土层——现在都在融化。

On the beach there is a jagged layer of thawing permafrost.

海滩上，有一个不规则的正在融化的永久冻土层。

Permafrost Photo: Dentren at en.wikipedia / cc – by – sa 3.0

多年冻土图片：Dentren at en.wikipedia / cc – by – sa 3.0

Permafrost warms up, and infrastructure built on it founders.

永久冻土温度上升，在此基础上修建基础设施。

An example of a tipping point is the thawing of the permafrost.

“气候引爆点”的一个例子就是永久冻土层的融化。

As the permafrost melts, the land loses its capacity to absorb water.

由于冻土融化，陆地会失去吸水性。

"As the permafrost melts, the land loses its capacity to absorb water," Xin said.

辛说：““随着冻土的消融，土壤失去吸水能力，会有更多的水分流失，退化就更严重。

"These permafrost deposits are now melting and releasing their methane," said Maslin.

“这些永久冻土中的沉积物开始融化，并释放出甲烷，”麦斯林说。

Not in the center. It is full of lakes, rivers and low vegetation resting on permafrost.

中心地区山不多.那里湖泊河流密布.低矮的植物生长在永久的冻土上.

Not in the center. It is full of lakes, rivers and low vegetation resting on permafrost.

中心地区山不多。那里湖泊河流密布。低矮的植物生长在永久的冻土上。

Warming temperatures may also help uncover archaeological evidence buried under permafrost.

温暖的气候也会帮助揭开哪些尘封在冻土之下的考古真相。

Their growth will likely counterbalance some of the increased emissions from melting permafrost.

植物的生长或许可以在某些程度上平衡由于永久冻土融化而不断增加的碳排放。

The presence of sea ice and of permafrost helps protect Arctic barrier islands for much of the year.

海冰和冻土层的出现很多年来帮助保护了北极障壁岛。

It also can be released directly as stored methane already in the permafrost is released as it thaws.

冰冻在永冻层中的甲烷也能随着永冻层的融化而释放。

Permafrost is defined as any ground that has stayed below freezing for more that two consecutive summers.

多年冻土是指任何连续两个夏天处于冰点以下的地面。

But the main exhibit is the completely preserved in a piece of permafrost mammoth, which was found in 1999.

最主要的展品是在冻土层中完好保存的猛犸象骨架，它被发现于1999年。

Yakutsk is the largest city in the world built on permafrost - soil that remains permanently frozen year round.

雅库茨克是世界上建设在永久冻土上最大的城市——土壤在全年都保持冰冻。

The permafrost contains immense amounts of frozen organic matter that have been accumulating for millennia.

永久冻土层经过千万年的累积形成，其中包含了巨量的冻僵的有机物。

The boreal forest will creep northwards, for example, as the permafrost thaws and carbon fertilisation increases.

例如，随着冻土融解，二氧化碳增多，针叶林将继续北移。

Other positive climate feedbacks that operate in the Arctic include the thawing of permafrost and vegetation changes.

在北极发生的其它气候正反馈还包括永久冻土融化和植被变化。

Methane is released when organic material in the thawing permafrost decomposes, which gradually releases methane.

当永冻层融化，其中的有机物质分解就会释放甲烷。

Guodong explains that the construction impact posed a greater threat to the plateau permafrost than global warming.

成国栋解释说，建设过程中对青藏高原永冻层所造成的威胁比全球气候暖化大。