美国国家航空暨太空总署最新卫星数据指出，北极冰海和格林兰岛融化的速率，比先前预计更快。

北极冰海融化

华盛顿外围马里兰州 Greenbelt 的美国航太署 Goddard 空间飞行中心气候科学家表示，北冰洋的浮冰可能在 2013 年晚夏即消失殆尽。

美国航太署 Goddard 空间飞行中心浮冰卫星计划科学家 Jay Zwally 说到道： ” 海洋浮冰急剧减少，速度比所有的预测都还要快速。我们不仅有大气暖化的问题，同时海水暖化也加速这个问题。浮冰面积的减少，让大家感到惊讶。这个显著的偏差，让我们知道也许我们已经到达极限点。

Jay Zwally

如果你某个程度推移玻璃杯然后放开来，玻璃杯还在；不过假如你推得太远，越过极限点，那么它就消失了。现在北冰洋发生的状况，就是海冰正在变薄，面积正减少中。这会使冰洋吸收更多太阳热力。即使气候不再暖化，保持现状，多数海洋浮冰在夏末将减少而且消失不见。所以目前北极冰洋很可能已到极限点。 ”

 

美国科罗拉多冰雪数据中心资深研究者 Mark Serreze 表示： “ 到了 2006 年九月，我们失去的浮冰，每十年超过百分之九。这相当于每年十万平方公里，这是可观的数量。 2007 年发生的事件，即是警讯。 ”

美国太空总署的卫星图显示出北极冰海在过去 30 年的平均面积。

美国太空总署的卫星图显示出北极冰海在过去 30 年的平均面积。绿色部份表示截至去年夏末所融化的面积。

Zwally 表示，显然剩馀的冰也变薄了。 ” 重点是目前剩馀的面积变更薄了。以前这里一向有很多浮冰，叁到四、五、六公尺厚，而现在多数已经消失。 ”

所 有气候模式都有其易变性和可能性，而融化的趋势比预期来的严重。

另一个可能性是会比预计的更加恶化。这是北极冰洋发生的真实现况，我们藉由卫星图确实看到比预计的更严重。他补充说明那些模式是经由地面观察与测量得到证实。

Arctic melting

Climate scientists at NASA's Goddard Space Flight Center in Greenbelt, Maryland, outside Washington, say the Arctic Ocean could be mostly ice free in late summer 2013. 

"The sea ice is decreasing faster than all the models predicted," says Jay Zwally, the ice satellite project scientist at NASA Goddard, "We not only have the warming of the atmosphere, we have a warming of the ocean that is affecting this.  It has been surprising to everybody, this decrease in area. This is a marked departure, and this is suggesting to us that maybe we are getting at this tipping point."

Jay Zwally

"If you push something like a glass to a certain point, and leave go, it will come back; but if you push it too far, past a tipping point, then it is gone," he explains.  "Now what is happening in the Arctic Ocean is the sea ice is getting thinner; it is decreasing in area.  This opens up the ocean to more heating from the sun, so it is very likely that the Arctic Sea ice is now at this tipping point, where even if the climate doesn't warm any more, stays as it is, most of the sea ice will decrease and disappear at the end of the summer."

"Up through 2006, in September we've been losing ice at the rate of a little more than nine percent per decade,” says Mark Serreze, a senior researcher at the U.S. National Snow and Ice Data Center in Colorado. “That's equivalent to about 100,000 square kilometers per year, which is quite a bit. What's happened in 2007 has just sent an exclamation point to this."

NASA satellite image shows Arctic over the last 30 years

This satellite image from NASA shows the average sea ice in the Arctic over the last 30 years. The green area indicates the melt at the end of last summer.

Zwally says there is clear indication that the remaining is thinning. "The key thing is that this area that is remaining is now thinner," he said. "There used to be a lot of ice here that was three- four, five, six meters thick, and most of that is gone."

All climate models have variability and the possibility that melting trends may lead to results less severe than predicted.

"The other possibility is that it could be worse than the models predict and this is an example, a specific example of the sea ice in the Arctic where what is happening, what we see with the satellite is actually worse than the models predicted," he adds, and he says those models are supported by ground based observations and measurements.




source:www.voanews.com