最后冰河时期地球有多冷?答案可能会让你大吃一惊

最后冰河时期地球有多冷?答案可能会让你大吃一惊

Climate scientists recently revised their prediction for the global temperature drop that occurred during the last Ice Age, finding the Earth was likely colder than previously suspected.

气候科学家最近修正了他们对最后冰河时期全球气温下降的预测，发现地球很可能比之前猜测的更冷。

The Last Glacial Maximum, also known as an ice age, occurred around 20,000 years ago when ice sheets were at their greatest volume, stretching across much of North America, Northern Europe and Asia. Following that period, the planet slowly began to warm, melting much of the glacial regions outside the poles, and causing sea levels to rise in turn.

最后一次冰川期，也被称为冰河时代，发生在大约2万年前，当时冰盖体积最大，覆盖了北美、北欧和亚洲的大部分地区。之后，地球开始慢慢变暖，融化了两极以外的大部分冰川地区，导致海平面上升。

A lingering question remains for scientists: exactly how cold was the last ice age?

科学家们一直有一个挥之不去的问题:最后冰河时期到底有多冷?

A team of researchers sought to answer that question in a new study published Wednesday in the journal Nature. Led by Dr. Jessica Tierney, associate professor in the Department of Geosciences at the University of Arizona, the team attempted to reconstruct the average global temperature during the Last Glacial Maximum to better understand the relationship between greenhouse gas levels and rising temperatures today.

一组研究人员在周三发表在《自然》杂志上的一项新研究中试图回答这个问题。在亚利桑那大学地球科学系副教授杰西卡·蒂尔尼博士的带领下，研究小组试图重建最后一次冰河期的全球平均温度，以更好地理解温室气体水平与当今气温上升之间的关系。

According to the study, the average global temperature has risen 11 degrees in the intervening period, to 57 degrees in the 20th century — far above the global average of 46 degrees in the Last Glacial Maximum.

根据这项研究，在此期间，全球平均气温上升了11度，在20世纪达到了57度—远高于最后一次冰河时期46度的全球平均气温。

“In your own personal experience that might not sound like a big difference, but in fact, it’s a huge change,” Tierney said in a statement.

蒂尔尼在一份声明中说:“以你个人的经历来看，这听起来可能不是什么大区别，但事实上，这是一个巨大的变化。”

Tierney’s team mapped out temperature changes across the globe to get a better idea of which areas have been most impacted by climate change in the post-industrial era. She said the greatest cooling occurred in high latitudes, such as the Arctic, where it was 25 degrees cooler than it is today.

蒂尔尼的团队绘制了全球的温度变化图，以便更好地了解哪些地区在后工业化时代受到气候变化的影响最大。她说，在高纬度地区降温幅度最大，比如北极，那里的气温比现在低25度。

“We’ve come up with a new estimate for how cold the last ice age (called the Last Glacial Maximum) was using both geological information and climate model simulations,” Tierney said in an email interview. “Our estimate for global cooling is a bit cooler than previous work. Our method also allows us to recreate maps of what temperatures were like during the LGM across the world.”

蒂尔尼在接受电子邮件采访时说:“我们利用地质信息和气候模型模拟，对最后一个冰河时代(被称为最后冰河时期的最大值)的寒冷程度做出了新的估计。”“我们对全球变冷的估计比之前的工作要低一些。我们的方法还允许我们重新绘制全球最后冰河时期的温度图。”

Ice ages provide researchers a baseline by which to compare later temperature shifts.

冰河时代为研究人员提供了一个基线，以比较以后的温度变化。

“Climate models predict that the high latitudes will get warmer faster than low latitudes,” Tierney said in a statement. “When you look at future projections, it gets really warm over the Arctic. That’s referred to as polar amplification. Similarly, during the LGM, we find the reverse pattern. Higher latitudes are just more sensitive to climate change and will remain so going forward.”

蒂尔尼在一份声明中说:“气候模型预测，高纬度地区将比低纬度地区更快地变暖。”“当你看一下未来的预测，北极的气温会变得非常高。这被称为极性放大。同样，在最后冰河时期，我们发现了相反的模式。高纬度地区对气候变化更敏感，而且未来仍将如此。”

Equilibrium climate sensitivity is an important measure used to predict how much Earth’s atmosphere would warm were carbon dioxide emissions to be doubled. Tierney pegged the sensitivity during the Last Glacial Maximum at 6 degrees, which is slightly higher than previous estimates, but still in line with the traditionally given range of 3.6 to 8 degrees.

平衡气候敏感性是一项重要的测量指标，用来预测二氧化碳排放量增加一倍后地球大气变暖的程度。蒂尔尼将最后一次冰川最大温度的敏感性定为6度，略高于之前的估计，但仍与传统上给定的3.6至8度的范围保持一致。