最后冰河時(shí)期地球有多冷?答案可能會(huì)讓你大吃一驚

最后冰河時(shí)期地球有多冷?答案可能會(huì)讓你大吃一驚

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.

氣候科學(xué)家最近修正了他們對(duì)最后冰河時(shí)期全球氣溫下降的預(yù)測(cè)，發(fā)現(xiàn)地球很可能比之前猜測(cè)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，也被稱為冰河時(shí)代，發(fā)生在大約2萬(wàn)年前，當(dāng)時(shí)冰蓋體積最大，覆蓋了北美、北歐和亞洲的大部分地區(qū)。之后，地球開(kāi)始慢慢變暖，融化了兩極以外的大部分冰川地區(qū)，導(dǎo)致海平面上升。

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

科學(xué)家們一直有一個(gè)揮之不去的問(wèn)題:最后冰河時(shí)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.

一組研究人員在周三發(fā)表在《自然》雜志上的一項(xiàng)新研究中試圖回答這個(gè)問(wèn)題。在亞利桑那大學(xué)地球科學(xué)系副教授杰西卡·蒂爾尼博士的帶領(lǐng)下，研究小組試圖重建最后一次冰河期的全球平均溫度，以更好地理解溫室氣體水平與當(dāng)今氣溫上升之間的關(guān)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.

根據(jù)這項(xiàng)研究，在此期間，全球平均氣溫上升了11度，在20世紀(jì)達(dá)到了57度—遠(yuǎn)高于最后一次冰河時(shí)期46度的全球平均氣溫。

“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.

蒂爾尼在一份聲明中說(shuō):“以你個(gè)人的經(jīng)歷來(lái)看，這聽(tīng)起來(lái)可能不是什么大區(qū)別，但事實(shí)上，這是一個(gè)巨大的變化。”

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.

蒂爾尼的團(tuán)隊(duì)繪制了全球的溫度變化圖，以便更好地了解哪些地區(qū)在后工業(yè)化時(shí)代受到氣候變化的影響最大。她說(shuō)，在高緯度地區(qū)降溫幅度最大，比如北極，那里的氣溫比現(xiàn)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.”

蒂爾尼在接受電子郵件采訪時(shí)說(shuō):“我們利用地質(zhì)信息和氣候模型模擬，對(duì)最后一個(gè)冰河時(shí)代(被稱為最后冰河時(shí)期的最大值)的寒冷程度做出了新的估計(jì)。”“我們對(duì)全球變冷的估計(jì)比之前的工作要低一些。我們的方法還允許我們重新繪制全球最后冰河時(shí)期的溫度圖。”

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

冰河時(shí)代為研究人員提供了一個(gè)基線，以比較以后的溫度變化。

“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.”

蒂爾尼在一份聲明中說(shuō):“氣候模型預(yù)測(cè)，高緯度地區(qū)將比低緯度地區(qū)更快地變暖。”“當(dāng)你看一下未來(lái)的預(yù)測(cè)，北極的氣溫會(huì)變得非常高。這被稱為極性放大。同樣，在最后冰河時(shí)期，我們發(fā)現(xiàn)了相反的模式。高緯度地區(qū)對(duì)氣候變化更敏感，而且未來(lái)仍將如此。”

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.

平衡氣候敏感性是一項(xiàng)重要的測(cè)量指標(biāo)，用來(lái)預(yù)測(cè)二氧化碳排放量增加一倍后地球大氣變暖的程度。蒂爾尼將最后一次冰川最大溫度的敏感性定為6度，略高于之前的估計(jì)，但仍與傳統(tǒng)上給定的3.6至8度的范圍保持一致。