If we want to see the future of our planet, we could also look to the past. The state of affairs during the last interglacial 125,000 years ago, to be more precise. So say the authors of a new study published in the journal Nature Communications.
Between the last interglacial, which lasted between 125,000 and 118,000 years ago, global temperatures were up to 1 ℃ higher than they are today. That may seem like a minor difference, but global warming caused massive melting of ice. First, the ice melted in Antarctica, then a few thousand years later it also melted in Greenland. As a result, the global sea level rose about 10 meters above the current level, flooding vast stretches of coastal areas for millennia.
"Sea levels rose by up to 3 meters per century, far exceeding the rise of approximately 0.3 meters observed in the past 150 years," the three study authors write in an article published in The Conversation. “The early loss of ice in Antarctica occurred when the Southern Ocean warmed at the beginning of the interglacial. This meltwater changed the way the Earth's oceans circulated, causing warming in the north polar region and melting the ice in Greenland. "
That's bad news, as the planet's surface temperature is expected to increase by 1 ℃ on average in the coming decades as a result of man-made climate change.
"What is surprising about the latest interglacial record is how high and fast sea level rose above current levels," the authors note. "Temperatures during the last interglacial were similar to those projected for the near future, which means that the melting of the polar ice sheets will likely affect future sea levels much more dramatically than anticipated to date."
Experts caution against drawing exact parallels between the last interglacial and today's because, they explain, the incoming solar radiation was higher than it is today due to differences in the Earth's position relative to the sun. Meanwhile, levels of carbon dioxide in the atmosphere were just 280 parts per million, compared to more than 410 parts per million today.
"Crucially, the warming between the two poles in the last interglacial did not occur simultaneously," he notes. But under current climate change caused by greenhouse gases, warming and ice loss are happening in both regions at the same time.
This means that if climate change continues unabated, the dramatic rise in sea level in the Earth's past could be a small taste of what is to come. "