Parts of ancient Antarctica were as warm as today’s California coast, and polar regions of the southern Pacific Ocean registered 21st-century Florida heat, according to scientists using a new way to measure past temperatures.
The findings, published the week of April 21 in the Proceedings of the National Academy of Sciences, underscore the potential for increased warmth at Earth’s poles and the associated risk of melting polar ice and rising sea levels, the researchers said.
Led by scientists at Yale, the study focused on Antarctica during the Eocene epoch, 40-50 million years ago, a period with high concentrations of atmospheric CO2 and consequently a greenhouse climate. Today, Antarctica is year-round one of the coldest places on Earth, and the continent’s interior is the coldest place, with annual average land temperatures far below zero degrees Fahrenheit.
But it wasn’t always that way, and the new measurements can help improve climate models used for predicting future climate, according to co-author Hagit Affek of Yale, associate professor of geology & geophysics.
“Quantifying past temperatures helps us understand the sensitivity of the climate system to greenhouse gases, and especially the amplification of global warming in polar regions,” Affek said.
The paper’s lead author, Peter M.J. Douglas, performed the research as a graduate student in Affek’s Yale laboratory. He is now a postdoctoral scholar at the California Institute of Technology. The research team included paleontologists, geochemists, and a climate physicist.
By measuring concentrations of rare isotopes in ancient fossil shells, the scientists found that temperatures in parts of Antarctica reached as high as 17 degrees Celsius (63F) during the Eocene, with an average of 14 degrees Celsius (57F) — similar to the average annual temperature off the coast of California today.
Eocene temperatures in parts of the southern Pacific Ocean measured 22 degrees Centigrade (or about 72F), researchers said — similar to seawater temperatures near Florida today.
Today the average annual South Pacific sea temperature near Antarctica is about 0 degrees Celsius.
These ancient ocean temperatures were not uniformly distributed throughout the Antarctic ocean regions — they were higher on the South Pacific side of Antarctica — and researchers say this finding suggests that ocean currents led to a temperature difference.
“By measuring past temperatures in different parts of Antarctica, this study gives us a clearer perspective of just how warm Antarctica was when the Earth’s atmosphere contained much more CO2 than it does today,” said Douglas. “We now know that it was warm across the continent, but also that some parts were considerably warmer than others. This provides strong evidence that global warming is especially pronounced close to the Earth’s poles. Warming in these regions has significant consequences for climate well beyond the high latitudes due to ocean circulation and melting of polar ice that leads to sea level rise.”
To determine the ancient temperatures, the scientists measured the abundance of two rare isotopes bound to each other in fossil bivalve shells collected by co-author Linda Ivany of Syracuse University at Seymour Island, a small island off the northeast side of the Antarctic Peninsula. The concentration of bonds between carbon-13 and oxygen-18 reflect the temperature in which the shells grew, the researchers said. They combined these results with other geo-thermometers and model simulations.
The new measurement technique is called carbonate clumped isotope thermometry.
“We managed to combine data from a variety of geochemical techniques on past environmental conditions with climate model simulations to learn something new about how the Earth’s climate system works under conditions different from its current state,” Affek said. “This combined result provides a fuller picture than either approach could on its own.”
Climate change is probably one of the most spoken about topics in the late 20th and 21st century. I have read of many different methods researchers use to try and determine why the weather changed over the years. I find it fascinating how life on Earth could change and adapt to the different climates over time. Information gathered by scientists in Antarctica shows that higher carbon dioxide levels in the Earth’s atmosphere at a certain stage caused the climate to change. Over the years there have been several debates on whether factories and cars emit more carbon dioxide than volcanoes. Climate change deniers say that volcanoes emit more carbon dioxide than all the world’s factory and car emissions put together. Climate change sceptics, however, say that human activities can emit about 135 times the amount of carbon dioxide of volcanoes each year (Katie Valentine, http://www.thinkprogress.org). Neither of these two theories have been proven, therefore, it cannot be said that releasing gases into the atmosphere causes the climate to change. Another example that I found, and which is worth mentioning, is desertification. The Sahara, in North Africa, is rapidly spreading southwards. Projects are underway to “re-vegetate” the regions which are starting to dry out, to fight against desertification and to save the people of those countries from famine. These two examples show that climate change is becoming an issue all over the world, whatever the cause may be. In my opinion it does not matter how hard we try to prevent climate change for example by cutting down on carbon emissions, it will still happen, because it has been happening over millions of years. So can we prevent a natural process from happening or should we just let nature take its course and adapt as our ancestors have in the past?
This leaves you to question how is the current generation going to respond to rapid climate changes due to global warming. If the temperature in Antarctica was so incommensurable with its current climate, shouldn’t this worry the current generation as to the methods we are going to use to prevent such an extreme case. The changes in temperature were mainly liked to Co2 concentrations. With the rapid increase in Co2 emissions due to industrialisation , it is quite alarming. One of my main concerns. Advances in modern science have helped with methods to reduce Co2 and the greenhouse effect using aerosol pumping into the upper atmosphere however the discoveries in this article are very shocking as to what we and our future generations should expect.
This is a fascinating topic. It is amazing how they can use fossils to not only formulate a geological time scale, as well as stipulate what animals looked like in the past but now technology is also able to use them to see what the climate was like when those animals lived. Could it be that the shifting of the tectonic plates from Pangea caused this change in temperature? Maybe when ice began to form on Antarctica in the late Cretaceous and Early Tertiary Period did these temperatures begin to drop. This could be due to the position Antarctica now had on the planet with reference to the sun.
it is quite an interesting topic. it is fascinating to know that there is technology and measurement techniques such as the carbonate clumped isotope thermometry available at the hands of humankind that enables them to combine data from a variety of geochemical techniques on past environmental conditions with climate model simulations to learn something new about how the Earth’s climate system works. The study of Antarctica during the Eocene, 40-50 million years ago showing that today, Antarctica is one of the coldest places on Earth. With the help of these instruments scientists are able to determine ancient temperatures and could now also assist in determining the outcome of these increase CO2 levels to global warming.
It’s almost unbelievable what science can do today – to think that it has become possible to determine the temperature of Antarctica 40 – 50 million years ago. Even more amazing is imagining the ancient inhabitants of Antarctica enjoying some leisure time in such a mild climate! But on a serious note, these findings give us greater insight into matters such as climate change. It seems to underscore the theory that the climate of a region,or even the whole earth, is cyclical in nature. Our own Karoo region used to be covered in water, but is now becoming more arid and is even expanding. Could global warming just be part of another cycle and could the same warming parts of the earth face another ice-age in a few million years? What is also impressive is the collaboration between disciplines, which just shows the value of cooperation and information-sharing in science. When everyone contributes a part of the puzzle, everyone benefits from greater understanding.
This is a very interesting topic because I was aware of the fact that areas with high temperatures on earth were once covered in ice but did not expect the coldest parts on the earth to have once been a very different climate being as warm as Florida. I am greatly impressed with the technology used to estimate these temperatures and thanks to this we can now increase our knowledge on how climates change and how climates are affected by greenhouse gasses and global warming. It will be very interesting to see whether or not they can use this information to predict the unforeseen future involving how the climate will keep on changing or keep a similar pattern of progression.
It is not at all surprising that the Antarctic region was once a warm area. The climate is after all an extremely delicate system that, if upset, can result in major changes. This is why Earth’s climate systems are forever changing. If one examines Africa, for example, scientific data shows that the Sahara was not always a desert. There have been a number of periods when Europe and some parts of north Africa were covered in ice. Some of these climate systems, particularly those that involve the cooling of regions in the north appear to be repeating themselves. The fact that this whole process of global warming is not new is helpful since research done could determine what we should expect as a result of global warming. Being knowledgeable about this topic will help save lives and maybe even delay the inevitable.
Who would have thought that Antarctica, the most desolate and coldest place on the surface of the earth used to be as hot as Florida?
What could have possibly changed the high temperatures to those below freezing point?
Would it be viable to assume that just as the deserts formed from high temperatures, and increased evaporation as well as the heating of descending air, Antarctica may have formed from the cooling down of its area by the cold breeze from the Oceans surrounding it? And because of the evolution theory, would it also be viable to assume that polar bears may have evolved from another species of animals? If not then how did they come about?
Could it also be that the meteorite that may have caused the extinction of dinosaurs may have also played a role in the sudden change of the nature of the temperature?
Molebogeng Nkagisang
Student no: u14105528