This article was first published by The Conversation. Space.com's Expert voices: Op-Ed and Insights was contributed by the publication.
Milo Barham, Senior Lecturer, Curtin University
Jussi Hovikoski Senior Scientist, Geological Survey of Denmark & Greenland
Michael B.W. Fyhn Geological Survey of Denmark & Greenland
Frozen northeast Greenland is an unlikely location to gain insight into the world's ever-warming. However, this region was different 50-60 million years ago.
Greenland's subtropical climate was a fitting name back then. It was the site of volcanic activity, which restructured land and ocean connections, and caused rapid warming.
An analogy for the current climate crisis is often made of the 56 million year-old abrupt global warming event, also known as Paleocene–Eocene Thermal Maximum (PETM).
Our research published in Communications Earth and Environment Monday, August 23rd, contains crucial details about the event, with a particular focus on Greenland’s involvement.
Related: Earth scorching hot 2021: Record temperatures, fire clouds, drought
Learn from Earth's past
A volcanic explosion that produced large quantities of molten rock in an area around Iceland, 56 million years ago, was the result of increased volcanic activity. Underground, magma "cooked" the sediments rich with organic material and converted the carbon stored into gas.
The result was the release of trillions of tonnes worth of greenhouse gases into the atmosphere. This caused an increase in ocean acidity, and a rise of global temperatures up to 5-8 degrees Celsius.
These environmental and ecological effects had enormous consequences. In just a few thousand year, mass extinctions and animal movements occurred. Now, fast forward to the publication of the Intergovernmental Panel on Climate Change's latest report. It is clear that there is an ever greater need to understand the Earth's climate systems.
The geological record offers a chance to learn from past climate events, which occurred over a much longer timeframe than any written history or human lives.
It could also warn us about the consequences of Earth's current climate turmoil, which is happening much faster than we realize.
Greenland's exotic landscapes
Northeast Greenland is home to the largest national park in the world, as well as one of the most remote areas on Earth.
Our study aimed to map the environment evolution and the geographic response of volcanic activity during the PETM event in northeast Greenland. The "smoking pistol" that drove PETM warming has been identified to be volcanic activity.
Greenland was also the gatekeeper of the once-narrow channel that linked the Atlantic and Arctic oceans (before the tectonic plates opened it more fully).
Greenland played an important role in the regulation of critical ocean connections that are climate-critical. These channels regulate the distribution of heat, dissolved gases such as carbon dioxide and oxygen, and nutrients in the atmosphere.
Related: Greenland is hit by a massive melting event after a record heat wave
Midnight sunset in the beautiful northeast Greenland wilderness. (Image credit: Milo Barham)
The international team of geologists carefully tracked sediments and lava flows along the shoreline in northeast Greenland and extracted rock cores from the seabed.
We identified and dated several microscopic plankton and plant fossils. This provided us with detailed information about their environment. These findings were combined with those gleaned by tracing sound waves beneath the seabed.
We measured the sound waves reflected by the sediment to map the thickness and evolution of the geological layers. This allowed us to see how the landscape has changed over time, even though it is partially covered by water.
This allowed us to carefully revive a picture of northeast Greenland from between 47 million and 63 millions years ago.
Hotter and wetter planet
We found that the PETM was around the time when volcanic uplift transformed deeper marine environments in northeast Greenland to shallow estuaries, rivers, and vegetated swampy floodplains.
Some fossilized carbonised leaf impressions in finely laminated sediment, taken from the Wollaston peninsula in northeast Greenland. (Image credit: Jussi Hovikoski)
The eruption of lava across the region began around 56 million years ago, creating volcanic rock piles hundreds upon metres high. The hot and humid climate at the time caused successive lava flows to form, eventually causing the surface to become a red soil known as laterite.
Dr Steven Andrews examines the boundary between successive flows of lava in Wollaston Forland, northeast Greenland. The eruption surface of a hot-climate lava flow is visible in the faintly reddish area directly above Dr Steven Andrews' head. (Image credit: Milo Barham)
Our data from northeast Greenland is consistent with Arctic greenhouse reconstructions at the time. Both depict lush, swampy forests inhabited by cold-blooded reptiles and primates, as well as hippo-like beasts. This is a picture unlike any you would see in the cooler world today.
Land bridges and ocean gateways
We also work to reconstruct seabed uplift and the emergence large areas of land from deep under the ocean. This is vital because it would have resulted in a significant obstruction to the channel that separates Greenland from Norway.
These blockages can be dangerous. Based on the geological records, we know that disruptions in critical ocean circulation can cause dangerously acidic or oxygen-starved seas and increased climate disturbance.
Despite this, the flow of water between Atlantic and Arctic was restricted by the PETM. This meant that there was less space for animals and plants to move about. The continental connection allowed species of plants and animals to migrate into cooler climates, thereby escaping the warming effects.
The future is back
Human activity, including agriculture and urbanization has largely destroyed the environment of today. This makes it more difficult for species to adapt to changing environments.
Even though we are still a ways from matching the total volume of greenhouse gas emission released during the PETM (which was over 900 ml), today's emissions rates are almost 10 times faster. Already, our ecosystems are showing signs of instability.
Recent research has shown that ocean circulation is declining, which could lead to climate tipping points. The world's inability to cope with the current climate crisis and ecological crisis is a major problem.
This article was republished by The Conversation under Creative Commons. You can read the original article.
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