According to a recent study produced by Columbia University, and funded by the U.S. National Science Foundation and the Keck Geology Consortium, the Arctic is now hotter than at any time during the last 1,800 years. The Medieval Warm Period, often cherry picked as a benchmark for global warming deniers, was 2 to 2.5 degrees Celsius cooler than the current high Arctic environment.
The study observed differences between the content of saturated and unsaturated fats in dead algae in lake sediments to determine temperatures through past ages. During cold periods, algae produce more unsaturated fats. During warm periods, the amount of saturated fats produced is greater. This provided researchers with a biological thermometer for past Arctic ages. You can view a very instructive video of how the differences in these fats is used as a thermometer here.
Earlier studies have shown that areas bordering the Arctic, such as southern Greenland and parts of Canada, were warmer than today. But the new data, coming from a Svalbard lake, show that the high Arctic was cooler. This broader picture shows that the Medieval Warm Period was more of a regional phenomena while, now, the entire Arctic is undergoing a massive heating not seen in ages.
This study is a major validation of others that have shown a regional warming during medieval times. One such study was the famous ‘Hockey Stick’ graph produced by Michael Mann.
1,800 Year Record Warming Put into Context
Natural cycles, often invoked by climate change deniers as a form of pseudo-intellectual argument, would result in the Arctic and the rest of the world cooling long-term. In fact, there is no natural force now acting on the Arctic that is capable of pushing its temperatures into a range not seen since 1,800 years ago. The Svalbard measurements now combine with a number of other sources, including Mann’s now-famous hockey stick graph, to provide solid evidence that the human forcing (greenhouse gas emissions) is pushing world temperatures unnaturally high.
(note that the Mann Graph now lags human-caused warming by about .1 degree Celsius, so the actual slope is even steeper than the one depicted)
As you can see in the graph, average world temperatures decline until major use of fossil fuels begins in the mid-19th century. At that point, temperatures rocket upward along a very steep slope. A very unnatural departure for the relatively stable Holocene epoch.
Response Times to Forcing Lag
What is most concerning is the fact that we are still in the early phases of Arctic and world warming. Because the areas of ice are so vast, because the ocean is so deep, because it takes lots of energy to move the atmosphere around and to heat it up, a huge amount of inertia exists. This inertia is fighting to keep world temperatures static. It is fighting to keep the glaciers and sea ice from melting. It is fighting to keep the weather systems in place.
But the vastly powerful human forcing of greenhouse gas emissions is moving these systems around like so many enormous toys. The fact that we are already seeing so much melt, that we are already seeing temperatures outside the range of nearly 2000 years is cause for serious, deep concern.
Geologists don’t have any kind of clear record for these kinds of changes ever moving along so fast. But they don’t have any kind of record for greenhouse gasses accumulating in the atmosphere at so fast a pace either. The most recent observable corollary occurred about 50 million years ago and happened at a speed 1/10th as fast as the human greenhouse gas accumulation. The related warming caused a mass extinction in the ocean and resulted in severe stresses to land animals whose end result was greatly reduced size and weight as animals concentrated in mountains and near less productive polar regions.
Inertia has already created a major overhang of climate impacts. At around 400 ppm CO2, the amount currently in the Earth’s atmosphere, Greenland and West Antarctica melt, contributing about 75 feet to sea level rise. The problem here is that the current forcing is likely enough to push another 100-200 ppm of CO2 out of the Earth’s oceans, forests, tundras and glaciers, lifting world CO2 into the range that could result in all the ice melting and another mass extinction in the oceans. That risk is current even if we stop producing CO2 today and will likely result in the need for CO2 capture from the atmosphere or possible, and very risky, applications of geo-engineering technologies. Continuing to burn fossil fuels at volumes great enough to increase CO2 concentrations by 2-3 ppm or more per year is nothing short of an exercise in madness and will likely result in a world with near 1000 ppm CO2 by the end of this century. And though a world at 600 ppm CO2 is tremendously difficult to live in, a world at 1000 ppm CO2 is a hellish nightmare.
Putting these things into context, even if we cease all fossil fuel emissions today, we are potentially on a path to conditions not seen in the last 10-30 million years. And, if we continue emitting fossil fuels in a business as usual manner, we are heading toward conditions not seen in the last 50 million years at least and perhaps never seen before.
As such, the current 1800 year warming happening in the Arctic is just another milestone along our current road. And that way, should we choose to continue, is little more than a short, hot road to hell.