Climate scientist Sam Potter forecasts Minnesota's future climate

By John King
Guest columnist

Climate scientist Sam Potter addressed the perils of climate change at the Long Prairie library November 2.  Potter outlined the basic science of climate change and then went on to explain some of the disturbing changes Minnesotans may experience as a result.

Potter, a 2005 graduate of Long Prairie High School, did undergraduate work in mathematics at Morris and received his PhD from Princeton University in Atmospheric and Oceanic Science.  After doing climate related research at the University of Washington in Seattle Potter returned to Minnesota in 2016. He has been a frequent speaker at climate change meetings throughout the state. 

Potter shared graphs and data with the audience illustrating how carbon dioxide has accumulated year after year in the atmosphere as a result of the burning of fossil fuels.  The heat-trapping gas is now over 410 parts per million, higher than at any time in the last 800,000 years. Scientists have concluded that the last time carbon dioxide levels were this high was 3 million years ago during the Pliocene when there were no continental glaciers and the arctic was ice free.  Carbon dioxide accumulation is not the only greenhouse gas trapping heat on Earth but it is by far the most troublesome. According to Potter the accumulation of these gases in the atmosphere has caused both surface and oceanic temperatures to rise. The warmer temperatures have caused rising ocean levels, created instability and melting of the continental glaciers of Greenland and Antarctica, reduced arctic sea ice to record low levels and changed weather patterns across the globe. As the carbon dioxide dissolves in ocean waters it creates an acid that is destroying coral reefs around the world and threatening entire ocean ecosystems. 

According to Potter, this is only the beginning.  “We have already seen these changes. And there is more to come, but it doesn’t need to be as bad as the worst case projections.”  Potter says scientists have known about the changing climate and its link with fossil fuels for more than 30 years, but the failure to act on that knowledge has brought us to the current crisis point where we are threatened with an impending climate catastrophe. “Every delay only makes it more urgent and more difficult.”

Global average surface temperature has climbed by more than one degree Celsius since the end of the 19th century, but, according to Potter, that is only part of the picture. Potter showed that temperatures in the northern latitudes have risen far more than the global average.  Minnesota’s average temperature has risen by two degrees Celsius just since the middle of the 20th century and, “If nothing is done, Minnesota is looking at a future of nine to 10 degree temperature increase.”

“Winter is the biggest story of Minnesota’s climate change”, says Potter.  The state has lost two weeks of below freezing days. The coldest day of an average winter is now 5 degrees warmer than 70 years ago.  If nothing is done to alter the worst case projections for Minnesota’s climate, Minnesota’s forests will change dramatically with conifers all but disappearing from the state.  Farming will become increasingly difficult with the weather alternating between torrential flooding and droughts. In worst case projections few if any lakes in the state will be frozen all winter long.

According to Potter, the worst case projections can be avoided by taking action now.  “Some of this is going to happen. We have to make realistic adaptations,”says Potter.  But according to Potter, with community action, proactive national policies and international cooperation, we can create a future different from the nightmare projections.

Editors note: Chuck Prentice of MN350 has been helping Sam Potter organize speaking engagements. You can reach Chuck at chuckprentice@yahoo.com