The Potential Impacts of Global Climate Change on Duluth, MN (Final Blog)

The Potential Impacts of Global Climate Change on Duluth, MN

Final Blog

While Duluth's mid-continental location spares he city from areas of potentially significant impacts of climate change such as small islands and coastal regions, Duluth is not immune to climate change. Not surprisingly, global climate change will affect all areas of the planet not matter their proximity to oceans, the equator, or anywhere else. The question is, how much of the looming giant that is global climate change will fall upon Duluth? 

 

 

 

• Intergovernmental Panel on Climate Change (IPCC) projections

  

Global warming in Duluth could be damaging.  A decrease in lake level orgreater lake level flucuations
 during summer months could prevent harbor use.  Conversely, this could decrease the length of harbor
 freeze-over and create a longer shipping seasing, thereby increasing commerce potential.

  

The IPCC is confident that climate change will certainly occur in Duluth.  Their data and analysis indicates a possible temperature change of 1-3 degrees C  (1.8-5.4 degrees F) from 2010-2039 in North America, which is to say even in the low end of the scenario, Duluth will get warmer.  So much for "the air-conditioned city.  But without getting ahead of ourselves, it must be noted that predictions call for warmer winters in higher latitudes and warmer summers is lower latitudes; of course, a mildening of Duluth's bitter winters is something that no resident wouldn't welcome with open arms.  However, looking further into the future the outlook is much more dire.  Temperature increases in Duluth's region for the years 2090-2099 is predicted to swell to 4-4.5 degrees C (7.2-8.1 degrees F).  An increase this significant will no doubt bring summer temps typical of a continental climate as soon as the end of the century. 

Precipitation is another factor which is predicted to change by IPCC research.  Much like the temperature change predictions, there is no place in the IPCC to look up exact precipitation details for Duluth, however, precipitation change can be inferred from other statements.  First, the IPCC predicts an increase in precipitation in all of North America but the southwest United States.  Furthermore, Canada is expected to see annual mean precipitation increases of 20%, and a 30% jump in the winter mean.  The IPCC also states the is is 'very likely' that precipitation will increase in higher latitudes.  Applying these statements leads to the conclusion that precipitation is predicted to increase because of Duluth's moderately high latitude and because of its proximity to Canada, Duluth could experience a rise in annual mean precipitation of as much as 20%.  Following along with the Canada statement, Duluth could expect as much as 30% more snow annually, a prediction that seriously affect the city which already receives more than its share of snowfall.

According to the IPCC's conclusions, Duluth's climate is predicted to become warmer and wetter.
While the short-sighted might agree that this shift in climate make their lawns greener and nothing more miss the damage that climate change could bring to the Lake Superior region.  in addition to the IPCC's predictions, the University of Minnesota SeaGrant Program predicts:  dryer summers with a reduction in soil moisture content, warmer nights, increased frequency and intensity of weather events, increased variability of climate with more instances of extremes, a lowered lake level due to increased evaporation, longer growing seasons, and impacts to species in all ecosystems.  Needless to say, 'warmer and wetter' is not the whole story.

• Extreme event projections

This diagram shows the relationships of extreme temperature to increased in variance and mean as well as
both combined.  Note that an increase in mean and variance yields will shift a normal temperature distibution
 towards a significant potential for very hot and record temperatures

Extreme events, note unlike temperatures and precipatiaon are expected to increase in Duluth.  IPCC scientists are certain that the entire globe can expect more frequent and intense daily warm temperature extremes alongside a decrease in   Duluth can also expect an increase in heat waves or other extended warm periods, something not often experienced in the lakeside city.  While the frequency of mid-latitude cyclone is predicted to increase, there is an expected 'poleward shift' of these cyclones which could bring increased storm activity to Duluth.  Also, despite the potentially wetter weather, Duluth falls within central North America, a region where the IPCC believes the frequency of droughts will increase.  On top of all this, changes in precipitation increase flood risk, putting a significant portion of the city at risk by a potential flooding of the St. Louis River. 

Wind speeds over Lake Superior have increased 5% per decade since 1985.  This could lead to more
 frequent and larger storm surge-like waves which could damage harbor structures.  Scientists also believe these
increased winds increas currents which disrupt the lake's food web.

  

According to UMN's SeaGrant, consensus among some climatologists indicated that the increase on extreme events in the Lake Superior region will create dramatically different climate than that which exist today.  They predict a normal day will feature widely variable high and low temperatures that push into the extremes, and the area will be increasingly plagued by opposing periods of drought and excess precipitation. 

  

• Local impacts of climate change

The most basic impact to consider for Duluth is the effect of increasing temperatures on energy resources. Incresing temperatures would likely affect the use of energy hogs such as air-conditioners. This increased demand is sure to coincide with increased energy demand throughout the world as temperatures rise.

This flow diagram traces the consequences of a reduction of Great Lakes water levels.  Of these, Duluth
would certainly suffer from decreased transportation and tourism.  While there are no fisheries in Duluth, the
impact to species and habitat would surely decrease the natural beauty of the area.

A more direct and major potential consequence is the reduction of water levels in Great Lakes/ Lake Superior, which could seriously harm Duluth and northern Minnesota's economy.  Sea-faring vessels come from all over the world to load up on taconite pellets (refined iron ore) mined from Minnesota's Mesabi Iron Range.  If these ships cannot reach the port's loading infrastructure the important taconite industry would be instantly crippled.  Duluth's economy is also centered upon tourism which is restricted mainly to harbor activities and outdoor activities.  A closing of the harbor and/or reduction in wildlife would also hurt the important local service-based economic sector.

Global climate change threatens the environment in a major way besides a potential reduction of the Great Lakes' volume.  A rise in surface temperatures on  Lake Superior has been observed since 1980, and with the prospect of increase future warming this trend is likely to increase, possibly at a higher rate of change.  Over the last three decades, the surface temperature of the lake has increased 2 degrees F ever year, a rate of increase twice that which was recorded on nearby land.  This two-pronged effect of decreased water levels and increased surface temperatures could severely disrupt and decrease the rich biodiversity of the area.  Because of this, the non-humans of the Duluth area are the most likely to take the brunt of potentially anthropogenic climate change.  Interstingly, for reasons attributed to global climate change, many birds appear to have extended their northern migration into Duluth, reaching a record of 74 birds species present during a 2000 count.  This largely anecdotal evidence serves to illustrate how the many varied inputs of climate change can create many different outcomes.  It also conveys the way which global ecosystem stresses will cause many various patterns of migration, shrinking and expansion of habitats, as well as increased isolation of species.

During the summer, Northern Minnesota is home to a large population of Bald Eagles.  A minor change to
 the trophic system by alterations in lake volume and temperature could potentially damage the eagle's food sources.
 A decline in Bald Eagle nesting near Duluth would also hurt tourism.

• Duluth's climate change mitigation measures

In response to emerging research regarding the reality of global climate change, Duluth became a part of of the "Cities for Climate Protection Campaign" sponsored by the International Council for Local Environmental Issues (ICLEI) in 2001.  By passing a resolution to join this project, the city will work towards the goal of a 20% reduction of carbon emissions and other pollutants by 2020.  Whether or not the city will attain this goal remains to be seen.  Towards this end however, the city completes greenhouse gas emission assessments to target areas of concern, establishes a structured set of emission reduction targets, and creates a sound strategy to meet these targets.  In practice, moves to meet these targets involve many small steps such as a switch to LED streetlights.

Sources:

"Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, 2007", http://www.ipcc.ch/publications_and_data/ar4/wg2/en/contents.html

Fourth Assessment Report of the Intergovernmental Panel on Climate Change - Sythesis Report- Summary for Policymakers, 2007, http://www.ipcc.ch/pdf/assessmentreport/ar4/syr/ar4_syr_spm.pdf

"Global Warming, What is Duluth Doing About It?",  http://www.doitgreen.org/article/gw/duluth.

"Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation - Summary for Policymakers", http://ipcc-wg2.gov/SREX/images/uploads/SREXSPM
brochure_FINAL.pdf

'Minnesota Climate Change Action Plan", http://www.pca.state.mn.us/index.php/component/
option,com_docman/task,doc_view/gid,9237.