Governor Walz has been confronted with decisions about various projects --pipelines, for example --as to ongoing risks of harm to the larger environment from leaks or spills that pollute streams or aquifers. He considered that climate change and global warming caused by GHG gas emissions was similar and issued Executive Order 19-37 directing State departments and agencies to reduce GHG emissions.
We have been asking the Metropolitan Council (MetC) and the Metropolitan Airports Commission (MAC) for decades to include environmental impacts from overflights as a topic in planning for more air traffic at Minneapolis-St. Paul International Airport (MSP). The MAC has unusual authorities under Minnesota law and rules for assessing the environmental impacts of MSP on-site projects, facilities, and operations:
1] the Commission may skip EAWs for smaller projects and, orginally assess cumulative impacts over time each year in the Assessment Of Environmental Effects or AOEE. The AOEE was originally a Hearing Examination to find the pertinent facts, such as the increased fuel used per boarded passenger using two regional jets rather than one B-727 to fly from Chicago Midway to MSP. Hint: 2 landings and two take-offs rather than one.
2] the Commision prepares Environmental Assessment Worksheets (EAWs) for larger projects and decides itself whether an Environmental Impacts Statement (EIS) is needed.
Jet exhaust contains substances that pollute the air, including GHG emissions. GHG and solids from jet aircraft operations are proportional to fuel used, hours of operation and proximity, creating local health risk in addition to their global warming impact. The Environmental Protection Agency and the Federal Aviation Agency officially found that commercial avaition added significant GHG volumes to the atmosphere, proportional to fuel consumption. Both fewer miles flown and less fuel used (less GHG released per hour) are possible improvements.
Note: Fuel efficiency --consumption in "miles per gallon" --for commecial flights is a very misleading parameter.
1. At cruise altitudes less fuel is burned per hour than at low alitudes: slightly less GHG is emitted traveling 500 miles at 36,000 feet altitude than traveling 120 miles per hour around airports!
2. Circling around an airport awaiting your turn to land is a net zero miles per gallon.
3. Flying from Indianapolis to Los Angeles via Dallas is shorter than flying via Minneapolis but longer than it used to when there was a hub in St. Louis. Still people fly from Indianapolis to LA via Minneapolis because it is cheaper --but uses more fuel and makes more GHG.
SMAAC notes that laws and rules have been amended over time. This is an issue times two in the Legislature. Undiscussed in the House, Senate Amendments to budget and omnibus bills modified the airports commissions' environmental responsibilities --and limited oversight by Legislative committees. Over the years, glycols (active mostly-liquid compounds in deicing fluid), aviation fuels and other substances were spilled or directed away from our metropolitan airports. So there are established health and environmental impacts risk at and around airports linked to the kind and frequency of air operations.