Climate Shock: Minnesota likely to warm another 5 degrees F by 2050

We know most of Minnesota has already warmed +2F to +4F in the past 30 years, but this one still comes as a bit of a shock.

A new Federal Advisory Committee Draft Climate Assessment Report from the "National Climate Assessment and Development Advisory Committee" or NCADAC released Friday projects that at current greenhouse gas emissions rates... Minnesota and the Midwest will warm an additional 5-degrees F by 2050.

Lake Superior waters are projected to see a 7-degree F increase by 2050.

Image: National Climate Assessment and Development Advisory Committee

The report is long detailed and well cited with credible sources current in climate change research. This thing is a beast, so I've tried to break it down into a more easily digestible read focused on the Midwest and Minnesota.

Here's an excerpt:

The rate of warming in the Midwest has markedly accelerated over the past few decades. Between 1900 and 2010, the average Midwest air temperature increased by more than 1°F. However, between 1950 and 2010, the average temperature increased twice as quickly, and between 1980 and 2010 it increased three times as quickly (Pryor and Barthelmie 2012). Warming has been more rapid at night and during winter. These trends are consistent with the projected effects of increased concentrations of heat-trapping gases, and the spatial variability of trends is also influenced by land-use changes and increased use of irrigation (Pan et al. 2009; Pryor and Barthelmie 2012).

The amount of future warming will depend on changes in the atmospheric concentration of heat-trapping gases. Projections for regionally averaged temperature increases by the middle of the century (2046-2065) relative to 1979-2000 are approximately 3.8°F for a scenario with substantial emissions reductions (B1), and 4.9°F for the current high emissions trend scenario (A2). The projections for the end of the century (2081-40 2100) are approximately 5.6°F for the low emission scenario, and 8.5°F for the high emission scenario (Pryor et al. in press).

Caption: Increasing annual average temperatures (top left) by the mid-century (2041-1 2070) as compared to the 1971-2000 period tell only part of the climate change story. 2 Maps also show projected increases in the number of the hottest days (days over 95°F, 3 top right), longer growing seasons (bottom left), and an increase in cooling degree days 4 (bottom right), which generally leads to an increase in energy use for air conditioning. 5 Projections are from Global Climate Models that assume emissions of heat-trapping 6 gases continue to rise (A2 scenario).

(Figure source: NOAA NCDC / CICS-NC. Data 7 from CMIP3 Daily Multi-model Mean.)

Another 10 days per year above 95F for the metro on average? Time to have my AC unit checked I think.

This kind of future warming will have wide ranging impacts on our Minnesota landscape. Here are the key effects highlighted in the report.

(I've removed the individual citations to make it easier to read, but they can all be found in the report text)

1. In the next few decades, longer growing seasons and rising carbon dioxide levels will increase yields of some crops, though those benefits will be increasingly offset by the occurrence of extreme events such as heat waves, droughts, and floods. In the long term, combined stresses associated with climate change are expected to decrease agricultural productivity, especially without significant advances in genetic and agronomic technology.

2. The composition of the region's forests is expected to change as rising temperatures drive habitats for many tree species northward. The region's role as a net absorber of carbon is at risk from disruptions to forest ecosystems, in part due to climate change.

3. Increased heat wave intensity and frequency, degraded air quality, and reduced water quality will increase public health risks.

4. The Midwest has a highly energy-intensive economy with per capita emissions of greenhouse gases more than 20% higher than the national average. The region also has a large, and increasingly utilized, potential to reduce emissions that cause climate change.

5. Extreme rainfall events and flooding have increased during the last century, and these trends are expected to continue, causing erosion, declining water quality, and negative impacts on transportation, agriculture, human health, and infrastructure.

6. Climate change will exacerbate a range of risks to the Great Lakes region, including changes in the range and distribution of important commercial and recreational fish species, increased invasive species, declining beach health, and harmful blooms of algae. Declines in ice cover will continue to lengthen the commercial navigation season.

Source: National Climate Assessment and Development Advisory Committee

Image: Paul Huttner - MPR News

Lake Superior: San Diego of the North? +7F by 2050?

The reduction of ice cover and warmer annual temperatures will raise Lake Superior water temps by +7F by 2050 according to the report.

That will have a remarkable impact on lake conditions...and may put Lake Superior into play as a warmer, more effective moisture source to "juice" intense rainfall events as the lake becomes an additional source of moisture and "heat energy" for incoming storms.

Another rather alarming excerpt:

Due to the reduction in ice cover, the temperature of 1 surface waters in Lake Superior during the summer increased 4.5°F, twice the rate of increase in 2 air temperature (Austin and Colman 2007). By 2050 and 2100, these surface temperatures are 3 projected to rise by as much as 7.0°F and 12.1°F, respectively (Mackey 2012; Trumpickas et al. 4 2009). Higher temperatures, increases in precipitation, and lengthened growing seasons favor 5 production of blue-green and toxic algae that can harm fish, water quality, habitat, aesthetics 6 (Ficke et al. 2007; Mackey 2012; Reutter et al. 2011), and potentially heighten the impact of 7 invasive species already present (Bronte et al. 2003; Rahel et al. 2008).

Overall the changes in this report are remarkable...and will take some time to digest.

Bottom line?

This magnitude of warming will likely cause some dramatic... and potentially alarming changes in our Minnesota Landscape.

Our forests will shift north. Pine forests may dissapear, and transition to hardwood forests in significant sections of northern Minnesota.

Prairies will also overtake areas that are now forested...possibly even the parts of Twin Cities metro.

Increases in the frequncy of extreme rainfall events will create more events like the multiple "500 to 1,000 year" flood events seen in Duluth and southern Minnesota in the past 9 years.

The changes we're already observing in Minnesota will continue...and the pace of change is likely to quicken in the next 30 years. Our children will live in a very different Minnesota than our parents did.


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