Taking Stock of Maine's 2021 Climate Indicators

Maine hit and surpassed many concerning climate change-related records in 2021, according to the Maine Climate Science Update published December 2021. Produced by the Scientific and Technical Subcommittee (STS) of the Maine Climate Council, the update provides a look at the latest climate science, notable climate news, and indicators linked with climate change over the past year.

We compiled Maine’s 2021 standout record-setting events and indicators below. You can find the complete Maine Climate Science Update, containing broader trends, historical analysis and forecasts here. The data serves as an interim update to the 2020 Scientific Assessment of Climate Change in Maine report - the scientific basis for the Maine Won’t Wait climate action plan.  

Grappling with these extreme events can feel overwhelming. Understanding impacts already happening in our state is integral as we work urgently together to reduce our greenhouse gas emissions and minimize climate warming. Here are 10 notable indicators from the Maine Climate Science Update 2021:

1. Since 1895, Maine’s annual average air temperature has increased by about 3°F, and precipitation has increased by about 6 inches (15%) in Maine. The Gulf of Maine has one of the fastest rates of warming of any ocean ecosystem in the world. In fact, 2015-2020 is the warmest five-year period recorded by instruments in the region. 
2. May to September 2020: driest period since 1895.
3. 2021: 2nd warmest year on record for Maine. The Gulf of Maine had its warmest fall on record, and 2021 may be among its warmest years on record.
   1. Warming in the Gulf of Maine also has impacts on marine species from lobsters to right whales. Puffin chick survival this past year was 65% below the previous 17 years because of climate-related stressors. 
4. Winter 2021: 3rd warmest winter [December + January + February] temperature since 1895 
5. Severe storms: an intense downpour on June 9th brought over 5 inches of rain to Downeast Maine in a matter of hours, causing extensive damage to communities and washing out 10 miles worth of the carriage road system in Acadia National Park. In Late October, another downpour washed out roads in Midcoast Maine and caused power outages and flash flooding. 
6. June 2021: 2nd hottest maximum monthly temperature since 1895 
7. July 2021: smoke from western state wildfires traversed the continent on the prevailing westerlies, reaching into Maine and degrading air quality.
8. August 2021: Warmest minimum temperature since 1895 (associated with humid conditions and unusually warm overnight lows). August 2021 was the most humid of all months statewide since 1950, potentially contributing to heat warnings near 100°F across much of Maine in a late summer heat wave.
9. Summer 2021
   1.  Warmest minimum [June + July + August] coastal temperature since 1895. 
   2.  2nd warmest minimum summer [June + July + August] temperature since 1895. Put another way, the coolest summer temperatures last year were the 2nd warmest they've been on record - meaning it just didn’t cool down as much as it used to. This can impact people's health if they are not able to cool down as well at night during heat waves.
10. Sea levels were generally above average along the Maine coast through the end of the year. Find a complete highest monthly sea level table on page 14 (and the latest data on the Maine Geological Survey’s Sea Level Rise Ticker). Some sea level records set in 2021: 
    1. Tide levels were in the top 10th percentile from January through September 2021 in Wells, Portland, Bar Harbor, and Eastport. 
    2. Record-highest October in Wells, Portland, Bar Harbor, Cutler, Eastport.
    3. Record-highest November in Wells and Bar Harbor