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Impacts on public health

Changes in Maine's climate also impact public health in the state. There is an increased risk of vector-borne diseases, contaminated drinking water, allergies and asthma, as well as impacts on the mental health and wellbeing of people in Maine. 

How does climate change increase the risk of tick-borne disease?

As Maine warms and winters become milder, it becomes more hospitable for migrating pests from the south. Deer ticks carry Lyme disease, and as tick populations increase and the season for encountering ticks expands, so does Lyme disease incidence in Maine.

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“The first documented case of Maine-acquired Lyme disease was diagnosed in 1986. In the 1990s, the great majority of Lyme disease cases occurred among residents of south coastal Maine, principally in York County. Currently the Midcoast area has the highest incidence of Lyme disease in the state. Based on 2020 data, six counties have rates of Lyme disease higher than the State rate (Hancock, Kennebec, Knox, Lincoln, Waldo, and Washington)” (Spring 2021).

LYME DISEASE IN MAINE  Contains interactive graph of incidences of lyme disease across years (2008-2018) and across all 16 counties.

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How does climate change increase the risk of mosquito-borne disease?

West Nile Virus (WNV) is a mosquito borne viral disease. It is transmitted to a person through the bite of an infected mosquito. As temperatures rise in Maine mosquito season extends past the summer months meaning longer breeding seasons and increased hatch rates. This leads to an increase in the chances of transmission.

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How is drinking water being impacted in Maine?

Roughly 50% of Maine people get their drinking water from public water utilities drawing water from surface water sources (primarily rivers and lakes) and/or groundwater aquifers. Communities that draw water from surface water sources will face new challenges as lakes warm and become increasingly prone to  harmful (toxic) algal blooms, cultural eutrophication and invasive aquatic plant infestations. Each threat poses its own set of challenges, but to understand the role that a warming climate plays in exacerbating these threats as well as the potential interplay between them, it may help to consider a simplified example:

Soil erosion caused by extreme rain events may result in nutrient rich sediments being washed into the lake.  As sediments build up near shore, new habitat is created for aquatic plant colonization, including invasive aquatic plants. The nutrient-laden runoff helps to spur increased plant growth (both for algae and higher plant forms) in the waterbody. Warmer water temperatures favor blue-green algae or cyanobacteria, and when present in high enough concentrations, cyanobacteria may be toxic to animals, including humans.

As the increased abundance of plants, algae and associated life forms (such as bacteria) die and decompose, the decayed material that results will break down. When it becomes largely dissolved in the water, it is referred to as Dissolved Organic Matter (DOM).  When DOM in the water supply is treated with chlorine, as it is in some Maine communities, harmful disinfection by-products may form. Drinking water suppliers must strictly limit the concentrations of these harmful by-products in the water supply.  Maintaining these limits in a warming Maine, may be increasingly challenging.

In addition to the above surface water supply concerns, coastal communities will also have to address ground water supply challenges posed by rising sea levels, such as salt intrusion into the groundwater.


Warming temperatures will increase pollen and asthma

Warming temperatures from climate change, along with increases in precipitation can contribute to longer pollen seasons and more potent pollen. Because as temperatures increase plants produce more pollen. This may prolong allergy season, hay fever and asthma as well as increase their frequency and severity.

"The ambient air monitoring network in the State of Maine meets required monitoring objectives as established by the EPA and the Clean Air Act."

ASTHMA AND CLIMATE CHANGE, WHAT YOU NEED TO KNOW by Editorial Staff, May 28, 2019. "Everyone's health is at risk from the impacts of climate change. Changing climate patterns are degrading air quality and increasing the frequency and intensity of certain types of extreme weather such as droughts, floods and wildfires. However, people living with lung disease face greater risks."

How is the climate crisis related to self care, mental health and well being?

As more and more people become aware of the reality of climate change and the urgency of the situation, an increasing number of people from around the world are experiencing anxiety, depression and grief related to the climate crisis (termed: climate grief, climate anxiety, or eco-anxiety). In September 2021, the biggest study yet on the mental health impacts of climate change surveyed 10,000 people, ages 16 to 25, from 10 different countries on their thoughts and feelings about climate change. An overwhelming number of respondents reported worry and over half reported feeling anger, sadness, or guilt connected to the climate crisis. Over 45% shared that these feelings have a significant negative impact on their daily lives. And while people of all ages report many of these feelings in connection with climate change, the experiences seem especially prevalent in young people.

Psychologists studying the mental health impacts of climate change are thankfully quick to validate feelings of anxiety, depression, anger, and grief. It is normal, even healthy, for us to feel anxious when we are under threat, just as it is normal to feel depression or grief when we experience loss. Climate change brings with it both threat and loss. It is also normal to feel angry when we find ourselves in an especially intense situation that we did not choose and within which we feel relatively powerless.


Many people of all ages, and, again particularly young people, are turning to action as a way to cope with their feelings. While collective action is a highly useful tool, relying on action alone and not giving ourselves time and space to process what we are feeling can lead to burnout, especially if we do not feel significantly and quickly successful in our endeavors. Because climate change is going to be part of the lived experience for the foreseeable future and because climate action can often necessitate an intense mixture of passion and patience, we face the challenge of building our capacity to hold intense emotions and process them on a continuing basis.

As more and more people experience climate-related anxiety, depression, anger, and grief, an increasing number of options for mental health support are rising to meet this growing need. From therapists who specialize in climate-related work, to groups dedicated to coming together to share climate-related feelings and support each other, to instagram accounts dedicated to providing mirroring and support for climate-related feelings, there are many places to turn. The important step is turning outward to talk with others about our experiences. Many of us are experiencing these feelings, and simply discovering that we are not alone is a powerful first step.


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The Maine Climate Science Portal was envisioned and developed by Maine Climate Action Now. Content development, to date, has been a largely-volunteer effort. Click here to see a full list of contributors.

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