A changing global climate is expected to continue to increase the average temperature of the atmosphere and oceans. According to most climate and environmental scientists (ipcc.ch), the major driver of climate change is the emission of carbon dioxide (CO2) as part of human activity, especially transportation and industry. The good news is that renewable energy sources like solar, wind and geothermal have become economically competitive. However, the use of energy keeps increasing so rapidly that the use of fossil fuels continues to increase exponentially (see graph below). This will be multiplied by a boom in energy-intensive AI and crypto currency. The increasing drilling and burning of fossil fuels emits more CO2 and triggers processes in nature (e.g., melting glaciers and thawing tundra) that will continuously amplify global warming.
The international Paris Agreement of 2015 (paris-agreement) committed to hold the increase in the global average temperature to well below 2.0°C (=3.6°F) above pre-industrial levels and pursue efforts to limit the temperature increase to 1.5°C. Unfortunately, by 2024 the average temperature has already increased by more than 1.5°C according to the World Meteorological Organization (wmo.int) - much sooner than predicted in 2015 - and the average temperature has already increased over pre-industrial levels by more than 2.0°C in Chatham (climate.copernicus.eu). The current trend is still accelerating. This will make increasingly large areas of the Earth and seas uninhabitable due to more frequent and severe droughts, heatwaves, rainfall, wildfires, storms and sea-level rise.
Graph of increasing CO2 in atmosphere (from the Scripps Institution of Oceanography, scrippsco2.ucsd.edu):
While Chatham has not yet experienced extreme weather events due to global climate change, the local temperature and the local sea level have both risen more than the global average due to Chatham's location near the Gulf Stream. According to data at the EPA (epa.gov/climate impacts cape cod), the temperature of the Atlantic Ocean around Cape Cod is warming at a rate three times faster than the global average. The Northeast United States also exceeds the global average of sea-level rise (climateactiontool.org). Chatham's exposure to the sea and separation from the mainland will expose Chatham to severe dangers in the near future.
Global warming is causing the sea level to rise due to expansion of warming waters and melting glaciers. The rate of sea-level rise is increasing exponentially. Chatham juts into the sea, so its beaches will be washed away, its coasts eroded and its floodplain continually expanded. Note (graphs below) that the sea level has been rising around the Cape and the trend is for it to rise faster and faster in the coming decades.
Actual and projected sea-level rise based on National Oceanography Centre data from Woods Hole (/psmsl.org) and NOAA data from Boston (noaa.gov):
Climate change is already producing and accentuating severe storm conditions around the world - as well as flooding, draught and wildfires. Extreme storms that historically came to Chatham once a century are now coming more and more frequently. A major storm during high tide would be particularly destructive in Chatham.
For Chatham's Wetlands Bylaws regulating development in the floodplain, see the section on Sustainable Regulation.
These Bylaws are tied to the floodplain defined by FEMA a decade ago, based on the historic record of hundred-year storms, without taking into account climate change.
Climate change will threaten Chatham's water acquifer through droughts and sea-level rise. Warming will change conditions that support Chatham's traditional flora and fauna, killing native plants and encouraging invasives. Fish and lobsters, for instance, have already shifted habitats away from Chatham, as have many birds and shellfish.
Chatham thrives as a seaside resort, summer retreat and retirement location with attractive beaches, marshes and forests. Already, the major beaches have to have their sand replenished annually or the beaches would be completely washed away. Tides are rising in the marshes and residential development continues to invade the woods. Climate disasters around the world have already cost trillions of dollars in damages, and the impacts are just starting to ramp up. Mass migrations, military conflicts and other forms of social unrest will increasingly impact life everywhere.
Preserving the health of Chatham's salt marshes can protect residential areas from storm surge and provide numerous benefits to the Town.
For information about ECAC efforts to preserve the marshes, see the ECAC salt marsh preservation page.
Chatham's current floodplain was defined by FEMA in 2014, based on historical storms prior to that. The floodplain was defined as the area that flooded during a 100-year storm. This official floodplain is the basis for regulations about flood insurance for properties and for Chatham's bylaws about wetlands development.
ECAC will post maps on this website of the areas of Chatham predicted to be flooded by major ("hundred-year") storms in coming decades.
The current Town map including properties in the FEMA floodplain is available at:
Town Map.
Roads that pass through areas of the floodplain are already getting flooded during high tides. Increasingly, they will become impassable during storms. In many cases, this will block access to hundreds of homes.
For instance, in this map projecting a major storm in 2070, the current floodplain of the area around Ridgevale and Hardings Beaches is predicted to be taken over by the sea and the floodplain will expand to encompass many more homes. Flooding of the streets here will cut off access on many other homes. This will present difficulties for emergency vehicles as well as residents.
