The ecological, economic and cultural consequences of climate change are many and far
reaching. One of the more pressing issues of climate change, particularly in low-lying Florida, is
sea level rise and its potential effects on coastal communities and natural marine ecosystems. The
entire state of Florida lies in the Atlantic Coastal Plain with a maximum elevation of 400 ft above
sea level. Florida has 2,276 miles of tidal shoreline and the Indian River Lagoon stretches 156
miles along the east central Florida coast.
No one can predict with certainty the extent or timeline of sea level rise to coastal
Florida. However, it is now widely accepted that climate change and global warming are occurring and
that coastal communities worldwide will be affected. We should all become more aware of the
potential impacts of sea level rise well before they occur so that prudent decisions can be reached
on how best to deal with and mitigate these impacts at the appropriate time. Let's start with a few
What is climate?
Climate may be thought of as weather patterns (temperature, precipitation, relative
humidity, winds, etc.) persisting and averaged in an area over long periods of time (e. g.,
thousands to millions of years). Climate has affected the evolution of both human history (cultural
and economic) as well as the global occurrence of natural ecosystems and regional biodiversity.
Weather, on the other hand, describes short-term atmospheric conditions for a particular place and
time. Weather conditions, as we all know, may change rapidly and can differ dramatically over short
What is climate change?
Climate change may be defined as significant changes in the measures of climate lasting
for extended periods of time (decades to thousands and millions of years).
What are the main drivers of climate change?
Climate change may come about through natural or anthropogenic (human-induced) causes.
Natural drivers of climate change include variation in such things as solar output, ocean currents,
volcanic activity and the earth's orbit around the sun. Man-induced drivers of climate change mainly
have to do with the increased levels of CO2 and other greenhouse gases in the atmosphere, brought
about by the burning of fossil fuels, and to a lesser extent, by tropical deforestation, as well as
some industrial and agricultural processes.
What is the "greenhouse" effect?
The "greenhouse" effect occurs when greenhouse gases accumulate in the atmosphere (often
referred to as a "blanket") preventing incoming solar radiation form escaping. This "trapped" solar
radiation is re-radiated back to the earth causing abnormal elevation of the earth's surface
temperatures. The average global temperature, for example, has risen by 1.4o F over the past century
and is estimated to rise between 2 to 11.5o F over the next one hundred years.
What are greenhouse gases?
The four main green house gases are water vapor, carbon dioxide (CO2), methane and
ozone. Increased levels of CO2, from human activities, i.e., the burning of fossil fuels and to a
lesser extent, tropical deforestation, are thought to be the major contributor responsible for the
greenhouse effect. Since the industrial revolution, CO2 levels in the atmosphere have increased
approximately 40 % (from 280 ppm (parts per million) to 392 ppm).
What causes sea level to rise?
It is estimated that sea levels are currently rising at a level of 3 mm/year and that
the rate of sea level rise is expected to increase well into the future. The two main factors
causing sea level to rise are: 1) the melting of ice sheets and glaciers in polar regions; and 2) to
a lesser extent, the thermal expansion of the world oceans associated with increased ocean
temperatures. These two factors have led climate scientists to conclude that global climates are
warming and they further attribute both phenomena to anthropogenic causes.
What other negative impacts of climate change are there?
In addition to sea level rise, there are many other (ecological, economic, cultural)
threats that climate change and global warming may potentially pose: adverse affects on water
supplies; changing landscapes and loss of wildlife habitat; threats to natural ecosystems (marine
and terrestrial) and biodiversity; higher risk of drought with direct implications for agriculture;
increased likelihood of fires and flooding, and more powerful seasonal storms, e.g., Hurricane
Sea Level Rise and the Indian River Lagoon:
Surrounded by the Atlantic Ocean and Gulf of Mexico and also inundated by waters from
the Everglades, low-lying Florida is particularly prone to climate change and rising sea levels.
Further, most of Florida sits on porous bedrock allowing for the infiltration of saltwater. Rising
sea levels can also erode beaches, submerge estuaries and low-lying wetlands, enhance seacoast
flooding and increase the salinity of estuaries.
As most of us realize, the Indian River Lagoon is one of the most biologically diverse
estuaries in the continental United Sates. Its abundance of natural fauna and flora is a result of
its geographical positioning overlapping both temperate and sub-tropical biomes with representative
species intermingling in a delicate balance. The IRL is also a mosaic of many different types of
distinguishable, yet interconnected habitats. Impacts from sea level rise could directly affect the
ecology, hydrodynamics, circulation patterns, depth and salinity of this shallow, bar-built, diverse