Senate Democrats

The Cost of Inaction: The Impacts of Climate Change on the Oceans and Drinking Water

“The complex relationship between oceans and climate change, as we currently understand it, cries out for reform in two core areas, governance and science.” –Admiral James D. Watkins, U.S. Navy (Ret.), Chairman, U.S. Commission on Ocean Policy Co-Chair, Joint Ocean Commission Initiative, May 10, 2007.

Despite his promises to the contrary in the 2000 election, President Bush has followed a voluntary only approach to climate change that has failed to produce meaningful reductions in greenhouse gas emissions.  At the same time, the decision by the Bush administration to ignore and censor peer-reviewed facts on climate change has unnecessarily politicized an issue of profound moral and scientific importance.

American leadership is needed to address climate change.  The longer the wait between now and enactment of policies that reduce greenhouse gases, the greater  the chance climate change will be more severe and more expensive to remedy.  This Fact Sheet, the first in a series to be published by the Democratic Policy Committee, will highlight the cost of inaction that climate change could have on oceans and our water supplies.


Climate change is transforming the world’s oceans through increases in the temperature and acidity of ocean water, along with alterations in its circulation, marine life, and ability to act as a natural “carbon sink.”  These oceanic transformations are being caused by the emission of carbon dioxide and other greenhouse gases and they threaten the ecological, nutritional, and economic benefits that the United States and the world obtain from healthy oceans.

Algae blooms and dead zones.  During periods of the year, oxygen levels in increasingly larger zones of coastal waters off of Washington and Oregon have dipped so low that these waters are incapable of supporting life.  The size of these zones has fluctuated over the years, but in 2006 it was the largest ever measured and covered an expanse that was slightly larger than Rhode Island. 

These areas, known as “dead zones,” are expanding because rising temperatures are creating stronger winds and modifying ocean currents, which in turn, are producing a surplus of phytoplankton that then dies and rots on the seafloor.  The continued expansion of these dead zones off the coasts of Washington and Oregon could have devastating impacts on commercial fishing, which produced more than $105 million to Oregon’s economy in 2006.[1]

Ocean currents.  Ocean currents, particularly within the North Atlantic, play a critical role in keeping the world’s climate stable.  The Gulf Stream carries warmer water from the equator into the North Atlantic, where it releases its heat into the atmosphere and helps stabilize and warm the climate in that region.  Once cooled in the North Atlantic, the water sinks and is circulated back through the Atlantic and the world’s other oceans.

Recently, however, the Greenland ice sheet has experienced record melting.  Last year, the ice sheet melted in an amount equivalent to two times of all the ice in the Alps or a layer of water more than one-half mile deep covering Washington, D.C.  According to the Woods Hole Oceanographic Institute, the largest non-profit oceanographic research institution in the world, “computer climate models show that if fresh water is added to sensitive locales in the North Atlantic Ocean, it would increase surface water buoyancy enough to brake the overturning circulation, and less warm water and heat would flow northward.”[2]

Ocean acidification.  The acidity of surface seawater has decreased from 8.21 to 8.10 since the beginning of the Industrial Revolution–the most abrupt change seen in 650,000 years (pH scale of 1 to 14 with 7 being neutral).  The most recent projections from the Intergovernmental Panel on Climate Change indicate that the average global surface ocean pH could decrease by as much as 0.3-0.4 units during the 21st Century.

The increased emissions of carbon dioxide are chiefly responsible for rising seawater acidity levels because carbon dioxide mixes with seawater and naturally produces carbonic acid.  The increased acidity of seawater is upsetting the delicate chemical balance necessary for corals and other sea animals to build the skeletons and shells they need to survive.  By the end of the century, scientists expect that without action to reduce carbon dioxide emissions, 70 percent of cold-water corals and other calcifying organisms will be exposed to corrosive waters which will deplete the carbonate ions necessary for their skeletons.  Those changes may devastate the reproductive grounds of sea bass, snapper, ocean perch and rock shrimp.[3],[4] 

Coral bleaching.  Coral reefs provide coastal communities protection from storm surges and habitats to more than 25 percent of the entire world’s known marine fish species.  Increasing ocean temperatures are threatening the health and ecological vibrancy of coral reefs as rising water temperatures kill off algae which provide food for the reef and leave behind reefs that are devoid of color.  These “bleached corals” result in catastrophic losses in biodiversity, fish populations, and further expose coastal regions to the threats posed by hurricanes and their accompanying storm surge.

The frequency of coral bleaching has been increasing exponentially.  From 1876 to 1979 only three bleaching events were recorded; 60 such episodes were recorded from 1980 to 1993.  Today, 50 percent of the world’s coral reefs are either under the imminent threat of collapse or face eventual destruction.  These losses are especially important in coastal states, like Florida, where reef-based tourism in the Florida keys generates $1.2 billion in annual revenue.[5]

Fishing.  Possible changes to the circulation of the world’s ocean currents threaten the vibrancy of the world’s fishing grounds.  The United Nations Environment Programme found that “climate change may slow down ocean thermohaline circulation crucial to coastal water quality and nutrient cycling and deep-water production in more than 75 percent of the World’s fishing grounds.”  In the United States alone, commercial and recreational fisheries contribute $60 billion to the economy each year and employ more than 500,000 people.[6]

A new study from the Scripps Institution of Oceanography at the University of California, San Diego has found that changing wind patterns play a significant role in the health of fish stocks.  Typically, winds drive an upwelling of nutrients to the ocean surface that support plankton growth and fish populations.  However, as global warming becomes more acute and heats the earth that additional warmth can drive changes in wind patterns that reduce this natural upwelling of nutrients.  In fact, the study by the Scripps Institution suggests that wind changes were behind the collapse of the sardine population in California.[7]

Marine life.  Inaction on climate change threatens the health and habitat of marine mammals.  Since approximately 1998, toxic algae blooms have been increasing, due in part to warming seawater, which speeds up microbial growth and allows aggressive algae and bacteria to move into areas that were once too cold for them.  This toxic algae is subsequently eaten in far greater amounts by species like sardines and anchovies, which, in turn, are eaten by larger marine mammals.

The ingestion of these small fish have contributed to massive die-offs of marine mammals–one of the key barometers of ocean health.  In the last decade, more than 14,000 seals, sea lions, and dolphins have died or become sick along the California shoreline.  In Maine two years ago, 800 harbor seals washed up dead, and in Florida the carcasses of hundreds of manatees have been found in mangrove forests and on beaches.  In addition, more than 650 gray whales have washed ashore along the West Coast over the last ten years.[8] 

Polar bears are also uniquely threatened by climate change.  The most recent report from the Marine Mammal Commission, the U.S. governmental body charged with providing independent oversight of marine mammals, has found that the most serious conservation issue facing polar bear populations are the potential effects of climate change and contaminants.  This is because the climate models from the Arctic Climate Impact Assessments project a “substantial decrease” in sea ice and snow cover, the habitat of polar bears.[9]

Drinking Water Supplies

Rising sea levels, more frequent and intense droughts, and decreased snow pack are endangering drinking water supplies across the United States.  These hydrologic changes, which are being caused by the emission of carbon dioxide and other greenhouse gases, threaten communities across the United States.

Salt water intrusion.  The sea level models used by the Intergovernmental Panel on Climate Change predict that in 100 years sea levels could rise by as much as 23 inches.  According to the models, as sea levels rise and begin flooding coastal communities, salt water would seep into fresh water aquifers and cause the water to become brackish and undrinkable.  The damage that sea water could cause fresh water would be amplified because according to new research from Ohio State University, depending on the texture of sand along a coastline, salt water may extend “50 percent further inland underground than it does above ground.”[10]  This is important because, according to the United States Geological Survey, about half the country receives its drinking water from underground sources.

The potential loss of drinking water resources would be acutely felt in coastal communities, especially in states like Florida and Louisiana, which are more susceptible to sea level increases.  The Center for Integrative Environmental Research at the University of Maryland has calculated that this type of seawater damage would be particularly severe in Mid-Atlantic States (where 95 percent of all water withdrawals are drawn from surface water recharge) and in Alaska (where $4.9 billion would be needed to repair sewer and drinking water systems).[11]

Declining snowpack.  Today, the American West relies on the melting of the mountain snowpack for approximately 75 percent of its water.  Over the last half of the20th century, there has been a 20 percent decline in snowpack in the Sierra Nevada Mountains and a 40 percent drop in the water content of snow in the Cascade Mountains in Oregon.  Even more ominously though, a report published in the February 22, 2008 issue of the journal Science finds that climate change trends support the conclusion that by 2040 most of the snowpack in the Sierra Nevada Mountains and the Rockies will melt each year by April 1.  This would lead to serious shifts in river flows that could prompt flooding along those rivers, periods of acute drought during the summer due to the increased likelihood of evaporation, and the depletion of underground water aquifers.[12]

Lake Powell and Lake Mead.  The Scripps Institution of Oceanography has completed an analysis that predicts that the there is a 50 percent chance that the “live storage,” the reservoir space from which water can be evacuated by gravity, in Lakes Powell and Mead will be gone by 2021.  Together, Lakes Powell and Mead help provide water to approximately 25 million people in seven states and areas in Northern Mexico.[13]  If this study is accurate, the communities which currently rely on these lakes could be forced to construct seawater desalination plants that can cost up to $100 million (for a 25 million gallon per day plant).  In comparison, in July of 2005, residents and businesses in the City of Phoenix alone consumed approximately 430 million gallons of water in one day.


[1] Los Angeles Times, “Dead zones off Oregon and Washington likely tied to global warming, study says,” February 15, 2008.

[2] Woods Hole Oceanographic Institute, “The Once and Future Circulation of the Ocean,” February 15, 2008.

[3] Nature, “Anthropogenic ocean acidification over the 21st century and its impact on calcifying organisms,” September 29, 2005.

[4] Frontiers in Ecology and the Environment, “Will human-induced changes in seawater chemistry alter the distribution of deep-sea scleractinian corals?” April 2006.

[5] World Resources Institute, “The Value of Coastal Ecosystems,” November 2006.

[6] Testimony of James L. Connaughton on the Reauthorization of Magnuson-Stevens, Senate Commerce Committee, November 16, 2005.

[7] Scripps Institution of Oceanography, “Scripps Scientists Peg Wind as the Force Behind Fish Booms  and Busts,” February 5, 2008.

[8]  Los Angeles Times, “Sentinels Under Attack,” July 31, 2006.

[9]  Arctic Climate Impact Assessment, “Future Climate Change: Modeling and Scenarios for the Arctic,”   June 2007.

[10]  Science Daily, “Climate Change Threatens Drinking Water, As Rising Sea Penetrates Coastal   Aquifers,” November 7, 2007.

[11]  Center for Integrative Environmental Research, “The US Economic Impact of Climate Change and                   the Costs of Inaction,” October 2007.

[12]  Science, “Human-Induced Changes in the Hydrology of the Western United States,” February 22, 2008.

[13]  Scripps Institution of Oceanography, ” When will Lake Mead go dry,?” January 23, 2008.