Global warming, deforestation, degraded water quality. You may be familiar with these buzzwords in relation to our changing climate, the threat to plant and animal species, and the general state of planet Earth. But what do these phenomena have to do with the Panama Canal?

The Panama Canal first opened for business in 1914, reducing the trip from the Atlantic Ocean to the Pacific Ocean around Cape Horn (the southern tip of South America) by 8,000 nautical miles. (A nautical mile is 1.1508 of a familiar statute mile.)

Today about 13,100 ships pass through the Panama Canal annually, and the number is expected to double within 50 years. However, Panama Canal Authority (PCA) officials warn that within a decade the canal's operation may be in danger. The major causes of this bleak scenario are global warming, deforestation, increased shipping traffic, and bigger seagoing vessels.

The 50-mile canal is cut through the isthmus that joins North and South America. The terrain was too mountainous to dig a sea-level canal from one coast to the other, so the American engineers built a lake-and-lock canal. When a ship enters the Panama Canal from the Atlantic Ocean, a series of 3 locks raises it 85 feet to the man-made Gatun Lake. The ship cruises across this 163.38 square mile reservoir to the system of locks and lakes that lower it on the Pacific side of the canal.

Gatun Lake serves not only as the "thruway" of the Panama Canal, it also provides fresh water for the locks, drinking water to Panama City, and water resources to local industries. Together with its sister reservoir, Madden, the Gatun reservoir collects water as it drains from nearby rainforests. As loggers, local farmers, and developers hack away at Panama's rainforests, much of the rain water is running to the ocean instead of down its usual path to the reservoirs.

If global warming causes the predicted changes in precipitation patterns so that Panama receives less rainfall than usual, water levels in the Gatun reservoir could drop further. During 1997-1998, the weather phenomenon El Niño caused a drought in Panama. Water was rationed in the metropolitan areas and the PCA imposed draft (depth) restrictions on some ships traveling the canal. The drought also closed the hydroelectric power plant at Gatun Lake.

Each passage through the canal requires 52 million gallons of freshwater to float the ship through locks. The fresh water flows from the reservoir through the locks and out to the ocean. As the number of ships continues to rise, so do the water requirements. Deforestation is also affecting the quality of the water that reaches the locks. The not-so-fresh water is causing build-up of sediment and growth of vegetation in the locks and canals. The PCA must dredge the locks to enable safe ship navigation through them.

• An Olympic-sized swimming pool holds approximately 253,125 gallons of water. How many swimming pool's worth of water are used for each passage through the Panama Canal?

To solve the problem of increased ship traffic, the PCA is widening the Gaillard Cut. The Gaillard Cut is an 8-1/2 mile excavation through the Continental Divide, connecting Gatun Lake to the Pedro Miguel Locks on the Pacific side. The cut was originally 300 feet wide, but was widened in the 1930s to provide a catch basin for slide debris in areas prone to rock slides. The cut has been widened several more times over the years.

The current project, scheduled for completion in 2002, will increase the Gaillard Cut's width to 630 feet on the straight parts and 720 feet on the curves. The extra width will enable two-way traffic for very large ships through what is now the narrowest part of the canal. The wider cut, of course, will increase the canal's water consumption.

• By what percent will the Gaillard Cut's width have increased from its original size in 1914 to its new size in 2002?

The PCA is currently analyzing the technical, economic, and environmental feasibility of increasing the Panama Canal's reservoir system. One possibility is the construction of new reservoirs, which would collect and store fresh rain water during Panama's seven-month rainy season. Other water-saving systems being considered are run-off basins to collect canal-water overflow, a parallel canal for small-vessel traffic, and a recycling system. A PCA official claims that these systems could reduce the canal's water requirements by 33% to 50%.

The PCA is also involved in a sustainable development program to conserve the Panama Canal watershed. The watershed includes the area that directs rainfall into Gatun Lake and a newly incorporated area that the PCA hopes will enable future growth. The expanded Panama Canal watershed covers an area approximately 1,364,000 acres, which is about 7% of Panama's entire territory. The watershed area includes 6 protected forests and national parks, which together cover 308,880 acres. Development of the expanded watershed area could increase active water storage by 600%.

• Based on the figures above, calculate Panama's area in acres.
  
  
• There are about 642 acres in one square mile. What is Panama's area in square miles? How does this size compare to the area of the state in which you live? ( Find the size of your state.)

An Alternate Shipping Route
Global warming may produce a competitor for the Panama Canal. The Northwest Passage through Canada's Arctic archipelago between the Atlantic and Pacific Oceans has long enticed shippers. Travel through the Northwest Passage could reduce the distance between Europe and the Far East by 4,700 nautical miles compared to the same trip via the Panama Canal. The polar ice caps have already thinned due to warm weather. Global warming over the coming decades could melt enough of the Arctic cap to let ships pass at least during the summer months. For several more months of the year, icebreakers could accompany ships through the passageway.

Some experts predict that global warming could make the Northwest Passage more dangerous for ships. A channel on the northern side of the passage is currently blocked by an ice plug. If warmer temperatures melt the plug, icebergs could go racing down the channel. Even the smallest icebergs can easily sink a ship.

Ecology experts have already expressed concern about what impact shipping would have on the delicate Arctic ecosystem. Christopher Sands, director of the Canada Project at the Center for Strategic and International Studies in Washington, proposes that the international community grant Canada special custodianship of the Arctic ecosystem, just as Australia has been granted a custodial role for the Great Barrier Reef.

• Read more about the possibilities of this alternate shipping route in the following articles: ENN.com's "Will global warming open Northwest Passage?" and Christian Science Monitor's "Arctic thaw opening up lucrative shipping route."

Learn More

• The Panama rainforest is not the only endangered rainforest. Read about the conservation efforts in Brazil in the Riverdeep article, "Saving a Part of Brazil."
  
  
• El Niño and his little sister La Niña cause strange weather worldwide. Read the Riverdeep article, "La Niña Brings Changes in the Weather."
  
  
• Learn more about the melting Arctic ice in the Riverdeep article, "A World on Thin Ice?"

More Links

• The Panama Canal Authority site provides general information about the history and operation of the Panama Canal. It also offers a Web cam and photo gallery.
  
  
• Discovery's The Unkindest Cut is a companion site to the Discovery Channel broadcast. It covers the history of the construction of the Panama Canal.