The majority of seaports around the world are unprepared for the potentially damaging impacts of climate change in the coming century, according to a new Stanford University study.

In a survey posed to port authorities around the world, the Stanford team found that most officials are unsure how best to protect their facilities from rising sea levels and more frequent Katrina-magnitude storms, which scientists say could be a consequence of global warming. Results from the survey are published in the journal Climatic Change.

"Part of the problem is that science says that by 2100, we'll experience anywhere from 1.5 to 6 feet of sea level rise," said the study's lead author, Austin Becker, a graduate student at Stanford. "That's a huge range."

Port authorities, like many government agencies and private companies, have to make tough financial decisions when it comes to funding infrastructure, he said. They need accurate information from scientists about what to expect, so that they can plan accordingly. Building a structure to withstand a 6-foot sea level rise would cost much more than trying to accommodate a 1.5-foot rise, said Becker, a doctoral candidate in the Emmett Interdisciplinary Program in Environment and Resources at Stanford.

In 2009, Becker distributed 160 surveys to members of the International Association of Ports and Harbors and the American Association of Port Authorities – the first worldwide survey of port authorities to address climate change adaptation. A total of 93 agencies representing major seaports on every continent, except Antarctica, responded. The majority of respondents ranked sea level rise and increased storm events associated with climate change high on their list of concerns. However, only 6 percent said that they intend to build hurricane barriers within the next 10 years, and fewer than 18 percent had plans to build dikes or other storm protection structures.

"As we saw with Katrina in 2005, storm and flood damage can devastate a regional economy for years after an event and have national impacts," said Becker. Katrina, a Category 5 hurricane, caused an estimated $1.7 billion of damage to Louisiana ports. This month, the region is bracing for flood damage once again, as the National Weather Service is predicting that the Mississippi River could crest in New Orleans on May 23.

And with scientists forecasting a doubling of Category 4 and 5 hurricanes in the Atlantic Ocean by 2100, it seems all the more imperative to start thinking about adapting port infrastructures now, he said.