The NOAA Ship Ronald H. Brown is a state-of-the-art oceanographic and atmospheric research vessel and the largest ship in the NOAA fleet.

(NOAA)

At a Glance

The study says the U.S. must expand its fleet of research vessels to accurately measure and assess the effects of climate change.The committee recommends that the U.S. create a long-term plan to sustain a vital fleet."NOAA is really hard-pressed to operate with just one ship," a sponsor of the study says.

A fleet of research vessels used by the United States to assess and measure climate change is shrinking,a new study says.

According to the study released last week by the National Academies of Sciences, titled ","the U.S. must expand its fleet of research vessels to accurately measure and assess the effects of climate change.

"The decreasing number of global and ocean class research vessels is creating a shortfall in the infrastructure required for sampling the global ocean and expanding collection into the polar regions," the committeenoted."These vessels are indispensable to the ocean observing system."

Robert Weller of theWoods Hole Oceanographic Institution inMassachusetts and co-chair of the committee that conducted the studytold weather.com that large vessels are an integral component of the multi-faceted observational system used to monitor climate change.

Weller noted that about15 years ago, the National Oceanic and Atmospheric Administration had three large ships that roamed the oceans collecting samples and data. A plan was devised to replace those ships when they came to the end of their approximate 30-year life cycle with two new ships, but only the Ronald H. Brown was built. Today it is the sole large ship carrying out observations.

"NOAA is really hard-pressed to operate with just one ship," Weller said, noting that a similar scenario is playing out with other agencies that provide ships for the fleet. For example, the Navy replaced some of its retiring ships with smaller vessels, Weller said.

In the past, Weller said, researchers believed autonomous sampling from smaller vessels would remove the need for people aboard the larger vessels, but that has proven to be false.

"For a number of reasons, there is probably an even greater demand for ships now," Weller said, noting the increasingly ice-free polar oceans, which are dangerous and require larger vessels to maneuver in the choppy waters.

"You really don't want to go there in a small ship, you want to go with a big ship to work in rough waters," he said.

He noted too that accurate observation requires adequate lab and storage space on the ship, another reason the committee is signaling a need forlarger vessels.

Today, there are 35 vessels in the fleet, but according to a report provided to weather.com by the NAS, that number will decrease to 18 to 22 vessels by 2027 unless more shipsare built to replace them.

"This is urgent in the sense that from funding to construction, it takes about 15 years to build a new vessel," Weller told weather.com.

The ocean plays a , according to the NOAA. It has absorbed released into the atmosphere from human activities, thereby lessening the climate effects of the world's carbon footprint. It also absorbs about 90 percent of the earth's surplus heat, the study notes.

Subtle changes in the ocean's surface temperatures at various locations can tell scientists much about the effects of human-caused climate change.The observational system that uses the vessels to collect data also monitors sea level rise.