AUGUSTA, Maine — Sen. Angus King added his voice to the climate change debate during a speech on the U.S. Senate floor Tuesday, where he said a northward migration of lobsters looking for colder water could soon devastate Maine’s fishery.

Lobster harvests in Maine have increased from about 50 million pounds a decade ago to 123 million pounds in 2011. While that statistic seems to oppose the argument that climate change is having a negative impact on the fishing industry, King said you need to look no further than a few hundred miles south in Connecticut and Rhode Island, to see what could become of the Gulf of Maine’s most lucrative fishery.

“The lobster makes up about 70 percent to 80 percent of our fisheries’ value, and what’s happening in Maine is that as the water gets warmer, the lobsters go north,” said King, according to the Congressional Record.

King presented a range of data that indicates that global levels of carbon dioxide are reaching a historical tipping point that could raise the levels of the oceans and move water temperatures off the Maine coast high enough to drive lobsters away.

“So this isn’t something where we can just say oh, well, we’ll do a few little things now and maybe it will be OK, and 100 years from now or 500 years from now somebody else will worry about it,” said King. “There could be a catastrophic event within years, certainly within decades.”

Such an event has already happened to the south because of warming water temperatures, said King.

“They were doing great in Rhode Island and Connecticut until the temperature started to kill them off,” said King. “We certainly hope it won’t happen [in Maine], but there’s a danger of a collapse and that’s what’s happened to our south. The lobster fishery in southern New England has essentially collapsed.”

Patrice McCarron, executive director of the Maine Lobstermen’s Association, said that climate change and its effect on lobsters is among the concerns of her association, but that she “sees what is happening in Maine differently.” She said Connecticut and Rhode Island have traditionally been at the southern end of the range of the American lobster, which is the species caught in Maine, and that most indications are that lobster will continue to thrive near Maine over the long term.

“They were already in a more vulnerable position,” said McCarron of the southern New England crustaceans. “There’s warmer water and that resource is also located at a very dense population center. That whole ecosystem is much more subject to human influence [than the lobsters in the Gulf of Maine].”

McCarron said data shows that the estimated lobster population off Maine’s southern coast has been “amazingly consistent and robust,” but that the numbers of lobster harvests in midcoast and Downeast Maine have “exploded in abundance,” which accounts for the heavy statewide harvests in recent years.

“While we’ve seen the abundance of the resource increase, we need to really look at what the potential future will be,” she said. “That is truly an unknown.”

While surface water temperatures in the Gulf of Maine have been somewhat volatile, McCarron said temperatures on the ocean floor have been largely stable, causing lobsters to come closer to shore in the winter and move a little farther out in the warmer months.

“Our fishery follows the lobsters,” she said. “That pattern has really remained the same for a long time.”

Glen Brand, director of Sierra Club Maine, said King’s speech was important because it laid out the climate change argument so clearly.

“Sen. King is right that it is urgent to set aside partisan bickering and delay, and begin reducing carbon pollution through energy efficiency and carbon standards for power plans, as President Obama’s climate plan has put forth,” said Brand in a prepared release.

Climate change has long been debated on the Senate floor, and a member of King’s staff said his speech Tuesday was intended as a way to engage in the conversation.

McCarron said King is establishing himself in Congress as a strong proponent of measures that will help sustain the lobster fishery.

“[Retired] Sen. Olympia Snowe has always been a tremendous leader for Maine in terms of looking at the big picture, into the future,” she said. “My sense is that Sen. King has really grabbed that torch and continued to carry it.”

In another move designed to protect Maine’s coastal resources and waterways, King on Wednesday introduced legislation that would authorize a study of the York River in southern Maine, which could lead to federal investments to protect the river’s economy and environment. The multi-year study would determine whether the York River is eligible to be designated as a Wild and Scenic Partnership River by the National Park Service.

Rep. Chellie Pingree, D-Maine, has submitted similar legislation in the U.S. House of Representatives.