During a week in which much of the world was wondering whether the president of the United States considers climate change a threat, in a Portland hotel conference room full of people who spend their lives in the water, the question of man-made warming wasn’t even being asked.

For the men and women who must pull a living, lobster trap by lobster trap, out of the Gulf of Maine, it isn’t up for debate — they have seen the change with their own eyes. When you find that the best spots for fishing have moved, or that there’s a new disease in the mix — when you have actually watched temperatures rise and the ocean ecosystem transform — there is no question at all, except over how you’re going to deal with it.

Instead, the Trump administration is doing its best to not confront it at all. President Donald Trump announced he was pulling the United States from the historic Paris climate accord, prompting the questions over whether he believed in man-made climate change, a question members of his cabinet answer in the negative without hesitation.

The president has also proposed a budget that would severely diminish government-funded research into climate change. Among many other items, it would hinder Maine’s ability to find out how warming waters will impact the lobster industry.

That is not an insignificant matter. The industry landed more than $500 million worth of lobsters last year — more than 80 percent of the state fishery. An entire sector of the economy — and entire coastal communities — depend on its health.

And as Dave Cousens, longtime president of the Maine Lobstermen’s Association, told the people in the hotel conference room earlier this month, the recent past shows the future is anything but certain.

Speaking at the International Conference & Workshop on Lobster Biology and Management, Cousens said he and other lobstermen watched over the decades as water temperatures rose and predators disappeared, putting the sweet spot for lobster reproduction over the entire Maine coastline. The annual harvest, fairly consistent at around 20 million pounds a year for more than a century, started shooting upwards starting the early 1990s, and last year, lobstermen landed 131 million pounds.

But not all the news is good. Lobsters have disappeared from Long Island Sound, and are all but gone from southern New England. The center of Maine’s lobster industry has moved too, from Casco Bay north to Stonington.

Cousens said that he already this year found “shedders,” or lobsters that have lost their hard shell. “You’re not supposed to get shedders where I fish now,” he said. “The biological clock of lobsters is shifting.”

Clearly, the changes in the Gulf of Maine that brought about the record landings are still churning, and what that means is unclear. Researchers believe a decline is coming, but just when it will come and how severe it will be is up for debate.

If we are to maintain the fishery, and prevent seaside communities from losing their heart and soul, understanding and preparing for that decline is key, as is pushing for policies that will slow climate change.

The same can be said of sea-level rise, for which communities along Maine coast and rivers must be ready. Or hurricanes in the South, or drought and wildfires in the West. Coal mining may benefit from a lax climate policy, but nearly every other industry or region will have to adjust to the effects of climate change.

Those effects are not a matter of debate — they are happening right now. Just ask a lobsterman.