Catholics should know that the effects of climate change are already being felt in the U.S., said one Catholic ecologist after President Donald Trump pulled the U.S. out of an international climate agreement.

Communities in the U.S. are already "dealing with climate change now," said William Patenaude, a Catholic ecologist, 28-year employee of Rhode Island's Department of Environmental Management, and author at CatholicEcology.net.

"For lots of us, this is not theoretical. This is reality," he added of climate change.

On Thursday, President Trump announced that the U.S. would be pulling out of the international Paris climate agreement.

Of all the countries that signed the agreement to cut down on carbon emissions and stem the rise in global average temperatures, the U.S. was considered a world leader and thus a key signer of the accord. Representatives of the Vatican were present at the 2015 UN climate conference in Paris where the agreement was reached.  Countries pledged various efforts to curb pollution and contribute to the Green Climate Fund, which was also funded by the private sector.

However, Trump said on Thursday that the deal was toxic for U.S. business interests and U.S. workers, particularly those in the fossil fuel industries. He said the agreement put "no meaningful obligations on the world's leading polluters" like China.

Thus, the U.S. would pull out of the agreement but work to "re-negotiate" a deal "on terms that are fair to the United States," he said.

House Republican Conference chair Cathy McMorris Rodgers (R-Wash.) said the agreement was entered into "without the approval of the American people or their elected representatives through a ratified treaty."

However, for Patenaude, a thriving economy and stronger environmental regulations can go hand-in-hand, and jobs don't have to suffer as a result of a nationwide move to clean energy.

The urgency of climate change should impel all Catholics to take a closer look at the environment and human causes of climate change, he insisted. His experience in Rhode Island forced him to consider the effects of climate change on his state and nearby communities.

"I was not always on the bandwagon for climate change," he admitted to CNA, but in his environmental work in Rhode Island, over time he began to notice substantial changes in precipitation and flooding "where we never really saw it before," which "culminated in some massive flooding in 2010."

The causes of this were clear, he said. Once the atmosphere warms due to increased amounts of greenhouse gases, it "can hold more moisture." This leads to heavier rainfall and flooding, which means that stormwater and wastewater infrastructure must be updated. Patenaude said he saw this firsthand as he examined 19 wastewater facilities in Rhode Island. Coastal towns will also have to take into account the possibility of rising sea levels and greater coastal flooding in the future.

"Climate change is an issue which is going to harm American citizens more and more, if we don't get our arms around it," he said.

Yet there's a "polarization" in American society on the issue that is troubling, he insisted, and environmentalists must learn to dialogue when they disagree.

President Trump, in his explanation of why the U.S. is pulling out of the Paris climate agreement, said that American jobs are at stake. According to one estimate he cited, under the agreement, production in the coal industry would be reduced by 86 percent by 2040 and natural gas by 31 percent, and 6.5 million industrial jobs would be lost.

The president is speaking to many Americans who are justifiably concerned that their livelihoods will disappear and their jobs will move overseas if the U.S. cuts carbon emissions and moves away from fossil fuels, Patenaude acknowledged, adding that "the environmental movement needs to begin to understand how to talk to those people."

Catholics must enter into dialogue with others about the environment and the economy, "that dialogue that Pope Francis talks about in Laudato Si, in a really meaningful way," he insisted.

For instance, he claimed that a successful attempt at dialogue was the Catholic Climate Covenant hosting a recent webinar on "just transitions" from older energy jobs to a new economy.

"What we need to do is, we need to let them know all of the things – all of the impacts that climate change will have on them, but also, the new economy is a bright future for us," he said.

"We can either continue that division," he said of today's divide, "or we can find new ways, better ways, truthful ways of being honest about the urgency of this issue and the hope, the promise that we can bring about from an economic and moral point of view by moving forward with a better, cleaner economy."