– Congressional Democratic leaders plan to tell President Donald Trump on Tuesday that any agreement to improve the nation's infrastructure must include funding to combat climate change.

House Speaker Nancy Pelosi and Senate Minority Leader Chuck Schumer consider the effects of climate change among the greatest long-term challenges to the nation's infrastructure, and will urge explicit funding to address it in any future legislation.

Schumer, D-N.Y., and Pelosi, D-Calif., sent Trump a letter Monday saying that "a big and bold infrastructure package must be comprehensive and include clean energy and resiliency priorities." They wrote, "To truly be a game-changer for the American people, we should go beyond transportation and into broadband, water, energy, schools, housing and other initiatives. We must also invest in resiliency and risk mitigation of our current infrastructure to deal with climate change."

It's unclear what the funding sources could be. An increase in the gasoline tax has been widely discussed as one option for infrastructure funding, but Schumer will not consider it unless Trump reverses some of the 2017 tax cuts for the wealthy, according to a congressional source. Schumer is concerned that poor and working-class taxpayers would wind up bearing too much of a burden if the gas tax went up.

The Democrats' plans create new hurdles as the two sides work toward achieving what could be a rare bipartisan victory this year: a massive infrastructure bill that both sides have promised to their political bases.

Schumer sent Trump a letter at the end of last year demanding the compromise bill include funding for projects that will "mitigate risks that the U.S. is already facing" due to a warming Earth. But such funding would challenge Trump to acknowledge the direct effects of global warming on the nation's infrastructure. Schumer and Pelosi are calling for "resiliency" improvements to transportation, water, waste and sewer systems and to critical infrastructure increasingly at risk of extreme weather.

A White House spokesman would not comment on the agenda for the upcoming meeting.

Trump is to meet Democratic leaders in the Oval Office on Tuesday in a bid to craft a broad funding package to repair the nation's roads, bridges, airports, utilities and other public works and facilities.

"The bottom line is this: If they're not going to put real money and have real labor and environmental protections, we're not going to get anywhere," Schumer said earlier this month.

Last month, Trump proposed investing at least $1 trillion for a package that included $200 billion in federal spending. That was less than last year's $1.5 trillion plan, which went nowhere.

This time, taxes could be part of the deal. Transportation Secretary Elaine Chao told a Senate subcommittee that "nothing is off the table" when asked if higher gasoline taxes or airport passenger fees were in the mix.