Sen. Kirsten Gillibrand said climate change is "truly the greatest threat to humanity that exists" and said flooding in Iowa showed the urgency policy leaders must take on this issue.

The New York Democrat offered condolences to Iowans suffering from flooding throughout the state at her Des Moines town hall Wednesday and recalled her own experiences in upstate New York seeing the effects of Hurricanes Sandy and Irene on families and agriculture.

"I know what's happening to your farms across your state, I know you've lost loved ones, and it is crippling," she said to a crowd at the River Center in Des Moines. "But it's one of the reasons why we deeply need to take on global climate change."

On Wednesday, 81 of Iowa's 99 counties were under a flood warning, flood advisory or a hazardous weather outlook. Many communities in southwestern Iowa were submerged; floodwaters forced residents to evacuate and destroyed crops.

After Hurricane Sandy, Gillibrand said she met with a couple whose two sons were swept away in the 2012 floods, she said. Meeting with the grieving parents was "the worst part of (my) life," Gillibrand said.

"That’s what happened all across America," Gillibrand said. "We saw lives lost in California with the wildfires. We’ve seen flooding, we’ve seen tornados, we’ve seen droughts. This is real. It is truly the greatest threat to humanity that exists."

To take on climate change, Gillibrand advocated for the Green New Deal, a proposal spearheaded by fellow New Yorker Rep. Alexandria Ocasio Cortez. One of the goals of the plan, having "net zero" carbon emissions in ten years, was aspirational, Gillibrand said.

"People will say, 'how can you possibly get there?'" she said. "John F. Kennedy didn't know that you could put a man on the moon in 10 years, it didn't matter. He wanted us to aspire to it, and you know what? He did it. So we should do the same."

Gillibrand also met with Iowans in Muscatine, Burlington and Ottumwa Wednesday. It was her first Iowa visit after officially announcing her presidential campaign, although she made trips to the state earlier this year after she announced her exploratory committee.

The Democratic 2020 candidate also talked about her support for "Medicare for all," publicly funded campaigns in American elections through tax revenue or donations, and universal public pre-kindergarten education while answering questions from the crowd. If anyone in the crowd didn't get their question answered, Gillibrand promised she'd be back — often.

"I will have an RV this summer with my kids and my husband," she said. "I hope to go to all of your towns."