Former Vice President Joe Biden insisted at Wednesday night's CNN town hall that his plan to address climate change went far enough, and he was forced to defend his relationship with the fossil-fuel industry.

Biden is scheduled to attend two high-dollar donor events on Thursday, one of them cohosted by the cofounder of the natural-gas company Western LNG.

The Biden campaign said the cofounder, Andrew Goldman, was not still involved in Western LNG, but Biden told the audience that if that "turns out not to be true, then I will not, in any way, accept his help."

The former vice president argued that he had the experience and know-how to implement effective climate policy in conjunction with global leaders, and he suggested that some of his 2020 competitors' plans weren't realistic.

And Biden insisted that his $1.7 trillion plan to fight climate change was "aggressive enough," even though he would spend trillions less than other 2020 candidates have proposed and has a later deadline for carbon neutrality.

Visit Business Insider's homepage for more stories.

Former Vice President Joe Biden insisted Wednesday night that his plan to address climate change went far enough, speaking at CNN's seven-hour climate-change town hall where he was also forced to defend his relationship with the fossil-fuel industry.

The 2020 Democratic presidential candidate was put on the defensive after an audience member asked him whether he could be trusted to stand up to the fossil-fuel industry given that he was scheduled to attend a fundraiser on Thursday hosted by a former executive in the gas industry.

Biden is scheduled to attend two high-dollar donor events on Thursday in New York. One is set to be hosted at the home of David Solomon, a partner at the investment firm Hildred Capital Partners. The Intercept reported that Solomon's event would be cohosted by Andrew Goldman, a cofounder of the natural-gas company Western LNG who previously advised Biden in the Senate and on his 2008 presidential campaign.

Biden insisted that Goldman "is not a fossil-fuel executive," and the Biden campaign said Goldman was not currently involved in Western LNG.

Read more: Joe Biden will solicit big money from Wall Street donors right after participating in CNN's climate town hall

"I was told by my staff he doesn't have any responsibility related to the company," Biden said. "If that turns out not to be true, then I will not, in any way, accept his help."

Biden added that his campaign "checks every contribution" to it to "make sure that we are not accepting money from people we said we wouldn't or we shouldn't."

Along with many other 2020 candidates, Biden has signed the "No Fossil Fuel Money" pledge, which requires candidates to reject donations of more than $200 from "S.E.C.-named executives of fossil fuel companies.''

David Turnbull, a spokesman for the group Oil Change US, told The New York Times that while Biden's fundraiser "may not technically violate the 'No Fossil Fuel Money' pledge as we have defined it, it pretty clearly goes against the spirit of the pledge."

The former vice president argued on Wednesday during the event, which was attended by 10 Democratic candidates, that he had the experience and know-how to implement effective climate policy in conjunction with global leaders, and he suggested some of his 2020 competitors' plans weren't realistic.

"Plans are great," Biden said. "Executing their plans is a very different thing. You still have to get the rest of the world to come along." He added: "I know almost every one of those world leaders."

Biden faced criticism from fellow Democrats earlier this year when a campaign adviser was quoted as saying Biden would pursue a "middle ground" approach to climate policy. His $1.7 trillion climate plan demands trillions fewer dollars and has a later deadline for carbon neutrality than the proposals of several other 2020 candidates.

CNN's Anderson Cooper asked Biden whether his approach was "aggressive enough."

"Yes, I think it is aggressive enough," Biden said. "It's gotten good reviews from most of the environmental community."

In response to another audience question, Biden said he wouldn't support a national or state-level ban on existing oil and gas fracking but supported prohibiting any new fracking on federal lands.

Biden attempted an optimistic tone, shooting down those who doubted the US could do much to solve the climate crisis.

"We're walking around with our heads down like: 'What are we going to do? We're in such great trouble,'" he said. "We're the United States of America, and there's not a damn thing we can't do once we set our minds to it."