Hollywoodactor and climate change activist Leonardo DiCaprio took aim at lawmakers whodismiss the link between man-made carbon emissions and global warming, sayingthose who do not believe in climate change "should not be allowed to holdpublic office."

DiCapriomade the comment during a one-hour talk on climate change with President BarackObama at the South by South Lawn festival at the White House on Oct. 3. Theevent coincided with the debut of DiCaprio's new documentary on climate changecalled "Before the Flood," which looks at the impacts of temperatureshifts across the world.

"Thescientific consensus is in and the argument is now over. If you do not believein climate change, you do not believe in facts, or in science or empiricaltruths," DiCaprio said. He went on to praise Obama as "a presidentwho has done more to create solutions for the climate crisis than any other inhistory."

Amongother actions, the Obama administration created the first greenhouse gasemissions standards for existing power plants, known as the Clean Power Plan,and finalized carbon emissions requirements for new power plants. The U.S.Supreme Court, however, temporarily stayed the Clean Power Plan in Februaryuntil legal challenges against the rule are resolved.

Inaddition to past climate efforts, the president told DiCaprio the U.S. willstart negotiations this week on an international aviation agreement that willrequire all major airlines and carriers to figure out how to lower theiremissions. The U.S. will also work on an international deal to reducehydrofluorocarbons, a potent greenhouse gas that is often used in refrigerantsand air conditioning systems.

Obamasaid he was "very proud" of the country's action on climate change inthe past eight years, which include a doubling in both car fuel efficiencystandards and clean energy production. But he said more work must be done bythe U.S. and other countries.

"Weget an incomplete [on global climate response], but the good news is we canstill pass the course if we make some good decisions now," Obama said. Thepresident said he expected the Paris climate agreement signed by roughly 200 countries in December2015 to take effect "in the next few weeks," after major emittersincluding the U.S., China and India officially ratified the pact.

"Officiallythis agreement will be into force much faster than I think many of usanticipated when we first organized it," Obama said.

Thefate of U.S. climate efforts could hinge on the outcome of the Novemberpresidential elections. Democratic nominee Hillary Clinton has pledged to uphold the Obamaadministration's climate policies, including the Clean Power Plan, whileRepublican competitor Donald Trump has called climate change a "hoax" and vowed toundo the Clean PowerPlan and many other regulations he said are standing in the way of energyproduction.