Bill Gates declared it's 'complete nonsense' to think planting trees will solve climate change. 'Pro-tree' Salesforce CEO Marc Benioff accused him of going on a 'tirade.'

• Bill Gates recently said that planting trees to address climate change is a "less proven" approach.
• Salesforce CEO Marc Benioff took offense, saying Gates went on an unnecessary "tirade."

Bill Gates and Marc Benioff apparently have very different ideas about how to address climate change — and how to spend their philanthropic dollars.

Gates was recently asked at the New York Times' Climate Forward summit what he does to offset his carbon footprint, and the billionaire said that he doesn't plant trees. He called it one of the "less proven approaches," and said the idea that climate change could be solved by planting enough trees is "complete nonsense."

"Are we the science people or are we the idiots?" Gates said. "Which one do we want to be?"

Salesforce CEO Marc Benioff, who has put $300 million toward planting trees to address climate change, took offense.

Benioff called New York Times climate reporter David Gelles to criticize Gates' opinion.

"I couldn't really understand why he was going on this tirade," Benioff told Gelles. "Number one, we all have to go net zero. And number two, we have to plant a trillion trees."

Benioff has been outspoken in the past about corporate climate responsibility — and the best ways to reduce carbon footprints.

"We think every company should be focused on how to sequester the carbon that they're creating, Benioff told Insider in 2019. "It's not that hard. We can all do it very easy."

He was a strong advocate for planting trees then, too.

"The one that we directly have in the most actionable form is more trees," Benioff said. "You can have 205 gigatonnes of carbon sequestration for every trillion trees. We need more trees."

While planting trees can help make a dent in the climate crisis and protecting existing forests is important, studies indicate that it's not enough to singularly solve climate change. In order to capture just 10% of the carbon dioxide we emit annually, we'd have to cover the entire contiguous US with trees, Insider previously reported. While planting more trees is a positive goal, there simply isn't enough space in the world for all of the trees we'd need.

And studies have found that extreme heat could make photosynthesis impossible for tropical trees and plants, meaning massive amounts of the tropical canopy could die off.

Gates, meanwhile, prefers to focus on "climate innovation," investing in climate technology for reducing carbon emissions and producing more clean energy. He's also said that it's unrealistic to expect people to change their lifestyles to solve the climate crisis — like telling people they shouldn't eat meat or live in a "nice house."

This isn't the first time Gates has feuded with another billionaire over climate action, either. He's also clashed with Elon Musk over how big an impact Tesla has (or hasn't) had on reducing emissions.

Neither Gates nor Benioff responded immediately to Insider's requests for comment.