James Martin/CNET

Google's parent company, Alphabet, said it's focusing on technology to fight climate change because the "crisis is the single biggest problem the world has now."

Astro Teller, head of Alphabet's X research lab, made the remark Friday during an interview at the Wired 25 conference in San Francisco. Teller also said many of the division's projects and past projects have touched on environmental issues. One failed initiative, called Project Foghorn, tried to create a carbon-neutral fuel out of seawater, but the new fuel wasn't cost-viable. Another project, called Dandelion, which has been spun out of X, uses geothermal technology to heat and cool homes.

"Our goal is to find and solve huge problems in the world," Teller said. "[Climate change is] taking up a lot of space in our windshield right now because it's just so big."

X, formerly called Google X, is the company's moonshot factory. Several of Alphabet's most ambitious projects, including driverless cars, drone delivery, and balloons that beam down internet connectivity, have been spun out of the X research lab.

Teller's comments come as Google has faced criticism over climate change. The Guardian last month reported that Google has made "substantial" contributions to some of the "most notorious climate deniers" in Washington, DC. Google told The Guardian it sponsors organizations across the political spectrum. "We're hardly alone among companies that contribute to organizations while strongly disagreeing with them on climate policy," a spokesperson said.

Earlier this week, more than 1,000 Google employees signed an open letter to CFO Ruth Porat demanding action on issues related to climate change. In the letter, employees urge a commitment from Google to reach zero emissions by 2030, as well as to shun contracts that "enable or accelerate the extraction of fossil fuels." The employees also called on the company to ban funding to think tanks, lobbyists or politicians that deny climate change or delay solutions. Additionally, the workers want Google to vow not to collaborate with groups that harm refugees or other groups affected on the "frontline" of climate change.

Google this week also launched an accelerator program to help startups working on projects related to sustainability and solving social problems.

X has had its share of controversy as well. Last October, The New York Times published a bombshell report on sexual harassment allegations at Google and Alphabet. One of the executives accused of misconduct was Rich DeVaul, a director at X. At the time, DeVaul apologized for an "error in judgment." He resigned from Alphabet a few days after the Times report. Teller wasn't asked about the accusations during Friday's interview.