Now, he may have his sights set on developing a vaccine to combat climate change by targeting the methane emissions of livestock.

ArkeaBio, a Boston-based ag-biotech startup, recently raised $26.5 million in a Series A financing round to "reduce greenhouse gas emissions" via the development of a "methane vaccine," the company announced in a May 8 press release.

Breakthrough Energy Ventures, founded by Gates and which first invested in ArkeaBio in 2022, led the financing round.

The company said:

"ArkeaBio's vaccine will provide an innovative, cost-effective, and scalable solution to reduce the world's livestock methane emissions, which currently generate the equivalent of 3 Billion Tonnes of CO2 annually and represent 6% of annual Greenhouse gas emissions."

ArkeaBio claims its "vaccination-based approach allows for much-needed decarbonization of global meat and dairy products across multiple geographies, supporting greater sustainability in agriculture."

Other investors in the recently completed financing round include The Grantham Foundation for the Protection of the Environment, AgriZeroNZ — a "partnership between the New Zealand government and major agribusinesses" — Rabo Ventures, Overview Capital and The51 Food & AgTech Fund.

"The funds raised in this Series A financing will play a pivotal role in expanding the research, development and deployment of the vaccine, including large-scale field trials and engagement along the supply chain," ArkeaBio said in its press release.