AP Pension, Copenhagen invested €75 million ($81 million) in 1GT Fund, managed by Morgan Stanley Investment Management.
A spokesman said it is the pension fund's first investment in the fund.
The private equity fund is focused on investments in companies that aim to reduce carbon emissions in sectors such as sustainable food and agriculture, the circular economy, energy and transport.
"We do not invest in the fund based on a philanthropic mindset. We primarily invest in it because we believe that it will be able to help deliver good returns to our customers. This must be achieved by investing in growth companies that are in the process of developing, which will bring their products to a wider market," Helle Aerendahl Heldbo, head of alternative investments at AP Pension, said in a news release Wednesday.
AP Pension has about €20 billion in assets.