Several research groups and tech startups are testing direct air capture devices that can pull carbon dioxide directly from the atmosphere. The technology works, but the early projects so far are expensive and energy intensive.

The systems use filters or liquid solutions that capture CO2 from air blown across them. Once the filters are full, electricity and heat are needed to release the carbon dioxide and restart the capture cycle.

For the process to achieve net negative emissions, the energy source must be carbon-free.

The world's largest active direct air capture plant operating today does this by using waste heat and renewable energy. The plant, in Iceland, then pumps its captured carbon dioxide into the underlying basalt rock, where the CO2 reacts with the basalt and calcifies, turning to solid mineral.

A similar process could be created with offshore wind turbines.

If direct air capture systems were built alongside offshore wind turbines, they would have an immediate source of clean energy from excess wind power and could pipe captured carbon dioxide directly to storage beneath the sea floor below, reducing the need for extensive pipeline systems.