For a sci-fi short story I was thinking how a briefcase size solution to climate change could look like. In the story humanity would buy the "solution" to clima

For a sci-fi short story I was thinking how a briefcase size solution to climate change could look like. In the story humanity would buy the "solution" to climate change from an alien high-tech travelling salesman. What I ended up is that it could be a small vial of some bio-engineered marine microorganism designed to bloom on every ocean surface, capture sunlight and use and use the energy to capture CO2 in some chemically stable molecule and then sink to the depths. And most of the briefcase would be actually filled with a manual describing how humanity can modulate the intensity of capture to the right level with bio-engineered viruses which predate on the artificial microorganism.