MCJ
MCJ, formerly My Climate Journey, is a Boston-based early-stage climate venture fund backing founders across the energy and industrial transition. It pairs the fund with a member community and the Inevitable podcast. Water is a small slice: as of 2026 MCJ has backed two water companies, Waterplan and Lilac Solutions, both as a co-investor.
Compiled by Antoine Walter, (don't) Waste Water, from official filings and direct intelligence in Leviathan.
The take
MCJ began as one man's homework done in public. In 2019 Jason Jacobs, fresh from selling his running app Runkeeper to ASICS, started a podcast called My Climate Journey to teach himself climate science out loud. The audience turned into a community of thousands, and the community turned into a fund. As of September 2024 MCJ manages more than 115 million dollars, having closed an 80.6 million dollar second fund, and it still runs the podcast, now called Inevitable, alongside the cheques.
MCJ is a generalist climate fund, not a water fund, and it is honest about that. It writes pre-seed to Series A cheques, on average around half a million dollars, across the whole sprawl of the energy and industrial transition: carbon removal, industrial decarbonization, the grid, circularity, climate resilience. Water shows up only where it overlaps that climate thesis, never as a category MCJ sets out to own.
That is why the two water companies MCJ tracks are really climate bets wearing a water coat. MCJ backed Waterplan, whose software stitches satellite imagery to hydrological models so a corporation can see where its factories will run dry, and Lilac Solutions, whose ceramic ion-exchange beads pull lithium out of salt-lake brine for the batteries the energy transition runs on. One reads water risk, the other mines a mineral from water, and both sit beside far larger piles of non-water climate companies.
MCJ has backed two water companies across two deals, both as a co-investor rather than the lead, riding alongside the likes of Breakthrough Energy Ventures, Y Combinator and BMW i Ventures. The way I read it, MCJ is the climate generalist a water search turns up by accident, a useful window onto how a broad energy-transition fund touches water at the edges rather than a water specialist wearing a climate label.
Water Commitment Score
Compiled from official filings, third-party records, and direct intelligence from investors and founders, in Leviathan · recomputed monthly · as of Jun 2026.
How they invest
Portfolio · 2 water companies
Invests alongside
Highlighted = profiled on (don't) Waste Water.
Frequently asked
- What does MCJ invest in?
- MCJ is an early-stage climate venture fund that backs founders across the energy and industrial transition, including carbon removal, industrial decarbonization, the grid, circularity and climate resilience. It writes pre-seed to Series A cheques. Water is not a focus area; MCJ's two tracked water companies, Waterplan and Lilac Solutions, are climate bets that happen to touch water.
- Is MCJ a water investor?
- MCJ is not a dedicated water fund; it is a Boston-based generalist climate investor. (don't) Waste Water rates its water commitment Occasional, because MCJ has backed two water companies as part of a much wider climate portfolio: Waterplan, a water-risk software firm, and Lilac Solutions, a lithium-extraction company that pulls its mineral from brine.
- What water companies has MCJ backed?
- MCJ has backed two water companies that (don't) Waste Water tracks, both as a co-investor. Waterplan combines satellite imagery and hydrological models so companies can measure and manage their water risk. Lilac Solutions uses ceramic ion-exchange beads to extract lithium directly from salt-lake brine for battery supply chains.
- Who runs MCJ?
- MCJ was founded by Jason Jacobs, who started the My Climate Journey podcast in 2019 and now serves as a venture partner. The fund is led by managing partners Cody Simms, who also hosts the Inevitable podcast, and David Aronoff, its chairman, with partners Yin Lu and Thai Nguyen rounding out the investment team.
- Is MCJ the same as My Climate Journey?
- Yes. MCJ is the current name of the firm that began as My Climate Journey, a climate podcast and community Jason Jacobs launched in 2019. It is now a Boston-based early-stage climate venture fund, a member community, and the Inevitable podcast. It is unrelated to the various construction and energy firms that share the MCJ initials.