What started as a series of informal conversations about a year ago among Governor Brown, his senior staff, and a few world leaders, has turned into a veritable global movement. The “Under 2 MOU,” which I blogged about on Thursday, just bumped its total from 57 signatories last week to 80 today, with each representing a city, state or region around the world that is pledging to limit global warming to under 2 degrees by 2100. That signatory number is expected to increase further this week during the UN climate negotiations in Paris.

Governor Brown and the U.S. Ambassador to France, Jane Hartley (fresh off hosting President Obama at her residence), co-hosted a signing ceremony at the Ambassador’s Residence in Paris today, which I attended as part of Berkeley Law’s sponsorship of the luncheon that followed.

The signing ceremony included signatory states and regions from places like Brazil, Holland, and Australia, as well as cities closer to home like Austin and Oakland. The event featured a press conference with remarks from the ambassador, governor, and a representative from the German state of Baden-Württemberg, which launched this effort with California earlier this year. With 30 media representatives in attendance, the hope is that this effort will get strong publicity both in California and around the world to encourage international negotiators this week in Paris to strike a more aggressive climate agreement.

Governor Brown addresses the luncheon following the Under 2 MOU signing.

In the luncheon that followed for Brown Administration officials, California’s business delegation, and other environmental leaders and elected officials from around the globe, Governor Brown noted that even the “Under 2” goal by 2100 many not be enough. Scientists say that even with two degrees warming, it only gives humanity a 50% chance at averting catastrophic climate change. “I don’t know about you,” Brown said, “but how many of us would board an airplane if it only had a 50% chance of not crashing? I want to see that 50% chance of catastrophe become 0%.”

But short of changing the name to the less-catchy “Under 1.5” MOU, this subnational effort may be one of the best chances that climate advocates have for pushing strong, global action on climate change. Particularly with the international process getting bogged down by deference to the lowest common denominator, as Ted and Cara have blogged about, an agreement among more progressive subnationals could lay the foundation for strong global coordination, albeit at a different level than what negotiators will hopefully be finalizing this coming week.

Credit for this Under 2 MOU certainly goes to the governor and other elected officials, but also to his senior advisor (and Legal Planet guest-blogger) Ken Alex, who helped brainstorm the idea, as well as a dedicated staff from California’s “State Department” in the Brown Administration. With so many roadblocks on the U.S. national and international scene, it’s encouraging to see how much progress California is making at home and now globally.