On Tuesday, California Governor Jerry Brown signed onto a pact between 12 regions in seven countries, including four U.S. states, binding each to reduce greenhouse gas emissions drastically. The goal of the cuts is to keep the rise in global average surface temperatures below 2º Celsius.

However, recent revisions by the Inter-Governmental Panel on Climate Change suggest global temperatures are projected to rise by less than 1º C over 30 years–and perhaps by less than 0.5º C.

A release from Governor Brown’s Office regarding the extreme pledge states:

“Under today’s agreement, the signatories commit to either reduce greenhouse gas emissions 80 to 95 percent below 1990 levels by 2050 or achieve a per capita annual emission target of less than 2 metric tons by 2050.”

The pact, entitled “Under 2 MOU,” is part of a global awareness campaign leading up to the December 2015 United Nations Climate Change Conference in Paris, France.

Founding signatories include: “California, USA; Acre, Brazil; Baden-Württemberg, Germany; Baja California, Mexico; Catalonia, Spain; Jalisco, Mexico; and Ontario, Canada, who participated in today’s signing ceremony in Sacramento, as well as; British Columbia, Canada; Oregon, USA; Vermont, USA; Washington, USA; and Wales, UK.”

The group represents a collective GDP in excess of $4.5 trillion, constituting the size of fourth largest GDP in the world and 100 million people, according to Brown’s release.

President Barack Obama has called climate change the greatest threat to national security, and Brown seems to agree.

California’s most recent Republican governor, Arnold Schwarzenegger, brought the state AB 32, the climate change legislation that created the state’s sweeping regulatory cap-and-trade system and the California Air Resources Board (CARB).

CARB Chair Mary Nichols also hosted a reception Tuesday at the Business and Climate Summit in Paris, where she worked to persuade additional global partners to join the new compact.

Governor Brown’s Tuesday statement detailed actions to be taken by signatories:

– Developing mid-term targets needed to support long-term reduction goals;

– Sharing technology, scientific research and best practices to promote energy efficiency and renewable energy;

– Collaborating to expand the use of zero-emission vehicles;

– Taking steps to ensure consistent monitoring and reporting of greenhouse gas emissions;

– Improving air quality by reducing short-lived climate pollutants such as black carbon and methane; and

– Assessing the projected impacts of climate change on communities.

The agreement fits in line with an executive order from Brown’s office last month to reduce California greenhouse gas emissions 40 percent below 1990 levels by 2030. Brown had already committed California to lowering levels to 80 percent below 1990 levels by 2050, the most “progressive” program in North America.

Full text of the agreement signed Tuesday is available on the Governor’s website.

Follow Michelle Moons on Twitter @MichelleDiana