Cal­i­for­nia is adding to its ros­ter of allies in the cli­mate change counteroffensive.

Envi­ron­men­tal groups are hail­ing an agree­ment signed Tues­day by Gov­er­nor Jer­ry Brown and an assort­ment of states, provinces and oth­er “sub­na­tion­al” gov­ern­ments to ratch­et up their own cli­mate strategies.

Billed as the “Under 2 MOU,” the mem­o­ran­dum of under­stand­ing is a pledge to advance poli­cies aimed at arrest­ing glob­al warm­ing at the U.N.’s crit­i­cal thresh­old of 2 degreesCel­sius. That’s the lev­el beyond which some sci­en­tists say the most cat­a­stroph­ic effects of cli­mate change would kick in and hence, has been wide­ly adopt­ed as a kind of holy grail of cli­mate pol­i­cy outcomes.

Even assum­ing that all par­ties deliv­er on their pledges, actu­al­ly hold­ing the line at 2 degrees would, of course, require seri­ous, sweep­ing transna­tion­al com­mit­ments from major emit­ters like the U.S., Chi­na and India, some­thing that nego­tia­tors have yet to achieve.

KQED’s Tara Siler spoke with Dan Kam­men, who heads the Renew­able and Appro­pri­ate Ener­gy Lab­o­ra­to­ry at UC Berke­ley, about the deal and how much dif­fer­ence this kind of sub­na­tion­al agree­ment can real­ly make in mov­ing the cli­mate needle.

One tenet of the agree­ment is the estab­lish­ment of mid-term emis­sions tar­gets “to sup­port long-term reduc­tion goals.” Brown set out a series of ambi­tious cli­mate goals in his Jan­u­ary inau­gur­al mes­sage, and more recent­ly set a tar­get to cut green­house gas emis­sions to 40 per­cent below 1990 lev­els by 2030. The state had already adopt­ed a 2050 goal to cut warm­ing emis­sions by 80 percent.

Join­ing Brown in sign­ing on to the MOU are rep­re­sen­ta­tives of provin­cial gov­ern­ments in Cana­da, Brazil, Ger­many, Mex­i­co, Spain and the Unit­ed King­dom, as well as state offi­cials from Ore­gon, Wash­ing­ton and Ver­mont. Pre­vi­ous­ly Brown had cob­bled togeth­er a West Coast cli­mate action col­lab­o­ra­tive with Ore­gon, Wash­ing­ton and British Colum­bia. Provin­cial offi­cials in France were expect­ed to sign on as well.