The pledges that countries have signaled they will make in Paris over the next two weeks to cut emissions will inevitably fall short of what is needed to solve the problem of climate change.

But many political leaders gathering there — including governors, mayors, and provincial cabinet secretaries — are pushing for more aggressive cuts. By the dozen, they are signing a voluntary agreement committing their jurisdictions to faster and deeper reductions in emissions of greenhouse gases than their national governments have promised.

“We are not moving fast enough,” Gov. Jerry Brown of California, who is helping to lead the effort, said in an interview. “We’ve got to do more.”