Brown noted the president's shifting views on NATO and other issues since he took office. Trump is expected to make a decision on whether the U.S. will stay in the groundbreaking Paris climate treaty when he returns from his overseas trip.
"I am cautiously optimistic that we’re going to make progress -- not as fast as I would like but not as disastrous as we were thinking just a few months ago," Brown said.
The governor appeared at the conference "Climate is Big Business," which is part of a Netherlands climate mission to California. The two-day event was co-hosted by the California Environmental Protection Agency and the Dutch government.
The appearance came about a week before Brown is set to leave for a larger climate change event in China. That country has emerged as a leader and key partner in the climate change fight as Brown continues to push ambitious anti-pollution and clean energy programs, even as the federal government backs away from such commitments under Trump.
In a speech to the group, Brown boasted that California has built up expertise in its environmental agencies that are "more numerous and coherent" than the federal government's, and took one dig at Republicans in Washington, D.C.
"If you can sense and see what's up ahead early enough, then the action you take will be easier to manage and a lot cheaper," Brown said.
"There's no free lunch here and no escape. If we dawdle along and the Congress doesn't do what it should do and the president doesn't take the action, probably they'll be thrown out in two years or four years or whatever it will take, but then we will have to spend more money."