SACRAMENTO, Calif. — Seeking to cement California's reputation as a global leader in combatting climate change, Gov. Jerry Brown on Monday signed two measures designed to push the state to 100 percent renewable electricity and so-called carbon neutrality by 2045.

Senate Bill 100 raises the state’s already ambitious goals for producing electricity from wind, solar and other green sources. The aim is to ensure greenhouse gas emissions are low enough that they can be absorbed by forests, oceans, soil and other natural systems.

Brown, who signed the bill amid a huddle of environmental and legislative leaders, also issued an executive order pushing the state to reduce its net output of greenhouse gases into the atmosphere — including from the single largest source, cars and trucks — to zero by the same 2045 deadline. Meeting the 100 percent carbon-neutral goal in just 27 years and potentially becoming “net negative” on carbon, gives California the most ambitious such target of any government in the world, the governor’s office said.

“There's no understating the importance of this measure,” Brown said, moments before signing the two actions. “SB 100 is sending a message to California and to the world that we're going to meet the Paris [climate] agreement. And we're going to continue ... to transition our economy to zero carbon emissions and to have the resiliency and the sustainability that science tells us we must achieve.”

The twin actions Monday were designed to be a drastic opening gesture by the governor, just before he will host a meeting of global leaders on the issue in San Francisco later this week. The Global Climate Action Summit will bring more than 5,000 government officials, business executives and environmentalists together in what is being billed as the largest meeting of "nonstate actors," who can play a key role in preventing the worst impacts of rising global temperatures.

The spotlight on Brown and this week’s summit is expected to be more intense because of President Donald Trump’s decision last year to withdraw the United States from the 2015 Paris climate accord. Under that agreement, nations pledged to take decisive steps to prevent temperatures from increasing more than 2 degrees Celsius above pre-industrial levels.

Any temperature hike of more than 2 degrees (or the safer goal of a 1.5-degree increase) is expected to set off more severe storms, droughts and wildfires. While some of those disasters have already been linked to global warming, higher temperatures could cause even more catastrophic outcomes, including pandemics and starvation, according to forecasts by some scientists.

While Brown did not name Trump during Monday's bill signing, he signaled in an interview afterward with NBC News that the summit's leaders will not shy away from calling out those — including Trump — who they believe are slowing progress on taming global warming.

"The Republican Party under Trump, and even before, is committed to deny and fight any effort to prevent the catastrophic horror of climate change," Brown said. "First they deny it, then they doubted it, then they revile others who are trying to do something. Others being all the countries of the world."

The governor, who is term-limited out of office in January, also criticized Trump's action last month to try to prevent California from enforcing more stringent vehicle fuel efficiency standards than the federal government. Allowing more gas guzzling cars, he said, will cripple efforts to build a new industry around electric and other zero-emission vehicles.

"If Trump succeeds, he will destroy the American car industry and China will be the dominant car-maker," Brown said, "because they are putting tens of billions into that.... He’s killing our own companies, by subsidizing fossil fuel and these old, clunky engines. In five years, the electric car will compete with the combustion car."

State Sen. Kevin de León, D-Los Angeles, wrote the bill to push 100 percent green energy in the state. De León, locked in a long-shot bid for the U.S. Senate against Dianne Feinstein, the Democratic incumbent, said the new law “sends an unmistakable message to the nation and the world: Regardless of who occupies the White House, California will always lead on climate change."

Under the new law, California will aim to hit 50 percent renewable energy in 2025 and 60 percent by 2030.

California is not the first government to promise that homes and businesses would be able to get all their electricity from sources that do not pollute the air and warm the atmosphere. Hawaii Gov. David Ige in June signed a similar bill, strengthening the state's commitment to generate 100 percent of its electricity from renewable energy resources by 2045. And some 80 British cities and towns pledged earlier this year to reach the 100 percent green power benchmark by 2050.

While California has been a leader on reducing the amount of electricity it gets from burning fossil fuels, the state has struggled to be as forward-leaning in reducing the greenhouse gas pollution spewed from cars and trucks. Those emissions have been ticking up slightly, despite California’s stringent fuel-efficiency standards, which are now being targeted by the Trump administration.