New Zealand and the US state of California have signed a pledge to help fight climate change by sharing ideas and best practices, including how to put millions more electric vehicles on the road.
Prime Minister Jacinda Ardern and California's Governor Gavin Newsom spoke about the agreement at San Francisco's Golden Gate Park.
The agreement does not commit either government to specific policies but outlines broad areas for co-operation.
"We have a natural connection and I'm so pleased we've put pen to paper today to confirm that and continue our co-operation on one of the great challenges of our generation," Ardern said.
Cars, trucks and other parts of the transport sector are California's biggest contributor of greenhouse gas emissions, and New Zealand's second largest behind agriculture, Ardern said.
California is moving to ban sales of new gas-powered cars in the state by 2035. New Zealand wants 30 per cent of all car sales to be electric by that year.
Newsom said he expects competition to grow in the electric vehicle market, which Tesla currently dominates, likening it to when Netflix started facing competition from other streaming services.
Ardern said her government will talk with Californian officials about programs that offer incentives for people to get rid of older, gas-guzzling cars.
New Zealand is home to five million people compared to California's population of 39 million and has a much smaller economy but both are experiencing the effects of climate change.
The US state just recorded its driest winter on record amid increasing drought conditions, while New Zealand's most recent winter was the hottest on record.
New Zealand is heavily focused on reducing emissions from its vital agriculture industry. Beef and dairy dominate the nation's farming sector and milk products are its largest export. Worldwide, cattle are a major source of emissions of methane, a potent greenhouse gas.
California is also home to a major farming industry. The agreement says the two governments may engage in joint projects to expand farming practices that build soil health, reduce methane emissions and boost water efficiency.
The memorandum of co-operation was signed by Jeremy Clarke-Watson, New Zealand's consul-general in Los Angeles, and Jared Blumenfeld, secretary of the California Environmental Protection Agency.
At last year's global climate change conference in Scotland, California signed a brief joint declaration with New Zealand and the Canadian province of Quebec to share information on climate policies including carbon markets.
Because of Ardern's high-profile role in the wake of the 2019 massacre of 51 worshippers at two mosques in Christchurch, the issue of gun control was also expected to come up.
Newsom is pressuring the state legislature to send him a package of gun reform bills in the wake of this week's killing of 19 children and two teachers at a Texas elementary school.
Less than a month after the Christchurch shootings, New Zealand's parliament voted to outlaw most automatic and semi-automatic weapons.
Newsom and Ardern did not publicly discuss gun control, though Ardern addressed her country's actions on the issue in response to a question about "shared values" between California and New Zealand.
"It was clear that the New Zealand public expected its politicians to find solutions and quickly," Ardern said.
"Are they the answer to all of our issues as they relate to weapons in New Zealand? No. But they were practical steps that we believe were necessary, and that would make a difference. And so we made them."
Australian Associated Press
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