The United States could be isolated politically following a decision to leave the Paris climate agreement, according to a Canterbury University political scientist.
The move has been viewed in New Zealand as a step backwards, not only for climate change but for the US as a powerful player on the international stage.
Associate Professor Bronwyn Hayward, who was selected as a world expert for an upcoming report by the UN Intergovernmental Panel on Climate Change (IPCC), said there was a significant risk it would result in the US being politically isolated, weakening Donald Trump and his country's negotiating power.
She said the situation was very different to when the US pulled out of the Kyoto climate agreement in 2001.
"The very big difference is that in 20 years there's been a big shift in public understanding... people can see climate change now, they understand it."
Dr Hayward said America-first policies were also not always in the interests of other countries, such as New Zealand.
"It actually makes it harder to get international agreements because it reminds the rest of the world that America is out for America."
"Trump ironically looks weak... he hasn't been able to make a clean break. He has had to offer the olive branch of re-entering the agreement and that's because of his own internal divisions within the White House and with the Republican party," she said.
Professor James Renwick from the School of Geography, Environment and Earth Sciences at Victoria University, who has also been involved with the IPCC, agreed it could be the beginning of the end for the US leading on the international stage.
"The Chinese are going to take over here and I imagine the balance of power will shift in that direction."
Prof Renwick expected the decision would spur on other countries to do more for the climate.
"In a funny way it could because it is giving the Chinese, the Europeans, New Zealand... all countries the opportunity to step into the breach and take leadership."
Trump's job rationale makes no sense - Macey
New Zealand's former climate change ambassador Adrian Macey, meanwhile, said Mr Trump's reasoning for withdrawing from the Paris Accord did not stand up.
Dr Macey was New Zealand's representative in numerous climate change negotiations.
Mr Trump's hope of extra jobs from the coal industry was not rational, he said.
"I don't think it's possible to revive that coal industry, or the fossil fuel industry, unless you dump massive subsidies into it.
"Already in renewable energy, there are five times as many jobs as there are in the fossil fuel area, and it's renewables - wind and solar - that are the real job creation factory."
Global conservation group World Wildlife Fund said the Paris agreement was bigger than one nation and one man. Its New Zealand campaigner, David Tong, said it was pleasing European leaders have said the accord could not be renegotiated.
"It's also hard to see what it is that Trump wants to renegotiate because much of what he is calling for is what the Obama administration did negotiate into the Paris agreement."