Carbon reduction targets that the USA set under Paris commitment aimed at reducing emissions by 26-28% in a decade.
May other United States allies expressed alarm at US' decision to back out, with leaders of France, Germany, and Italy noted with regret Trump's decision to do so.
She added that the global climate would "survive" Trump's maximum presidential term of eight years.
Beijing's emphatic support for the Paris deal comes as the world's second-largest economy promotes itself as a champion of globalisation, capitalising on Trump's inward-looking stance on trade and foreign policy.
At an election campaign event in York, he said: "Given the chance to present a united front from our global partners she (Mrs May) has instead opted for silence and once again subservience to Donald Trump".
In 2015, there was a huge worldwide deal to do something about climate change. OPEC and 10 other countries led by Russian Federation agreed last week to extend for nine months, to March, a production cut of 1.8 million barrels a day initially agreed on in November.
However, his decision to pull the US from the voluntary agreement isolates the country from most of the rest of the world.
The Democratic-led states of California, New York and Washington also asserted their opposition to the president's move, pledging to uphold the global accord's goals to reduce greenhouse gas emissions that contribute to global warming. Facebook founder, Mark Zuckerberg also slammed this decision and shared his thoughts on climate change.
Despite the decision by the United States, the second biggest polluter after China, to pull out of the deal, many analysts suggest the shift to a low-carbon economy is now unstoppable, with renewable prices tumbling and new clean technology being developed and deployed. Former US presidentBarack Obama, whose deal with China was instrumental to forging the Paris agreement, accurately assessed Trump's move by calling it a "rejection of the future".
"While the USA decision is disheartening, we remain inspired by the growing momentum around the world to combat climate change and transition to clean growth economies", said Canadian Prime Minister Justin Trudeau.
China's overseas investment in renewable energy deals exceeding $1 billion each soared 60 percent to $32 billion in 2016, according to the US-based Institute for Energy Economics and Financial Analysis, which expects the trend to continue.