Overshadowed by his decision to describe some of those who took part in the far-right rally in Charlottesville as “very fine people”, Donald Trump announced plans to scrap regulations designed to protect roads and other infrastructure from climate change.

Under Barack Obama, the US federal government was required to consider the effects of global warming when planning infrastructure, such as the risk of flooding from predicted sea level rise.

Mr Trump complained that such regulations were slowing down projects, claiming it had taken 17 years to build a road in a state that he would not name.

The US President wants to spend $200bn of government money over 10 years on improving infrastructure as part of a $1 trillion programme involving private funds.

However a Republican from South Florida, where recent flooding has seen fish swim in the streets of Miami, one of the most vulnerable cities in the world to sea level rise, condemned Mr Trump’s plans saying they were not “fiscally conservative” but “irresponsible”.

Speaking at Trump Tower in New York, Mr Trump said: “I just signed a new Executive Order to dramatically reform the nation’s badly broken infrastructure permitting process.

“Just blocks away is the Empire State building. It took 11 months to build. But today, it could take as long as a decade.

“We used to have the greatest infrastructure anywhere in the world, and today we’re like a third-world country. No longer will we allow the infrastructure of our magnificent country to crumble and decay.”

He suggested the Democrats in Congress, who joined forces with rebel Republicans to defeat his healthcare proposals, would back his infrastructure plans.

Mr Trump has described global warming as a “hoax” and has appointed a string of climate science deniers to key posts. He’s also announced the US will withdraw from the Paris Agreement on climate change.

Carlos Curbelo, a Republican in the House of Representatives who serves South Florida, said spending vast amounts of infrastructure that would not stand up to the changing weather was a false economy.

“Sea level rise and the risk of severe flooding are a reality for communities across the country,” he said in a statement.

“When you’re on the front lines like South Florida, we know the importance of having more resilient building codes to protect our infrastructure, especially when taxpayer dollars are used.

“This Executive Order is not fiscally conservative, it’s irresponsible, and it will lead to taxpayer dollars being wasted on projects that may not be built to endure the flooding we are already seeing and know is only going to get worse.”

And Jessica Grannis, of the Georgetown Climate Centre, told ABC News: “What this order will do is ensure that we will waste more taxpayer money because federal agencies will no longer have to consider long-term flood risks to federally funded infrastructure projects.”

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Rafael Lemaitre, former director of public affairs at Federal Emergency Management Agency, who worked on the Obama-era order, told Reuters that Mr Trump was getting rid of “the most significant action taken in a generation” to safeguard US infrastructure.