A sea of protesters swarmed in front of the White House on Saturday to voice displeasure with President Donald Trump's stance on the environment and demand that he rethink plans to reverse the climate change policies backed by his predecessor.

The People's Climate March, the culmination of a string of Earth Week protests that began with last Saturday's March for Science, coincides with Trump's 100th day in office, the end of the traditional "honeymoon" period for a new president.

As temperatures rose above 90F under hazy skies in the nation's capital, tens of thousands of people marched from the grounds of the US Capitol and passed the White House en route to the Washington Monument for a rally.

Many of the protesters carried signs with slogans such as "The seas are rising and so are we" and "Don't be a fossil fool". As the procession passed the Trump International Hotel on Pennsylvania Avenue, marchers booed and chanted "shame".