"Obviously, he must have scientists coming to talk to him all the time, so he is obviously not listening to the scientists," she said.
The Metropolitan Police have deployed more than 10,000 officers to manage the climate protests. They had made more than 1000 arrests and charged 71 people for breaching public order, obstructing traffic or obstructing police.
Demonstrators gathered under the banner of the group "Extinction Rebellion" have blocked the Waterloo Bridge over the Thames River and parked a pink sailboat at the intersection at the Oxford Circus.
They camped at the Marble Arch at Hyde Park and staged a "die-in" in the central hall at the Natural History Museum, beneath a skeleton of a blue whale, to raise awareness of the ongoing "mass extinction" brought about by humans. They also took their clothes off during an April 1 Brexit debate in Parliament.
Organisers say they have three core demands: for the Government to "tell the truth" about climate change; to reduce carbon emissions to net zero by 2025; and to form a citizens assembly to monitor progress. They call climate change an existential threat to humanity and the planet.
"I am full of hope," said Sarah Shurety, a business consultant who came to Parliament Square with a letter she wanted to deliver to her representative. It read: "No bees. No flowers. No fruits. No me. No you."
Shurety said she thought the demonstrations were worth the disruption.
"I've heard the people who say, 'oh, I can't get to work.' I think that pales into insignificance the destruction of the planet," she said.
London Mayor Sadiq Khan, though, seemed to reaching the limit of his tolerance.
"I share the passion about tackling climate change of those protesting, and support the democratic right to peaceful and lawful protest," he said.
"But this is now taking a real toll on our city - our communities, businesses and police. This is counter-productive to the cause and our city."
Boris Johnson, a former London mayor and a potential future prime minister, used his column in the Telegraph to say: "I cannot find it in my heart - no matter how smug, irritating and disruptive they may be - to condemn these protesters today."
Johnson said he, too, laments the global rise in pollutants and the loss of species. But he said there is reason for cautious optimism - that Britain has been a global leader in carbon reductions.
And in the next few weeks, Johnson reported, the British Government will announce a target of net zero emissions by 2050.
"That would be an amazing achievement; but the evidence of the last few years is that it can be done, not through hair-shirted Leftyism but solid Tory technological optimism," he wrote.
