World leaders were put on the spot yesterday when hundreds of thousands demanded more investment in environmentally friendly technologies to stop climate change.

Across the world, people came out ahead of the UN’s climate change summit, which starts tomorrow in New York.

In central London about 7,000 marched on Parliament calling for cleaner energy and a stop to “green cuts.”

WWF chief climate change adviser Leo Hickman told the Morning Star: “The intention of it was to show our leaders — not just David Cameron or the UK leaders but our global leaders — that the public deeply care about climate change.”

To Mr Hickman the silence on the topic is understandable in the face of world conflict, “but climate change is a threat multiplier.

“It can exacerbate all of these issues and become its own mega-problem as the decades play out.”

For some at the march the effects were already a harsh reality.

Kye and Nicole are the parents of Zane Gbangbola — a seven-year-old boy from Surrey who died of gas poisoning in February due to last winter’s floods.

Mr Gbangbola and his son were found unconscious after a local landfill started leaking cyanide gas into the rising waters, which flooded the family cellar. Zane was pronounced dead once in hospital, his father is now paraplegic.

“Politicians need to wake up to the fact that there are millions of people that need to be protected from ills of climate change,” said Mr Gbangbola.

He said that the government had not been held accountable for the consequences of the worst floods for decades.

“If the right strategies to alleviate flooding had been put in place, we wouldn’t be having this conversation, Zane would be here and I’d still be doing runs around London for charity.”

Marching with the family were celebrities including designer Vivienne Westwood and actress Emma Thompson, but also families with pushchairs, picnic baskets and their pets.

Many had come from outside London to show their support for the cause.

Julie, who had come from Sussex, said: “By being silent we give away our power but perhaps by standing up and showing ourselves we can begin to step into a greater power.

“Unstoppable — that’s how it feels like today.”