Scientists will be able to use up to £1 billion of the aid budget inventing new technology to tackle the climate crisis in developing countries, Boris Johnson is to announce.

The Prime Minister will commit the clean energy fund named in honour of British physicist and suffragette Hertha Ayrton in a speech at the United Nations in New York on Monday.

Putting an emphasis on technology’s potential to answer the climate emergency, he will also announce a further £220 million from the overseas aid budget to save endangered species from extinction.

But environmental groups warned changes to economic policies were essential to thwart environmental disaster, rather than relying solely on technology.

The PM will make the commitments at the UN General Assembly where he will hold joint Brexit talks with French President Emmanuel Macron and German Chancellor Angela Merkel.

He will also meet European Council president Donald Tusk as he tries to get a new deal ahead of the current October 31 Brexit deadline. A bilateral meeting is also scheduled with US President Donald Trump.

The Ayrton fund aims to encourage scientists to develop and test cutting-edge technology to help reduce emissions in developing countries and to help them meet their carbon targets.

It is named after the scientist who helped further women’s rights and make major scientific advancements at the turn of the 20th century, including in electricity.

Ahead of the announcement, the PM said: “I have always been deeply optimistic about the potential of technology to make the world a better place.

“If we get this right, future generations will look back on climate change as a problem that we solved by determined global action and the prowess of technology.”

The fund aims to cut emissions by means including providing affordable access to electricity to some of the one billion people who are still off the grid, and designing low-emission vehicles.

The new international biodiversity fund will aim to halt the loss of species, with the world’s animal populations estimated as having declined by nearly two thirds in half a century.

The PM hopes the money will save the black rhino, African elephant, snow leopard and Sumatran tiger from extinction.

The fund will help invest in projects to cut down on illegally-traded products to reduce the demand for hunting, to train anti-poaching rangers and to help communities find alternative means to make a living other than poaching.

“We cannot just sit back and watch as priceless endangered species are wiped off the face of the earth by our own carelessness and criminality,” the PM said.

WWF UK welcomed the “important acknowledgement” of the scale of the crisis but warned that funding new technologies alone is not enough to solve the “planetary emergency”.

Executive science and conservation director Mike Barrett said: “Investment in technology is welcome but the Government must back this up with trade policies that actively combat climate change and reduce deforestation.”

Mr Johnson will announce the biodiversity fund at a WWF event.

Greenpeace UK head of politics Rebecca Newsom said the PM was destined for “a flop” in his first big test on environmental leadership, saying new finance must come in addition to the aid budget to “avoid undermining other vital” support.

She said a crackdown on poachers is “not enough to stop rampant deforestation”, and said a greater impact would come from pausing trade talks with Brazil until the Amazon is protected, scrapping a third runway at Heathrow, banning fracking and tripling renewable energy by 2030.

“The collection of pet projects announced here falls desperately short of the radical action and bold vision demanded only last week by millions of kids and grownups in the largest climate protest in history,” she said.

“Scientists have been clear that to tackle the climate and nature emergency we need to rethink many aspects of our society and our economy.”

Friends of the Earth campaigner Paul de Zylva said the spending is “dwarfed” by Government support for fossil fuels and environmentally-harmful practices.

Labour tried to paint the spending as an effective cut after the UK leaves the EU, saying the £220 million “is paltry” compared to the £3 billion it said the UK spent on biodiversity as a member of the EU.

“It makes crystal clear that the no-deal Brexiteers are in fact looking for ways to cut spending in all these areas, as soon as the UK leaves,” the MP said.

Meanwhile, International Development Secretary Alok Sharma will announce a further £175 million of aid money to be used on climate initiatives in the developing world.

Of that, £85 million will be spent protecting one billion people from natural disasters such as typhoons and hurricanes with earlier warnings, as well as handling their aftermath.

The rest will be used to help cut the costs of disaster risk insurance.