Boris Johnson has unveiled a combined £1.2bn in funding for new efforts to tackle the climate emergency and protect endangered species as he prepares to attend the annual gathering of world leaders at the United Nations in New York.

While at the UN general assembly, the prime minister will use a speech to announce £1bn in aid money for UK inventors to seek funding for high-tech initiatives connected to areas such as renewable energy and lower levels of pollutants.

He will separately announce a £220m fund to tackle the erosion of biodiversity, focusing on desperately endangered species such as the black rhino and Sumatran tiger.

Downing Street hopes Johnson’s environment speech will be the highlight of a trip that is likely to be dominated by questions about Brexit, but the plans prompted a withering response from Greenpeace, which said it amounted to “a flop” in terms of world leadership on the issue and fell well short of the vision required.`

The World Wildlife Fund (WWF) charity, which will be hosting the UN event at which Johnson will announce the biodiversity fund, praised the plan but warned that focusing only on technological solutions for the climate emergency would not be sufficient.

The £1bn innovation fund is billed as seeking “the latest cutting-edge tech” in areas such as sustainable electricity supplies for developing countries, improved battery technology and ways for heavily polluting industries such as steel and cement to reduce emissions.

Coming from the aid budget, the fund is named after Hertha Ayrton, a pioneering Victorian-era physicist and engineer, who was also a passionate suffragette and whose daughter, Barbara Ayrton-Gould, was a Labour MP at the time of the Attlee government.

Announcing the new biodiversity fund with what is described as an initial £220m in funding, Johnson was expected to warn that species and habitats were vanishing faster than at any other time in history.

The money will be targeted at better law enforcement to protect environments, prevent poaching and hamper the trade in illegal wildlife goods.

Speaking before the UN meeting, to which he was heading on Sunday, Johnson said he had “always been deeply optimistic about the potential of technology to make the world a better place”.

He said: “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.”

On biodiversity, he said: “It is a privilege to share our planet with such majestic beasts as the African elephant, the black rhino and the beautiful pangolin. 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.”

Rebecca Newsom from Greenpeace UK said: “This is the first big test of Boris Johnson’s climate and environmental leadership on the world stage, and he’s heading for a flop.

“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.”

On protecting wildlife, Newsom said the UK would have a much bigger impact “if it paused trade talks with Brazil until the Amazon is protected while committing to putting environmental and human rights protections at the heart of all future trade deals”.

Mike Barrett from WWF UK praised the biodiversity fund and said the innovation money was “an important acknowledgment of the scale of the global crisis”.

But he added: “Investment in technology is welcome but the government must back this up with trade policies that actively combat climate change and reduce deforestation.”

In New York, Johnson is set to hold a series of talks likely to touch on Brexit, including with Donald Tusk, Emmanuel Macron, Angela Merkel, and Ireland’s Leo Varadkar.

Other bilateral meetings include Donald Trump; the Indian prime minister, Narendra Modi; the New Zealand PM, Jacinda Ardern and Egypt’s President Abdel Fatah al-Sisi.