The Pope demanded justice for the weak and affirmed the rights of the environment on Friday in a forceful speech to the United Nations that admonished against “a selfish and boundless thirst for power and material prosperity”.

A day after making history by becoming the first Pope to address Congress, Francis for the first time asserted that nature – as well as humanity – had rights.

“It must be stated that a true ‘right of the environment’ does exist,” Francis said.

An attack on the environment was an assault on the rights and living conditions of the most vulnerable, he said, warning that at its most extreme, environmental degradation threatened humanity’s survival.

“Any harm done to the environment, therefore is harm done to humanity,” Francis said. “The ecological crisis, and the large-scale destruction of biodiversity, can threaten the very existence of the human species,” he concluded.

The speech, delivered in Spanish to an overflowing hall, came on the eve of a UN conference intended to adopt 17 new goals for a more sustainable model of development, and during the last stretch of negotiations on a deal to fight climate change.

The pope’s appearance, on the second leg of the pontiff’s tour of the US, prompted an enormous security crackdown in Manhattan. Traffic was halted for blocks, while outside the UN, delegates and workers began lining up before dawn to try to get a glimpse of the pope.

Sections of Francis’s speech were clearly aimed at the assembled world leaders and UN staff, raising the bar for the international community in resolving injustice and poverty.

While praising the UN for its work – Francis took care to mention secretaries, maintenance people and other unsung workers during a brief meeting with staff before the address – he urged the institution to aim for a higher standard.

Without the United Nations efforts to protect peace and human rights, “mankind would not have been able to survive the unchecked use of its own possibilities”, Francis said.

But he said that international institutions needed to do more, counselling the UN against complacency, or what Francis dismissed as “idle chatter”.

The setting of laudable targets on its own was not enough to deal with the problems of the poor. “We need to ensure that our institutions are truly effective in the struggle against all these scourges,” the pope said.

In the wide-ranging speech, the pope alluded to the recent nuclear deal with Iran (which he described as “proof of the potential of political goodwill”) and reaffirmed girls’ rights to education. Among those in the audience was Nobel laureate Malala Yousefzai, the Pakistani education campaigner who was shot and injured by the Taliban in 2012.

Francis also took a swipe at international financial institutions – though not by name – saying that banks needed to reform to make the world more equitable.

He expressed deep concern for the persecution of Christians in the Middle East, where they and other religious groups, have been “forced to witness the destruction of their places of worship, their cultural and religious heritage” and been forced to flee or face death or enslavement.

In every area of conflict – including Ukraine, Syria, Iraq, Libya, South Sudan and the Great Lakes region in Africa – Francis said it was essential that human beings “take precedence over partisan interests, however legitimate the latter may be”.

Francis’s inclusion of Ukraine is noteworthy because he has been gently criticized for not speaking forcefully enough against Russia’s conflict with Ukraine.

Although the speech was overwhelmingly progressive in its tone, Francis also made it clear that he upholds the Catholic church’s doctrine on abortion, calling for the “absolute respect for life in all its stages”. The pope also invoked “moral law written in nature itself” to insist on the “natural difference” between men and women.

But his strongest words were reserved for his defence of “this common home of all men and women”.

Francis had already declared himself a powerful force against global poverty, social injustice and climate change with the release of his encyclical on the environment in June.

With his moral authority and charisma, the pope has helped re-frame climate change from an arcane set of negotiations into an issue with sweeping moral implications.

Publication of the 180-page encyclical in June injected a much-needed sense of momentum into preparations for upcoming climate change negotiations in Paris, and launched a frenzied organising effort by Catholic and other religious groups.

As the encyclical made evident, the pope believes that unrestrained capitalism of the current economic order is trampling upon the rights of the poor and the weak, and destroying the environment.

Such economic practices encouraged what he called a “culture of waste” in which the poorest and weakest were seen as disposable.

But while the encyclical referred to the rights of individuals, the poor, and future generations, it made no such claims for the the Earth itself.

In his address to the UN, the pope deployed even stronger language, implying that the environment is not merely a necessary tool for human survival, but an element of the same creation, and therefore in possession of rights.

“We Christians, together with the other monotheistic religions, believe that the universe is the fruit of a loving decision by the Creator, who permits man respectfully to use creation for the good of his fellow men and for the glory of the Creator; he is not authorized to abuse it, much less to destroy it,” he said.

Sacrifice the environment, and wrongs against the weak and the poor were bound to follow, he said. “The misuse and destruction of the environment are also accompanied by a relentless process of exclusion,” Francis told the UN.

“A selfish and boundless thirst for power and material prosperity leads both to the misuse of available natural resources and to the exclusion of the weak and disadvantaged,” he said.

For Ban Ki-Moon, the UN secretary-general, the pope has proved a formidable ally in the faltering efforts to reach a deal to fight climate change. After his address, the swell of optimism was almost palpable among those who hope he can inject fresh momentum to the Paris talks.

“At the end of the day negotiators are human beings. At the end of the day world leaders are human beings,” said Rachel Kyte, the World Bank’s climate envoy, after the address .

“Pope Francis has once again reminded world leaders that alleviating poverty and preserving the environment are part of the same struggle,” Greenpeace said in a statement.

Jimmy Burns, a papal biographer, said the UN offered Francis an important platform to address a global audience as “the world’s most popular spiritual leader, and focus the attention of world leaders on the need for action beyond words”.

“It also contained an alert call on world powers at the Security Council for their failure to agree on a peaceful settlement in the Middle East, while holding up the nuclear agreement between the western powers and Iran as an example of constructive diplomacy,” Burns said.