Washington — The interests of the world’s peoples are shared, more than at any point in human history, and the international community must embrace “a new era of engagement” to confront pressing challenges such as nuclear proliferation, climate change and economic crisis, President Obama told the United Nations General Assembly.

In his September 23 address to world leaders, Obama said the first nine months of his presidency have shown a renewed effort by the United States to engage with the world and to live up to its own values. But, he said, “those who used to chastise America for acting alone in the world cannot now stand by and wait for America to solve the world’s problems alone.”

Rich countries and poor countries alike share a common future and no longer can afford to indulge their differences. “The time has come for the world to move in a new direction. We must embrace a new era of engagement based on mutual interests and mutual respect, and our work must begin now,” Obama said.

The world will continue to face grave challenges such as violent extremism, protracted conflicts, genocide, nuclear proliferation, the effects of climate change, poverty and pandemic disease unless leaders confront the status quo, he said.

“I say this not to sow fear, but to state a fact: The magnitude of our challenges has yet to be met by the measure of our action,” Obama said.

The international community has reached a pivotal moment, the president said. The United Nations “can either be a place where we bicker about outdated grievances, or forge common ground,” where nations can focus on “what drives us apart, or what brings us together,” a place where tyranny is indulged or a place that provides moral authority.

“In short, the United Nations can be an institution that is disconnected from what matters in the lives of our citizens, or it can be an indispensable factor in advancing the interests of the people we serve,” he said.

The president outlined “four pillars” that he said are fundamental to a better future for everyone: “nonproliferation and disarmament; the promotion of peace and security; the preservation of our planet; and a global economy that advances opportunity for all people.”

He renewed his call for a world without nuclear weapons, saying failure to act against proliferation efforts by countries such as North Korea and Iran “will invite nuclear arms races in every region, and the prospect of wars and acts of terror on a scale that we can hardly imagine.”

The United States will keep its end of the bargain, he said, including working with Russia to substantially reduce strategic warheads and launchers, ratifying the Nuclear Test Ban Treaty, and working to bring the treaty into force to permanently prohibit nuclear testing. The Nuclear Non-Proliferation Treaty, which grants every nation the right to peaceful nuclear energy but calls for global disarmament, is “the basic bargain” against the terror of nuclear weapons, and Obama said the 2010 review of the treaty “could be pivotal in determining whether this compact will be strengthened or will slowly dissolve.”

Restating his commitment to diplomacy with North Korea and Iran, Obama said both countries must still be held accountable for their pursuit of nuclear weapons. “The world must stand together to demonstrate that international law is not an empty promise, and that treaties will be enforced. We must insist that the future does not belong to fear,” he said.

Obama said the world must be determined to confront violent extremism with the undisputed view that “the murder of innocent men, women and children will never be tolerated.”

He called for the implementation of the Comprehensive Peace Agreement in Sudan, and pledged that despite setbacks, false starts and tough days, he would not waver in his pursuit of “a just and lasting peace between Israel, Palestine and the Arab world.”

“We continue to call on Palestinians to end incitement against Israel, and we continue to emphasize that America does not accept the legitimacy of continued Israeli settlements,” he said. Just as the United States “does Israel no favors” when it does not couple its unwavering commitment to Israel’s security “with an insistence that Israel respect the legitimate claims and rights of the Palestinians,” other member states in the United Nations “do the Palestinians no favors when they choose vitriolic attacks against Israel over a constructive willingness to recognize Israel’s legitimacy and its right to exist in peace and security,” he said.

On climate change, Obama said “the days when America dragged its feet” on the issue “are over,” and wealthy nations that caused the environmental damage in the 20th century “must accept our obligation to lead.” But, to be successful, fast-developing countries must also reduce carbon dioxide emissions and poor nations must have help in adapting to the effects of climate change.

“There will be no peace unless we take responsibility for the preservation of our planet,” he said. “Our efforts to end conflicts will be eclipsed by wars over refugees and resources. Development will be devastated by drought and famine.” The world also faces the judgment of future generations by failing to act, he said.

The president also said the world needs “a global economy that advances opportunity for all people,” that addresses despair, disease and poverty, and also reforms the global financial sector “so that we put an end to the greed, and the excess and the abuse” that has caused the current financial crisis. Just as wealthy nations must open their markets and help those with less, developing nations must root out corruption, “for opportunity cannot thrive where individuals are oppressed and businesses have to pay bribes,” he said.

Obama said democracy and human rights are essential to achieving those four pillars. “Governments of the people and by the people are more likely to act in the broader interests of their own people, rather than the narrow interest of those in power,” he said, and true leadership “will not be measured by the ability to muzzle dissent or to intimidate and harass political opponents at home.”

Just as no country should be forced to accept the tyranny of another, no individual should have to accept the tyranny of their own government, he said.

“The people of the world want change,” Obama said. “The United States of America will never waver in our efforts to stand up for the right of people everywhere to determine their own destiny.”

Full text of President Obama’s address to U.N. General Assembly.