Secretary-General Ban Ki-moon said Friday that one of the main lessons from Superstorm Sandy is the need for global action to deal with future climate shocks.

Ban told the U.N. General Assembly that it is difficult to attribute any single storm, like Sandy, to climate change.

"But we all know this: extreme weather due to climate change is the new normal," he said. "This may be an uncomfortable truth but it is one we ignore at our peril."

With a new round of global climate talks set to begin on Nov. 27 in Doha, Qatar, the U.N. chief urged the world's nations to reach a legally binding agreement by 2015 to rein in the emissions of heat-trapping gases in order to stop the planet from overheating.

Ban also gave U.N. member states an update on damage to the U.N. headquarters complex — mainly from flooding to the cooling system which in turn affected the U.N.'s data center — and responded to complaints about poor communication with diplomats, staff and the public. He pledged to improve communications, which came under scrutiny while the storm shut down U.N. headquarters for several days.

Ban said the world's best scientists have been sounding the alarm about climate change and people have seen with their own eyes the devastation from storms like Sandy, whose winds and flooding claimed more than 170 lives in the Caribbean and along the U.S. East Coast, especially in New York and New Jersey.

"There can be no looking away, no persisting with business as usual, no hoping the threat will diminish or disappear," he warned.

"Our challenge remains clear and urgent: to reduce greenhouse gas emissions, to strengthen adaptation to the even larger climate shocks we know are on the way no matter what we do, and to reach a legally binding climate agreement by 2015 as states agreed to do last year in Durban," he said.

Ban called this "an opportunity" to steer the world on a more sustainable path that will create jobs and new energy systems and lead to greater stability.

"This should be one of the main lessons from Hurricane Sandy," he said. "Let us make this wise investment in our common future."

Ban also announced a U.N. fund drive for victims of Sandy.

General Assembly President Vuk Jeremic opened Friday's meeting with a call for diplomats to observe a minute of silence for the victims of Sandy and this week's earthquake in Guatemala that killed over 50 people.

Jeremic announced that he and the secretary-general will be attending the upcoming Doha climate talks, which end on Dec. 7.

The two-decade-old negotiations have had limited success in creating a global regime to rein in greenhouse gases which a large majority of climate scientists say are warming the Earth, with potentially devastating consequences for poor countries ill-prepared to deal rising sea levels, floods and other effects of a changing climate.

Actions taken and pledged so far fall well short of what the U.N. experts say is needed to achieve the stated goal of preventing global temperatures from rising more than 2 degrees Fahrenheit (1.2 degrees Celsius) above current levels by the end of this century.

The only existing binding treaty, the 1997 Kyoto Protocol, was shunned by the U.S. because it doesn't impose any emissions targets on China, thus leaving out the two biggest carbon emitters on the globe. After Canada, Japan and Russia dropped out, the treaty's second commitment period covers only about 15 percent of global emissions.

After painstaking negotiations in Durban last December, countries agreed to create a new pact by 2015 that would take effect five years later and include both developed and developing countries.