Climate scientists say it's difficult to link a single weather event to global warming but some say the damage caused by Sandy was worse because of rising sea levels.
A small minority of scientists still question whether the warming seen in recent decades is due to human activities, such as the carbon emissions from the burning of fossil fuels.
"Let us avoid all the skepticism. Let us prove wrong all these doubts on climate change," Ban said.
Climate scientists have already observed changes including melting Arctic ice and permafrost, rising sea levels and acidification of the ocean, shifting rainfall patterns with impacts on floods and droughts.
Low-lying Pacific island states, in particular, are losing shoreline to rising seas, expanding from heat and the runoff of melting land ice.
Governments represented at the Doha conference have started talks on crafting a new global climate treaty that would take effect in 2020. They are also discussing how to rein in greenhouse gas emissions before then, partly by extending the Kyoto Protocol, a treaty limiting the emissions of most industrialized countries that expires this year.
The U.S. never joined Kyoto, because it didn't cover emerging economies such as India and China, which now has the world's highest carbon emissions.
With only a few days remaining to agree on the Kyoto extension and other issues, the head of the U.N. climate change secretariat, Christiana Figueres, reminded the delegates that the "eyes of the world" are upon them.
"Present and future generations are counting on you," she said.
Karl Ritter can be reached at www.twitter.com/karl_ritter