World leaders are holding a summit on climate change at the United Nations.
UN Secretary-General Ban Ki-moon urged leaders and delegates from some 120 countries to set a "new course" on climate change at the opening of the one-day meeting on September 23.
The summit's aim is to galvanize member states to sign up to a comprehensive new global climate deal at talks in Paris next year, and generate agreements from business leaders on how they will reduce their firms' carbon footprints.
President Barack Obama called on all countries to join the United States in making "ambitious investments in clean energy and ambitious reductions in our carbon emissions."
Brazil's President Dilma Rousseff said tackling climate change and development were not contradictory goals, saying "we have reduced poverty and we have protected the environment."
The president of the European Commission, Jose Manuel Barroso, encouraged European leaders to agree on an "ambitious" proposal by the commission that includes a target to reduce greenhouse-gas emissions by 40 percent by 2030, when compared with 1990 levels.
On the eve of the summit, the World Bank said governments and some 1,000 companies will join forces to push for policies setting a price on carbon emissions to encourage a shift to cleaner energy technologies.
But the absence of the leaders of major countries, including China, the world's biggest polluter, and India, the No.3 carbon emitter, are casting a cloud over the event.
In another development, the Rockefellers, who made their vast fortune on oil, announced their charitable organization, with assets worth some $860 million, would divest from fossil fuels.
Hundreds of protesters marched through New York City's financial district on September 22 and blocked streets near the stock exchange to denounce Wall Street's role in raising money for businesses that contribute to climate change.
Protesters stopped traffic on Broadway south of the New York Stock Exchange. Three people were arrested.
The demonstration -- called Flood Wall Street -- came a day after an international day of action.
In New York City, some 300,000 took to the streets in what activists said was the largest protest ever held on climate change.
Meanwhile, fresh data show ice in Arctic seas shrank this summer to the sixth-lowest level in 36 years of monitoring.
Scientists are concerned about the ice melting from manmade global warming because the melting may change the weather further south.
Studies have linked the ice melting to changes in the jet stream, which can produce extreme weather.
Meanwhile, the temporary ice in Antarctic waters is hitting record high levels. Scientists attribute that to wind and local climatic conditions.
With reporting by AP and Reuters