Global warming is feared for its environmental, health and financial impacts and in an effort to avert the unwanted threats of the changing climate, environmental activists organize social movements and hold events that could lead to the reduction of greenhouse gas emission.

One such event will take place in New York City this Sunday, Aug. 21, two days ahead of the United Nations Climate Summit, which will also be held in the same city. The People's Climate March is anticipated to be the biggest protest on climate policy in history.

Over 1,400 organizations have endorsed the event and students have called on rallyers from over 300 college campuses. The march, which will begin at 11:30 in the morning and will pass through Midtown Manhattan on a two-mile route, expects over 100,0000 participants, which include  notable personalities in the business, politics and the entertainment industries such as former U.S. vice president Al Gore, U.N. Secretary-General Ban Ki-moon and Hollywood star Leonardo DiCaprio.

Organizers and participants of the event hope that the march could encourage world leaders, with over 100 of them joining the climate summit next week, to make meaningful commitments that could reduce the global emission of greenhouse gases, which is attributed as a significant factor in the changing climate.  

Earlier this month, UN's World Meteorological Organization (WMO) revealed that the concentration of the carbon dioxide in the atmosphere rose at a historical rate last year, an increase associated with industrialization. Man-made activities such as combustion of fossil fuels for electricity and transportation are the primary sources of carbon dioxide emission particularly in developed countries.

"This march is going to have a serious political impact, maybe not today, but certainly in the months and years to come," said Jamie Henn, from the environmental group 350.org, which has helped organized the event.

Those who are too far from New York to participate in the march also have opportunities to take part in over 2,700 other climate events that will coincide with the rally in the Big Apple including those that will take place in London, Melbourne, New Delhi, Jakarta and Rio de Janeiro.

"It's not just mobilizing in New York - we have over 2,000 events scheduled worldwide," said 350.org spokesman Hoda Baraka. "So many people are mobilizing, not just in New York, but all over the world - it's bringing together people from all different walks of life, all of them united in a call for action for climate change."