Thousands of climate activists flooded the streets of Midtown, Manhattan on Sunday, initiating Climate Week ahead of the UN General Assembly in New York City.

Demonstrators held signs saying "End Fossil Fuel Use,""Declare a Climate Emergency" and "I didn't vote for fires and floods." The protesters implored US President Joe Biden and global leaders phase out fossil fuels, emphasizing their role in exacerbating climate change.

President Biden is among the world leaders set to attend the United Nations General Assembly, which is scheduled to formally open on Tuesday.

"We hold the power of the people, the power you need to win this election," said Emma Buretta, 17, of Brooklyn of the youth protest group Fridays for Future. "If you want to win in 2024, if you do not want the blood of my generation to be on your hands, end fossil fuels."

The 75,000 people who marched on Sunday came from about 700 organizations and activist groups, and drew people from all spheres.

"We have people all across the world in the streets, showing up, demanding a cessation of what is killing us," US Congresswoman Alexandria Ocasio-Cortez told a cheering crowd. "We have to send a message that some of us are going to be living on, on this planet 30, 40, 50 years from now. And we will not take no for an answer."

UN 2015 goals missing target

Many scientists say greenhouse gases from burning fossil fuels contribute to global warming, leading to extreme weather events, including hurricanes, heatwaves, floods, wildfires, and droughts seen around the world currently.

Curbing CO2 emissions is pivotal in tackling climate change. Scientists caution that within the next five years, the world may witness unprecedented high temperatures, with a significant chance of surpassing the critical mark of an average 1.5 degree Celsius increase.

Ahead of the upcoming UN COP28 climate summit, over 80 nations aim to establish an accord to progressively eliminate coal, oil, and gas.

A recent UN study cautioned about escalating global warming risks, emphasizing the need for comprehensive actions and drastic emission reductions, including significantly reducing coal-powered energy by 2030, according to news agency Reuters.

On Monday, the UN Sustainable Development Goals Summit starts, aiming for a "global rescue plan," according to UN Secretary-General Antonio Guterres. He noted that merely 15% of the sustainable development objectives adopted in 2015 were likely to be achieved, with some metrics heading in reverse.

To reach the 2015 target of net-zero carbon emissions by 2050, it's essential to eliminate the use of fossil fuels that can't have their emissions captured or compensated.

Fossil fuels reliance under scrutiny

Several leaders from top carbon-producing nations won't participate or present at a new special summit on Wednesday led by the UN Secretary-General, reserving the platform for countries pledging tangible actions.

While President Biden has notably championed green manufacturing and allocated billions for clean energy, critics argue he hasn't taken strong enough measures to reduce the US's reliance on fossil fuels.

On Friday, California sued five major oil companies, claiming they caused billions of dollars in damages and downplayed the dangers associated with fossil fuels to the public.

In the last century, the US has been the top cumulative emitter of carbon dioxide, although China now emits most annual emissions.

There is increasing global concern as climate change-induced severe weather events become more commonplace Deutsche Welle

Protesters have experienced climate change events

Sunday's protests marked a weeklong global initiative by Climate Group, a non-profit pushing for climate action. Over 500 protests are planned in 54 countries, including the U.S., Germany, England, South Korea, and India.

The rallies, a precursor to the upcoming the COP28 summit, reflect increasing global concern as climate change-induced severe weather events become more commonplace.

American University sociologist Dana Fisher studies environmental movements and took a survey of march participants. She said 86% of those surveyed had experienced extreme heat recently, 21% floods and 18% severe drought. They mostly reported feeling sad and angry.

"Our lives are on the line." 22-year-old Nalleli Cobo told AFP news agency.