On September 21 , hundreds of thousands of protestors from all over the world gathered on the streets to call for action against climate change.

Activists from more 150 countries took part in demonstrations right before the world leaders' meeting of the United Nation's emergency Climate Change Summit in New York City today, The Guardian reported.

The demonstrations make up the biggest global call for action on climate change in history. In New York, more than 300,000 people marched, three times bigger than what the organizers expected.

Recent reports have kept revealing how serious the situation is and how important it is to act immediately.

Over the decades, scientists and experts repeatedly warned the governments and international organizations about the urgency of the situation. Activists kept putting pressure on governments to take action, but the accomplishments so far haven't been enough to stop the worsening problem.

The activists hope this massive march will be effective in putting more pressure on governments to hear their demands.

The demonstrators all came from different backgrounds, however they were all asking for one thing: that world leaders acknowledge the severity of global climate change and immediately take action on the issue instead of just promising to do so.

Celebrities like Leonardo Di Caprio and Mark Ruffalo who are well-known for their participation in environmental causes such as conversation efforts were seen marching side by side with activists.

Former and current politicians like UN secretary general Ban Ki-moon, former US vice-president, world-famous primatologist Jane Goodall and the mayor of New York City Bill de Blasio were also among the demonstrators.

The US Secretary of State John Kerry, on the issue, said that the global climate change is as urgent a matter as the current Ebola crisis in West Africa and the ISIS threat in the Middle East.

Kerry said, "While we are confronting ISIS, and we are confronting terrorism and we are confronting Ebola, this also has an immediacy that people have to come to understand. There is a long list of important issues before all of us, but the grave threat that climate change poses warrants a prominent position on that list," The Guardian reported.