Leaders gather to commit to action on climate change

Climate change has been a huge issue for a long time now - with many people worried about melting glaciers - huge pieces of ice - causing rising sea levels.

Melting glacier, Greenland

World leaders, including US President Barack Obama, have held a special meeting, to try to stop the problem getting worse.

During the meeting, the President warned that a failure to act on climate change is a "betrayal" of future generations.

120 world leaders gathered at the summit at the U.N. headquarters in New York

He said climate change was moving faster than efforts to address it, and the US and China had a responsibility to lead other nations.

China has now pledged to take firm action on climate change for the first time.

The summit, which took place in New York, was the first major gathering of high-level leaders since 2009.

What is climate change?

Scientists say a rise in man-made greenhouse gases has resulted in some shrinking of glaciers, sea levels going up slightly and the temperature of some seas around the world rising. Greenhouse gases are produced by many things including burning fossil fuels like oil, natural gas and coal.

Satellite image showing water temperatures in the Pacific Ocean

Animals Under threat

Animals like polar bears, seals and penguins could be under threat if there isn't enough food as a result of changing conditions. Small islands may be also be lost, if sea levels rise in the future.

Polar Bear in the Arctic Barents Sea region

"The world must set on a new course"

Leonardo DiCaprio, who has been appointed as a United Nations representative on climate change, told the UN audience that climate change was not ''a fiction''.

The Hollywood actor said there was ''evidence that accelerated climate change is here, right now''.

Hollywood actor, Leonardo DiCaprio said: ''I believe that mankind has looked at climate change as if it was a fiction''

The meeting was hosted by UN Secretary General Ban Ki-moon.

As he closed the summit, Mr Ban hailed the meeting, saying "never before have so many leaders gathered to commit to action on climate change".

                          

UN Secretary General Ban Ki-moon asked world leaders to take action

He said: "Today, we must set the world on a new course," said UN Secretary-General Ban Ki-moon "I am asking you to lead".

Many protestors demonstrated outside the meeting. They're angry at some businesses who they claim can use too many fossil fuels. Protestors want them to use cleaner, more environmentally friendly fuels for the future.

From CBBC newsround

Street protests demanding urgent action on climate change have attracted hundreds of thousands of marchers in more than 2,000 locations worldwide.

The People's Climate March is campaigning for curbs on carbon emissions, ahead of the UN climate summit in New York next week.

In Manhattan, organisers said some 310,000 people joined a march that was also attended by UN chief Ban Ki-moon.

Earlier, huge demonstrations took place in Australia and Europe.

"This is the planet where our subsequent generations will live," Mr Ban told reporters. "There is no 'Plan B' because we do not have 'Planet B'."

The UN Secretary General was accompanied by primatologist Jane Goodall and the French Ecology Minister, Segolene Royal.

New York hosted the largest of Sunday's protests, drawing more than half of the 600,000 marchers estimated by organisers to have taken part in rallies around the world.

In Manhattan, Ban Ki-moon (in blue hat) was flanked by primatologist Jane Goodall (to his right) and French ecology minister Segolene Royal

Manhattan echoed to the sound of chants, horns and drums as the colourful protest progressed through the streets.

Organisers of the Manhattan event said it surpassed the largest previous protest on climate change.

They said the massive mobilisation was aimed at transforming climate change "from an environmental concern to an everybody issue".

Business leaders, environmentalists and celebrities joined the demonstration.

Hollywood actor Leonardo DiCaprio also took part, having been appointed as a UN representative on climate change last week.

Many of the marchers in New York wore costumes associated with indigenous people

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Brazil builds giant Amazon observation tower

Construction has begun on a giant observation tower in the heart of the Amazon basin to monitor climate change.

The Amazon Tall Tower Observatory is expected to rise 325m from the ground.

Its instruments will gather data on greenhouse gases, aerosol particles and the weather in one of the largest continuous rain forests on the planet.

Brazilian and German scientists hope to use the data to better understand sources of greenhouse gases and answer questions on climate change.

The tower is being constructed out of steel that was brought thousands of kilometres from the south of Brazil to the site, about 160km (100 miles) from the Amazonian city of Manaus.

Manaus-the state capital of Amazonas

Because of its height, the tower will make it possible to investigate the alteration and movement of air masses through the forest over a distance of several hundred kilometres.

"The measurement point is widely without direct human influence, and therefore ideal to investigate the meaning of the forest region for the chemistry and physics of the atmosphere," said Jurgen Kesselmeier, the project coordinator for the German side, quoted on the Max Planck Institute for Chemistry in Mainz website.

The Amazon jungle is one of the world's most sensitive ecosystems, with a powerful influence on the intake and release of carbon into the atmosphere.

"The tower will help us answer innumerable questions related to global climate change," said Paulo Artaxo, from the University of Sao Paulo.

The tower will be integrated into an existing structure of smaller measuring towers in the region.

When finished, it will complement a similar observatory built in 2006 that already stands in Central Siberia.

The Amazon rainforest is responsible for absorbing tonnes of greenhouse gases from the atmosphere

From BBC Sci/ Environment