Rising temperatures across the planet have set more records as the US government announced the globe experienced its hottest month of March since record keeping began in 1880.

The period of January to March was also the warmest on record, according to the monthly report by the National Oceanic and Atmospheric Administration (NOAA).

The latest data, which takes into account global averages across land and sea surfaces, follows announcements from the same US government scientists that 2014 was the hottest year in modern history.

Scientists warn fossil fuel burning is pushing more greenhouse gas into the atmosphere, leading to increased temperatures, melting of polar ice and glaciers, and rising seas.

For March, the average global temperature was 0.85 degrees Celsius above the 20th-century average.

"This was the highest for March in the 1880-2015 record, surpassing the previous record of 2010 by 0.05C," the report said.

For the first three months of the year, the average temperature worldwide was 0.82 degrees above the 20th-century average.

That marked the highest ever recorded for that period, surpassing the previous record in 2002 by 0.05 degrees.

Also of concern was the finding that Arctic sea ice was the lowest on record for March.

"The average Arctic sea ice extent for March was 430,000 square miles (1,113,699 square kilometres, 7.2 per cent) below the 1981-2010 average," the report said.

"This was the smallest March extent since records began in 1979."

Climate change 'bigger than my presidency': Obama

US president Barack Obama has used his weekly address to urge action on climate change, saying it posed the world's biggest single threat.

"Today, there's no greater threat to our planet than climate change," Mr Obama said in his weekly address, which had an environmental theme to mark Earth Day on April 22.

"Climate change can no longer be denied, or ignored," he added, noting that 2014 was the hottest year on record.

The US is the second largest greenhouse gas emitter after China, and Mr Obama has pledged to reduce US climate pollution by 26-28 per cent from 2005 levels by 2025.

"This is an issue that's bigger and longer-lasting than my presidency," he said.

"This is the only planet we've got. And years from now, I want to be able to look our children and grandchildren in the eye and tell them that we did everything we could to protect it."

Mr Obama, who has made the fight against climate change one of his priorities, hopes to help seal a global deal at an international climate conference in Paris in December.

Earlier this year Australia's peak science body CSIRO and Bureau of Meteorology said updated climate change predictions confirmed what they had been saying for years: Australia is on track for increasingly extreme weather.

AFP