Nasa has announced that the last six months were the warmest on record since 1880. April, May, June and August were each hotter than they have ever been before, while the month of July was the fourth-warmest it has ever been.

The findings, experts claim, suggest that the current period is the warmest ever experienced by human civilisation.

Washington DC-based Nasa says April to Sept was hottest on record. Their findings were backed up by the National Climatic Data Center. In this animation the deviation of global temperatures away from the average temperature are revealed, with blue being below average and red above average, for each month. Credit: Nasa

The research, reported by Slate, reveals how April was the first month in more than 800,000 years that atmospheric carbon dioxide reached 400 parts per million.

April - Hottest on record, 0.77°C (1.39°F) above the 20th century average of 13.7°C (56.7°F).

May - Hottest on record, 0.74°C (1.33°F) above the 20th century average of 14.8°C (58.6°F)

June - Hottest on record, 0.72°C (1.30°F) above the 20th century average of 15.5°C (59.9°F)

July - Fourth hottest on record, 0.64°C (1.15°F) above the 20th century average of 15.8°C (60.4°F)

August - Hottest on record, 0.75°C (1.35°F) above the 20th century average of 15.6°C (60.1°F)

September - NCDC to publish its results soon.

A separate record of global temperatures by the National Climatic Data Center matched up to Nasa’s on how the planet is warming.

June, for example, was found to be 0.72°C (1.3°F) above the 20th century average of 15.5°C (59.9°F) - the highest on record.

For August, the surface temperature reached 16.35C (61.45F), above the 20th century average of 15.6C (60.1F).

September, meanwhile, was found to be 0.8°C (1.4°F) above the 1951 to 1980 average, breaking a previous record in 2005 according to Nasa.

‘If we continue a consistent departure from average for the rest of 2014, we will edge out 2010 as the warmest year on record,’ said NCDC climatologist Dr Jake Crouch.

Dr Crouch said that if the rest of the months this year are merely in the top five warmest - which is quite likely - then 2014 will rank as the warmest year on record.

It was ocean temperatures that were found to be particularly warm in the latest findings. By comparison surface temperatures in the US, Europe, Central Asia and Australia were near average.

But the latest findings come as several states in the Western US continue to experience a ‘mega-drought’ - and scientists in California have warned it could last a century.

The warnings come after sediment studies showed California is currently experiencing the driest spell since 1580, and that the regular rainfall seen during the last century is likely to have been a temporary deviation in a cycle of droughts and very occasional rainfall over the last 3,000 years.

In 2013, California received less rain than in any year since its formation as a state in 1850.

Itis thought that later this year El Niño will also contribute to global temperatures, with the Noaa’s Climate Prediction Center saying there is a 60 to 65 per cent chance of at least a weak El Niño developing in autumn or winter.

However it is not thought this will be enough to end the drought that is currently plaguing the US West Coast, despite it being expected to bring more rain.