Global average temperature in March this year has exceeded the average for 20th century by 1.07 deg C as against 1.04 C rise that February recorded. The figures from Japan Meteorological Agency also show that the last 11 months have been the hottest ever recorded for the corresponding months since 1891.

Meanwhile, Nasa data recorded March as 1.28 C above the average from 1951-1980, continuing the relentless 1 deg rise in average temperatures seen in six months now.

Based on the temperatures of the first three months of this year and the rising carbon levels, 2016 is set to beat 2015 as the hottest year on record.

Carbon dioxide in the atmosphere has reached 409.44 parts per million on April 9 at measuring station at Hawaii's Mauna Loa, a rise of almost ten ppm in a year. The last time such an increase was seen was in 1998 when a 3.7 ppm rise was recorded, writes the Scientific American.

The year 2015 began with a breaching of the 400 ppm level of carbon.

"Where you assign the peak will depend on whether the focus is on daily, weekly or monthly averages. The monthly peak is certainly still ahead of us," says Ralph Keeling, a geochemist at Scripps Institution of Oceanography in California who measures atmospheric CO2 every day at Mauna Loa and other stations. "The recent daily values were extraordinarily high, however, so perhaps [they] won't be overtaken."

While it is natural that CO2 concentrations typically peak just before summer when plants begin to draw in CO2, Keeling suspects that won't be able to bring down 400 ppm ever again.

Atmospheric CO2 has risen by nearly 100 ppm since the first measurements began at Mauna Lao in March 1958. This has been enough to drive temperatures up by a degree. The Earth has in its distant past seen much higher levels of carbon dioxide but that was much before human species appeared.

The last decade alone saw a jump by nearly 30 ppm propelled by feverish economic growth.

"The atmospheric and oceanic CO2 increase is being driven by the burning of fossil fuels," says Pieter Tans, a senior scientist at the National Oceanic and Atmospheric Administration's Earth System Research Laboratory, who leads the U.S. government effort to monitor global greenhouse gas levels. "When the burn rate is high, the CO2 increase rate is also high."

Global emissions
The global emissions of carbon dioxide from energy sector have leveled off since a couple of years now at around 32 billion tones, with renewable energy making a big impact, according to the IEA. However, current emissions cannot avert a temperature increase of 2.7 °C by 2100, the agency cautioned unless a major course correction is applied. Energy accounts for two thirds of global greenhouse gas emissions.

Total global emissions from human activities stand at roughly 40 billion metric tones but dry periods have seen increased incidents of forest fires as well as deliberate clearing of land by burning, all of which throw up more carbon into the air.

The El Niño—a warming of tropical Pacific Ocean waters that changes weather patterns across the globe—last year was also responsible for shifting rainfall patterns and drying forests and contributing to a CO2 spike. In 1998, the El Nino led to a record CO2 jump of nearly four ppm.

However, the temperature rise and resulting heat wave which has already killed many in India this year, is yet another evidence of climate change and its impact. Greenland's ice sheet has melted three months earlier this year, with 1.7 million square kilometers showing signs of melting last week.

This kind of melt is normally seen around May, said Peter Langen, a climate scientist at the Danish Meteorological Institute.