The amount of greenhouse gases in the earth’s atmosphere climbed to an unprecedented level last year, the World Meteorological Organization (WMO) said Monday, warning that further inaction on climate change would turn the world into a hostile place.
During spring 2015 in the northern hemisphere, global carbon dioxide (CO2) levels rose above the symbolically significant level of 400 parts per million (ppm) molecules of air.
“We will soon be living with globally averaged CO2 levels above 400 parts per million as a permanent reality,” WMO Secretary General Michel Jarraud said three weeks ahead of the UN climate conference in Paris, where countries aim to agree on emission curbs.
“We have to act now to slash greenhouse gas emissions if we are to have a chance to keep the increase in temperatures to manageable levels,” he warned.
Most of the net warming effect seen in the atmosphere over the past decade was caused by CO2, produced mainly from burning coal and oil, as well as cement production.
In addition, natural reservoirs that keep CO2 out of the atmosphere have been destroyed by deforestation.
“Every year we report a new record in greenhouse gas concentrations. Every year we say that time is running out,” said Jarraud.
Since 1990, the net warming effect seen in the atmosphere has increased 36 per cent mainly because of man-made CO2 emissions, but also because of an increase in other gases such as methane or nitrous oxide, according to the UN agency.
CO2 traps heat in the atmosphere, leading to higher temperatures, heatwaves, floods, melting ice, rising sea levels and more acidic oceans.
“The laws of physics are non-negotiable,” Jarraud said.
CO2 concentration in the air last year climbed to 143 per cent of the level seen before the industrial revolution in the 19th century, WMO reported.
In addition, methane emitted by agriculture and other industries reached 254 per cent of the pre-industrial level, while nitrous oxide from fertilizers and factories stood at 121 per cent.
WMO said that the effect from rising CO2 levels is amplified because higher surface temperatures create more water vapour, another important greenhouse gas.