Greenhouse gases in the atmosphere hit record levels during 2014 and will make the planet a more dangerous place for future generations, the World Meteorological Organisation has warned.
The organisation released its 2014 report on concentrations of carbon dioxide, methane, nitrous oxide and other greenhouse gases yesterday. It emphasised the large scale contribution to global warming made by water vapour in the air.
Moisture in the air “amplifies warming” it says. A warmer atmosphere heated up by greenhouse gases means the air can hold more water vapour, causing further warming.
Atmospheric concentrations of carbon dioxide, the most important and longest-lived greenhouse gas, has now reached it highest level yet, with a global average of 397.7 parts per million (ppm).
Levels in the Northern Hemisphere peaked above the 400ppm level during spring 2014, a “symbolically significant” threshold, the organisation said.
With the global average so close to this point already, it expects the average to exceed 400ppm as early as next year.
With carbon dioxide levels so high "we are moving into uncharted territory at a frightening speed", said the organisation's secretary general Michel Jarraud.
His warning comes only weeks ahead of the UN Climate Change Conference COP 21 to be held in Paris from November 30 through December 11th.
Questions remain as to whether the meeting will manage to deliver a unified international response to controlling greenhouse gas emissions given the lack of progress made at previous conferences.
While COP 21 is about controlling the release of greenhouse gases, the organisation’s report is not looking at emissions but rather the level of these gases in the atmosphere above us.
Most of the warming effect comes from carbon dioxide, methane and nitrous oxide and once released, all of three remain in the atmosphere for a long time. Water vapour in the air is short-lived but its abundance helps to trap large amounts of heat while it is there.
Further increases in carbon dioxide concentrations will lead to disproportionately high increases in warming from water vapour, the organisation said.
Every year the report highlights rising levels for greenhouse gas concentrations and “every year we say that time is running out,” Mr Jarraud said.
“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 added.
“Past, present and future emissions will have a cumulative impact on both global warming and ocean acidification. The laws of physics are non-negotiable.”
Exceeding the 400 ppm global average won’t change things , “it is just another number, it goes up every year”, said Gerald Fleming, head of forecasting at Met Éireann.
“The real issue is levels of these gases are going up despite past agreements. There is no real sign of these increases abating,” he said.
