The presence of greenhouse gases in the Earth's atmosphere last year reached its highest levels since pre-industrial times, a report released by the United Nations World Meteorological Organization (WMO) warns Monday.

The tourism sector contributes around 5 per cent of global greenhouse gas emissions. [un.org]?

The latest edition of WMO's Greenhouse Gas Bulletin, which places special focus on rising nitrous oxide concentrations, also notes that the rate of increase of greenhouse gases has recently accelerated.

"Even if we managed to halt our greenhouse gas emissions today – and this is far from the case – they would continue to linger in the atmosphere for decades to come and so continue to affect the delicate balance of our living planet and our climate," said WMO Secretary-General Michel Jarraud.

According to the report, the 20 years to 2010 saw a 29 per cent increase in "radiative forcing" – the warming effect the gases have on the Earth's climate – from greenhouse gases, with carbon dioxide accounting for 80 per cent of this increase.

"Now more than ever before, we need to understand the complex, and sometimes unexpected, interactions between greenhouse gases in the atmosphere, Earth's biosphere and oceans," Mr. Jarraud said.

Human activities, such as fossil fuel burning and agriculture, are major emitters of greenhouse gases, which trap radiation within the Earth's atmosphere, causing it to warm and spur climate change.

Speaking at a press conference earlier today, WMO Deputy Secretary-General Jeremiah Lengoasa called for further development in the alternative energy sector to stem the rapid growth of greenhouse gases.

"Unless there is the investment made by funding alternative energy sources that are non-polluting, in particular as a viable substitute for fossil fuels, then the kind of steps that are required in scientific terms to cap or stem the growth would not happen and so we anticipate that these investments have to be made," he told reporters.

Carbon dioxide, methane, and nitrous oxide are the three main contributors to greenhouse gasses, with carbon dioxide's atmospheric abundance rising by 39 per cent since the start of the industrial era in about 1750.