"It is worth recalling that the last time the Earth experienced a comparable concentration of CO2 was 3-5 million years ago," WMO Secretary-General Petteri Taalas said.
Nitrous oxide is 300 times more potent than carbon dioxide as a greenhouse gas, although it is found in the atmosphere in smaller quantities.
"The public needs to know the global implications of such actions," a scientist told "Newsweek."
The flights would have generated seven times more carbon emissions per person than a standard commercial flight.
Earth had not seen carbon dioxide concentrations above current levels for at least two million years.
If the military were a country, its fuel usage alone would make it the 47th largest emitter of greenhouse gases in the world, lying between Peru and Portugal.
The soft drink industry generates vast amounts of waste product. Could some of this be put to good use?
"Our American colleagues strongly oppose even mentioning the Paris Climate Agreement in the strategy, as well as the United Nations' 2030 sustainable development goals," Russian Foreign Minister Sergey Lavrov said.
Stratocumulus clouds became unstable as CO2 concentrations increased, simulations reveal.
In recent times, researchers have been developing new types of "organic" solar cells that could be applied to various building parts, like windows, in order to generate energy.
Legally binding deal will give developing nations more time to reduce the use of factory-made hydroflourocarbon gases.
Ninety-three million Nigerians do not have reliable access to electricity.
By bringing emissions down to the Paris climate talk target, the U.S. will improve air pollution to the point that it could save hundreds of thousands of lives
It is one of the few things that can drastically reshape our world, altering it forever
A host of Californian political and business leaders are Paris to tout their state's success as a carbon-slashing powerhouse.
A Chatham House report says shifting to a plant-based diet could drastically lower global greenhouse gas emissions.
The impact that animal agriculture has on our planet cannot be underestimated.
Revelation may mean China has emitted close to a billion additional metric tons of carbon dioxide into the atmosphere each year
Republicans say the plan, designed to lower carbon emissions by 2030, will eliminate American jobs and cost taxpayers.
It took threatening C-level compensation packages, but the world's biggest companies are finally getting environmentally responsible.