Matt McGrath, BBC NEWS
Potent, climate-warming gases are being emitted into the atmosphere but are not being recorded in official inventories, a BBC investigation has found.
Air monitors in Switzerland have detected large quantities of one gas coming from a location in Italy.
However, the Italian submission to the UN records just a tiny amount of the substance being emitted.
Levels of some emissions from India and China are so uncertain that experts say their records are plus or minus 100%.
These flaws posed a bigger threat to the Paris climate agreement than US President Donald Trump’s intention to withdraw, researchers told BBC Radio 4’s Counting Carbon programme.
Bottom-up records: Among the key provisions of the Paris climate deal, signed by 195 countries in December 2015, is the requirement that every country, rich or poor, has to submit an inventory of its greenhouse-gas emissions every two years.
Under UN rules, most countries produce “bottom-up” records, based on how many car journeys are made or how much energy is used for heating homes and offices.
But air-sampling programmes that record actual levels of gases, such as those run by the UK and Switzerland, sometimes reveal errors and omissions.