US President Donald Trump’s announcement of the American withdrawal from the Paris Accord is not the only threat to achieving the ambitious targets of the climate agreement and may not be the biggest, the British Broadcasting Company BBC warned while unveiling the results of a recent investigation.

“Potent, climate-warming gases are being emitted into the atmosphere but are not being recorded in official inventories,” the BBC asserted, pointing a finger at homegrown problems in the heart of Europe as well as countries as far away as India and China.

Among the key provisions of the accord signed by 195 countries in December 2015 is the requirement that all participants submit an inventory of their own greenhouse-gas emissions every two years. But in its Counting Carbon program the BBC noted that air-sampling programs that record actual levels of gases “sometimes reveal errors and omissions," and some countries cheat.

The program pinpoints Italy as one of the cheaters, based on a Swiss claim – an accusation Italy has denied, saying its inventory is correct and compliant with UN regulations.  Stefan Reimann of the Swiss Federal Laboratories for Materials Science and Technology, however, that Italy’s inventory may be too short.

Between 2008 and 2010, Reimann said, scientists at the Jungfraujoch monitoring station in the Alps traced emissions of the ozone-depleting chlorofluorocarbon HFC-23 to a location in northern Italy. Emissions estimated at 60-80 t/y are still from coming from there, he said, despite the fact that Italy’s official inventory for the Paris Accord only lists emissions in the range of up to 10 t/y or even 2-3 t/y.

Outside Europe, the investigation identified China and India as countries breaking air quality rules. “Levels of some emissions from India and China are so uncertain that experts say their records are plus or minus 100%,” the Counting Carbon team asserted.

Another suspected global warming culprit, carbon tetrachloride, has been banned in Europe since 2002; however, Reimann said the Swiss air quality station “still sees 10,000-20,000 t coming out of China every year.” There is no Chinese inventory for this gas, as it is banned, he explained.

China’s approach to monitoring and reporting output of warming gases to the UN is spotty and subject to constant and subject to significant revision, the Swiss climate scientist said, adding that the People’s Republic’s last submission was only about 30 pages, compared with several hundred for the UK.

The investigation unveiled in the TV report also turned up what it said are “vast uncertainties” in carbon emissions inventories being drawn up by developing countries in particular. Levels of the world’s second most important greenhouse gas, methane, for instance, have been rising in recent years for reasons not entirely explainable. In any case, the accuracy of adding emissions levels to inventories is in doubt, especially in India, which is home to 15% of the world's livestock, BBC warned.

Anita Ganesan of the University of Bristol, who has overseen air monitoring research in India, said in an interview officials there are vague about the accuracy of reporting and probably underreport. International scientists working in Russia have reported similar uncertainties about methane emissions there. Euan Nisbet, a professor at Royal Holloway, University of London, told the BBC that the warming impact from increasing  methane emissions “is enough to derail Paris.”

All in all, Counting Carbon presented a grim outlook for slowing global warming.

Although the rules covering how countries report their emissions are currently being negotiated, Glen Peters, from the Centre for International Climate Research in Oslo, Norway told the program that if progress in curbing greenhouse gases cannot be tracked sufficiently, “you basically can't do anything.”.

“Without good data as a basis, Paris essentially collapses. It just becomes a talkfest without much progress," Peters said.