In 1997 most countries in the world signed up to the Kyoto Protocol, part of which involved what’s called the emission trading scheme. This allowed industrialized countries struggling to cut greenhouse gas emissions set by the protocol to buy carbon units from those that could, thus offsetting their carbon production. But a new report shows how things haven’t been particularly above board, with the majority of credits generated by Russia and Ukraine – accounting for roughly 600 million tonnes of carbon, equivalent to the entire U.K.'s emissions in 2012  – having been falsely created.

“Some early projects were of good quality, but in 2011-2012, numerous projects were registered in Ukraine and Russia which had started long before and were clearly not motivated by carbon credits,” Vladyslav Zhezherin, a co-author of the study, told BBC News. “This was like printing money.”

Basically, a carbon unit is the permission to emit one tonne of CO₂. The United Nations distributes quotas of carbon units to industrialized nations, setting a limit on the amount of emissions each country is allowed to pump into the atmosphere. Some countries are simply more efficient at reducing their emissions, meaning that they don’t need all the carbon units allocated to them. Other countries, however, struggle to limit their emissions. Under the emissions trading scheme, those that have a surplus can sell their units to those countries who need them.

But there is another way to get more carbon units than a country is initially given. A UN scheme called Joint Implementation (JI) allows countries to invest in and pay for emissions reduction projects in other countries where the cost of cutting greenhouse gas emissions might be cheaper than attempting to slash their own emissions. The country that paid for the project can then get more carbon units. While this scheme doesn’t necessarily cut overall emissions, it does offset them.

An example of JI might be replacing a coal-fired power plant with a more efficient combined heat and power plant.  

It was this JI that Russia and Ukraine were exploiting. Projects in these countries were paid for by other countries to reduce their emissions, but in some cases, chemicals known to cause global warming were purposely created, only to then be destroyed so cash could be claimed for reducing emissions. A large number of the projects simply didn’t exist at all.

The report, published by the Stockholm Environment Institute, shows how out of 872 million tonnes of carbon thought to be offset under the JI scheme, around 600 million tonnes came from projects with “questionable environmental integrity.” The authors suggest that the reason this was allowed to happen is because each country is responsible for the management and inspection of their own JI projects. While nations such as Germany and Poland are very strict with their inspections, those in Russia and Ukraine were pretty much non-existent. The authors call for tighter controls, monitoring, and enforcement when rules are broken with JI projects in the future.