Just 16 countries have set clear goals for cutting greenhouse gas emissions that will allow them to match their ambitious pledges to tackle climate change.

In a new report, climate experts have warned of discrepancies between big promises made on the global stage and domestic targets backed up by law.

The Intergovernmental Panel on Climate Change issued a warning earlier this month of catastrophic outcomes without drastic emissions cuts over the next decade.

In light of this, and with an upcoming major UN summit to discuss the world’s approach to global warming, the authors of the report say nations need to set clear plans about how they are going to stop pumping greenhouse gases into the atmosphere.

“We have 12 years to get our act together, and in order to do that you really need to know what you are going to be doing in the next six months, in the next two years, in the next 12 years,” explained Dr Michal Nachmany from the Grantham Research Institute on Climate Change and the Environment.

“So you need to set really clear targets in order to know you are on track to meeting those goals.”

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In total, 157 countries have made international commitments to slash their emissions under the Paris climate agreement – known as nationally determined contributions, or NDCs.

However, to be worth anything these promises must be translated into domestic commitments and policies on renewable energy, green transport and sustainable agriculture to lay out a realistic pathway.

The analysis by Dr Nachmany and Emily Mangan from the World Resources Institute found that nations have been slow to mirror their NDCs in national policies.

So far only 58 countries (from 157) have backed up those commitments with economy wide targets for emissions reductions, and just 16 of those are as ambitious as the ones they promise in their NDCs.

Besides this handful of nations, which range from Canada to Papua New Guinea, the European Union has also set such targets – but because the bloc has not divided up the relative contribution of its 28 member states there is some confusion about how the EU will achieve them.

“It doesn’t say in the EU NDC that the UK has to cut X and Germany has to cut Y and France has to cut Z,” said Dr Nachmany.

Further confusion will come as the UK departs the EU altogether, leaving the country to set its own NDC.

Dr Nachmany said the fact that so few countries had matched their NDCs with national targets does not mean other nations are doing nothing to cut their emissions, but she urged more transparency in the way they go about it.

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“If you don’t say where you want to go, how do you say if your policy is stringent enough? How do you know if you are on your way to meeting it?” she asked.

An additional complication comes as the target year for most NDCs is 2030, while most countries have only planned ahead to 2020. The authors say leaders need to start looking further ahead in their planning.

“In terms of policy planning, 2020 is yesterday and 2030 is around the corner when you plan for energy infrastructure, budget, all of these things,” said Dr Nachmany.

Leaders will gather in Katowice, Poland, in December to discuss efforts to close the gap between current action to tackle climate change and the goals of the Paris agreement.