Although the UK Government played a leading role in the successful Paris climate change agreement, the participation of Great Britain in the landmark is now in doubt.

It was just six months ago that the UK government was praised for its leading role during the negotiations of the Paris climate change agreement, the first legally binding commitment on curbing carbon emissions by all 195 United Nations countries. But, after last week’s vote in favour of Brexit, the possibility for the UK to participate in that landmark accord seems now far away.

“There is a risk that this could kick EU ratification of the Paris agreement into the long grass,” Jonathan Grant, director of sustainability at PwC, was reported as saying by the Guardian last Friday, “Today’s outcome is a major setback for the type of collaboration needed to tackle global environmental issues such as climate change. The UK government has been a champion of climate action at home, within the EU, and in Paris. This leadership is at risk, with many supporters of Brexit also opposed to climate policies such as carbon taxes and efficiency standards.”

When and how will the UK ratify the Paris Agreement?

The United Kingdom, as an EU member state, negotiated on key issues such as greenhouse gas emissions limits as part of the bloc, and was expected to take on its own tally of emissions reductions based on an EU-wide “burden-sharing” agreement, yet to be established.

But even though the UK is individually party to the agreement, as a sovereign nation, the accord in law has been ratified by neither the government nor the EU yet. Then, it will be up to next prime minister, probably Eurosceptic, to decide on whether to ratify it.

Yet, the current government, led by David Cameron, could act as a matter of urgency in the next three months and became the second EU member state to ratify the agreement individually after France, which has already done it earlier this month. But, given the host of pressing issues following from the referendum, this is unlikely and would probably cause discontent among sections of the pro-Brexit right, which are also climate change sceptics.

Thus, if the UK decides to stay in the Paris accord, it would have to agree its own contribution to emissions cuts. These would most likely be based on the Climate Change Act, which sets out long-term targets on greenhouse gases and five-yearly “carbon budgets” that governments must meet. In order to renege on the act’s commitments, it  would equire its repeal, as favoured by some Brexit campaigners, but this is unlikely in the short term as they lack broad enough support in parliament.

“The UK has signed up to the Paris agreement in its own right. Outside the European Union the UK can still play a leading role in fighting climate change. It should ratify the Paris agreement as soon as possible, pass the fifth carbon budget under our domestic Climate Change Act and turn this into an ambitious international pledge to cut emissions,” said Stephen Cornelius, chief adviser on climate change at WWF-UK.

That will be largely an issue for the UK, which accounts for less than 2% of global emissions. However, it the signal that the referendum vote to leave sends to the world that is of much wider concern.

What implications could the Leave campaign’s victory have worldwide in terms of climate change?

The Leave campaign’s victory might spur groups opposed to climate action worldwide. Many climate sceptics around the world will have been encouraged by the Brexit vote, as there is so much overlap between the two camps, and environmental and carbon goals under the EU were a key target of the Leave campaigners.

For example, one of the leaders of the Leave camp, Lord Lawson, is also founder of the Global Warming Policy Foundation, a climate sceptic think-tank, while Trump himself hailed the referendum result in visiting the UK. Some of his supporters share his climate scepticism, and the common cause with Brexit campaigners will have given both sides a boost.

Therefore, the outcome of referendum on Brexit  might not only cause delays to the Paris accord coming into effect, but it could also provide an opening for aspiring right-wing leaders – including Donald Trump – to try to unpick the pact.

Besides  being a setback to the UN in itself, it would also concern participants because of the US presidential election this year.

Indeed Donald Trump gave his word to withdraw from the Paris agreement, if elected. Therefore, proponents of the agreement are hoping for a quick process of ratification, since the agreement would immediately come into effect if ratified by EU member states and it would be much harder for countries to renege upon afterwards.

However, the climate consensus within the EU, a key driver of actions on climate change within the UN and other international institutions, could be endangered by the calls from right-wing parties for further breaks from the EU. Without a unified EU, support for those actions could decline.

Although the wider political implications will take time to work out, it is already clear that the Brexit vote will be used as a rallying cry for an agenda frequently including climate scepticism, together with curbs to immigration and to government regulation.