Dr Neal Hockley, of Bangor University, said Wales' chances of meeting the targets were ambitious but largely down to the "politics of the issue".

The Welsh government agreed working with Westminster is "very important".

But it said it was "disappointing and frustrating" that the UK government had not shared its climate strategy.

A spokesman added: "Despite us participating in good faith in various workshops and with requests for information over the last several years, the UK government did not choose to share its net zero strategy with us in a meaningful way or timeframe ahead of publication.

"It made it impossible to ensure the Welsh and UK strategies were coherent.

"We agree that the UK and devolved governments need each other to enable and support delivery of our ambitious climate targets and would remind the UK government that transparency and collaboration, as captured by the COP theme of 'working together', is very important."

A UK government spokesman said: "We worked closely with the Welsh government to develop the Net Zero Strategy - our comprehensive, UK-wide plan to cut pollution, deploy clean energy and create jobs in new industries.

"The UK government will continue to engage regularly with the devolved administrations as we work together to end our country's contribution to climate change by 2050."

Thousands of protesters joined a climate change demonstration in Cardiff on Saturday

Last week, the Welsh government published its latest update on its vision to become carbon free by 2050.

However Dr Hockley, a senior lecturer in environmental economics and policy, said he did not think either the UK government or the Welsh government were clear on how to reach the net zero target by 2050.

"I don't think there's a fully concrete plan to get us to 2050, to net zero," he told BBC Wales' Politics Wales programme.

"In fairness to the Welsh government, a lot of the policy tools that are going to be required to get us there lie with the UK government.

"It's clear there's not brilliant communication between the UK government and the Welsh government on these issues, and that's something that's going to have to change."

He added: "There are so many unknowns and too many hard decisions that need to be taken if we were to get to net zero by 2050 that haven't yet been taken.

"That will depend on the politics of the issue and I'm not going to try and predict politics."

Lord Deben, chair of the independent climate change committee, told BBC Wales he thought the UK government had historically not been good at working with the other nations or regional government.

He said: "I very much hope the accession for Michael Gove as communities and levelling up secretary will mean they will go to some real effort to get a much better partnership between the central government, the nationalities and local government.

"I use Wales as the example of this because the Welsh government has built a relationship with local government, which is exemplary - better than anywhere else in the United Kingdom."