Local celebrity Cerys Mathews and Carmarthenshire West and South Pembrokeshire MP, Nick Ainger, have been thanked by Friends of the Earth for supporting the Climate Change Bill.
The bill, which was overwhelmingly approved by MPs in the House of Commons last week, will place a legal duty on the government to make major cuts in emissions of the gases that are causing climate change.
Since Friends of the Earth launched its campaign for a strong law three years ago, more than 200,000 people throughout the UK have contacted their MPs to ask them to back the bill.
Pembrokeshire Friends of the Earth's climate change campaigner, Gordon James, said:
"The support we have received from Cerys Mathews and Nick Ainger MP on this issue has been extremely valuable.
"We would also like to thank all those locally who wrote to, or met, their MPs or helped in other ways to secure this victory.
"We now face the challenge of bringing about major cuts in emissions of climate-changing gases and are calling on all politicians to support big improvements in energy efficiency and a major expansion in renewable energy."
The Climate Change Bill is expected to come into force by the end of the month.