It is nearly five years to the day since David Cameron posed for his photo opportunity with the huskies at the Arctic Research Station at Ny Alesund in Norway. He told us then to "vote blue, go green". That the government is open to scrapping all 227 of the UK's environmental protections shows just how far his green mask has slipped.

Among the safeguards under threat as part of the 'red tape challenge' is the Climate Change Act, the first of its kind in the world. Introduced by Labour, it places a duty on the secretary of state to ensure that the net UK carbon account for greenhouse gases for the year 2050 is at least 80% lower than in 1990.

The last Labour government put at the heart of its plans for Britain's future a transition to a low-carbon economy. The Climate Change Act was vital to that strategy. The binding targets ensure that departments set out a clear roadmap for carbon reduction, and this in turn gives businesses the certainty they need to invest.

The prime minister says that the process is about scrapping legislation that is a burden to industry. If that's the case then why is the act included on the list at all? After all, the emission targets have had support from across the business community; the CBI said it combined "the two things we really need: long-term clarity on policy direction and flexibility in its delivery". It's why 10 of the UK's largest firms recently wrote to Cameron urging him to take up the recommendations made by the committee on climate change to extend the UK's reduction targets beyond 2020.

Cameron says the responsibility will be on ministers to fight to save individual legislation. This is extremely worrying. There are already grave concerns that energy secretary Chris Huhne is becoming the most ineffective minister in Whitehall. Why hasn't he already made a public statement in support of the act and given the low-carbon sector the reassurance it needs?

A secretary of state must be a strong voice around the cabinet table, pushing their priorities over those of other departments. After nearly a year in the job, Chris Huhne's record is looking less than impressive.

He lost his fight with George Osborne over when the green investment bank will be able to borrow, meaning that green businesses will have to make do with a government fund until at least 2015. This will only exacerbate Britain's fall under this government's watch, from third to 13th in world green technologies investment, as was highlighted in the recent report from the Pew Environment Group.

He threw the solar industry into chaos after announcing an early review of feed-in tariffs and slashed incentives for community solar projects. Carbon capture and storage projects two, three and four are delayed. Worries are being raised over his plans for electricity market reform. The energy bill is significantly behind schedule in parliament. And now he's allowed the prime minister to put our entire carbon reduction strategy up for review.

Climate sceptics are lurking ready for any excuse to derail our green future. The Campaign to Repeal the Climate Change Act group has already launched a petition.

If the prime minister wants to have any green credentials, he needs to come out and tell us that the Climate Change Act is here to stay. He has exempted issues of national security from his review. In 2009, William Hague argued that climate change was an issue of national security, so why isn't that the case now? The fact that Cameron is prepared to consider abandoning legally binding targets tells us what we already know; his claim to be 'the greenest government ever' is completely false.

• Luciana Berger MP is shadow minister for energy and climate change.